OF THE 
 
 UNIVERSITY 
 
 OF 
 
 LIBRARY 
 

 
 SMITHSONIAN INSTITUTION 
 
 UNITED STATES NATIONAL MUSEUM 
 Bulletin 88 
 
 REVISION OF PALEOZOIC STELLEROIDEA 
 
 WITH SPECIAL REFERENCE TO NORTH 
 
 AMERICAN ASTEROIDEA 
 
 BY 
 
 CHARLES SCHUCHERT 
 
 Professor of Paleontology, Yale University 
 Sew Haven 
 
 WASHINGTON 
 
 GOVERNMENT PRINTING OFFICE 
 1915 
 
SMITHSONIAN INSTITUTION 
 
 UNITED STATES NATIONAL MUSEUM 
 Bulletin 88 
 
 REVISION OF PALEOZOIC STELLEROIDEA 
 
 WITH SPECIAL REFERENCE TO NORTH 
 
 AMERICAN ASTEROIDEA 
 
 BY 
 
 ' '*" 
 
 CHARLES SCHUCHERT 
 
 Professor of Paleontology , Yale University 
 New Haven 
 
 WASHINGTON 
 
 GOVERNMENT PRINTING OFFICE 
 1915 
 
PALEONTOLOGY 
 
 BULLETIN OF THE UNITED STATES NATIONAL MUSEUM. 
 ISSUED MARCH 20, 1915. 
 
ADVERTISEMENT. 
 
 The scientific publications of the United States National Museum 
 consist of two series, the Proceedings and the Bulletins. 
 
 The Proceedings, the first volume of which was issued in 1878, are 
 intended primarily as a medium for the publication of original, and 
 usually brief, papers based on the collections of the National Museum, 
 presenting newly-acquired facts in zoology, geology, and anthro- 
 pology, including descriptions of new forms of animals, and revisions 
 of limited groups. One or two volumes are issued annually and dis- 
 tributed to libraries and scientific organizations. A limited number 
 of copies of each paper, in pamphlet form, is distributed to specialists 
 and others interested in "the different subjects as soon as printed. 
 The date of publication is printed on each paper, and these dates are 
 also recorded in the tables of contents of the volumes. 
 
 The Bulletins, the first of which was issued in 1875, consist of a 
 series of separate publications comprising chiefly monographs of large 
 zoological groups and other general systematic treatises (occasionally 
 in several volumes), faunal works, reports of expeditions, and cata- 
 logues of type-specimens, special collections, etc. The majority of 
 the volumes are octavos, but a quarto size has been adopted in a few 
 instances in which large plates were regarded as indispensable. 
 
 Since 1902 a series of octavo volumes containing papers relating to 
 the botanical collections of the "Museum, and known as the Contribu- 
 tions from the National Herbarium, has been published as bulletins. 
 
 The present work forms No. 88 of the Bulletin series. 
 
 RICHARD RATHBUN, 
 Assistant Secretary, Smithsonian Institution, 
 
 In charge of the United States National Museum. 
 
 WASHINGTON, D. C., January 27, 1915. 
 
 3 
 
 M650670 
 
TABLE OF CONTENTS. 
 
 Page. 
 
 Preface 9 
 
 Terminology as applied to the skeleton of Paleozoic Asteroidea 13 
 
 Finding list of Paleozoic Stelleroidea 18 
 
 Remarks on the development of Paleozoic Stelleroidea 27 
 
 Geological 27 
 
 Distribution 27 
 
 Preservation and occurrence 28 
 
 Asterid evolution 30 
 
 General observations 30 
 
 The most primitive fossil starfish 31 
 
 Origin of the wriggling type of starfish 32 
 
 The asterid radicle 34 
 
 Ontogeny 36 
 
 Regeneration 37 
 
 Number and character of rays 38 
 
 Development of the parts 39 
 
 Anus 39 
 
 Madreporite 39 
 
 Spinosity 41 
 
 Ambulacralia 41 
 
 Adambulacralia 43 
 
 Inframarginalia 43 
 
 Supramarginalia 45 
 
 Radialia 46 
 
 Accessory plates 47 
 
 Ocular plates -^, 48 
 
 Centro-dorsal 48 
 
 Primary disk-plates 49 
 
 Axillary ossicles 49 
 
 Interbrachial areas 50 
 
 Classification 51 
 
 Catalogue of Paleozoic Stelleroidea 51 
 
 Description of genera and species 51 
 
 Class Stelleroidea 51 
 
 Subclass Asteroidea 51 
 
 Phanerozonia 51 
 
 Family Hudsonasteridae 53 
 
 Hudsonaster 53 
 
 Siluraster 65 
 
 Family Palseasteridse 66 
 
 Palseaster , 67 
 
 Australaster 72 
 
 5 
 
6 TABLE OF CONTENTS. 
 
 Description of genera and species Continued. 
 Class Stelleroidea Continued. 
 
 Subclass Asteroidea Continued. 
 
 Phanerozonia Continued. p age . 
 
 Family Promopalaeasteridae 73 
 
 Subfamily Mesopalaeasterinae 74 
 
 Mesopalseaster 74 
 
 Spaniaster 95 
 
 Miomaster 96 
 
 Devonaster 97 
 
 Subfamily Promopalasasterinse 102 
 
 Promopalasaster 102 
 
 Subfamily Anorthasterinae 125 
 
 Anorthaster 125 
 
 Family Xenasteridae 128 
 
 Xenaster 129 
 
 Agalmaster 131 
 
 Rhenaster 133 
 
 Eifelaster 133 
 
 Trimeraster 134 
 
 Family Neopalaeasteridse 134 
 
 Neopalseaster 134 
 
 Family Palasterinidae 138 
 
 Petraster 138 
 
 Lindstromaster 148 
 
 Palasterina 150 
 
 Uranaster 154 
 
 Palseostella 155 
 
 Pseudopalasterina 156 
 
 Family Lepidasteridae 157 
 
 Lepidaster 158 
 
 Helianthaster 159 
 
 Lepidasterella 160 
 
 Family unknown 161 
 
 Astropecten 161 
 
 Ataxaster 161 
 
 CryjDtozonia .- 162 
 
 r~Family Stenasteridae 163 
 
 / Stenaster 163 
 
 Tetraster 167 
 
 Family Monasteridaa 170 
 
 Monaster 170 
 
 Family Urasterellidee 172 
 
 Urasterella 173 
 
 Family Calliasterellidaa 190 
 
 Calliasterella 190 
 
 Family Compsasteridse 191 
 
 JaeJcelaster 192 
 
 Compsaster 192 
 
 Family Schuchertiidae 194 
 
 Schuchertia 195 
 
 Family Palasteriscidae 199 
 
 Palasteriscus 200 
 
 Echinasterella... 200 
 
TABLE OF CONTENTS. 7 
 
 Description of genera and species Continued. 
 Class Stelleroidea Continued. 
 
 Subclass Asteroidae Continued. 
 Cry ptozonia Continued . 
 
 Family Palasteriscidae Continued. Page. 
 
 Loriolaster 201 
 
 Cheiropteraster 202 
 
 Family Schoanasteridae . 202 
 
 Schcenaster 202 
 
 Family Palseosolasteridae 207 
 
 Palxosolaster 209 
 
 Echinasterias 211 
 
 Echinodiscaster 211 
 
 Echinostella 212 
 
 Medusaster 212 
 
 Subclass Auluroidea 213 
 
 Order Lysophiurae 215 
 
 Family Protasteridae 215 
 
 ^fseniaster 216 
 
 [_ Eophiura. . 222 
 
 Bohemura 223 
 
 L-Palseum 223 
 
 Protester 224 
 
 Akpidaster 228 
 
 Gregoriura 233 
 
 Bunderibachia 234 
 
 Palxophiomyxa 234 
 
 Family Palaeophiuridae 235 
 
 Palseophiura 235 
 
 Sturtzura 236 
 
 f-JSygasterella 237 
 
 ; Ptilonaster 239 
 
 Family Encrinasteridse 241 
 
 Encrinaster 241 
 
 Order Streptophiurae . 246 
 
 Family Ophiurinidae 246 
 
 Ophiurina 246 
 
 Tremataster 247 
 
 Family Lapworthuridae 248 
 
 Squamaster 249 
 
 ^Lapworthura 250 
 
 r Sturtzaster 252 
 
 _ Bdellacoma 254 
 
 THhopalocoma 254 
 
 Hallaster 254 
 
 Sympterura 256 
 
 Furcaster 261 
 
 Palastropecten 261 
 
 Family Eoluidiidae 262 
 
 Eoluidia 262 
 
 Eospondylus 263 
 
 Miospondylus 263 
 
 Family Aganasteridae 263 
 
 Aganaster 263 
 
 Family Cholasteridae 265 
 
 Cholaster. . . 265 
 
8 TABLE OF CONTENTS. 
 
 Description of genera and species Continued. 
 
 Class Stelleroidea Continued. p age . 
 
 Subclass Ophiuroidea 267 
 
 Family Onychasteridee 268 
 
 Onychaster 268 
 
 Forms whose relationships are unknown 274 
 
 Cribellites carbonarius 274 
 
 Order Ophiocistia , 275 
 
 Family Eucladiidse 276 
 
 Eucladia 276 
 
 Euthemon 279 
 
 Bibliography 281 
 
 Explanation of plates 289 
 
 Index.. 303 
 
REVISION OF PALEOZOIC STELLEROIDEA WITH 
 SPECIAL REFERENCE TO NORTH AMERICAN 
 ASTEROIDEA 
 
 By CHARLES SCHUCHEET 
 
 Professor of Paleontology, Yale University, New Haven. 
 
 PREFACE 
 
 This memoir had its inception in 1896, and came about through 
 the force of circumstances. The writer, at that tune assistant curator 
 in the United States National Museum, was made aware of the desire 
 of Mr. I. H. Harris, of Waynesville, Ohio, to present to that institu- 
 tion his extensive collection of Ordovicic fossils. He had long known 
 Mr. Harris, having met him as a young man, about the year 1876, 
 at which time the Harris collection was already widely known, not 
 only for its quantity, but more especially for its many choice speci- 
 mens of the rarer species of starfishes, crinids, and trilobites. Twenty 
 years later came Mr. Harris's desire to present to the National 
 Museum the collection upon which he had been at work for fifty 
 years. This gift brought to the National Museum not less than 40 
 asterids, 35 (31 on one slab) ophiurids from the Cincinnatic strata 
 (the great majority from the Waynesville formation), besides an 
 asterid and 12 specimens of Ony chaster flexilis from the Keokuk 
 formation at Crawfordsville, Indiana. Some years later the National 
 Museum acquired the very valuable E. O. Ulrich collection, in which 
 there were also many good starfishes. Accordingly, it is safe to state 
 that in no other museum are there so many Ordovicic asterids, in so 
 great a variety and in such excellent preservation. 
 
 The material of the Harris collection seemed to show that its com- 
 plete study would not only reveal much new knowledge, but give an 
 insight as well into the probable evolution of the Paleozoic starfishes. 
 When these facts were made known to the then director of the National 
 Museum, Dr. G. Brown Goode, he asked the writer to invite Mr. Harris 
 to join him in a work on the Ordovicic starfishes. This was done and 
 Mr. Harris was greatly pleased to undertake the joint authorship. 
 He did all he could to further the work, but it went very slowly, 
 because the present writer was so much occupied with curatorial 
 work as well as the arranging of museum exhibits for the expositions 
 in which the United States Government participated and which came 
 
 9 
 
10 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 nearly every year. Unfortunately, Mr. Harris died on October 17, 
 1897, when the work was still in the first stages. 
 
 At odd times during subsequent years the writer kept up his studies 
 and in the spring of 1904 the work on the Asteroidea was practically 
 completed. Then came his appointment to the chair of paleontology 
 at Yale University. Here new duties and new lines of thought kept 
 him away from the study of the Paleozoic ophiurids which had been 
 planned, but the hope was strong that somehow the time would be 
 found to complete the work. However, this hope has not materialised, 
 others have gone to work on the starfishes, and one genus and general- 
 ization after another has slipped away. Therefore it was thought 
 best to revise what had been done, bringing the asterids up to date. 
 In regard to the ophiurids, it was found impossible to restudy the 
 specimens, but as the writer had kept abreast of the literature, this 
 was put into order and is here presented, in the hope that subsequent 
 workers will find it useful in enabling them to find the references on 
 any species and the taxonomic status of any form. 
 
 A study of the specimens in the Harris collection made it plain 
 that no satisfactory taxonomic and systematic results would follow 
 unless the undertaking also embraced many other Paleozoic forms, 
 of Europe as well as of America. Species and genera had been pro- 
 posed in a very loose manner; in fact, most of the Paleozoic litera- 
 ture on asterids and ophiurids up to the tune this work began had 
 no other value than to force the reviser under the rules of nomencla- 
 ture to recognize the names proposed. The International Rules of 
 Zoological Nomenclature have here been strictly followed. Under 
 these circumstances, all of the type-specimens had to be seen, and most 
 of them have been accessible. In this way the work finally came to 
 be extended to all Paleozoic Stelleroidea. To make it plain how little 
 the American Paleozoic starfishes were known in 1889, it will suffice 
 to give one example: Miller in his North American Geology and 
 Palaeontology lists 23 species under Palseaster'j in the present work 
 there is but a single form of this genus, the genotype, P. niagarensis, 
 the remainder having been distributed among seven genera, all new 
 and proposed in the past few years or at this tune. As a result, every 
 paleontologist will be obliged to disregard what he has learned re- 
 garding American Paleozoic starfishes and start anew. To facilitate 
 this, a list has been prepared and is here presented of all the names 
 so far given to Paleozoic asterids and ophiurids, with cross references 
 to the names adopted in this work. 
 
 Now that this study is finished, at least for the present, it is plain 
 to the author that his species and genera are also in some cases too 
 comprehensive. The future student will restudy the specimens along 
 with the new material and go more deeply into the detailed structure 
 of the parts. He who attempts this, along with painstaking recon- 
 
EEVISION OF PALEOZOIC STELLEROIDEA. 11 
 
 struction of the skeleton as it was in life, will learn where to separate 
 and what to reject. 
 
 During the past 10 years, Schondorf has revised most of the German 
 asterids and has studied deeply into the structure of the ophiurids. 
 His work is very detailed and the best extant on the Paleozoic forms. 
 Every student of Stelleroidea intending to do thorough work will 
 have to examine his results. In classification he has laid the founda- 
 tion, and has shown that some asterids are not Asteroidea at all, but 
 that they and the bulk of the so-called ophiurids of the Paleozoic must, 
 because of their peculiar structure, ambulacral and otherwise, be 
 referred to another class, the Auluroidea. 
 
 In regard to the evolution of the Asteroidea, the writer hoped 
 to find the time to present his views concerning it in detail in this 
 memoir, but that also is not possible. However, the main lines 
 and often the generic directions of organic change are stated and 
 will be found either in the introductory pages or scattered through- 
 out the work, generally in the remarks under the generic discussions. 
 These results in connection with the work of Schondorf, it is thought, 
 ought soon to place the Paleozoic Stelleroidea in such order that 
 a final classification, based on ontogeny, chronogenesis, and phyl- 
 ogeny, and embracing not only the Paleozoic forms but those of 
 Mesozoic, Cenozoic, and Recent time as well, can be made. 
 
 Many museums and individual paleontologists have loaned the 
 writer the specimens in their collections or in their keeping, and he 
 wishes here to thank them, one and all, for these loans. The greatest 
 bulk of the material studied is of course in the United States National 
 Museum in the Harris and Ulrich collections; a number of Trenton 
 specimens and some from the English Siluric have also been given 
 to the National Museum by Mr. Walter R. Billings, of Ottawa. 
 Since the writer has been in New Haven, Dr. R. S. Bassler, of the 
 National Museum, has often kindly helped him to further his studies, 
 and during the past year has made a large number of photographs 
 of the specimens under his ' charge. The many Mississippic speci- 
 mens in the Frank Springer collection have not been studied. 
 
 The author is greatly indebted to Dr. F. A. Bather, of the British 
 Museum (Natural History), for a large number of gutta-percha and 
 wax squeezes made by him of certain species in that great museum. 
 These casts, which are all in the United States National Museum, 
 have enabled the writer to understand several genera that otherwise 
 he could not have worked out. He is also indebted to him for many 
 bibliographic corrections and suggestions. 
 
 The second largest American collection is at Harvard University, 
 in the Museum of Comparative Zoology. Most of the material is 
 in the Charles D. Walcott, Charles B. Dyer, and Charles Wachsmuth 
 collections. In the first-named collection there is excellent material 
 from the Middle Ordovicic; the second has many fine specimens 
 
12 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 from the Cincinnatic formations; while the Wachsmuth material has 
 species from the Mississippic. To all of this material the author 
 has had access through the kindness of Director Samuel Henshaw 
 and Profs. R. T. Jackson and P. E. Raymond. 
 
 At the University of Chicago there is a great deal of excellent 
 material in the W. F. E. Gurley, Charles Faber, and U. P. James 
 collections, to which Weller has added other specimens. All of this 
 material has been studied through the courtesy of Prof. Stuart 
 Weller. Most of it is from the Cincinnatic formations. 
 
 All of the specimens described by E. Billings and now in the Vic- 
 toria Memorial Museum in Ottawa, Canada, have been seen at one 
 tune or another. In this matter the writer was much aided by the 
 late Dr. J. F. Whiteaves and more recently by Drs. P. E, Raymond 
 and E. M. Kindle, to the latter of whom thanks are also due for 
 several photographs reproduced in this memoir. Most of the speci- 
 mens are from the Ordovicic. 
 
 In the University of Toronto there is much material from the 
 Ordovicic and Siluric in the Sir Edmund Walker collection, and there 
 may be studied a great many specimens of Stenaster salteri. All of 
 this has been seen through the great liberality of Prof. William A. 
 Parks. 
 
 The genotype of Pakeaster, from the museum of Cornell University, 
 was loaned to the author at different times by Prof. H. S. Williams. 
 It is one of the best preserved of Paleozoic specimens and has become 
 very valuable because of the continual discussion that centers 
 around the species, P. niagarensis. 
 
 To all the specimens in the Peabody Museum of Yale University 
 access was had through the kindness of the late Prof. Charles E. 
 Beecher. Among them is the unique branching form, Eucladia 
 beecfieri. 
 
 Photographs have been made for this memoir by Dr. John M. 
 Clarke of specimens in the New York State Museum, and by Prof. 
 George H. Hudson, of Plattsburg, New York, of other material. 
 Prof. Arthur M. Miller loaned two specimens that he collected and 
 deposited in the State University, Lexington, Kentucky. Prof. George 
 W. Harper, of Cincinnati, loaned a specimen of Palseaster darkana 
 ( = Hudsonaster incomptus) . 
 
 Nearly all the original drawings were traced from the specimens 
 by aid of the camera lucida. These outlines were then inked and 
 shaded by the late Dr. J. C. McConnell, a draftsman and artist of 
 the first rank. 
 
 To Miss Clara Mae LeVene the writer is especially thankful for 
 the great interest she has taken hi getting the manuscript into order 
 for the printer, keeping the bibliography up to date and correctly 
 citing it, and for the careful reading of the proof. 
 
REVISION OF PALEOZOIC STELLEBOIDEA. 13 
 
 TERMINOLOGY AS APPLIED TO THE SKELETON OF PALEOZOIC 
 
 ASTEROIDEA. 1 
 
 Abactinal. 
 
 See Body-wall. The integumentary skeleton opposite to that having the ambu- 
 lacral grooves, or that of the upper or dorsal side of the animal. Also known 
 as the aboral surface. See Actinal. 
 
 Aboral. 
 
 See Abactinal. 
 
 Accessory plates. 
 
 This term refers to the abactinal longitudinal columns, or transverse rows, of small 
 plates between the radials and supramarginals (=radial accessory plates or dorso- 
 laterals), or between the inframarginals and supramarginals (=ambital plates or 
 intermarginals), or where there are no radials, to all the ossicles between the two 
 supramarginal columns. There may also be accessory actinal plates which are 
 termed accessory interbrachials, accessory actinals, or inter actinals. The accessory 
 plates form the secondary skeleton and are inserted between the columns of 
 the primary skeleton. It is in the secondary skeleton that much of the 
 specific and generic evolution takes place. See Interbrachial. 
 
 Actinal. 
 
 See Body-wall. The integumentary skeleton with the ambulacral grooves, or 
 that of the under or ventral side of the animal. Also known as the oral surface. 
 
 Adambulacrals. 
 
 The single columns of prominent plates adj oining the ambulacrals . There are never 
 more than two of these columns in a ray, one on each outer side of the depressed 
 ambulacrals. They are generally large and thick and bear the larger, or adam- 
 bulacral, spines . These spines may be inwardly directed and serve as a protection 
 for the tube-feet. The oral armature in Paleozoic species usually consists of five 
 pairs of modified adambulacrals, each pair being the oral projection of two united 
 columns of adjoining rays. They are also called Adambulacralia. Also see Inter- 
 brachial. 
 
 Ambital. 
 
 The abactinal space between the infra- and supramarginal columns, occupied by 
 accessory plates. These are best developed in the axillary disk areas (disk ambi- 
 tals), while those of the rays are referred to as ray ambitals. They are also 
 known as intermarginals. 
 
 Ambulacral. 
 
 Ambulacral grooves (five or more), plates, or ossicles are situated actinally and per- 
 radially along the center of the rays and disk. They are also called ambula- 
 cralia. The ambulacral columns are in pairs, the interlocking movable plates 
 of adjoining columns may be alternate or opposite (always so in recent forms), 
 and the plates of a column may be superposed like the tiles on a roof. The 
 podial openings through which the fleshy tube-feet protrude are situated be- 
 tween the sutures of adjoining plates. In early forms there are but two columns 
 of podial openings in each ray, one on each side of the axial line, but in later 
 forms there may be as many as eight columns. The ambulacral grooves may 
 be tapering or petaloid. 
 
 Anal opening. 
 
 The only Paleozoic form in which an anal opening may exist visually is Hudson- 
 aster. Here it is on the disk between the central plate and the madreporite. 
 The anal pore is nearly always obscured in fossil starfishes, and is absent in some 
 recent species. 
 
 1 Also in the main applicable to the Auluroidea and somewhat to the Ophiuroidea. 
 
14 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Arcs. 
 
 See Axil. 
 Axil. 
 
 The angle formed by the junction of the rays. Also known as arcs. In primitive 
 forms each axil is occupied by a single plate, the axillary inframarginal. In 
 others this plate is crowded orally and its place occupied by two prominent 
 proximal inframarginals. In forms with large disks having well-developed 
 marginals these are termed disk marginals. Also see Ambital and Interbrachial. 
 Bivium. 
 
 The two rays of a starfish that inclose between them the madreporite. When 
 oriented toward the student, the ray on the left is numbered 1 and the other on 
 the right is numbered 5. A line drawn through the madreporite and the center 
 of the upward directed ray (ray 3) divides the animal into symmetrical halves 
 (=left and right sides). The upper left-hand ray is numbered 2 and the one 
 opposite is 4. Rays 2, 3, and 4 form the trimum. 
 Body-wall. 
 
 The outer surface of both disk and rays, made up of movable calcareous plates 
 which are either closely adjoining or form a more or less loose network of ossicles. 
 These are held together in the living animal by connective tissue and muscular 
 fibers, which after death soon decompose, freeing the plates. It is for this reason 
 that fossil starfishes are so rarely found entire. Imbedded in the body-wall 
 everywhere are blunt, short, calcareous spines, arranged in a more or less 
 definite order, and often movable upon the underlying plates. 
 
 Covering the whole surface of the body, including the spines and pedicellarise, 
 is a delicate membrane or skin, clothed externally with closely placed vibratile 
 cilia, which keep the integument clean. The calcareous skeleton of starfishes 
 is therefore integumentary. 
 Csecal pores. 
 
 The openings between reticular plates for the protrusion of the respiratory csecal 
 processes. These pores are either restricted to the abactinal area or may be 
 distributed over the entire body. The processes are also known as papulx. 
 Central disk. 
 
 See Disk. 
 Central disk plate. 
 
 A prominent plate, most conspicuous in primitive forms, which often appears in 
 the center of the disk. It holds the same position as the centro-dorsal plate in 
 embryonic crinids of the genus Antedon. Also called the abactinal-central plate 
 or simply central plate. 
 Centro-dorsal plate. 
 
 See Central disk plate. 
 Disk. 
 
 The central portion of a starfish. In this work, the term generally applies only to 
 the abactinal central area formed either by the union of the rays, or by the rays 
 plus the axillary areas. The mouth is in the center of the disk on the under or 
 actinal side . Disk plates are the small plates over this area on the abactinal side . 
 Central disk plate refers to a larger primary plate in the center of the disk. There 
 may be other large primary plates, but these are more properly referred to the 
 rays. See Radial, Interradial, Marginal, and Ambital. 
 Inframarginal. 
 
 See Marginal plates. 
 Interbrachial. 
 
 The actinal and marginal areas between the rays . These spaces have plates derived 
 from various regions. In primitive forms, but a single plate is present, the 
 axillary interbrachial, derived by crowding orally the axillary inframarginal. 
 In other genera, inframarginals are crowded in pairs orally and form interbrachial 
 
REVISION OF PALEOZOIC STELLEBOIDEA. 15 
 
 areas, the interbrachial marginals. Or the adambulacrals may enter into the 
 construction of these areas, forming interbrachial adambulacrals. When the adam- 
 bulacrals and inframarginals are separated by small plates, the latter are called 
 accessory interbrachials; they may extend almost to the distal ends of the rays. 
 
 Interradial. 
 
 A point half-way between the perradii. The interambulacral areas are inter- 
 radial in position. See Perradial. 
 
 Interradial plates. 
 
 These abactinal plates are rarely retained in living mature starfishes. In many 
 Paleozoic genera they are large, interradial in position, five in number, and 
 lie inside the basal or proximal supramarginals and between the primary radials. 
 They may be homologous with the basals of crinids. They are also known as 
 
 Madreporite ormadreporic plate. 
 
 A sieve-like or spongy plate, with many irregular openings for the circulation 
 of sea water into the so-called "stone canal, " or better, into the water- vascular 
 system. It is commonly granular or striated, and in Asteroidea is abactinal 
 on the disk, basally situated between two rays, but in the Auluroidea is prob- 
 ably always actinal in position. In recent multiradiate forms there are species 
 with more than one madreporite. 
 
 Marginal plates. 
 
 In general the plates which make up the marginal columns bounding the rays, 
 or disk, or the entire animal. They are parts of the primary skeleton. In the 
 early Paleozoic genera the inframarginal and supramarginal columns are usually 
 not directly superposed, making one column of superposed halves as in Meso- 
 zoic and Recent starfishes, but the former column lies outside or laterally of 
 the latter. The inframarginals are then the true marginals, and form a part 
 of both the abactinal and actinal sides. In the primitive arrangement the 
 inframarginals adjoin the adambulacrals, but in derived forms with large pen- 
 tagonal disks they are separated from the latter by accessory interbrachial plates. 
 The situation of the marginals is, however, not always at the margin of the 
 disk and rays, but they may retain their primitive position beside the adam- 
 bulacrals; this is more especially true in forms having a well-developed pen- 
 tagonal disk. These plates are also referred to as marginalia, supramarginalia, 
 and inframarginalia. 
 
 In some forms the supramarginals are not recognizable as such, while the infra- 
 marginals are well-developed; and in others none of the marginals are distinctly 
 discernible. Sometimes the plates of the inframarginal columns adjoin one 
 another, while those of the supramarginal series are separated by small acces- 
 sory supramarginal pieces. Then the inframarginals may be separated from 
 the supramarginals by ambital ossicles (see Ambital) . A proximal supramarginal 
 is the proximal plate of a column and may not be homologous with the primary 
 supramarginal in primitive forms. Proximal inframarginal is used in a similar 
 way and refers to the proximal axillary plate, two of which of adjoining col- 
 umns occupy an axil or lie on either side of the axillary marginal. The latter 
 in primitive forms alone occupies the angle between the rays. The marginals 
 in large disks without angles may be termed disk infra- and supramarginals. 
 The large disk of some species is formed by the oral crowding of pairs of 
 proximal inframarginals, the interbrachial marginals. 
 
 Measurements. 
 
 The size of starfishes is usually given in millimeters along the greater and lesser 
 radii, that is, from the center of the mouth or disk to the tips of the rays. The 
 symbol for this line is R. The smaller radius is from the center of the animal 
 to the center of the interradii; the symbol is r. 
 50601 Bull. 8815 2 
 
16 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Mouth angle plate. 
 
 See Oral armature. 
 Ocular plate. 
 
 A single large, grooved eye-plate occupying the distal ends of rays and support- 
 ing a sensory tentacle at the base of which occurs the eye-spot. They appear in 
 the larval stage as the primary radials and with growth pass outward, remain- 
 ing at the tip of the rays as the oculars. They are also known as terminals. 
 These large plates are not present .as such in early Paleozoic genera, and are 
 unknown before the Carboniferous. 
 Oral. 
 
 See Actinal. 
 Oral angles. 
 
 The interradial actinal areas around the mouth. 
 Oral armature. 
 
 The pairs of plates, usually five in number, composing the apices around the 
 central actinal opening or mouth. In most Paleozoic forms the armature 
 consists of the proximal modified adambulacral plates. These pieces are also 
 known as Mouth angle plates. 
 
 In some Paleozoic forms (Hudsonaster) there lies in front of each pair of mouth 
 angle plates a single plate; this is known as the Torus. 
 
 Gregory (1900, p. 241) writes that "the Oral Skeleton (or actinostomial ring) 
 consists of a solid calcareous ring around the mouth. It is composed of thirty 
 plates in a quinqueradiate starfish, there being always six times as many plates 
 as there are rays. Each segment of the oral skeleton consists of two pairs of 
 ambulacral, and of one pair of adambulacral ossicles. In Asterias [a cryp- 
 tozonian] the ambulacral plates are more prominent than the adambulacrals, 
 and project into the oral cavity." 
 
 When the ambulacral elements are the more prominent, the oral skeleton is said 
 to be of the ambulacral type. This is only present in cryptozonians. When 
 the adambulacral ossicles are the most prominent, the oral skeleton is of the 
 adambulacral type. This latter construction is the more primitive and occurs 
 in all the Phanerozonia, but is also present in some of the cryptozonians. 
 Ossicles. 
 
 See Plates. 
 Papulae. 
 
 In living Asterias, a cryptozonian, from between the spicular plates there rise 
 from all parts of the external surface short and small integumentary protuber- 
 ances that are used for respiration. In the more heavily plated Phanerozo- 
 nia they are limited to the abactinal surface enclosed between the supramar- 
 ginal plates. It is probable that papulae were present in all Paleozoic forms 
 having rounded or spicular ossicles, issuing in the open spaces between the 
 plates. They probably were absent in the earliest closely plated starfishes, 
 such as Hudsonaster. See Csecal pores. 
 Paxillse. 
 
 Minute calcareous processes arranged around large spines. None are known 
 in Paleozoic genera. 
 
 "Another type of spines occurs as part of the structures known as 'paxillse.' 
 Each paxilla consists of a thick plate supporting a number of short, calcareous 
 pillars, the summit of each of which is covered by a group of small spines. 
 In some Phanerozonia * * * the paxillse occupy almost the whole abactinal 
 surface of the Asteroid" (Gregory 1900, p. 247). 
 Pedicellarids. 
 
 Pincer or scissors-like calcareous appendages, attached to the spines, the plates, 
 or the skin, which keep the body-wall clean of parasites. None have as yet 
 
KEVISION OF PALEOZOIC STELLEROIDEA. 17 
 
 been detected with certainty in Paleozoic genera. In the primitive Recent 
 forms they are also absent, the integument being protected by an abundance 
 of closely set spines. 
 
 "The Pedicellarise of Asteroids are of four main types. The simplest form con- 
 sists of a row of pairs of small, sessile, opposable spines; these are the 'pseudo- 
 pedicellariae.* The members of the second set are ' sessile.' The next advance 
 is the development of a stalk; of these pedunculate pedicellariae there are two 
 varieties: (1) the 'forficiform,' in which the two hooks are attached to the near- 
 est end of the basal plate nearest to them; (2) the 'forcipiform,' in which the 
 two hooks cross one another and are attached to the end of the basal plate far- 
 thest from them " (Gregory 1900, p. 247; also see Verrill 1914, pp. 25-34). 
 Perradial. 
 
 The area along the center of the rays. The ambulacra are perradial in position. 
 
 See Interradial. 
 Plates. 
 
 Some writers restrict the term plates to the five primary radials, five interradials, 
 and the central disk piece, and refer to all the other calcareous parts as ossicles. 
 The word plates is here used in the widest sense, and as interchangeable with 
 ossicles. For the sake of brevity the plates will be often referred to as margi- 
 nalia, radialia, etc. 
 Podial openings. 
 
 The rounded openings between the ambulacral plates for the protrusion of the 
 
 locomotor organs, the podia or water- tube-feet. See also Ambulacral. 
 Primary radial. 
 See Radial. 
 Primary skeleton. 
 
 The skeleton of a starfish is made up of primary and secondary ossicles. The 
 primary skeleton consists of the longest inherited and the first appearing plates 
 in the young, as the ambulacral, adambulacral, marginal and radial columns, 
 plus the primary pieces of the disk. All the other ossicles inserted between 
 these are of the secondary skeleton. 
 Radial 
 
 Refers only to the prominent abactinal primary plates holding a radial position. 
 Where present, they form columns of continuous reticular or separated radialia, 
 situated along the radial center of the rays. Proximal radials are those on or 
 near the disk and should not be confounded with the primary radials, the 
 probable homologues of the radials in crinids. These plates are also known as 
 median dorsals, dorsals or carinals; also as radialia. 
 Rays. 
 
 The radial "arms " of starfishes. These are hollow and contain the digestive, 
 reproductive, and water-vascular systems and other organs. The rays merge 
 gradually and without sharp demarcation into the central disk. 
 Respiratory pores. 
 
 See Csecal pores. 
 Secondary skeleton. 
 
 See Primary skeleton and Accessory plates. 
 Spines. 
 
 See PaxillsR and Pedicellarids. 
 Supramarginal. 
 
 See Marginal plates. 
 Terminals. 
 
 See Ocular plate. 
 
18 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Torus. 
 
 See Oral armature. 
 Trimum. 
 
 See Bivium. 
 Vertebral ossicles. 
 
 In the Ophiuroidea each, pair of adjoining ambulacralia is united into a single 
 plate, the vertebra of the arms. As the arms are very flexible, these ossicles 
 articulate upon one another as do the bones in the vertebral column of verte- 
 brates. 
 
 FINDING LIST OF PALEOZOIC STELLEROIDEA. 
 
 Page. 
 
 Acroura (Ophiura) schlotheimii Minister. Known to the writer only from the list 
 in Woodward, Geol. Mag., dec. 2, vol. 1, 1874, p. 7. Siluric. 
 
 Agalmaster Schondorf 131 
 
 A. grandis Schondorf 132 
 
 A. intermedius Schondorf 133 
 
 A. miellensis Schondorf 132 
 
 Aganaster Miller and Gurley 263 
 
 A. gregarius (Meek and Worthen) 264 
 
 A. (?) ep. Miller and Gurley =Lapworthura (f ) ep . 251 
 
 Alepidaster Meek 228 
 
 A. flexuosus (Miller and Dyer) 231 
 
 A. granuliferus (Meek) 230 
 
 A. gregarius Meek= Aganaster gregarius 264 
 
 A. miamiensis (Miller) 233 
 
 A. f, new species -.- 230 
 
 Anorthaster, new genus 125 
 
 A. miamiensis (Miller) 127 
 
 Archaeasterias 'M.\JlleY=Xenaster 129 
 
 ? Argaster "0.2^1 Mesopalxaster 74 
 
 A. antiqua Gregory = Mesopalxaster (?) antiquus 86 
 
 Aspidosoma Goldi\i88=Encrinaster 241 
 
 A. arnoldi Goldf\i8s=Encrinaster arnoldi 243 
 
 A. eifelense SchondoTi=Encrinaster eifelensis 244 
 
 A. goldfussi Sch6ndori=Encrinaster goldfussi 243 
 
 A. grayss. Spencer=Encrinaster (?) grayse 245 
 
 A. petaloides SimonovitBch=Encrinaster petaloides 243 
 
 A. petaloides goslariensis Halfar=J!?icrmaser petaloides goslariensis 243 
 
 A.f pontis Cla,Tke=Encrinaster pontis 244 
 
 A. roemeri Schdndori=Encrinaster roemeri 244 
 
 A. schmidti Sch6ndoTi=Encrinaster schmidti 244 
 
 A. tischbeinianum Roemer=Jncrwaster tischbeinianus 244 
 
 Asterias Graham, Anthony, and 3ameB=Petraster (?) americanus 146 
 
 A. acuminatus Simonovitsch= Mesopalseaster (?) acuminatus 93 
 
 A. anthonii Dana=Pefr aster (?) americanus 146 
 
 A. antiqua ILi8mger=Lindstrdmaster antiquus 149 
 
 A. antiqua Troost= Mesopalseaster (?) antiquus 86 
 
 A. antiquata Ijocke=Promopalseaster spedosus 109 
 
 A. asperula Roemer= Urasterella asperula 188 
 
 A. asperula Roemer (pait)=Eoluidia decheni 262 
 
 A. constellata Thorent= Urasterella (?) constellata .' 187 
 
 A. matutina 'BsX\.=Hudsonaster matutinus '. 57 
 
 A. montanus Stschurowsky= Urasterella montana 189 
 
 A. primseva Salter and Soweiby=Stenaster (?) obtusus 167 
 
REVISION OF PALEOZOIC STELLEROIDEA. 19 
 
 Page. 
 
 Asterias primordialis Anon.=Promopalseaster, sp. undet 108 
 
 A. (Archseasterias) rhenana M.ulleT=Xenaster (?) rhenanus 131 
 
 A. spinosissima Roemer. An unsolved starfish from the Lower Devonic of 
 Bundenbach, Germany. See Roemer, Palaeontographica, vol. 9, 1863, p. 147, 
 pi. 29, fig. 4; and Schondorf, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, 
 vol. 62, 1909, p. 33. 
 A. sp. undet. Hall 1847Ccelaster tenuiradiatus . 
 
 Asteriscus antiquus Pictet=Lindstromaster antiquus 149 
 
 Astropecten Link . . 161 
 
 A. (?) schluteri Stiirtz 161 
 
 Ataxaster Jaekel 161 
 
 A. pygmxus Jaekel 161 
 
 Australaster, new genus 72 
 
 A. giganteus (Etheridge) - - 73 
 
 A. (?) stutchburii (Etheridge) 73 
 
 Bdellacoma Salter 254 
 
 B. vermiformis Salter 254 
 
 Bohemura Jaekel 223 
 
 B. jahni Jaekel 223 
 
 Bundenbachia Stiirtz 234 
 
 B. beneckei Stiirtz 234 
 
 B. grandis St\\rtz=Palaophiomyxa grandis 235 
 
 Calliaster Trautschold=CaZtoerea 190 
 
 C. mirus TT&\itschold=Calliasterella mira 190 
 
 Calliasterella, new name 190 
 
 C. mira (Trautschold) 190 
 
 Cheiropteraster Stiirtz 202 
 
 C. giganteus Stiirtz 202 
 
 Cholaster Worthen and Miller 265 
 
 C. peculiaris Worthen and Miller 266 
 
 Ccelaster Sandberger=$/>ara'aster 95 
 
 C. americanus D'Orbigny=Peraser (?) americanus 146 
 
 C. latiscutatus Sandberger=parmister latiscutatus 96 
 
 C. tenuiradiatus D'Orbigny, Prodr. de Paleont., vol. 1, 1849, p. 22. Based on 
 
 an isolated madreporite described as Asterias, sp. undet., Hall, Pal. New 
 York, vol. 1, 1847, p. 18, pi. 4, figs, lla, 116. 
 
 Compsaster Worthen and Miller 192 
 
 C. formosus Worthen and Miller 193 
 
 C., new species 194 
 
 Cribellites carbonarius Tate 274 
 
 Devonaster, new genus 97 
 
 D. chemungensis, new species 101 
 
 D. eucharis (Hall) 98 
 
 E chinas terella Stiirtz 200 
 
 E. ? darwini Clarke 200 
 
 E. sladeni Stiirtz 200 
 
 Echinasterias Stiirtz 211 
 
 E. spinosus Stiirtz 211 
 
 EchJLnodiscaster Delage and Herouard 211 
 
 E. multidactylus (Stiirtz) 211 
 
 Echinodiscites SchucheTt=Echinodiscaster 211 
 
 Echinodiscus Stwrtz=Echinodiscaster 211 
 
 E. multidactylus St\ulz=Echinodiscaster multidactylus 211 
 
20 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Page. 
 
 Echinostella Stiirtz 212 
 
 E. traquairi Stiirtz 212 
 
 Eifelaster Schondorf 133 
 
 E. follmanni Schondorf 134 
 
 Encrinaster Haeckel 241 
 
 Encrinaster Haeckel (p&rt)=Protaster. . . : 224 
 
 E. arnoldi (Goldfuss) 243 
 
 E. eifelensis (Schondorf) 244 
 
 E. goldfussi (SchSndorf). . r 243 
 
 E. grayse, (Spencer) 245 
 
 E. petaloides (Simonovitsch) 243 
 
 E. petaloides goslariensis (Halfar) 243 
 
 E. pontis (Clarke) 244 
 
 E. roemeri (Schondorf) 244 
 
 E. schmidti (Schondorf) 244 
 
 E. tischbeinianus (Roemer) 244 
 
 Eoactis Spencer. See Urasterella 173 
 
 E. simplex Spencer. See Urasterella girvanensis 186 
 
 Eoluidia Stiirtz 262 
 
 E. decheni Stwtz 262 
 
 Eophiura Jaekel 222 
 
 E. bohemica, new species 222 
 
 Eophiurites Stiirtz =Eoluidia 262 
 
 E. decheni (Stiirtz) =Eoluidia decheni 262 
 
 Eospondylus Gregory 263 
 
 E. primigenius (Stiirtz) 263 
 
 Etheridgaster Gregory= Monaster 170 
 
 E. clarJcei Gregory = Monaster clarJcei 172 
 
 Eucladia Woodward 276 
 
 E. (?) beecheri, new species 278 
 
 E. johnsoni Woodward 276 
 
 E. woodwardi Sollas 277 
 
 Eugaster ILal\=EiLgasterella 237 
 
 E. continnus Ringueberg=Eugasterella ( ?) concinna 239 
 
 E. logani H&\\=Eugasterella logani 238 
 
 Eugasterella, new name 237 
 
 E. ( ?) concinna (Ringueberg) 239 
 
 E. logani (Hall) 238 
 
 Euryak annulatum DeKay. Apparently a lysophiurid. See Hall, Pal. N. Y., 
 
 vol. 3, 1861, p. 134 (nomen nudum). 
 
 Euthemon Sollas , 279 
 
 E. igerna Sollas 279 
 
 Furcaster Stiirtz 261 
 
 F. (?) daoulasensis (Davy) 261 
 
 F. palseozoicus Stiirtz 261 
 
 Gregoriura Chapman 233 
 
 G. spryi Chapman. . .- 234 
 
 HaUaster Stiirtz 254 
 
 #./or&m(Hall) 255 
 
 Helianthaster Clarke (part)==PaZa20$oZoster 209 
 
 Helianthaster Roemer 159 
 
 H. filiciformis Woodward 160 
 
 H. gyalum Clarke =PaZasoso Zoster ( ?) gyalum 210 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 21 
 
 Page. 
 
 Helianthaster gyalum Clarke (paTtyLepidasterella babcocki 160 
 
 H. , new species Clarke Lepidasterella babcocki 160 
 
 H. rhenanus Roemer 159 
 
 H. roemeri Clarke PaZasoso Zoster roemeri 211 
 
 Hisingeraster Stiirtz =Lindstromaster 148 
 
 H. antiqua Sturtz=Lindstrdmaster antiquus 149 
 
 Hudsonaster Stiirtz 53 
 
 H. batheri, new species 65 
 
 H. incomptus (Meek) 61 
 
 H. matutinus (Hall) 57 
 
 E. milleri, new species 60 
 
 H. narrawayi (Hudson) 59 
 
 H. rugosus (Billings) 64 
 
 Jaekelaster Stiirtz 192 
 
 /. petaliformis Stiirtz 192 
 
 Lapworthura Gregory 250 
 
 L. cylindrica Parks= Tseniaster cylindricus 220 
 
 L. miltoni (Salter) 251 
 
 L. sollasi Spencer 251 
 
 L. (?)sp 251 
 
 Lepidaster Forbes 158 
 
 L. grayi Forbes 158 
 
 Lepidasterella, new genus 160 
 
 L. babcocki, new species 160 
 
 Lindstromaster Gregory 148 
 
 L. antiquus (Hisinger) 149 
 
 Loriolaster Stiirtz 201 
 
 L. mirabilis Stiirtz 201 
 
 Medusaster Stiirtz 212 
 
 M. rhenanus Stiirtz 212 
 
 Mesopaleeaster, new genus 74 
 
 M. ( ?} acuminatus (Simonovitsch) 93 
 
 M. (?) antiquus (Troost) 86 
 
 M. bellulus (Billings) 91 
 
 M. caractaci (Gregory) 92 
 
 M. ( ?) cataractensis, new species 89 
 
 M. (?) clarki (Clarke and Swartz) 94 
 
 M . ( ?) dubius (Miller and Dyer) 85 
 
 M.finei (Ulrich) 81 
 
 M. granti (Spencer) 89 
 
 M. intermedius, new species 79 
 
 M. ( ?) lanceolatus, new species 82 
 
 M. (?) parviusculus (Billings) 87 
 
 M. proavitus, new species 83 
 
 M. sha/eri (Hall) ; 77 
 
 M. ( ?) wilberanus (Meek and Worthen) 84 
 
 Miomaster Schondorf 96 
 
 M. drevermanni Schondorf 96 
 
 Miospondylus Gregory 263 
 
 M. rhenanus (Stiirtz) 263 
 
 Monaster Etheridge 170 
 
 Monaster Gregory= Australaster 72 
 
 M. darkei (De Koninck) 172 
 
22 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Page. 
 
 Monaster giganteus 'Ethendge=Australaster giganteus 73 
 
 M. stutchburii JZtheridge=Australaster stutchburii 73 
 
 Neopalseaster, new genus 134 
 
 N. crawJordsmlUnsis (Miller) 136 
 
 Onychaster Meek and Worthen 268 
 
 0. asper Miller 272 
 
 0. barrisi (Hall) 272 
 
 0. confragosus Miller 273 
 
 0. demissus Miller 274 
 
 0. flexilis Meek and Worthen 270 
 
 Ophiopege ~Bohm=Aganaster 263 
 
 Ophiura obtusa Eichwald= Pro taster (Ophiura) obtusus. 
 
 0. (?) ramosa Fahrenkohle. Unknown to writer. See Bull. Soc. Imp. Nat. 
 
 Moscow, n. ser., vol. 17, 1844, p. 208, pi. 3, figs. 1-3; and Woodward, Geol. 
 
 Mag., dec. 2, vol. 1, 1874, p. 7 (listed only). Coal Measures. 
 
 0. rhenana Sturtz= Miospondylus rJienanus 263 
 
 0. salteri Salter and Sowerby =Protaster ( ? ) salteri 227 
 
 0. schlotheimii Munster= Acroura (Ophiura) schloiheimii. 
 
 Ophinrella Stwrtz=Eospondylus 263 
 
 0. primigenia St\irtz=Eospondylus primigenius 263 
 
 Ophiurina Stiirtz 246 
 
 0. lymani Stiirtz 247 
 
 Palseaster Hall 67 
 
 Paleeaster of authors =Hudsonaster } Mesopalseaster, Devonaster, Promopal- 
 
 seaster, Anorihaster, Neopalseaster, Petraster, Palasterina, Monaster, Uras- 
 
 terella. 
 
 Palseaster (Monaster) Etheridge= Monaster 170 
 
 Paleeaster (Monaster) Etheridge (part) =Australaster 72 
 
 P. (Argaster) antiqua Hall= Mesopalseaster ( ?) antiquus 86 
 
 P. antiquatus H&ll=Promopaldeaster speciosus 109 
 
 P. antiquus Miller= Mesopalseaster ( f) antiquus 86 
 
 P. asperrima Salter= Urasterella (?) asperrima 187 
 
 P. caractaci Salter= Mesopalseaster caractaci 92 
 
 P. clarkana Miller =Hudsonaster incomptus 61 
 
 P. clarkei De Koninck= Monaster clarkei 172 
 
 P. clarkei Mi\ler=Hudsonaster i/icomptus 61 
 
 P. clarki Clarke and Swartz= Mesopalseaster ( f) clarki 94 
 
 P. coronella Salter=Stenaster (?) coronella 167 
 
 P. crawfordsvillensis Miller = Neopalseaster crawfordsmllensis 136 
 
 P. dubius Miller and Dyer= Mesopalseaster (?) dubius 85 
 
 P. dyeri 1&eek=Promopal3easter dyeri 120 
 
 P. eucharis Il f d,ll=Devonaster eucharis 98 
 
 P. exculptus M.i\\eT=Promopalseaster exculptus 117 
 
 P. find Ulrich= Mesopalseaster finei 81 
 
 P. ( Monaster) giganteus Etheridge =^Lttsratoer giganteus 73 
 
 P. granti Spencer= Mesopalseaster granti 89 
 
 P. granulosus ILall=Promopalseaster granulosus 112 
 
 P. granulosus MeekPromopalseaster speciosus 109 
 
 P. harrisi Miller= Urasterella grandis 180 
 
 P. hirudo Salter= Urasterella hirudo 188 
 
 P. imbricatus Salter= Tetraster (?) imbricatus 169 
 
 P. incomptus Meek.=Hudsonaster incomptus 61 
 
 P. jamesi Hall Petraster ( ?) americanus 146 
 
REVISION OF PALEOZOIC STELLEROIDEA. 23 
 
 Page. 
 
 Paldeaster longibrachiatus Miller =Promopalxaster spinulosus 115 
 
 P. magnificus Miller =Promopal9easter magnificus 122 
 
 P. matutinus Hall=Rudsonaster matutinus 57 
 
 P. miamiensis Miller =Anorthaster miamiensis 127 
 
 P. montanus Trautschold= Urasterella montana 189 
 
 P. niagarensis Hall 69 
 
 P. obtusus Salter=Stenaster (?) obtusus 167 
 
 P. parviusculus Billings= Mesopalseaster ( f ) parviusculus 87 
 
 P. pulchellus Billings= Urasterella pulchella 178 
 
 P. pygmsea Eichwald. Not known to writer. Middle Ordovicic, Pulkowa, 
 
 Russia. 
 
 P. ruthveni Salter= Urasterella ruthveni 187 
 
 P. shajferi Hall= Mesopalseaster shajferi 77 
 
 P. simplex Miller and Dyer=Hudsonaster incomptus 61 
 
 P. spedosus Meek=Promopalseaster spedosus 109 
 
 P. spinulosus Miller and ~Dyer=Promopalxaster spinulosus 115 
 
 P. squamatus Salter. Not known to writer. See Cat. Woodwardian Mus., 1873, 
 
 p. 47; and Woodward, Geol. Mag., dec. 2, vol. 1, 1874, p. 7 (listed only). 
 
 Bala of England. 
 
 P. ( Monaster] stutchburii Etheridge=Australaster ( ?) stutchburii 73 
 
 P. wilberanus Hall= Mesopalseaster ( ?) wilberanus 84 
 
 P. ? wilsoni Raymond Promopalseaster wilsoni 106 
 
 P. wyJcoffi Miller and Gurley=Promopalseaster wykoffi 119 
 
 Palaeasterina Gregory =Palasterina 150 
 
 Paleeasterina of authors =Petraster 138 
 
 P. antiqua S&lter=Lindstr6master antiquus 149 
 
 P. approximata Miller and Dyer=Petr aster spedosus 142 
 
 P. fimbriata Meek and WorthQn=Schcenaster fimbriatus 204 
 
 P. rugosa Billings Hudsonaster rugosus 64 
 
 P. spedosa Miller and Dyer=Petr aster spedosus 142 
 
 Palaenectria Stmtz=Palseostella 155 
 
 P. devonica StiiTtz=Palssostella solida 156 
 
 Palaeocoma Miller (p^Tf)=Ptilonaster 239 
 
 Palseocoma S&lter=Sturtzaster 252 
 
 Palaeocoma (Bdellacoma) Salter =Bdellacoma 254 
 
 Palaeocoma (Bhopalocoma) SsilteT=Rhopalocoma 254 
 
 P. colvini SalteTStiirtzaster colvini 253 
 
 P. cygnipes Salter Sturtzaster cygnipes 253 
 
 P. cylindrica Billings= Txniaster cylindricus 220 
 
 P. marstoni Salter= Sturtzaster marstoni 253 
 
 P. princeps MilleT=Ptilonaster princeps 240 
 
 P. pyrotechnica S&lter=Rhopalocoma pyrote'chnica 254 
 
 P. spinosa Billings= Tssniaster spinosus 219 
 
 P. vermiformis Salter = Bdellacoma vermi/ormis 254 
 
 Palseodiscus ferox Salter=an echinid. See Jackson, Mem. Boston Soc. Nat. 
 
 Hist., vol. 7, 1912, p. 250. 
 
 Palseophioinyxa Sturtz 234 
 
 P.grandis (Sturtz) 235 
 
 Palseophiura Sturtz 235 
 
 P. simplex Sturtz 235 
 
 Palaeosolaster Sturtz 209 
 
 P. gregoryi Sturtz 209 
 
 P. (?) gyalum (Clarke) 210 
 
24 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Palxosolaster roemeri (Clarke) 211 
 
 Paleeospondylus Stuitz=Palastropecten 261 
 
 P. zitteli Sturtz=Palastropecten zitteli ". 262 
 
 Paleeostella Stiirtz 155 
 
 P. solida Stiirtz 156 
 
 Paleespondylus Stiirtz =Palastropecten 261 
 
 Palaeura Jaekel 223 
 
 P. neglecta, new species 223 
 
 Palasteracanthion Stiirtz= Urasterella 173 
 
 Palasterina Billings (p3tft)=Schuchertia 195 
 
 Palasterina McCoy 150 
 
 P. antiqua SsdteT=Lindstr omaster antiquus 149 
 
 P. bonneyi Gregory 153 
 
 P. follmanni Sturtz=Pseudopalasterina follmanni 157 
 
 P. (?) jamesi D&na l =Petraster (?) americanus 146 
 
 P. kinahani Baily= Uranaster kindhani 155 
 
 P. primseva (Forbes) 153 
 
 P. (?) ramseyensis Hicks 154 
 
 P. rigidus Billings =Petraster rigidus 141 
 
 P. rugosa Billings =Hudsonaster rugosus 64 
 
 P. stellata BillingB=Schuchertia stellata 196 
 
 Palasteriscus Stiirtz 200 
 
 P. devonicus Stiirtz 200 
 
 Palastropecten Stiirtz 261 
 
 P. zitteli Stiirtz 262 
 
 Palmipes antiqua Forbes= Lindstromaster antiquus 149 
 
 Petraster Billings 138 
 
 P. (?) americanus (D'Orbigny) 146 
 
 P. (?) antiqua Shumard= Mesopalxaster (?) antiquus 86 
 
 P. bellulus Billings = Mesopalseaster bellulus 91 
 
 P. rigidus (Billings) . % 141 
 
 P. rigidus (Billings) (p&Tt)=Hudsonaster matutinus 57 
 
 P. smyihi McCoy 147 
 
 P. spedosus (Miller and Dyer) 142 
 
 P. wilberianus Meek and Worthen= Mesopalseaster ( ?) wilberanus 84 
 
 Promopalaeaster, new genus 102 
 
 P. bellulus, new species 113 
 
 P. ^m'(Meek) 120 
 
 P. exculptus (Miller) 117 
 
 P. granulosus (Hall) 112 
 
 P. magnificus (Miller) 122 
 
 P. prenuntius, new species 107 
 
 P. spedosus (Meek) 109 
 
 P., sp. undet 108 
 
 P. spinulosus (Miller and Dyer) 115 
 
 P. wilsoni (Raymond) [ 106 
 
 P. wykoffi (Miller and Gurley) 119 
 
 Protaster Forbes 224 
 
 Protaster Kall=Hallaster 254 
 
 P. f barrisi TL2il\=Onychaster barrisi 272 
 
 P. biforis Gregory 226 
 
 P. brisingoides Gregory=Sturtzura brisingoides 236 
 
 P. daoulasensis Davy = Fur caster (?) daoulasensis 261 
 
REVISION OF PALEOZOIC STELLEROIDEA. 25 
 
 Protaster decheni Dewalque= Tremataster (?) decheni 248 
 
 P. elegans Parks= Txniaster elegans 221 
 
 P. flexuosus Miller and DyeT=Alepidaster flexuosus 231 
 
 P. forbesi Hall= Hallaster forbesi 255 
 
 P. (?) granuliferus lAeek=Alepidaster granuliferus 230 
 
 P. (?) gregarius Meek and Worth en =Aganaster gregarius 264 
 
 P. groomi Sollas and Sollas 227 
 
 P. leptosoma Salter =Sturtzur a leptosoma 237 
 
 P. miamiensis Miller =Alepidaster miamiensis 233 
 
 P. miltoni SalterLapworthura miltoni 251 
 
 P. (Ophiura)obtususEichwald. Unknown to the writer. See Schichtensystem 
 
 Esthland, p. 193; Lethsea Rossica, p. 661; and Woodward, Geol. Mag., dec. 
 
 2, vol. 1, 1874, p. 7 (listed only). Siluric of Russia. 
 P. petri Salter. Unknown to the writer. See Salter, Cat. Mus. Pract. Geol., p. 30; 
 
 and Woodward, Geol. Mag., dec. 2, vol. 1, 1874, p. 7 (listed only). Probably 
 
 Bala, Church Stretton, England. 
 
 P. ( f ) salteri (Salter) 227 
 
 P. sedgwickii Forbes 225 
 
 P. (?) stellifer Ringueberg 228 
 
 P. (?) whiteavesianus Parks 227 
 
 Protasteracanthion Stiirtz= Urasterella 173 
 
 P. primus Stiirtz= Urasterella asperula 188 
 
 ProtasterinaUlrich==.47epw/aser 228 
 
 P . fimbriata Ulrich=Alepidaster fiexuosus 231 
 
 P. flexuosa 3aio.eB=Alepidaster fiexuosus 231 
 
 Protoeuryale C. F. Roemer=a crinid. 
 
 Protopalseaster Hudson= Hudsonaster 53 
 
 P. caractaci Spencer= Mesopalseaster caractaci 92 
 
 P. nanawayi Hudson = Hudsonaster narrawayi 59 
 
 Pseudopalasterina Sturtz 156 
 
 P.follmanni (Sturtz) 157 
 
 Ptilonaster Hall 239 
 
 P. princeps Hall 240 
 
 Bhenaster Schondorf 133 
 
 R. schwerdi Schondorf .,*. 133 
 
 Rhodostoma Sollas and Sollas =Sturtzura .7. 236 
 
 R. leptosoma Sollas and Sol\&s=Sturtzura leptosoma 237 
 
 Rhopalocoma Salter 254 
 
 R. pyrotechnica Salter 254 
 
 Roemeraster Stiirtz= Urasterella 173 
 
 R. ( ?) acuminatus Sturtz = Mesopalseaster ( ?) acuminatus 93 
 
 R. asperula Stiirtz= Urasterella asperula 188 
 
 Salteraster Stiirtz= Urasterella * 173 
 
 S. asperrimus Stiirtz= Urasterella (?) asperrima 187 
 
 Schoenaster Meek and Worthen 202 
 
 S. fimbriatus Meek and Worthen 204 
 
 S. (?) legrandensis Miller and Gurley 206 
 
 S. (?) montanus Raymond 207 
 
 S., new species 206 
 
 S. (?) wachsmuthi Meek and Worthen 205 
 
 Schuchertia Gregory 195 
 
 S. laxata, new species 198 
 
 S. ordinaria, new species 199 
 
26 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Page. 
 
 Schuchertia stellata (Billings) 196 
 
 Siluraster Jaekel 65 
 
 S. perfectus Jaekel 66 
 
 Spaniaster Schondorf 95 
 
 S. latiscutatus (Sandberger) 96 
 
 Squamaster Ringueberg 249 
 
 S. echinatus Ringueberg 249 
 
 Stenaster Billings 163 
 
 Stenaster Billings (part)= Urasterella 173 
 
 S. (?) confiuens Trautschold 167 
 
 S. (?) coronella (Salter) 167 
 
 S. grandis Meek= Urasterella grandis 180 
 
 S. huxleyi Billings= Urasterella huxleyi 182 
 
 S. (?) obtusus (Forbes) 167 
 
 8. pulchellus Billings= Urasterella pulchella 178 
 
 S. salteri Billings 165 
 
 Stiirtzaster Etheridge 252 
 
 S. colvini (Salter) 253 
 
 8. cygnipes (Salter) 253 
 
 8. marstoni (Salter) 253 
 
 S. (?) mitchelli Etheridge 254 
 
 Stiirtzura Gregory 236 
 
 S. brisingoides (Gregory) 236 
 
 S. leptosoma (Salter) 237 
 
 S. leptosomoides Chapman 237 
 
 Sympterura Bather 256 
 
 S. minveri Bather 256 
 
 Tseniaster Billings 216 
 
 T. australis McCoy =Sturtzura brisingoides 236 
 
 T. cylindricus (Billings) 220 
 
 T. elegans Miller 221 
 
 T. meafordensis Foerste 221 
 
 T. schoharise. Ruedemann 220 
 
 T. spinosus (Billings). 219 
 
 Taeniura Gregory= T&niaster 216 
 
 T. cylindrica Gregory = Tseniaster cylindricus 220 
 
 Tetraster Nicholson and Etheridge 167 
 
 T. asperrimus Nicholson and Etheridge = Urasterella (?) asperrima 187 
 
 T. (?) imbricatus (Salter) 169 
 
 T. sp. indet. Nicholson and Etheridge= Urasterella girvanensis 186 
 
 T. wyville-thomsoni Nicholson and Etheridge 168 
 
 T. wymlle-thomsoni Nicholson and Etheridge (part) = Hudsonaster batheri 65 
 
 Tremataster Worthen and Miller 247 
 
 T. (?) decheni (Dewalque) 248 
 
 T. diffidlis Worthen and Miller 247 
 
 Trentonaster Sturiz=Schuchertia 195 
 
 T. stellata Sturtz== Schuchertia stellata 196 
 
 Trichotaster plumiformis Wright. A 10-rayed asterid from the Wenlock lime- 
 stone at Dudley, England, in the collection of Dr. Grindrod. Insufficiently 
 described to be regarded as defined. See Quart. Journ. Geol. Soc., vol. 29, 
 1873, p. 421; also Woodward, Geol. Mag., dec. 2, vol. 1, 1874, p. 7 (listed as 
 Trochitaster plumiformis). 
 
 Trimerast er Schondorf ... 134 
 
BEVISION OF PALEOZOIC STELLEKOIDEA. 
 
 27 
 
 Page. 
 
 Trimeraster parvulus Schondorf 134 
 
 Trochitaster plumiformis WTight=Trichotaster plumiformis. 
 
 Uranaster Gregory 154 
 
 U. elizse, Spencer 155 
 
 U. kinahani (Baily) 155 
 
 Uraster hirudo Forbes= Urasterella hirudo 188 
 
 U. obtusus ~FoTbes=Stenaster (?) obtusus 167 
 
 U. primsevus Forbes=PaZasmna primseva 153 
 
 U. ruthveni Forbes= Urasterella ruthveni 187 
 
 Urasterella McCoy 173 
 
 Urasterella Stiirtz I8$3=Stenaster 163 
 
 U. (?) asperrima (Salter) 187 
 
 U. asperula (Roemer) 188 
 
 U. (?) constellata (Thorent) 187 
 
 U. girvanensis, new species 186 
 
 U. grandis (Meek) 180 
 
 U. hirudo (Forbes) 188 
 
 U. huxleyi (Billings) 182 
 
 U. montana (Stschurowsky) 189 
 
 U., new species 189 
 
 U. pulchella (Billings) 178 
 
 U. ruthveni (Forbes) 187 
 
 U. selwyni McCoy 188 
 
 U. ulrichi, new species 183 
 
 Xenaster Simonovitsch 129 
 
 X. dispar Schondorf 131 
 
 X. elegans Schondorf 131 
 
 X. eucharis Schondori=Devonaster eucharis 98 
 
 X. margaritatus Follmann=^". elegans 131 
 
 X. margaritatus Simonovitsch 131 
 
 X. margaritatus Simonovitsch (part)=J5T. dispar and Agalmaster grandis 131, 132 
 
 X. (?) rhenanus (Miiller) 131 
 
 X. simplex Simonovitsch =Spaniaster latiscutatus 96 
 
 REMARKS ON THE DEVELOPMENT OF PALEOZOIC STELLEROIDEA. 
 
 GEOLOGICAL. 
 
 Distribution. This memoir treats of the following Paleozoic 
 Stelleroidea : 
 
 Species. 
 
 North 
 Ameri- 
 can 
 species. 
 
 Euro- 
 pean 
 species. 
 
 Southern 
 Hemis- 
 phere 
 species. 
 
 Asteroidea... 
 Auluroidea. . 
 Ophiuroidea. 
 
 Total. . . 
 
 110 
 
 59 
 
 5 
 
 174 
 
 11 
 
28 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Arranged geologically the distribution is as follows : 
 
 
 Ordo- 
 vicic. 
 
 Siluric. 
 
 Devonic. 
 
 Lower 
 Carbon- 
 iferous. 
 
 Upper 
 Carbon- 
 iferous. 
 
 Permic. 
 
 Asteroidea 
 
 46 
 
 16 
 
 36 
 
 6 
 
 6 
 
 
 
 Auluroidea 
 
 15 
 
 17 
 
 24 
 
 3 
 
 
 
 
 
 OphiuToidea 
 
 
 
 
 
 
 
 5 
 
 o 
 
 o 
 
 
 
 
 
 
 
 
 Total 
 
 61 
 
 33 
 
 60 
 
 14 
 
 6 
 
 
 
 
 
 
 
 
 
 
 Of all of the Paleozoic Stelleroidea (174 species), not a single one 
 is common to North America and Europe. Of genera having specific 
 representation in more than one continent there are the folio whig: 
 Hudsonaster, 5 in America, 1 in Scotland; Mesopalseaster, 13 (7 doubt- 
 ful) in America, 1 in England, ? 1 in Germany; Petraster, 3 in America 
 (1 doubtful), 1 in Australia; Stenaster, 1 in America, ? 1 in Ireland and 
 Wales, ? 1 in England, ? 1 in Kussia; Urasterella, 5 in America, 1 in 
 Scotland, ? 1 in Wales, ? 1 in France, 2 in England, 1 in Australia, 
 1 in Germany, 1 in Russia; Paldeosolaster, 1 in Germany, ? 1 in 
 America; Protaster, ? 2 in America, 1 in England, 2 (1 doubtful) in 
 Wales; Tremataster, 1 in America, ? 1 in Belgium. Of Ophiuroidea, 
 none have wide distribution. 
 
 Nearly all of the species have very short geologic ranges, but very 
 few occurring in more than a single formation. Mesopalxaster 
 intermedius ranges from the ? Utica to the Maysvillian, M. sliafferi 
 from the Maysvillian to the Richmondian, Alepidaster flexuosus from 
 the basal Edenian to the upper Maysvillian, Hudsonaster incomp- 
 tus from the Edenian into the Richmondian, Promopalxaster mag- 
 nificus and Petraster spedosus from the Maysvillian to the Rich- 
 mondian. 
 
 These tables also show that the Ophiuroidea do not begin earlier 
 than the Lower Carboniferous (Burlington) and that the Auluroidea 
 cease to exist after the same period, for none are as yet known in the 
 Upper Carboniferous or Permic. The latter attained their maximum 
 of development in the Siluric and Devonic, with very rapid decline 
 in the Lower Carboniferous. 
 
 The great development of Asteroidea in the Ordovicic is due to the 
 marked specific evolution of the genera Mesopalseaster and Promo- 
 palseaster in North America. This knowledge is the result of care- 
 ful work by local collectors in areas abounding in good fossils. On 
 the other hand the marked rise hi specific representation in the De- 
 vonic is due to the protracted collecting in the earlier beds of this 
 period, the roofing slates of Bundenbach, Germany. 
 
 Preservation and occurrence. Starfishes are most often preserved 
 in sandstones and muds tones and least often in limestones. The 
 
REVISION OF PALEOZOIC STELLEROIDEA. 29 
 
 reason why they occur less frequently in limestones is partially 
 accounted for by the fact that during the weathering process they 
 are almost always ruined. Those found in such deposits nearly 
 always occur in the thin shale partings between the bedded limestones. 
 In coarse sandstones they are less often seen, probably because these 
 sediments are so much moved by the storm waves action that 
 destroys the skeleton by separating the plates. Unless a starfish 
 is quickly covered by sediment it is sure to be broken up and jumbled 
 into a mass of unrelated ossicles, because the skeletal parts are rarely 
 coossified. Hence the best preserved specimens are found in mud- 
 stones and especially in the fine-grained, somewhat muddy sand- 
 stones. Here they usually occur as fine molds, since all of the calcium 
 carbonate has been dissolved out by the atmospheric waters. Such 
 material is apt to be fairly abundant in individuals, and although a 
 little difficult to study is often well preserved. Its interpretation is 
 dependent on artificial casts or squeezes in wax or gutta-percha. 
 When found in black slates, as at Bundenbach, the skeleton is pre- 
 served in iron pyrite, and even though these sediments have been 
 subjected to mountain making, the specimens can be cleaned me- 
 chanically of the adhering slate. The process is, however, a laborious 
 one and has been successfully used only by Stiirtz and his two prep- 
 arators. In the calcareous shales asterids are often well preserved, 
 with the original skeleton more or less permineralized and the ossicles 
 cemented together so that parts of the individuals weather out as 
 free fossils. This is particularly the case in the Bichmondian deposits 
 of Ohio and Indiana. 
 
 As a rule, starfishes are obtained in single specimens and as acci- 
 dental finds, and for this reason they are among the rarest of known 
 Paleozoic animals; they are the " fancy fossils" of the local collectors 
 and the " choice specimens" of the museums. All of this is, however, 
 due to the accident of preservation plus their great destruction 
 through weathering. That starfishes and ophiurids were common, 
 though probably not so abundant as aulurids, is proven when they are 
 located in their entombing sediment and then quarried for. This 
 is best seen in the well-known Lower Devonic slates of Bundenbach, 
 where the quarrying for roofing material has produced as many 
 starfishes as all other localities put together. A great variety 
 has also been secured here, so that it is the only locality and time 
 of which we can say that we know the starfish fauna. The most 
 remarkable starfish find, however, is that made near Saugerties, 
 New York, where over 400 examples of the Middle Devonic 
 Devonaster eucharis were found in a fine-grained, somewhat muddy 
 sandstone, extending over an area of 200 square feet. They occur 
 as natural molds, and as the animals are found closely associated 
 with Grammy sia, it is thought that while feeding on these bivalves 
 
30 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 they were suddenly entrapped by the engulfing sand. In the 
 crinid bed of the Keokuk formation at Crawfordsville, Indiana, the 
 ophiurid Ony chaster flexilis is also often met with. 
 
 Aulurids, although as a rule not well preserved, are probably more 
 often seen than starfishes, and certainly are far more abundant than 
 ophiurids. The latter condition is, however, probably explained by 
 the fact that no ophiurid is known older than the Carboniferous. 
 Of the aulurid Tseniaster elegans 31 individuals occur on one small 
 slab. It is probable that if aulurids and asterids were systematically 
 dug for, a far greater harvest would result than that now at hand. 
 Whenever such specimens are found in place, such prospects should 
 be followed up by digging or by prolonged search on the part of the 
 local workers. 
 
 It is very seldom that a Paleozoic asterid is so well preserved that 
 all of its parts can be made out, and this is especially true as regards 
 the dorsal side. During the decay of the animals it is probably 
 true that in most cases the individual lies with its ventral side down, 
 and as the soft parts vanish the dorsal skeleton sinks in irregularly 
 over the actinal skeleton. It is the central region of the disk that 
 suffers dismemberment most. Then, as the two sides of the skeleton 
 finally come to be fully compressed, the rays take on an unnaturally 
 great width, so that in many of the fossils preserved in shales the 
 ambulacral furrow is considerably wider than in nature. For 
 these reasons it is often impossible to say whether the ambulacralia 
 are of the opposite or the alternate arrangement, and what was the 
 original structure of the disk and the interambulacral areas. 
 
 ASTERID EVOLUTION. 
 GENERAL OBSERVATIONS. 
 
 The majority of the starfishes studied by the writer are from 
 the Ordovicic strata of North America. Collectively these show 
 considerable evolution, for at this early time in the history of the 
 earth Phanerozonia, Cryptozonia, and primitive ophiurids ( = Aulu- 
 roidea) are present. Even near the base of the Middle Ordovicic 
 the two former groups appear to be equally common, while the 
 aulurids are as a rule rare and small, though there are occasional 
 large ones. Here the primitive phanerozonian asterids are also small, 
 hardly ever exceeding 15 mm. in diameter, while the derived and 
 far more complex Cryptozonia are large, some of them having rays 
 exceeding 50 mm. In the Lower Ordovicic of America no starfishes 
 are known, while the few that have been reported from Great Britain 
 appear to the writer to be from the Middle Ordovicic. 
 
 These facts show that in spite of their absence in Lower Ordovicio 
 rooks tjfcere must have lived at that time various kinds of starfishes^ 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 31 
 
 Not only this, but we may confidently add that the varied organi- 
 zation of those of the Middle Ordovicic proves that there is a long 
 previous history of which paleontology knows nothing. The origin 
 of the Asteroidea goes back in all probability to the Proterozoic, as 
 may be inferred from the complex metamorphosis of the starfish 
 larva. In all of the Cambric, however, not a single starfish has been 
 found, and this is the more surprising when one considers the abun- 
 dance of life unearthed from these sediments in so many places 
 throughout the world. This may mean that a preservable starfish 
 skeleton was not evolved until Lower Ordovicic time, where they 
 will surely be found. 
 
 TJie most primitive fossil starfish. Of the Ordovicic starfishes, the 
 genus Hudsonaster is the most primitive, but with the full quota of 
 parts in the primary skeleton that an unmodified or unspecialized 
 starfish must have. Among living starfishes this primitive skeleton 
 is rarely seen, but occurs in Heterasterias volsellata, "and in a few 
 other species, especially when young" (Verrill 1914:27). There are 
 other genera with a simpler skeleton (Stenaster and Tetraster), but these 
 are clearly cryptozonian forms that have originated in a phanerozonian 
 stock not unlike Hudsonaster. The oldest Hudsonasters (see plates 1 to 
 6) are small animals about 10 mm. in diameter, with thick, highly con- 
 vex, closely adjoining plates, all of which are devoid of spines ex- 
 cepting the adambulacrals, which have simple, minute, articulating 
 spines. On the ventral side there are in each radius double columns 
 of rectangular ambulacralia, with the pieces of each ambulacrum 
 arranged opposite to one another, or nearly so. Outside of these are 
 single columns of adambulacralia of about the same number as the 
 ambulacrals; they are, however, somewhat larger and more trans- 
 verse. These are laterally bounded by much larger, highly convex, 
 granulated, very prominent marginals, which, as they border the 
 animals and are simple ossicles (there are not here two superposed 
 marginalia as is so common in living forms), are the inframarginal 
 columns. In the axils of the rays lies a single large marginal plate, 
 the axillary, and these occupy the entire interbrachial areas. Around 
 the inner sides of these axillaries the adambulacralia continue, the 
 two basal pieces being the largest and the essential elements of the 
 oral armature. All of the ventral ossicles are, therefore, seen to be 
 of the primary skeleton. 
 
 On the dorsal side of Hudsonaster, the rays have medially promi- 
 nent columns of radials, while on each side of these are other columns 
 of thick ossicles, alternating with the radialia, and these are the 
 supramarginals. The former ossicles continue closely adjoining to 
 near the center of the disk, where lies a single large plate usually called 
 in this memoir the central disk plate, or, more rarely, the centro-dorsal. 
 In the same way, the supramarginals abut in the axils upon a single 
 
 50601 Bull. 8815 3 
 
32 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 large ossicle, the basal supramarginal plate. It is thought that the 
 ancestors of Hudsonaster had a dorsal disk skeleton made up of a 
 centro-dorsal, a first ring of 5 primordial radials, and a second ring 
 of 10 plates, 5 of which are" the second radials, and 5 interradial 
 pieces, the primordial supramarginals. In Hudsonaster, however, 
 some progression has taken place in the disk in the way of increase 
 of size. Therefore additional ossicles of the secondary skeleton have 
 developed to take up this space, these accessory disk pieces being 
 inserted between the centro-dorsal and the first ring of primordial 
 radials. Such* a development of a small number of accessory pieces 
 here is a hint of future complexity and the rise of the secondary skel- 
 eton, and we shall see how in later and derived genera their number 
 becomes multitudinous and their places of insertion nearly everywhere 
 in the older portions of the skeleton between the columns of ossicles. 
 
 The supramarginals do not margin the animals, but lie inside the 
 inframarginals and axillaries which do margin Hudsonaster and most 
 of the Paleozoic asterids. 
 
 From Hudsonaster to all other progressive asterids of the Phane- 
 rozonia type, the change lies mainly in the increasing number of the 
 ossicles, relative decrease in the size of the plates, introduction of 
 many new series of Accessory pieces, absorption and removal of 
 others, with a marked general tendency to break up the stiff and 
 ponderous inherited skeleton into one of small pieces, thus affording 
 greater flexibility and greater podial strength through the endless 
 duplication of ambulacral parts. These developmental tendencies 
 take place more especially on the dorsal area and are further accent- 
 uated through increase of body cavity, which demands an enlarged 
 skeletal covering. The disk widens, and along with it the proximal 
 parts of the rays, so that interbrachial areas are also affected, until 
 finally in more than one phylum pentagonal asterids result. The 
 interbrachial areas are dorsaUy increased by the insertion of acces- 
 sory pieces between the infra- and supramarginalia, and ventrally 
 by the crowding into these areas of, first, the single axillaries, and 
 then more and more of the oldest inframarginals in pairs, assisted 
 also here by the development of accessory ossicles. 
 
 Origin of the wriggling type of starfish. From Hudsonaster to the 
 other progressive asterids of the Cryptozonia type the evolutionary 
 tendencies are in the same directions, but here even greater flexibility 
 appears to be the main stimulus. Accordingly, the entire dorsal skel- 
 eton tends to break up into small loosely adjoining pieces and finally 
 even into a spicular spinose mesh. In these forms the ossicles of the 
 primitive columns are no longer discernible as such, and this tendency 
 is very apt to be likewise true of the primordial disk plates. On the 
 ventral side the inframarginals are no longer wholly present as such, 
 but may be here mixed up with the dorsal skeletal complex. How- 
 
EEVISION OF PALEOZOIC STELLEKOIDEA. 33 
 
 ever, some of these plates are at times retained in the interbrachial 
 areas as large pieces, and in many forms they are still to be made 
 out clearly on the sides of the growing distal ends of the rays. Here 
 the inframarginals occur as columns of tiny closely adjoining ossicles 
 situated directly beside the adambulacrals, and in a few cases the 
 whole five primary dorsal columns (one radial, two supramarginal, and 
 two inframarginal) can be made out without any accessory pieces be- 
 tween them. In other words, a Paleozoic cryptozonian may retain 
 the marginals throughout life, but because of their small size and 
 isolation one from another by accessory pieces or because of intense 
 spiculization, they are no longer recognizable as such. The classifies - 
 tory value of the presence or absence of marginalia is discussed else- 
 where (under Cryptozonia), and as the inframarginals are seemingly 
 or actually lost independently in a number of phyla the term is 
 here used as expressive of this condition, and not necessarily of 
 relationship. 
 
 Spencer (1914:9) takes up the origin of the wriggling habit from 
 another point of view, that is, from a study of living Stelleroidea as 
 described by MacBride. The former states that the living forms can 
 be grouped into two divisions as follows : 
 
 The graspers. Asteroid forms in which the tube-feet are used for walking, and for 
 grasping and pulling open the bivalve shells of the mollusks upon which they usually 
 feed. The ambulacralia form an arch to take the pull. 
 
 The wrigglers. Ophiuroid forms in which the tube-feet have lost locomotory powers 
 and become much reduced. The animals progress by wriggling movements of the 
 arm, and the ossicles of the ambulacral groove are extensively modified for this pur- 
 pose. The food is pushed into the mouth by the first two pairs of tube-feet, which 
 become considerably enlarged and are known as buccal tentacles. 
 
 If we trace the history of the forms backward we find that the difference between 
 them tends to disappear. Both the ' ' graspers } ' and the ' ' wrigglers ' ' descended from 
 a third group, which I call provisionally "the primitive Asterozoa." 
 
 The postulated " primitive Asterozoa" above referred to are based 
 upon the earliest stages of growth of starfishes, and had the following 
 characters. The animals were attached to the ground by a well- 
 developed, flexible stalk (seen in Asterina and Asterias); the disk 
 was small compared with the five arms. In connection with the 
 water-vascular system there were two series of ossicles, (1) a double 
 column of flooring pieces forming the sides of the ambulacrum, and (2) 
 a paired covering series as a protection to the soft structures under- 
 neath. The podia emerged between the flooring pieces and these at 
 first "were arranged not exactly opposite to each other, but slightly 
 alternating, and in consequence we find that both the flooring and 
 covering plates, which are in direct association with the podia, are 
 not exactly opposite, but arranged alternately. " 
 
34 
 
 BULLETIN 88. UNITED STATES NATIONAL MUSEUM. 
 
 The rays terminated in a single ossicle with an unpaired tube-foot 
 that later developed at its outer end a pigment spot and finally an 
 "eye." 
 
 At last the animal lost the stalk and moved about freely as the 
 primitive asterozoon. The flooring plates changed into ambulacralia 
 and the roofing plates into adambulacralia, while the tube-feet were 
 used not for grasping and crawling but for passing small particles of 
 food to the mouth. 
 
 Inf 
 
 Ax 
 
 FIGS. 1 AND 2. VENTRAL AND DOKSAL VIEWS OF THEORETIC PHYLEMBRYO OF STELLEROIDEA, INDICATING 
 
 HOW THE RAYS ARE INTRODUCED. BASED ON HUDSONASTER. A d, ADAMBULACRALS; Am, AMBULA- 
 CKALS; AX, MARGINAL AXILLARIES; CZ>,CENTRO-DORSAL; /72/,INFRAMARGINALS; Rl , PRIMORDIAL RADIALS: 
 R2 TO Rll, SUBSEQUENT RADIALSJ Sml , DORSAL INTERRADIALS OR PRIMORDIAL SUPRAMARGINALSJ Sm2 
 TO SmlO, SUBSEQUENT SUPRAMARGINALS. 
 
 The asterid radicle. Hudsonaster is held to be very near the radicle 
 that gave rise through modification and inheritance to all subsequent 
 Stelleroidea. A study of the various species and specimens of Hud- 
 sonaster, reinforced by the chronogenesis of this genus and the de- 
 velopmental stages in the individuals, which are discernible in the 
 youthful distal ends of the rays when contrasted with the mature 
 proximal region of the same, has led the writer to speculate on the 
 probable skeletal characters of the radicle of the Stelleroidea. An 
 analysis of mature H. matutinus and of half-grown H. incomptus 
 shows that their ancestors must have been devoid of all disk accessory 
 pieces, or for that matter of all secondary ossicles, since it appears 
 that it is on the disk that these plates first arise. Further, the 
 same material indicates that the younger the individual specimen, 
 or the older the species geologically, not only the smaller is the 
 specimen, but the fewer plates has it in any column. As the 
 
REVISION OF PALEOZOIC STELLEROIDEA. 
 
 35 
 
 ossicles, other than those of the disk, the interbrachial areas, and the 
 accessory pieces, are introduced in all the columns at the distal ends 
 of the rays, we are permitted, in theorizing as to the characters of the 
 radicle, and from what has been learned from Hudsonaster, to elimi- 
 nate all of the rays with their ventral and dorsal ossicles down to 
 the disk. If this is done, there finally results a tiny depressed and 
 mammillated spheroid, made up dorsally of 11 primary plates, and 5 
 marginal axillaries, and ventrally of a limited number of adambu- 
 lacrals and ambulacrals around the mouth. To make this matter 
 clearer, two diagrams are presented of the probable characters of the 
 direct ancestor of Hudsonaster (see 
 figs. 1 and 2) . 
 
 By taking away the rays down to 
 near their bases, i. e., to R2, and 
 correspondingly decreasing the size 
 of the primordial supramarginals, we 
 get the dorsal structure of a late stage 
 of the probable typembryo of the 
 Stelleroidea, as illustrated in fig. 3. 
 
 If all of the ray plates are com- 
 pletely removed, we apparently get 
 the typembryo of the class Stelle- 
 roidea, as iUustrated in figs. 4 and 
 
 5. It Should be Stated here, how- FlG - S.-DORSAL VIEW OF THEORETIC TYPEM- 
 ,, t , , . ,, BRYO OF STELLEROIDEA AT THE BEGINNING 
 
 ever, that the number of the adam- 
 bulacrals and ambulacrals in figure 
 5 is entirely conjectural, though 
 these plates and those of the mouth 
 frame are among the first to develop 
 in living forms. 
 
 If the developmental views just stated are correct, it follows that 
 the five branches of the water- vascular and nerve rings of the typ- 
 embryo of Stelleroidea grow outward along the radii, developing as 
 they grow the rays or arms with their dorsal and ventral skeletons. 
 In other words, the growing tips of the radii spread outward beyond 
 the disk, and each one gives rise to nine columns of ossicles (one 
 radial, two supramarginal, two inframarginal, two adambulacral and 
 two ambulacral) . The radial plates continue as simple columns, while 
 upon the primordial supramarginals and the axillaries rest pairs 
 of columns, the supramarginals and inframarginals, respectively. 
 
 In Echini, however, the growing tips of the radii do not spread 
 beyond the disk (apical disk of oculars and genitals) but remain 
 internal and give rise to new ossicles, the ambulacrals (same ossicles 
 in Stelleroidea) and interambulacrals ( = adambulacrals of Steller- 
 
 OF RAY DEVELOPMENT. THE PRIMORDIAL SUP- 
 RAMARGINALS HERE HAVE ON EACH SIDE THE 
 BASAL PIECES OF TEN SUPRAMARGINAL COL- 
 UMNS. CD, CENTRO-DORSAL; Rl, PRIMORDIAL 
 RADIAL; R2, SECOND RADIAL; Sml, DORSAL IN- 
 
 ^ERRADIAL OR PRIMORDIAL SUPRAMARGINAL; 
 82, BEGINNING OF SUPRAMARGINAL COLUMNS. 
 
36 
 
 BULLETIN 
 
 UNITED STATES NATIONAL MUSEUM. 
 
 oidea), all of which appear from underneath the ventral edges of 
 the oculars, each plate in turn being pushed orally 1 . 
 
 In any event, whatever the pre-Hudsonaster evolution was, we 
 are on safe ground in indicating what the developmental changes 
 were, starting with this genus. We will not take up all of the skele- 
 tal parts and discuss them in detail, but will attempt only the more 
 essential portions. 
 
 Ontogeny. Ontogenetic stages of development in the ossicles 
 of asterids can readily be made out to some extent in any well pre- 
 served specimen. The variations can best be seen in those forms 
 with the least number of plates and therefore in the more primitive 
 genera. Here all of the primary ossicles are introduced at the tips 
 of the rays in the seven primary columns. The youngest pieces are 
 also the smallest and the simplest. At first they are globular, 
 
 FIGS. 4 AND 5. DORSAL AND VENTRAL VIEWS OF THEORETIC TYPEMBRYO OF STELLEROIDEA. Ax, VEN- 
 TRAL OR MARGINAL AXILLARIES OR BASAL INFRAMARGINALS; CD, CENTRO-DORSALJ R, PRIMORDIAL 
 RADIALSJ Sml, DORSAL INTERRADIALS OR PRIMORDIAL SUPRAMARGINALS. 
 
 smooth, and loosely adjoining. Tracing them down the columns, 
 the specific characters are seen to develop and finally the basal pieces 
 are found to be the most modified of all. This is particularly true 
 of the dorsal columns where the most ornate plates are the oldest. 
 In the different species of Hudsonaster one can also trace the changes 
 chronogenetically, as for instance in the basal radialia and supra- 
 marginalia. In the oldest species these plates are not at all, or but 
 very slightly stellate, more so in H. incomptus, and most so in the 
 youngest and largest species, H. rugosus. 
 
 In the stocks with more complex skeletons, the ontogenetic varia- 
 tions in the plates can be traced in the same way. However, as these 
 forms almost always have more or less of accessory plates that are 
 introduced nearly throughout the entire skeleton during the juvenile 
 growth and even at maturity, the study is complicated by the inter- 
 mixture of ossicles of varying age. 
 
 i See Jackson, Phytogeny of the Echini, Mem. Boston Soc. Nat. Hist., vol. 7, 1912. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 37 
 
 Spinosity can also be studied ontogenetically because the youngest 
 ossicles do not have spines, and when these appear they are smaller 
 and less characterized than the older ones situated in the proximal 
 portions of the columns. 
 
 Many of the ontogenetic changes observed by the writer are re- 
 corded throughout this work, and their significance in related species 
 and genera has been made use of in discerning the phylogenetic 
 lines of descent. 
 
 Regeneration. Among living starfishes it is common to regrow 
 arms that have been lost through accidental causes. From the 
 base of the severed ray a new growing tip is established, forming 
 a juvenile arm that gradually grows to full size and assumes 
 mature characteristics. Schondorf (1909a: 96-97) states that this 
 habit has been pronounced since the Jurassic but that he has failed 
 to find marked regeneration in Paleozoic asterids. He did, how- 
 ever, note partial replacement of minor losses among the Devonic 
 species. Stiirtz, who has handled more Paleozoic asterids than any 
 other paleontologist, also has not noted a single case of marked 
 regeneration. The same is true for the 400 Devonaster eucJiaris 
 found in a limited area of the Middle Devonic of New York. 
 Clarke, in describing this find (1912: 44-45), however, does note a 
 few specimens " which show the existence of only four instead of 
 the normal five arms." These are the only examples of four-rayed 
 Paleozoic starfishes so far recorded. 
 
 The writer has also been unable to find a single case of regenera- 
 tion, but in the Middle Ordovicic cryptozonian Urasterella ulrichi 
 he describes a specimen with two normally developed rays and three 
 short stumps. All of the arms are normal for the species, except 
 for the length of three rays and their terminations, which are blunt. 
 (See pi. 29, fig. 1.) It seems to him that this occurrence is not due 
 to the accident of fossilization or weathering, but is an actual case 
 of loss in life with subsequent healing of the wounds, but without 
 regeneration of the lost parts. 
 
 During most of the Paleozoic, the starfishes could have had no 
 carnivorous enemies other than the cephalopods; as for marine 
 fishes, the armored Arthrodires did not appear until the Middle 
 Devonic, while the ancient sharks were not common until Lower 
 Carboniferous (Mississippi) time. It is possible that regeneration 
 among the starfishes is connected with the rise of carnivorous ene- 
 mies, but as the habit is so common among living forms it is more 
 probable that this power has always been inherent in the class. 
 Regeneration among the crinids has been noted in several cases 
 where lost distal ends of arms were being replaced by immature 
 growths. Such have been seen in the Lower Carboniferous (Bur- 
 lington and Keokuk formations) of America. 
 
38 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Number and character of rays. In the geologically oldest and the 
 most primitive asterids as well there are always 5 rays, no multirayed 
 form being known back of the middle of Siluric time. In the most 
 primitive genus of Phanerozonia, Hudsonaster, the rays are short and 
 stout, there is a large disk without interbrachial arcs, and the skele- 
 ton is simple but ponderous. From this type originate those with 5 
 slender rays and also forms with more or less large interbrachial arcs, 
 the pentagonal starfishes. 
 
 Long, slender, and flexible-rayed genera without marginalia are 
 present as early as the most primitive Phanerozonia, i.e., as early as 
 the older Middle Ordovicic, indicating that the two main types of 
 asterid development arose still earlier. The same is true for the 
 ophiurid ancestors (Auluroidea). In fact, slender-rayed Crypto- 
 zonia are more commonly seen in the Middle Ordovicic than are the 
 Phanerozonia. 
 
 Multi-rayed Phanerozonia with primitive arm construction appear 
 in the Middle Siluric (Wenlock) in Lepidaster. This genus has rays 
 which are short and stout, reminding one in this respect strongly 
 of the primitive 5-rayed forms. An insufficiently described 10- 
 rayed form (Trichotaster plumiformis) is recorded from the Middle 
 Siluric (Wenlock) of England. In Helianihaster of the Lower Devonic 
 there are from 14 to 16 rays and here they are long and slender, 
 while in the Upper Devonic there is a form with only 1 1 rays. Lepid- 
 astereUa of the Upper Devonic has 24 arms. 
 
 All of the multi-rayed Cryptozonia have slender rays and rather 
 large disks. None are older than the Lower Devonic, where Medusaster 
 has from 12 to 15 rays, Echinasterias 25, Palxosolaster 27 to 29 
 (an Upper Devonic species referred doubtfully to this genus has 24 
 or 25) , Echinostella 28 or 29, and Echinodiscaster 29. 
 
 Curiously, no multi-rayed starfish is known hi the Paleozoic later 
 than the Devonic. Further, the arms may be either odd or even in 
 number in the same genus or even species. How the living multi- 
 rayed starfishes introduce their rays is explained under Palseosolas- 
 teridse (p. 207). 
 
 Verrill (1914: 12-17) holds that the multi-rayed forms arose as 
 " ' sports/ which have persisted by heredity and natural selection 
 because they were advantageous." The advantage lay in "the 
 increased number of ambulacral sucker-feet. " Most of these forms 
 are now living in shallow water among the rocks exposed to the surf. 
 He states: " This is true of the seven species of Heliaster, with very 
 numerous rays; and of Pycnopodia, with 20 to 24 rays; and of the 
 various shallow-water and littoral species of Solaster and Crossaster, 
 which usually have 9 to 15 rays (rarely 8 or less). It is also true of 
 the numerous 6-rayed species of Asterias, Pisaster, and allied genera." 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 39 
 
 On the other hand, the increase of rays is more probably due " to 
 the advantage gained in holding their food securely, and in opening 
 bivalves, than for holding to the rocks, though both go together." 
 
 "The ability to cling tenaciously to rocks may be perfected in 
 other ways, involving equally an increased number of sucker-feet. 
 This is often attained by lengthening the rays, * * * by crowding 
 the suckers into more than four rows, * * * and by increasing 
 the size and strength of the suckers." 
 
 DEVELOPMENT or THE PARTS. 
 
 Anus. In all living starfishes the anus apparently lies in the next 
 interradius to the right of the madreporite, or in the direction as the 
 clock goes, but in no Paleozoic asterid is there positive evidence of 
 an anal opening. However, it is extremely rare in these forms to find 
 the disk so well preserved as to make it possible to locate so small 
 an orifice. In certain specimens of Hudsonaster, immediately adj acent 
 to the centro-dorsal plate, there is an open space that either is the 
 anal opening or where a plate has dropped out in fossilization. 
 Schondorf has also failed to find this structure in the German Paleo- 
 zoic asterids, but has indicated its probable position in Spaniaster 
 (see fig. 8) and Calliasterella. 
 
 Madreporite. In more than half of the Paleozoic asterids the 
 madreporic plate has not been seen. In many cases this is due to the 
 infallen condition of the disk skeleton and the jumbled state of the 
 ossicles; in others it is due to the fact that it is so small as not to be 
 readily distinguished among the mass of other small plates. Finally, 
 a great number of asterids are known only from the actinal side. 
 
 The madreporite in size varies from minute to very large and 
 ponderous. It may be round, oval, or many-sided, concave, and 
 depressed beneath the disk pieces, or protruding cone-shaped (Petras- 
 ter) . As a rule, it is marked by striations that are coarse or very fine, 
 straight or wavy lined, or it may be crenulostriate or with granular 
 surface. In Petraster the surface canals enter into two spirals that 
 carry the water into the stone canal. In living forms with more 
 than six rays there may be two or more madreporites, but in no 
 Paleozoic species has more than one been seen. 
 
 In all of the Paleozoic phanerozonians the madreporite appears 
 to be always dorsal in position. In the most primitive genus, Hud- 
 sonaster, the plate may be large and conspicuous or at times can not 
 be made out even when the disk is fairly well preserved. In no 
 Mesopalseaster has this sieve plate been seen, although good speci- 
 mens are at hand, a condition probably due to its small size among 
 the small skeletal pieces of this genus. In Spaniaster it is very small. 
 In Promopalseaster the madreporite is usually conspicuous and large, 
 
40 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 and the same is true for Xenaster and Agalmaster. The plate is also 
 known in Palseaster, Devonaster, Neopalseaster, and Palasterina. 
 
 In multi-rayed phanerozonians the madreporite is unknown in 
 Lepidaster and Lepidasterella. In Helianthaster it is large, conspic- 
 uous, and situated on the edge of the disk, more actinal than abac- 
 tinal. On the other hand, in the cryptozonian multi-rayed genera 
 the madreporite is apparently always actinal and more or less large, 
 as in Palseosolaster and Echinodiscaster. This plate is probably also 
 always actinal on large-disked Cryptozonia such as Palasteriscus 
 (plate enormously large), and OJieiropteraster (here small and situ- 
 ated near the mouth) . 
 
 Among the five-rayed Paleozoic cryptozonians the madreporite 
 is known only in Monaster (large) , Urasterella (medium) , and Jaekel- 
 aster (small) . In all it is always on the abactinal area. 
 
 From this evidence we see that in the five-rayed Phanerozonia, 
 forms that are more or less rigid, the madreporite is always on the 
 dorsal or upper side of the animals, this being true for the deeply 
 stellate as well as for the pentagonal species. In the multi-rayed 
 genera, however, there is a marked tendency for this plate to move 
 outward to the edge of the disk. In the five-rayed cryptozonians 
 the madreporite so far as known is always dorsal, but in the large- 
 disked or pentagonal forms and the multi-rayed species this plate is 
 apparently always ventral. 
 
 Spencer (1914:35-38) says that "many Paleozoic Asterozoa do not 
 appear to have a madreporite" and he is "inclined to regard this, 
 in these old forms, as usually a primitive feature." The present 
 writer, it is true, states above that in more than half of the Paleo- 
 zoic asterids the madreporic plate has not been seen. This is due in 
 most cases, however, to poor preservation, and in others to the fact 
 that the plate is so much like the other disk plates as not to be dis- 
 tinguishable from chem. Spencer concludes further that it appears 
 that the madreporite originated on the ventral side, or at least was 
 marginal, in the primitive forms, and that it passed over in later 
 Asteroidea to the dorsal side. In Eudsonaster we have the most 
 primitive known starfish, and here in H. incomptus it is a large and 
 conspicuous plate on the abactinal side. Further, the evidence of 
 the Paleozoic starfishes (Phanerozonia), so far as the present writer 
 knows them, is that this plate is always dorsal in position, and he is 
 inclined to the view that all of them had the madreporite, that it 
 originated on this side, and that in later cryptozonian multiradiate 
 forms it moved outward to the margin of the disk or to the actinal 
 surface. In regard to the Auluroidea, the writer has seen the 
 madreporite so rarely that no deductions as to its original position 
 in these forms can be made. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 41 
 
 Spinosity. In general, it can be said that spines are least developed 
 in the heavily plated Phanerozonia, more so in those forms where 
 the dorsal skeleton is made up of small ossicles in abundance, and 
 fully in most of the Cryptozonia stocks. 
 
 In primitive Hudsonaster, all of the plates other than the am- 
 bulacrals are more or less well tuberculated, and these granules do 
 not now carry spines, if they ever did. In later forms, however, as 
 Promopalseaster, they may all have borne spines, some of them of 
 large size. Small club-shaped spines occur here in considerable 
 abundance along the sides of the inframarginals and the adambula- 
 crals. In Palseaster there are brushes of delicate spines along the inner 
 edge of the adambulacrals. In Mesopalseaster the ventral spines are 
 better developed, fully so in Promopalseaster, and probably equally so 
 in most post-Ordovicic forms. 
 
 Among the primitive cryptozonian genera Stenaster and Tetraster 
 no spines are now seen, but undoubtedly such were present on the 
 actinal side. In Ur aster ella the entire dorsal skeleton is more or less 
 spinose, consisting of long, nonarticulating, slender rods, the dorsal 
 extensions of the ossicles. In the multi-rayed Cryptozonia of the 
 Devonic, spinosity is at its greatest development in the Paleozoic. 
 
 Ambulacralia. Undoubtedly the most important skeletal parts of 
 the Stelleroidea are the ambulacrals. In general they undergo the 
 least alteration during geologic time of the entire asterid skeleton, 
 and therefore any marked variation must be of broad classificatory 
 value. Schondorf * is well aware of this fundamental value and has 
 made full use of it in denning his three " classes, 57 Asteroidea, Aulu- 
 roidea, and Ophiuroidea. In the Asteroidea the ambulacralia of ad- 
 joining columns are nearly always placed directly opposite one 
 another, with the podia issuing through openings that are not in the 
 plates themselves, but laterally between two adjoining ambulacrals 
 and the corresponding adambulacrals. Among the Paleozoic asterids 
 one is not always certain whether the ambulacralia are arranged 
 lt opposite" or "alternate," because the specimens in nearly all cases 
 have suffered more or less from distortion. In many good specimens 
 they are very slightly alternate, but in all such cases the arrange- 
 ment is said to be alternate. In other fine fossils they are now 
 alternate, but a close study seems to show that originally they were 
 practically opposite in arrangement. On the other hand, certain of 
 the species with wide ambulacral furrows and large ambulacralia, as 
 in Promopalseaster, Anorthaster, and Urasterella, have an alternate 
 arrangement, while in other species of the first and last named genera 
 they are just as certainly opposite. The writer therefore does not 
 
 i Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, pp. 206-256; Palaeontographica, vol. 57, 1910, 
 pp. 1-56. 
 
42 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 lay much stress upon this feature among the Ordovicic asterids, nor 
 does he regard it even necessarily as of specific value, but in the later 
 Asteroidea the arrangement is always opposite or nearly so. Ver- 
 rill (1914:20) states that he has noticed the alternate arrangement 
 in living Pycnopodia "as an abnormal variation in some of the 
 rays, and also that it may occur from lateral bending." Evi- 
 dently the alternate disposition is a fixed character among some 
 Ordovicic forms, as in AnortJiaster, but more will certainly be dis- 
 covered in these old strata and probably rather among the Crypto- 
 zonia than the Phanerozonia. The writer is led to this view because 
 of the alternate arrangement in many Auluroidea, a subclass of 
 Stelleroidea that seems to have had its origin in some cryptozoniaii 
 asterid. Out of the Auluroidea with opposite ambulacralia came the 
 Ophiuroidea with their highly modified ambulacrals which are 
 coossified into " vertebral ossicles." In the Auluroidea the arrange- 
 ment of the ambulacrals is either alternate or opposite, but they are 
 never coossified but are so modified as to suggest the Ophiuroidea 
 rather than the Asteroidea. The structure of these plates is de- 
 scribed elsewhere and need not be repeated here. 
 
 The ambulacrals are very variable in number throughout the 
 genera. In Hudsonaster, Stenaster, and Tetr aster there are as few as 
 10 in a column, while in Promopals&aster there are certainly 50 and 
 possibly as many as 60. The cryptozonian genus Urasterella has 
 certainly over 100 in a column. In general, these ossicles abut 
 against each other, but in Urasterella and other genera they overlap 
 proximally to a certain extent. As yet the writer has seen no 
 Paleozoic asterid with more than 2 columns of ambulacrals, though 
 in Promopalseaster magnificus the proximal areas of the rays for a 
 short distance have 4 columns of podial openings. Here, however, 
 the ossicles have not yet wedged themselves into 4 columns of 
 ambulacralia. 
 
 In shape and surface contour there is also considerable variation 
 among the ambulacralia. In Hudsonaster, Tetraster, and several 
 Devonic genera they are more or less rectangular, either squarish or 
 drawn out laterally. In other forms of Hudsonaster, along with 
 Stenaster and Urasterella, the ossicles are h- -shaped, with the lateral 
 shaft thin, thus allowing for large, elongate podial openings. The 
 more primitive genera have the outer surfaces plain or slightly ridged, 
 while in derived forms like Promopalseaster the ridges are high and 
 straight or have their medial terminations orally directed. In 
 P. magnificus, the ridges in the proximal region are arranged in pairs 
 having the shape of a tuning fork; in P. wyleqffi one sees that these 
 ridges approach one another in pairs transitional to their transforma- 
 tion into the tuning-fork form. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 43 
 
 Adambulacralia. Adambulacralia are present in all Stelleroidea. 
 They are best and typically developed in the Asteroidea, more or 
 less modified in the Auluroidea, and completely altered into the thin 
 scalelike side plates of the Ophiuroidea. In number and relative 
 size they vary as do the ambulacralia, being least numerous and 
 largest in the most primitive genera. Originally they probably 
 bore no spines at all, the plates being practically smooth. In Hud- 
 sonaster and most Ordovicic and Siluric, and some Devonic genera, 
 their surfaces are granular to tubercular. These protuberances in the 
 younger genera may have borne small spines, but long before these 
 appeared each adambulacral bore two or more stout or slender, com- 
 paratively long spines along its ambulacral edge. 
 
 In most of the Paleozoic genera there are in each column as many 
 adambulacrals as there are ambulacrals, and both series are as a rule 
 arranged opposite one another. In Anorfhaster, however, there are 
 fewer and therefore larger adambulacrals than ambulacrals, and 
 these latter ossicles clearly alternate with one another. 
 
 In the Phanerozonia the adambulacrals never margin the rays 
 but always lie inside of the bordering inframarginals. In the Crypto- 
 zonia, however, the adambulacrals margin the animals and here the 
 ossicles are usually small, though at times they are relatively large 
 and make a stout outer skeletal frame as in Stenaster, Tetraster, 
 and Schcenaster (?} montanus. The same is true in Encrinaster 
 of the Auluroidea. 
 
 The adambulacrals in probably all the Paleozoic Phanerozonia 
 continue into the oral region and each two adjoining columns meet 
 here in a pair of modified, elongate, pointed pieces, the most promi- 
 nent ossicles of the oral armature. No other skeletal parts lie in 
 front of these oral ossicles except in the phanerozonian Hudsonaster 
 narrawayi (pi. 1, fig. 1) and in the young of the cryptozonian 
 Urasterella ulrichi (pi. 30, fig. 7). Both are primitive forms of 
 their respective phyla and whether these five pieces or tori are to 
 be interpreted as five spines or whether they represent five primi- 
 tive orals is not yet determinable. 
 
 Inframarginalia. In the great majority of Paleozoic Phanero- 
 zonia the inframarginals alone margin the animals, and only in a 
 few forms (Spaniaster, Miomaster, RJienaster, and Neopalseaster) 
 have the supramarginals moved outward and completely covered 
 the inframarginals, so that the two columns together equally bound 
 the rays and disk. That condition is a peculiarity common to most 
 Paleozoic phanerozonians, while the wholly superposed arrange- 
 ment distinguishes nearly all the Mesozoic, Cenozoic, and Recent 
 genera of the same kind of Asteroidea. 
 
 The inframarginals are usually the most conspicuous ossicles of 
 the Paleozoic Phanerozonia, and this is especially true where the 
 
44 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 skeleton is strong and devoid, or nearly so, of accessory ossicles. 
 They are ponderous in Hudsonaster, Palseaster, Australaster, Devon- 
 aster, Xenaster, Trimeraster, Petraster, etc. When the smaller 
 accessory plates are introduced, the inframarginals also reduce in 
 size; this development is best seen when passing from the heavily 
 plated Hudsonaster to the more abundantly plated Mesopalseaster 
 and finally Promopalseaster. The next step in this phyletic line 
 would be pronounced a cryptozonian because the infra- and supra- 
 marginals could not be distinguished from the abundance of acces- 
 sory ossicles. In fact, it is not always easy to make out the various 
 categories of plates even in Promopalseaster, and here one must 
 resort at times to a study of the tips of the rays where the seven pri- 
 mordial columns are not yet disturbed by the introduction of accessory 
 pieces. 
 
 In primitive Hudsonaster, where the inframarginals are compara- 
 tively very large, there are only half as many of these ossicles as 
 there are of adambulacrals, but in the great majority of Paleozoic 
 genera of Phanerozonia this marked difference tends to be less 
 decided and toward equalization. In certain phyla, as, for instance, 
 from Hudsonaster to Mesopalseaster and Promopalseaster, the equal- 
 ization has gone on rapidly, hi fact, in but a short part of Ordovicic 
 time. In more conservative stocks, as from Hudsonaster to Devonic 
 Xenaster and Trimeraster, the equalization is far slower, as is seen 
 in the following figures: Hudsonaster, 12 inframarginals and 24 
 adambulacrals; Trimeraster, 14 and 23; and Xenaster, 20 and 32, 
 respectively. In nearly all the genera these columns of plates alter- 
 nate with one another.' This of course must be so where the number 
 of ossicles is different in the two columns, and complete alternation 
 is retained even in certain species where the numbers of ossicles are 
 alike, as for instance in Promopalseaster spinulosus. On the other 
 hand, in Mesopalseaster sJiafferi, where there are 16 inframarginals 
 and 18 adambulacrals, the plates alternate in the proximal half of 
 the ambulacra and are opposite one another distally. A study of 
 the growing ray tips shows that the various ossicles all appear 
 practically of one size and where there are more adambulacrals than 
 inframarginals, the former are crowded orally. The latter develop- 
 ment appears to be the primitive type of growth, but this mode is 
 rapidly changed to one in which the seven columns of primordial 
 ossicles appear in cycles or rings. This type of growth is easily made 
 out in primitive forms such as Hudsonaster and Mesopalseaster, and 
 in some species of Promopalseaster. However, when accessory plates 
 are developed in abundance, and especially in forms where the seven 
 primordial columns of plates remain of one size, their introduction 
 in cycles can only be made out in very young individuals or at the 
 
KE VISION OF PALEOZOIC STELLEKOIDEA. 45 
 
 extreme tips of the rays, conditions not often attained among these 
 fossils. 
 
 In the great majority of Paleozoic Phanerozonia the inframar- 
 ginals and adambulacrals lie closely adjacent to one another. In 
 typical asterids they are not separated by the introduction of acces- 
 sory interbrachial pieces until in the Devonic. Here in Xenaster 
 and Trimeraster isolated pieces, and finally a column of them, are 
 inserted in the proximal half of the rays. In the large-disked asterids, 
 this separation occurs much earlier, in the Middle Ordovicic in 
 Petraster. 
 
 In Paleozoic Phanerozonia where the skeleton is made up of an 
 abundance of more or less equal-sized ossicles, one notices also on 
 the distal portions of the rays a tendency for the inframarginals to 
 appear on the dorsal side and not to remain on the ventral, as in 
 primitive stocks. This alteration brings the adambulacrals to the 
 margin of the rays, and is a hint as to how Phanerozonia gradually 
 change into Cryptozonia. It is best seen in Promopalseaster, Petras- 
 ter, and Mesopalxaster. In Australaster it is a marked feature, in 
 fact, one can say that the distal parts of the rays in that genus are 
 cryptozonian while the bulk of the arms are still phanerozonian. 
 This ontogenetic appearance is in harmony with phylogenetic devel- 
 opment and chronogenesis. The living Echinaster sepositus is in 
 youth also a phanerozonian, but at maturity is a typical cryptozo- 
 nian. In so typical a cryptozonian as Ur aster ella, one still finds in 
 half -grown U. ulrichi a number of inframarginals in the interradial or 
 axillary areas. The same retention of the first formed inframargin- 
 als is also met with among the multi-rayed Cryptozonia in Helianih- 
 aster, and even among the Auluroidea in Encrinaster. 
 
 It has just been pointed out how the inframarginal columns are 
 eliminated as marginal plates. They are not, however, removed 
 from the skeleton in these early forms by resorption or by failure 
 of development, but for want of special growth. In other words, 
 the inframarginals are probably present in all Paleozoic Asteroidea, 
 but because of lack of specialization through the developmental 
 tendency to greater skeletal flexibility, remain small and are lost 
 as such in the mass of the dorsal plates. This apparent eh'mination 
 of the inframarginals has gone on independently in various stocks 
 as pointed out elsewhere, and therefore the absence of large marginals, 
 either infra- or supramarginals, or both series, is not of ordinal value. 
 
 Supramarginalia. In Hudsonaster the prominent supramarginal 
 plates of the dorsal side are placed decidedly inside of the inframar- 
 ginals, though the former clearly overlap the latter. This primitive 
 position is retained in many Paleozoic genera, and apparently not 
 before the Devonic do these two columns of ossicles come to lie 
 wholly upon one another, and then they together margin the animals. 
 
46 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 It is apparently always a rare condition in the Paleozoic, but as the 
 post-Devonic asterids are as yet little known, we can more accurately 
 say that the modern type of Phanerozonia is unknown before Devonic 
 tune. It should be added here that complete superposition of the 
 supra- upon the inframarginalia undoubtedly took place in more 
 than one stock and at different times. Accordingly, to group all 
 asterids with large marginalia into the " order" Phanerozonia is 
 further proof that these terms cannot be used in the phyletic sense. 
 Phanerozonia and Cryptozonia are, however, of use in a descriptive 
 way. 
 
 The supramarginals, and the inframarginals as well, in primitive 
 forms gradually attain larger size down the columns from the tips 
 of the rays toward the disk and mouth. In other words, the older 
 the ossicle in primitive genera, the larger is its size, and in all such 
 forms the pairs of supra- and inframarginal columns terminate in 
 single plates, the primary or basal supramarginals and the primary 
 or basal inframarginals. The latter ossicles in the most primitive 
 genera are situated in the axils of the rays and are therefore also 
 known as axillary marginals, and in the more specialized genera the 
 axillaries and even pairs of inframarginals are crowded orally into 
 the interbrachial areas. The basal supramarginals in primitive 
 forms always occur prominently on the disk, in derived genera they 
 are, however, less conspicuous, and where the disk skeleton is made 
 up of small ossicles, they are generally indistinguishable in the mass 
 of plates. 
 
 We have seen that accessory interbrachial plates in some genera 
 are developed between the inframarginals and adambulacrals, and 
 to a greater extent the same is true of the development of ambital 
 accessory pieces between the former columns and the supramarginals. 
 In probably all cases where the rays and disk grow wider the addi- 
 tional space is largely covered in by the development of accessory 
 plates. As it is in the disk area, and therefore necessarily in the 
 basal portion of the rays as well, that the main increase of body 
 extent takes place, here are developed the greatest number of these 
 pieces. Rarely are the ambital accessory pieces crowded in between 
 these columns beyond the proximal third of the rays. This is best 
 seen in Devonaster and Xenaster, but in the large-disked forms, as 
 Petraster, they extend farther out and are present to within the 
 outer third of the rays. Ambital accessory plates may also be 
 present in Mesopal&aster, but are more definitely so in Promopalse- 
 aster (especially in P. magnificus) , and in both genera they occur 
 throughout the greater part of the rays. 
 
 Radialia. In many Paleozoic genera of Phanerozonia and even 
 among some of the Cryptozonia, a more or less prominent column of 
 ossicles is seen down the center of the dorsal side of the arms. These 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 47 
 
 are the radial columns of ossicles, which are especially well seen in 
 Hudsonaster, Spaniaster, Devonaster, Xenaster, CaUiasterella, and 
 less prominently in Mesopalseaster, Promopalseaster, and Petraster. 
 The prominence of the radials is lost in the same way as has been 
 described for similar reduction in the supramarginals and inframar- 
 ginals. 
 
 In primitive genera the supramarginals and radials lie closely 
 adjacent as prominent columns, but in the great majority of Paleo- 
 zoic Asteroidea these columns are more or less extensively separated 
 from one another by the introduction of radial accessory plates. The 
 latter are always small pieces and in general one can say that their 
 number increases with geologic time and with the evolutionary 
 complexity of the various stocks. At first the accessory pieces appear 
 singly between the plates in the proximal region of the rays, where, 
 increasing in numbers, they separate the primary columns more and 
 more and finally also crowd in between the individual ossicles, es- 
 pecially the proximal radials, pushing these apart more or less com- 
 pletely. This is true not only in chronogenesis but also in onto- 
 genesis. It is best seen in a study of the dorsal areas beginning with 
 Hudsonaster and Spaniaster, and proceeding to Mesopalseaster, 
 Devonaster, Promopalseaster, and Urasterella. In the forms with 
 great disks the development of accessory plates is extreme, as may be 
 seen in Petraster speciosus. 
 
 The columns of radial plates are less persistent in development 
 than any other of the primary columns. Like all of the primary 
 plates, the radials are apt to lose their ponderosity and in the course 
 of geologic time become smaller. In this way they may lose their 
 individuality in the mass of dorsal plaies, but in some cases radialia 
 appear to fail to develop throughout the greater part of the rays, 
 although one or more primordial ossicles of each radius are present 
 on the disk. In certain species of Mesopalseaster, and more especially 
 in Promopalseaster, the radialia are either not present or have been 
 squeezed out of the mid line of each radius so as to be unrecognizable. 
 In other forms of the latter genus they are well developed and arranged 
 in linear columns. Promopalseaster as a rule has no radialia on the 
 rays and the space between the supramarginals is occupied by many 
 small accessory radial pieces. Among the Cryptozonia, radialia are 
 usually not discernible as such on the rays, though present on the disk. 
 
 Accessory plates. These small pieces of irregular form are space 
 fillers between all of the primary columns of plates, with the exception 
 of the ambulacrals and adambulacrals. As the body cavity grows 
 larger, skeletal increase takes place either through enlargement of 
 the seven primordial columns of ossicles or by the intercalation and 
 formation of new pieces, the accessory plates. The former method 
 
 50601 Bull. 8815 4 
 
48 BULLETIN 
 
 is the one least often resorted to. The accessory pieces appear first 
 chronogenetically on the disk, separating the primordial ossicles 
 one from another in various ways, and as the body cavity grows 
 larger in the course of geologic time, they wedge all of the primary 
 columns apart proximally except the ambulacrals, which compensate 
 for the widening of the rays by growing in size transversely. Some 
 accessory plates also develop in the interbrachial areas separating 
 the interbrachial marginals, as in Trimeraster and Xenaster, while 
 in the large-disked forms, as Petraster, their number becomes excessive. 
 
 Ocular plates. The large ocular plates seen in so many living 
 Phanerozonia are very rarely developed in Paleozoic forms. In 
 fact, the writer knows of but a single occurrence, in the Lower Car- 
 boniferous genus Neopalseaster. 
 
 It seems to the author that these ossicles should have considerable 
 significance in phylogeny because their large growth indicates that 
 they are much older plates than any of the small adjacent pieces. 
 In other words, in all genera where the ocular or sensory tentacle 
 does not lie in an enlarged and grooved plate, the newly developed 
 ossicles of either the ventral or dorsal side appear distally to the pre- 
 viously borne pieces, i. e., at the tips of the rays, whereas in the stocks 
 having ocular plates the new skeletal arrivals appear not at the tips 
 of the rays but on the proximal side or inside of the eye ossicles 
 Therefore, where ocular plates are present, these pieces are not only 
 enlarged in size with age, but progressively pushed farther and farther 
 outward as well by the growing ray tips that lie on their inner sides. 
 This mode of growth may have originated once or several times, 
 there being in the latter case parallel developments of ocular plates. 
 This is a study that can not be pursued far among Paleozoic genera, 
 but in the later forms may be productive in the discerning of 
 phylogenetic lines. 
 
 After the above was written the writer read in Verrill (1914: 20-22) 
 that Fewkes has shown the ocular plates to be the first to appear in 
 the young, and that with growth they are pushed distaUy because 
 of "the budding in of new plates between the apical plate and the 
 one next to it. 7 ' These observations on living starfishes are therefore 
 in harmony with the study of Neopalseaster, and go to show that the 
 bulk of Paleozoic starfishes insert the plates of the primary columns 
 in a different way, i. e., always distally. On this ground alone most 
 of the Paleozoic starfishes should be grouped by themselves and 
 apart from most of the subsequent Phanerozonia. 
 
 Centro-dorsal. In the center of the disk of many Paleozoic genera 
 of Asteroidea and of some Auluroidea is seen a more or less prominent 
 plate, which is thought to be the equivalent of the centro-dorsal of 
 the embryo of the living crinid Antedon (Comatula). It is a promi- 
 nent though small plate in most of the forms of Hudsonaster and in 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 49 
 
 Palxaster; it is also well developed though less conspicuous in Meso- 
 palseaster, Spaniaster, Xenaster, Agalmaster, Devonaster, Neopalseaster, 
 Palasterina, Monaster, CalliastereTla, and Urasterella. 
 
 As the disk plates are rarely well preserved, and as the centro- 
 dorsal has been seen in many Paleozoic species, the writer thinks- 
 it will be found in most of the forms of this era. 
 
 Primary disk plates. In the most primitive and oldest Paleozoic 
 asterids the centro-dorsal is surrounded by a variable but small 
 number of diminutive accessory disk pieces. In mature Hudsonaster 
 they form a single ring, but in the young of the cryptozonian Uras- 
 terella ( U. ulrichi) and in mature CalliastereTla there are none of these 
 accessory pieces present. For these reasons it is thought that in 
 the Ordovicic there will be found a small asterid, even more primitive 
 than Hudsonaster, that will be devoid of accessory disk pieces. 
 
 Around the centro-dorsal of young Urasterella and in mature 
 Calliasterella, there follows directly a ring of five larger plates. The 
 same five plates are also seen outside of the single ring of accessory 
 pieces in Hudsonaster and Spaniaster, and directly beyond the two 
 rings of accessories in Mesopalseaster. These more or less large 
 plates are radial in position and are the basal radialia above which 
 continue the columns of successively formed radials. 
 
 Keturning to Hudsonaster, we see that the first ring of prominent 
 plates has 10 pieces, 5 of which are radial in position, the remainder 
 interradial. The same is true for Spaniaster and Xenaster, while 
 Calliasterella has an equal number of plates in the second ring. An 
 analysis of these disks shows that 5 of the plates are either primary 
 or secondary radialia, while the remainder are situated interradially, 
 and upon them rest the 10 columns of supramarginals. The first 
 prominent ring in Mesopalseaster sJi'Offeri and Devonaster and the 
 second ring in Urasterella ulriclii each have 15 plates, 5 of which 
 are radialia, while the other 10 are supramarginals. Simplifying 
 these statements and cutting out the accessory pieces, we learn that 
 the disks of these genera and others could be added are composed 
 of a centro-dorsal, a first ring of 5 radialia, and a second one with 5 
 radialia and 10 basal supramarginaiia. This, then, is the same struc- 
 ture postulated for the hypothetic phylembryo of Asteroidea and 
 deduced through reduction of ossicles, as gleaned from a partial 
 ontogenesis of Hudsonaster. 
 
 Axillary ossicles. In the most primitive asterid, Hudsonaster, one 
 sees in each axilla a single large plate, on either side of which adjoin 
 the 10 columns of inframarginals. The same arrangement obtains 
 in Siluraster, Palseaster, and Australaster (here the genus occurs in the 
 Permo-Carboniferous, and the axillaries are very large contrasting 
 with the smaller ones of the Ordovicic Hudsonaster). In no other 
 Paleozoic genera does this same development hold, though the single 
 
50 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 axillaries occur in many other forms where they are, however, pushed 
 orally into the skeleton of the interbrachial areas. Single, not double, 
 axillaries, therefore, make the simplest and smallest type of inter- 
 brachial areas. Further complexity and enlargement of these areas 
 are produced by crowding into them orally, first the axillaries and 
 then one or more pairs of proximal inframarginals. 
 
 In Hudsonaster narrawayi one sees tiny single plates proximal to 
 each axillary. These are clearly of no marked morphologic value and 
 are to be interpreted as accessory plates. Similar single ossicles are 
 also seen in genera with large interbrachial areas, as in Promopalseaster. 
 They are regarded as space-fillers and without ancestral significance. 
 
 Interbrachial areas. The simplest type of interbrachial area is that 
 just described. Increase in size and complexity of interbrachial struc- 
 ture is a natural result from an enlarged body cavity. The first change 
 in this direction is seen in Mesopaldeaster, Spaniaster, Miomaster, and 
 Devonaster, where the axillaries are crowded orally and surrounded 
 distally by a pair of adjoining basal inframarginals, and proximally by 
 a variable number of adambulacrals. The same development is seen 
 but hi somewhat modified form in the cryptozonian genera Urasterella 
 (U. ulrichi and U. girvanensis) and CaUiasterella. Here the axillaries 
 are present only in the young, but may be retained to maturity; in 
 either case they may or may not be margined distally by basal infra- 
 marginals. As the inframarginals in these forms are vanishing (pri- 
 mitive Cryptozonia), we should expect to find related genera devoid 
 of even the axillaries, and such is the case in Stenaster and Tetraster. 
 
 The next step in the enlargement of the interbrachial areas consists 
 of the inward crowding of pairs of basal inframarginals, one or more 
 at a time. In Trimeraster these areas have the single axillaries and a 
 pair of basal inframarginals, with the second pair of proximal infra- 
 marginals making the margin of the axils. In Xenaster the first and 
 second pairs of proximal inframarginals are enclosed, while in Pro- 
 mopalseaster there are from one to three pairs in each interbrachial 
 area. As these areas enlarge, it follows that more and more of the 
 adambulacrals must also take part in the expansion. These ossicles 
 are therefore called interbrachial adambulacrals. Further enlarge- 
 ment, but not to any marked extent, takes place through the insertion 
 of a variable number of accessory disk interbrachials. This is best 
 seen in Trimeraster and Xenaster. 
 
 Abnormal enlargement, but to a small extent, of the interbrachial 
 areas takes place through oral crowding entirely of adambulacrals in 
 pairs and through the increase in size of some of these ossicles. This 
 type of development is known only in Anorthaster. 
 
 It has been shown how enlargement of the interbrachial areas comes 
 about through oral crowding of the axillaries, proximal inframargi- 
 nals and adambulacrals pieces of the primary skeleton but the 
 
REVISION OP PALEOZOIC STELLEROIDEA. 51 
 
 greatest expansion is brought about by the introduction of more and 
 more accessory disk pieces between the adambulacrals and inframar- 
 ginals. The beginning of this development of the secondary skeleton 
 is seen in Petr aster and is variously progressive in the different species. 
 They finally crowd more and more distally into the rays, as may be 
 seen in Uranaster and Palseostella. Among the large-disked Crypto- 
 zonia, as Schuchertia and the Palasteriscidse, it is the ambital and 
 abactinal accessory pieces that go to enlarge the arcs and body cavity. 
 
 CLASSIFICATION. 
 
 A good history of the various attempts at classifying the fossil 
 starfishes is given by Spencer (1914: 39-52). How recent starfishes 
 are classified may be learned from Verrill (1914:24), and it will be 
 seen that his principles are not always applicable to fossil forms be- 
 cause of the loss of parts through fossilization. In subsequent pages 
 the author will give his groupings up to superfamilies, but the time 
 is not yet at hand for an ordinal classification applicable alike to 
 fossil and recent starfishes. 
 
 Catalogue of Paleozoic Stelleroidea. A catalogue of all Paleozoic 
 starfishes was published by the writer in April, 1914, under the title 
 "Fossilium Catalogus, Anirnalia, part 3, Stelleroidea palseozoica," pp. 
 53 (Junk, Berlin). It gives the entire bibliography of the genera and 
 species up to that date, and an outline of the classification adopted. 
 The actual date of several new genera is of the work above cited, 
 although they are also printed in the present book as new. This 
 Bulletin is there cited as of 1914 and is now to be corrected to 1915. 
 The above-mentioned catalogue will always be useful for ready refer- 
 ence to the literature, although the larger volume repeats all of the 
 essential references, corrected to November, 1914. 
 
 DESCRIPTION OF GENERA AND SPECIES. 
 
 Class STELLEROIDEA. 
 
 Subclass ASTEROIDEA. 
 
 PHANEROZONIA Sladen. 
 
 Asteroidea nearly always with large marginal plates. These consist 
 in the Mesozoic and later asterids Qf completely superposed inframar- 
 ginals and supramarginals; in the Paleozoic the rule is that the in- 
 framarginals alone border the animal, while the supramarginals are 
 always dorsal, generally alternate with the inframarginals, and are 
 placed farther inward though resting more or less upon the latter. 
 
 Ambulacrals always present and opposite in arrangement in post- 
 Paleozoic forms. In the oldest and most primitive Paleozoic forms 
 they are apt to be alternate throughout the rays, or only so distally 
 in the young parts. By far the greater number of Paleozoic forms, 
 however, have the opposite arrangement. 
 
52 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Oral armature always with the adambulacral pieces most con- 
 spicuous. 
 
 This order is not known to appear before the Middle Ordovicic, 
 and in the Paleozoic contains the following families: 
 
 Hudsonasteridae. Xenasteridae. 
 
 Palaeasteridae. Neopalaeasteridae. 
 
 Promopalaeasteridae. Palasterinidae. 
 
 Mesopalaeasterinae. Lepidasteridae. 
 
 Promopalaeasterinae. 
 Anorthasterinae. 
 
 These seven families of Paleozoic asterids are all related to one 
 another and seemingly had their origin more or less directly in 
 Hudsonaster or a form very similar to it. Therefore the family 
 Hudsonasteridae is the primordial stock out of which all asterids 
 progressively developed. Hudsonaster is massively and simply 
 built, with the spines rudimentary and restricted to the adambula- 
 crals and inf ramarginals ; it is a small rigid asterid with few and 
 comparatively large ossicles, nearly all of which are of the pri- 
 mary skeleton. From it the evolutionary tendency was to get rid 
 of the rigidity and ponderosity through the comparative reduction 
 in size of the plates and the introduction of many smaller sec- 
 ondary pieces, along with an abundance of spines. With this ten- 
 dency once established, there arose several others: (1) elongation 
 of rays, with greater flexibility and greater power of locomotion 
 through the indefinite duplication of pairs of podia; (2) increase of 
 body cavity in three different ways. This took place through the 
 development of interbrachial areas (a) by the inward crowding of 
 the single interbrachial axillaries, followed by more and more pairs 
 of proximal inf ramarginals; (&) through the insertion of an indefinite 
 number of accessory ossicles between the adambulacrals and the 
 inf ramarginals, forcing the latter more and more outward; and 
 (c) through the introduction of supernumerary rays. The latter 
 development is probably abnormal, in that the tendency arose in 
 the later larval life as is explained elsewhere. (See p. 207.) With 
 these changes of the actinal side naturally must arise compensating 
 growths of the abactinal surface and accordingly here is seen the 
 introduction of accessory ossicles in various places. 
 
 Starting with Hudsonaster, there is one phyletic line developed 
 through the elongation of rays, flexibility, and the increase in size 
 of the oral region by the (a) method from the primitive Hudson- 
 asteridae into the derived Palaeasteridae, Promopalaeasteridae, Xen- 
 asteridae, and Neopalaeasteridae. This is the most satisfactory line 
 of evolution, resulting in the greatest variety of genera. Again 
 with Hudsonaster as the radicle, another phyletic line is established 
 through the increase of the body cavity by the (6) method, giving 
 
REVISION OF PALEOZOIC STELLEROIDEA. 53 
 
 rise to the Palasterinidse. This line of change is not at all so pro- 
 ductive of genera as the former. Finally, a third phyletic line is 
 established through larval adaptation, causing a sixth ray to develop 
 and thereafter pairs of rays, resulting in the multi-rayed asterids of 
 the family Lepidasteridae. 
 These phyletic lines may be expressed taxonomically as follows: 
 
 Superfamily Promopalseasteracea, new. 
 
 Includes families Hudsonasteridae, Palseasteridse, Promopalseasteridae, and 
 Xenasteridae. The Neopalseasteridae developed out of the Promopalaaasteridse. 
 Superfamily Palasterinacea, new. 
 
 Includes family Palasterinidse. 
 Superfamily Lepidasteracea, new. 
 
 Includes family Lepidasteridse. 
 
 HUDSONASTERID.E, new family. 
 
 Most primitive known Phanerozonia. 
 
 Small, five-rayed, heavily plated asterids, with narrow ambulacral 
 furrows and slightly alternate ambulacralia. The incipient inter- 
 brachial arcs are occupied by single axillary marginal plates. Abac- 
 tin ally the rays have five columns of ossicles, the radials in the center 
 being bounded on either side by the supramarginals and inframarginals; 
 the latter margin the rays and the ossicles of adjoining columns alter- 
 nate with one another. There are no accessory ray plates of any 
 kind. The disk has a prominent central disk piece separated by a 
 small number of accessory disk plates from a ring of five large basal 
 radials and five large basal interradial ossicles. Spines rudimentary 
 and apparently restricted to the adambulacrals and inframarginals. 
 
 This family contains the genera Hudsonaster Stiirtz and Siluraster 
 Jaekel. 
 
 Genus HUDSONASTER Sturtz. 
 
 Plates 1-6. 
 
 Palseaster (part) of authors. 
 Hudsonaster STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 
 pp. 224, 225. 
 Protopalseaster HUDSON, Ottawa Naturalist, vol. 26, 1912, p. 25; vol. 27, 1913, 
 
 pp. 77-84. RAYMOND, Ottawa Naturalist, vol. 26, 1912, p. 105 (genoholo- 
 
 type, P. narrawayi). SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palaeontgr. 
 
 Soc. for 1913), 1914, p. 21. 
 
 The name is derived from the " Hudson River formation/ 7 an 
 Ordovicic series of strata of long endurance. If the stratigraphic 
 term is used correctly, then these rocks have as yet furnished no 
 starfishes of this genus; for this reason Hudsonaster is a misnomer 
 and has no significance, but under the rules of nomenclature it must 
 be accepted. 
 
 Generic characters. Disk small and without actual interbrachial 
 arcs. Rays five, short, tapering rapidly. 
 
54 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Abactinal area of rays occupied by three columns of large, thick, 
 more or less tumid or carinate, closely adjoining, tuberculate plates; 
 more or less of the inframarginal plates are also to be seen, making 
 five visible columns of plates on each ray abactinally. There is, 
 therefore, a single radial column bounded on each side by two columns 
 of supramarginal and two of inframarginal plates. The latter 
 columns are the marginal plates both actinally and abactinally, but 
 on the dorsal side are overlapped by the supramarginals. In the 
 center of the disk there is a small but very tumid plate (central 
 disk plate) around which is a nearly complete circle of smaller acces- 
 sory plates and an open space which may represent an anal opening. 
 Outside of this first circle of accessory plates there is a ring of 10 
 very large plates that in the geologically later species are stellate 
 on the surface, 5 of which are radial and 5 interradial in position. 
 The radial plates are the basal radial plates of the 5 medial columns, 
 while the 5 interradial plates give rise to the 10 larger and conspicu- 
 ous supramarginal ossicles. The basal supramarginals adjoin one 
 another in the axillary areas, and in the geologically later forms 
 these also have stellate surfaces. Between each of the 5 inter- 
 radial plates there is inserted a single plate, making a second but 
 disconnected ring of accessory plates. 
 
 Madreporite abactinal, more or less large, adjoining one of the 
 large interradial plates and between the basal plates of two supra- 
 marginal columns of ossicles of adjoining rays. 
 
 No accessory ambital or abactinal plates. 
 
 Spines appear to be absent everywhere except on the inframarginal 
 and adambulacral ossicles. Otherwise the surface is granular or 
 tuberculate. 
 
 Inframarginal plates well-developed, tuberculate, and common 
 to both the actinal and abactinal areas. These proximally adjoin the 
 five isolated and large axillary marginals, each one of which occupies 
 .an axil of the rays. Each plate, except the axillary ones, bears on 
 its outer edges one to three apparently smooth, small spines. 
 
 Axillary plates quite conspicuous, marginal, and one in each 
 actinal axil. In at least one of the species there is a single tiny acces- 
 sory piece orad to each axillary (H. narrawayi), and it is only seen 
 on the inside of the skeleton. 
 
 Adambulacral plates numerous, one or two to each inframarginal 
 plate and two on each side of each axillary marginal plate. All of 
 these pieces bear at least two spines, one on the inner and another 
 on the outer edges. 
 
 Oral armature consisting of at least five pairs of pointed and elon- 
 gate basal adambulacral plates; each bears spines like the other 
 ambulacrals. In rare cases issuing from beneath these ossicles may 
 be seen five single stout spines or plates (tori) that are connected 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 55 
 
 with the pairs of ambulacral armature pieces. In H. narrawayi above 
 or dorsal to the pair of large oral pieces there is another but smaller 
 and modified pair of ambulacral ossicles clearly also a part of the oral 
 armature. 
 
 Ambulacral grooves originally narrow and regularly tapering. Am- 
 bulacral plates rectangular, practically opposite or very slightly 
 alternating, one to each adambulacral plate. The ambulacralia 
 of each column may be so closely adjoining as to leave almost no 
 space for the podial openings, or there may be laterally between 
 adjoining ossicles very large openings. 
 
 Genoholotype. The genotype selected by Sttirtz is Pdlasterina 
 rugosa Billings. The above generic definition is, however, largely 
 based upon Palxaster incomptus Meek and P. matutinus Hall. 
 
 Distribution. Restricted to the middle and upper portion of the 
 Ordovicic. The following are the known species : 
 
 H. matutinus (Hall). Trenton. 
 
 H. narrawayi (Hudson). Black River. 
 
 H. milleri, new species. Trenton. 
 
 H. incomptus (Meek). Maysvillian and Richmondian series. 
 
 H. rugosus (Billings). Lower Richmondian, Charleton forma- 
 tion. 
 
 H. ~batheri, new species. Upper Ordovicic, Girvan, Scotland. 
 Remarks. Sttirtz is unfortunate in selecting as the genotype of 
 Hudsonaster, Palasterina rugosa Billings, a very poorly known starfish 
 from the Richmondian of Anticosti Island. Therefore his original 
 definition of Hudsonaster is not only very imperfect, but the specimen 
 is wrongly interpreted. His characterization of the genus is as 
 follows : 
 
 Of Palasterina rugosa only the abactinal side is known. On the disk occur orna- 
 mented, deeply crenulate, star-shaped plates. Four [the specimen is distorted and 
 has forced into view one of the inframarginal columns, while the one on the other side 
 of the ray is shoved out of sight] regular and decided columns mark the rays, and of 
 these the outer rows are stronger than the inner columns. The outer columns consist 
 of unmistakable marginal plates [one is inframarginal, the other is a supramarginal 
 column]. According to Billings there are even traces of the actinal marginals to be 
 seen from the abactinal side. Spines absent [the usual spines of this genus are also 
 present here]. The arms terminate sharply in points. 
 
 Sttirtz is correct in saying that this species can not be included in 
 Palasterina and also that the genus has come to embrace a variety 
 of unrelated genera. However, he does not say what are the 
 actual generic characters of Hudsonaster, but as P. rugosa is not a 
 Palasterina he concludes that as "new generic names are required 
 I propose Hudsonaster for Palasterina rugosa Billings. " This 
 species is undoubtedly congeneric with Palseaster incomptus, a form 
 fully described in this work both from the actinal and abactinal sides, 
 and is therefore taken as the genotype for the above generic defini- 
 tion. 
 
56 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 The adopted genotype of Protopalseaster (P. narrawayi) is described 
 at length and in detail by Hudson, but, thinking the specimen 
 showed the actinal side, he described the ambulacrals as epineural 
 plates roofing over the ambulacral furrow, a character that he of 
 course recognized as wholly anomalous for starfishes. Raymond 
 later on showed that the actinal side of this specimen lies buried in 
 the rock and that the entire abactinal plates are now gone, so that 
 the view is of the actinal plates from their inner side, i. e., an inter- 
 nal view of the ventral skeleton (later Hudson combats this view). 
 Under these circumstances nearly all of Hudson's generalizations 
 are fallacious and especially his statement that "we are dealing 
 with an unrecognized and very archaic morphological type which 
 links the Edrioasteroidea with the Stelleroidea " (1912 : 24) . A proper 
 interpretation of the specimen shows it to be a primitive but other- 
 wise a normal early Paleozoic starfish. Even though Hudson's 
 genus is far better determined generically than that of Stiirtz, it 
 must give way to the older name Hudsonaster. No one regrets this 
 more than the writer, because the generic name Protopalseaster ex- 
 presses the phyletic relationship of these primitive starfishes and is a 
 name that he has had in manuscript for the past 15 years. 
 
 Hudsonaster has its nearest known relationship in Palseaster, but 
 differs at once from the latter in that the rays have abactinally five 
 columns of plates, while Palseaster has but four. In other words, 
 Palseaster has no radial columns of ray plates, but their place is oc- 
 cupied by numerous small accessory pieces. The abactinal disk 
 of Palseaster is also quite different hi having numerous small acces- 
 sory ossicles, while in Hudsonaster this area is devoid of these pieces 
 and instead there are disk plates that are larger, far less numerous, 
 and with a definite arrangement. 
 
 The plate arrangement of Hudsonaster is simple and primitive 
 in that it distinctly retains to maturity much of the larval plate 
 structure of recent species and does not develop accessory ambital 
 or accessory abactinal plates as do its descendants Mesopalseaster 
 and particularly Promopalseaster. In Hudsonaster the axils are 
 occupied by single, large, axillary marginals, against which rest 
 the columns of inframarginal plates of adjoining rays. In the other 
 two mentioned genera, interbrachial arcs begin to develop by crowd- 
 ing orally the axillary marginals, when, as in Mesopalseaster , the 
 proximal plates of the inframarghial series of adjoining rays abut 
 against each other. In Promopalseaster this crowding of the infra- 
 marginal plates into the interbrachial areas is continued, always a 
 pair of plates at a time passing orally. For other remarks on the 
 development and distinction between these genera, see Mesopalse- 
 aster and Promopalseaster. 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 57 
 
 In the Lower Carboniferous genus Neopalseaster the primitive 
 disk structure of Hudsonaster is also retained in its essential fea- 
 tures. Otherwise these genera are easily distinguished, as is pointed 
 out in the remarks on Neopalseaster. 
 
 HUDSONASTER MATUTINUS (Hall). 
 Plate 2, fig. 2; plate 3, fig. 2; plate 5, figs. 1, 2. 
 
 Asterias matutina HALL, Nat. Hist. N. Y., Pal., vol. 1, 1847, p. 91, pi. 29, figs. 
 
 5o, 56. 
 Palxaster matutinus HALL, Twentieth Eep. N. Y. State Cab. Nat. Hist., 1868, 
 
 p. 283, pi. 9, fig. 2; rev. ed., 1868=1870, p. 325, pi. 9, fig. 2. 
 Petraster rigidus (part) BILLINGS, Geol. Surv. Canada, Can. Org. Bern., dec. 3, 
 
 1858, pi. 10, fig. 36 (not fig. 3a). HALL, Twentieth Rep. N. Y. State Cab. 
 
 Nat. Hist.,1868, p. 294; rev. ed., 1868=1870, p. 337. 
 
 Original description. "Body small, with five radiating arms, 
 arms elongated (length twice and a half the width of the body), 
 terete, acute, composed of three rows of plates [abactinally], which 
 join above by their lateral margins. Beneath each upper lateral 
 row of plates there is an inferior lateral range [inframarginal] vis- 
 ible, leaving the sulcus beneath the middle row, which is often 
 depressed. The dorsal places are somewhat hexagonal; those of the 
 arms quadrangular; surface punctate or granulate, perhaps from the 
 removal of the spines covering the surface. 
 
 "The specimen is considerably crushed, and two of the arms 
 broken off at the base; the madreporiform tubercle upon the back 
 is not visible in our specimen. From its condition, the structure 
 can not be entirely made out, but it is sufficiently clear to enable 
 any one to recognize the species." 
 
 Emended description. Specimen of the usual size (No. 3, Mus. 
 Comp. Zool.) measures: R, = 14 mm., r = 3.5 mm., R = 4r. The larg- 
 est specimen (Ottawa, Billings collection): 11 = 16 mm., r = 5 mm., 
 R = 3.1r. The smallest New York specimen (No. 26, Mus. Comp. 
 Zool.): R = 7 mm., r = 2.5 mm., R = 2.8r. Width of rays at base 
 from 2.5 mm. to 5.5 mm. 
 
 Rays short, tapering rapidly, convex abactinally and flat actinally. 
 Disk comparatively large, probably convex abactinally during life. 
 
 Abactinal area of rays consisting of 5 ranges of large, thick, 
 and tumid granular plates. The 3 medial ranges, when not 
 distorted by pressure, conspicuous, with the 11 to 12 plates of 
 each column closely adjoining and considerably elevated above 
 the inframarginal ranges. The proximal plates of each supra- 
 marginal range lie against the large interradial plates and are 
 more or less superposed on the large axillary marginals. In the 
 center of the disk there is a distinct highly convex plate, around 
 which is arranged a nearly complete ring of seven smaller pieces 
 
58 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 and a vacant space which may be an anal opening. Five other 
 small quadrangular plates are intercalated, one proximally to each 
 of the large radial basal plates. Outside of these 12 intercalary 
 plates there is a ring of 10 quite large and conspicuous plates, 5 of 
 which are radial and 5 interradial in position. The radial plates are 
 largest and are the basal pieces of 5 medial or radial columns, while 
 against the 5 interradial plates rest the 10 inframarginal columns. 
 
 Madreporite abactinal, quite small, situated immediately above a 
 large interradial plate and between two basal supramarginal plates. 
 Its position in relation to the anal opening is apparently as in P. 
 incomptus. 
 
 Inframarginal plates in mature examples about 14 to a col- 
 umn, and when not displaced completely, inclosing the adarnbu- 
 lacral plates and margining the rays. The axils are occupied by a 
 very large, oval, axillary marginal plate. Each inframarginal bears 
 upon its outer surface one to three short, slender, pointed spines, 
 which are finely striated longitudinally. 
 
 Adambulacral plates small, subquadangular in outline and about 
 19 in a column in specimens having 13 inframarginals. Each plate 
 bears on both the outer and inner edges a single spine and is like 
 those of the inframarginal ranges. 
 
 The oral armature consists of 5 pairs of elongate adambulacrals, 
 each pair being situated directly orad of the large axillary marginal. 
 
 Ambulacral plates I -shaped, practically opposite or but very 
 slightly alternating, one to each adambulacral plate. In the ex- 
 panded medial portion the ambulacralia are slightly superposed one 
 above the other proximally, while the lateral portion of each plate 
 is very slender, leaving between adjoining pieces comparatively large 
 podial openings. 
 
 Locality and formation. From the Trenton limestone, as follows: 
 The type-specimen was found in the " shelly layers" at Trenton 
 Falls, New York (Amer. Mus. Nat. Hist., No. 199), and another 
 specimen was secured there by Mr. Rust (New York State collection). 
 Dr. Walcott collected a slab with three individuals in the Lower 
 Trenton at Rathbone Brook, near Newport, Herkimer County, New 
 York; and Mr. Taylor got two specimens at Deerfield, Oneida County, 
 in the same State (Mus. Comp. Zool., Nos. 26 and 3). Mr. W. R. 
 Billings found a specimen in the Trenton at Lachine, Quebec, and 
 another from Government House Bay, Ottawa. 
 
 Remarks. H. matutinus is intermediate in structure between the 
 older E. narrawayi and the younger H. incomptus. It is larger than 
 the former, has more plates in each of the columns, while the ambu- 
 lacrals are deeply cut out for the podia, which is not the case in H. 
 narrawayi. As H. matutinus is most closely related to H. incomptus 
 more detailed comparisons must be made between them. Actinally 
 
KEVISIOISr OF PALEOZOIC STELLEEOIDEA. 59 
 
 the former differs in the wider ambulacral grooves. The difference 
 of greatest value, however, is found on the abactinal area of the 
 disk. In both species there is a central disk plate surrounded by a 
 ring of accessory plates. In H. matutinus there are eight plates in 
 this ring and in H. incomptus there are seven. Between all the basal 
 radials in the latter species there is an accessory plate, or these are 
 five in number, while in the former there are only two such plates. 
 Again, the proximal plates of the supramarginal columns in H. 
 incomptus are larger than any others of the abactinal area, while in 
 H. matutinus they are smaller than the basal radials and their form 
 and ornamentation are quite different. The madreporites are also 
 quite different. In general, H. incomptus is larger, stouter, the rays 
 broader and the disk has a greater number of accessory pieces. These 
 features are still more pronounced in H. rugosus (Billings). Viewing 
 these differences developmentally, the distinctions are slight, which 
 proves the three forms to be genetically related, but specifically the 
 differences are sufficiently marked to be regarded both morpholog- 
 ically and geologically as of specific value. 
 Apotype.Csii. No. 60603, U.S.JST.M. 
 
 HUDSONASTER NARRAWAYI (Hudson). 
 
 Plate 1, fig. 1; plate 2, fig. 1; plate 4, fig. 1. 
 
 Protopalseaster narrawayi HUDSON, Ottawa Naturalist, vol. 26, 1912, p. 25, pis. 
 1-3; vol. 27, 1913, pp. 77-84, pis. 8, 9. RAYMOND, Ottawa Naturalist, vol. 26, 
 1912, pp. 105-107. HUDSON, Bull. N. Y. State Mus., No. 164, 1913, pi. 5 
 SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. for 1913), 1914, 
 p. 21, fig. 19. 
 
 Description. Specimens small, an average individual from St. 
 Paul, Minnesota; measuring: R = 5 mm., r = 3 mm., R = 1.6r. Width 
 of ray at base 2.7 mm. The three good specimens show only the 
 actinal side while the fourth free siliceous one is too poorly preserved 
 to make out more than the form. 
 
 Inframarginal columns have from 6 to 9 plates, while the adambu- 
 lacrals and ambulacrals each have from 11 to 12. Ambulacral plates 
 large and solid, rectangular, with slightly rounded ends. As these 
 plates are not t- -shaped as in other species of this genus it may be 
 shown that this character is of generic value, in which case Proto- 
 pal&aster will have to be revived. 
 
 Inside of each of the large axillary plates lies a pair of oral armature 
 pieces that are in form very much like the adjoining adambulacrals. 
 From beneath these ossicles projects a stout and long, rounded, arma- 
 ture rod, the torus (a tooth or chisel), the 5 teeth meeting together 
 in the center of the mouth. These armature rods and more especially 
 the 10 pairs of ambulacral armature pieces are seldom seen in fossil 
 starfishes, and none shows it more clearly than the Yale specimen 
 
60 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 of H. narrawayi. In the holotype of this species, here illustrated, 
 are seen additional pairs of oral armature ossicles. These are situated 
 directly above or dorsal to the pairs of large armature plates, and are 
 probably overlapping ambulacralia modified into the actinostomial 
 ring. 
 
 Locality and formation. In the Black Kiver formation, as follows: 
 The holotype was found by Mr. J. E. Narraway at City View, near 
 the Central Experimental Farm at Ottawa, Canada; it is now in his 
 private collection. An excellent specimen was found by Mr. 
 Townshend near Kirkfield, Ontario, and is now in the Peabody 
 Museum of Yale University. Many years ago Dr. Ulrich found a 
 fine specimen at St. Paul, Minnesota, and another good one in the 
 Lower (Glade) Lebanon limestone of the Stones River series at 
 Shelbyville, Tennessee. These two specimens are in the United 
 States National Museum (Nos. 60602, 60619). Mr. Moritz Fischer 
 secured a coarsely silicified individual of this genus at Curdsville, 
 Kentucky, and this is now in the Beecher collection in the Yale 
 Museum; it may, however, prove to be of another species, distin- 
 guished by its stouter appearance, wider disk, and smaller axillary 
 plates. 
 
 Remarks. Originally the writer included specimens of this form 
 under P. matutinus, regarding them as but young individuals of 
 Hall's species. However, as the specimens are all geologically older, 
 are always smaller and stouter, and with fewer plates in all of the 
 columns, Hudson's species is retained as valid. It is the ancestral 
 form and the most primitive species of Hudsonaster and hence the 
 most primitive Paleozoic starfish. It is primitive because of its 
 extreme simplicity of structure, in that the columns and plates are 
 reduced to the smallest number and all of them are closely adjoining 
 and without intercalary plates of any kind. Then the spines are 
 developed only on the actinal side and as protection for the podia. 
 For further information see generic remarks under Hudsonaster. 
 
 Cat. Nos. 60602, 60619, U. S. N. M. 
 
 HUDSONASTER MELLERI, new species. 
 
 Plate 4, fig. 2. 
 
 Description. Of this form there is at hand but a single poorly 
 preserved individual showing the actinal side. It is a more slender 
 species than H. matutinus, has a larger and more rectangular axillary 
 plate, and the proximal inframarginals have each about 13 to 15 
 plates and the adambulacrals from 18 to 20. No ambulacrals are 
 preserved. The specimen measures: R = about 12 mm., r = 3 mm. 
 Width of ray at base 4 mm., at mid-length 3 mm. 
 
 Locality and formation. Found by Prof. Arthur M. Miller, after 
 whom the species is named, in the Lower Lexington (Wilmore) 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 61 
 
 limestone of the Trenton, in Fayette County, Kentucky. The 
 holotype is in the collection of the State University of Kentucky at 
 Lexington. 
 
 HUDSONASTER INCOMPTUS (Meek). 
 
 Plate 6, figs. 1, 2. 
 
 "Goniaster" of AGASSIZ, GRAHAM, ANTHONY, and JAMES, Amer. Journ. Sci., 
 
 ser. 2, vol. 1, 1846, p. 441 (nomen nudum). 
 Palseaster incomptus MEEK, Amer. Journ. Sci., ser. 3, vol. 4, 1872, p. 275; Geol. 
 
 Surv. Ohio, Pal., vol. 1, 1873, p. 64, pi. 4, figs. 5a, 5&. 
 Palseaster simplex MILLER and DYER, Journ. Cincinnati Soc. Nat. Hist., vol. 1, 
 
 1878, p. 29, pi. 1, fig. 6. MILLER, N. Amer. Geol. Pal., 1889, p. 266, fig. 380. 
 Palseaster darlcei MILLER, Journ. Cincinnati Soc. Nat. Hist., vol. 1, 1878, p. 102, 
 
 pi. 3, fig. 5. 
 Palseaster clarkana MILLER, Journ. Cincinnati Soc. Nat. Hist., vol. 3, 1880, p. 236. 
 
 Original description (P. incomptus). " Small; rays rather short, or 
 only about once and a half as long as their breadth at their inner ends, 
 and rapidly tapering to their outer extremities, which are somewhat 
 obtusely angular. Disk equaling in breadth the length of the rays. 
 Dorsal side of the rays composed each of three rows of pieces that are 
 wider than long, about nine in each row, and increase rather rapidly in 
 size inward to the margin of the disk, which is composed of smaller 
 pieces; a few very minute pieces apparently some times occur between the 
 rows on the dorsal side of the rays [none are apparent in our material]. 
 Surface of the dorsal pieces a little granular, but apparently without 
 spines. Madreporiform piece rather small, a little oval, or almost 
 circular [or trapezoidal], nearly flat, and marked by fine, irregularly 
 interrupted, radiating striae. Ventral side unknown." 
 
 Emended description. B, = 11 mm., r = 6 mm., R = 1 .8r. Width of 
 ray at base 6 mm. Another larger specimen measures: R = 16 mm., 
 r = 7 mm., R = 2.3r. Width of ray at base 8 mm. Smallest speci- 
 men: 11 = 4.5 mm., r = 2 mm. 
 
 Rays short, stout, tapering rapidly, convex abactinally and longi- 
 tudinally ridged, flat actinally. Disk large, probably very convex 
 abactinally during life. 
 
 Abactinal area of rays consisting of five columns of large, thick, 
 tumid, alternating, granulose plates. In the center of the disk there 
 is a distinct, highly convex plate around which is arranged a nearly 
 complete ring of seven smaller pieces and a comparatively large open 
 space which possibly represents an anal opening. This ring is fol- 
 lowed by another composed of five large interradial plates between 
 each of which laterally and somewhat centrally is intercalated a 
 smaller plate radial in position. Laterally and distally to each of 
 the five large interradial plates are five large radial plates which are 
 the basal pieces of the five radial columns. Against the basal plates 
 of the medial ranges there adjoin laterally two large stellate ossicles, 
 
62 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 each of which is the proximal plate of a supramarginal column. 
 The rays are margined by the inframarginal plates. There are 10 
 plates in each radial and 9 in each supramarginal column. 
 
 Madreporite abactinal, situated interradially and dis tally against 
 the large interradial plate of the second ring, which is in front of the 
 anal opening, and between two of the proximal supramarginal plates. 
 It is trapezoidal in form, flat, and marked by very fine, dichotomous, 
 radial striae. 
 
 Inframarginal plates completely inclosing all other plates and com- 
 mon to both the abactinal and actinal surfaces. Usually there are 
 9 or 10 in a column, not counting the axillary plates. Spines are 
 present at least along the inner edges of the inframarginals. 
 
 Abactinally the axillary marginals are not prominent but actinally 
 they are very conspicuous. No spines appear to be connected with 
 these ossicles. 
 
 Adambulacral plates small, subquadrate, usually 2 to each 
 inframarginal or from 18 to 22 plates in each column. From 4 to 
 6 are situated around the inner edge of each axillary, of which the 
 2 central ones are largest, being one of the 5 pairs of plates 
 making the oral armature. The adambulacral plates originally bore 
 on their lateral and inner edges numerous, very short, thick spines. 
 
 Ambulacral plates nearly entirely concealed by the adambulacral 
 plates, apparently as numerous as the latter, and, so far as can be 
 determined, like those in P. matutinus Hall. 
 
 Locality and formation. In the lower, middle, and upper beds of 
 the Cincinnatic (Ordovicic). Ten specimens have been studied: 
 Four in the Harris collection in the United States National Museum 
 (No. 40882) from the Richmond formation (Waynesville division) 
 about Waynesville, Ohio; another from the same place and formation 
 in the University of Chicago Museum (Gurley collection, No. 10977); 
 one from the hill quarries in the Maysvillian series (Vaupel collection, 
 U. S. Nat. Mus., No. 60616) back of Cincinnati; another, said to be 
 from Cincinnati, in the University of Toronto (Walker collection, 
 No. 691 H. R.); the type-specimen, now in the Museum of Com- 
 parative Zoology, also from Cincinnati; one in the Ulrich collection 
 of the United States National Museum (No. 60617), found back of 
 Covington, Kentucky, in the Maysville formation, about 315 feet 
 above low-water mark in the Ohio River; and the type of Palxaster 
 simplex Miller, found near Raysville, Ohio (Faber collection, Uni- 
 versity of Chicago Museum, No. 8830). The holotype of P. darkana 
 Miller is in Professor Harper's collection at Cincinnati, while another 
 specimen is in the Ulrich collection of the National Museum (No. 
 60618). 
 
 Remarks. The writer has seen the type-specimen of Palseaster 
 simplex Miller, which agrees with the description and figure given 
 
KEVISION OF PALEOZOIC STELLEEOIDEA. 63 
 
 by its author, and it is like other specimens in the Harris collection 
 known to be H. incomptus (Meek) . Of the latter, Meek only described 
 the abactinal area, while Miller's specimen shows the actinal side. 
 The four specimens in the Harris collection unmistakably affirm 
 that both forms are identical, and since Meek's name has priority 
 it is here accepted. * 
 
 For remarks as to the relationship of this species see H. matutinus. 
 
 Through the kindness of Prof. George W. Harper, principal of the 
 "Woodward High School, Cincinnati, Ohio, the writer was enabled to 
 study the type of Palseaster darkana Miller." The specimen is a 
 little abraded, but shows all the characters of H. incomptus except that 
 it is much smaller in size. The abactinal area on a cursory examina- 
 tion shows but three columns, but in several places can be seen pro- 
 jecting small parts of the inframarginal columns. The disk also shows 
 the same general arrangement and number of plates as in H. incomptus. 
 There is therefore nothing except the smaller number of plates in the 
 columns to distinguish P. darkana from H. incomptus. Bearing 
 in mind that the former is but one-third the size of the latter, it is 
 not remarkable that P. darkana should have but 6 or 7 plates 
 while H. incomptus has 9 to 10 plates in the same columns. The 
 entire difference is accounted for when one regards P. darkana as 
 the young of H. incomptus. 
 
 Another small but very poorly preserved specimen showing the 
 actinal area is in the Ulrich collection of the National Museum and 
 agrees with the type of P. darkana. Its measurements are: 
 11 = 4.5 mm., r = 2 mm., K = 2.2r. 
 
 The only ontogenetic character observable in these small speci- 
 mens of H. incomptus is that the columns have fewer ossicles, and the 
 same is true of the abactinal area of the disk. It has a central disk 
 plate, the first ring of small plates and the second ring of basal radial 
 and interradial plates. But no intercalated small plates radial in 
 position are present. The second ring of 10 plates and the central 
 plate are the most prominent. If one were theoretically to reduce 
 the size of the animal still more, the plates of the first ring would be 
 the first to go and the rays would be simultaneously very much 
 shortened, probably obsolete, resulting in a hemispheric nonstellate 
 starfish. The abactinal area seemingly will then have but a central 
 disk plate and 10 others, 5 radial and 5 interradial in position. On 
 the actinal side there will be but the 5 axillary marginal plates 
 separated from one another by the ambulacra! furrow and the 
 ambulacralia. This hypothetic animal therefore closely resembles 
 a very young Comatula without the stalk or column, and also the stage 
 of living asterids following the brachiolarial. 
 
 Cat. Nos. 40882, 60616, 60617, 60618 U.S.N.M. 
 
 50601 Bull. 8815 5 
 
64 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 HUDSONASTER RUGOSUS (Billings). 
 
 Plate 3, fig. 1. 
 
 Palasterina rugosa BILLINGS, Geol. Surv. Canada, Rep. of Progress for 1853-1856, 
 
 1857, p. 291; Geol. Surv. Canada, Can. Org. Remains, dec. 3, 1858, p. 77, pi. 
 
 9, figs. 2a-c. 
 Palasterina rugosa WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 
 
 (Paleeontogr. Soc. for 1861), 1862, p. 27. 
 Hudsonaster rugosa STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 
 pp. 218, 224, 225. 
 
 Original description. "Two inches [not over 47 mm.] in diameter, 
 rays five, acute at their apices and rapidly enlarging to a breadth 
 of four lines [about 11 mm.] at the disk, which is eight lines [about 
 17 mm.] in width. The specimen shows the upper [or abactinal] 
 side of the fossil only; some of the plates are absent from the center 
 of the disk, but those which remain are very prominent in their 
 centers, and roughly ornamented by four or five deep crenulations 
 or furrows from near the center to the edges, producing a star-like 
 appearance resembling a half-worn plate of Glyptocrinus decadac- 
 tylus; their diameter is from one to two lines [largest diameter 4 mm.]. 
 
 "The rays are composed (at least the backs and sides of them) 
 of four rows of plates [due to distortion, a careful analysis shows 
 five columns] which are so very, prominent that they appear to be 
 almost globular, and even pointed in their centers, the central 
 [radial] rows are the smallest [as in H. incomptus]', the first four 
 plates of the outer [supramarginal] row occupy three lines in length, 
 and of the inner [radial] rows nearly as many. Toward the point 
 of the arm all diminish rapidly in size. 
 
 "Beneath the outer [or supramarginal] rows two others can be 
 seen [the inframarginal], which are probably the outer marginal plates 
 of the under [or actinal side], corresponding to those of Petrasier 
 rigidus." 
 
 Locality and formation. Richmondian series, Charleton formation, 
 at Charleton Point, Anticosti Island. Two specimens collected by 
 J. Richardson are now in the Victoria Memorial Museum at Ottawa, 
 Canada (No. 1999). 
 
 Remarks. The same description was republished in 1858 with 
 the addition of three figures. These, and a direct examination of 
 the two type-specimens, show that this species clearly belongs to 
 Hudsonaster and that it is closely related to H. incomptus. The 
 smaller free specimen preserves a portion of the disk and parts of 
 two rays and shows clearly the presence of a single large axillary 
 plate. H. rugosus, however, attained a considerably larger growth, 
 has a greater number of plates in each column and these are described 
 as "almost globular," while in H. incomptus the abactinal plates are 
 very convex but not globular. Then the basal supramarginal and 
 
REVISION OF PALEOZOIC STELLEROIDEA. 65 
 
 radial plates are much more decidedly ornate. Each of the supra- 
 and inframarginal columns has 14 plates against 9 in H. incomptus, 
 and of adambulacrals there are not less than 24 in a column against 
 18 to 22 in the same form. All of the ossicles are as strongly papillose 
 but not more so than in H. incomptus. The detail of the disk is not 
 determinable. 
 
 HUDSONASTER BATHERI, new species. 
 Plate 3, fig. 3. 
 
 Tetraster wyville-thomsoni NICHOLSON and ETHERIDGE (part), Mon. Silurian 
 Foss. Girvan Dist., Ayrshire, fasc. 3, 1880, p. 324, pi. 21, figs. 1, 2 (not the 
 other figs.). 
 
 A small Hudsonaster. R = 6 mm., r = 2.7 mm. The largest 
 specimen: R = 8 mm. 
 
 Actinal side only known. Inframarginal columns the largest, 
 with 8 or 9 distinctly tuberculate plates. Inside of these are 
 the columns of narrower and slightly shorter adambulacrals that 
 lie somewhat below the level of the inframarginals ; there are 
 10 or 11 of these plates bounding the ambulacral grooves, and the 
 pieces of adjacent columns are opposite or nearly opposite one 
 another. The ambulacral grooves are very narrow and deep and 
 no ambulacralia are discernible. 
 
 Formation and locality. Dr. F. A. Bather made wax squeezes 
 for the writer from three natural molds in the collection of Mrs. 
 Robert Gray, Edinburgh; the originals are from the Upper Ordovicic 
 of Thraive, Girvan District, Scotland. The holotype is the specimen 
 illustrated as above cited. 
 
 Remarks. Nicholson and Etheridge confused at least one of these 
 specimens with their Tetraster wyville-thomsoni , a species of totally 
 different construction, a cryptozonian, described elsewhere in this 
 work. Actinally the new species is in harmony with Hudsonaster 
 and although the abactinal side is unknown, it is thought that it 
 will be found to be like that in H. matutinus. 
 
 Cat. No. 60601, U.S.N.M. 
 
 Genus SILURASTER Jaekel. 
 Text fig. 6. 
 
 Siluraster JAEKEL, Zeits. geol. Ges., vol. 55, 1903, Protokol, p. 13 (106), figs. 2, 
 3, on p. 108. SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palaeontgr. Soc. for 
 1913), 1914, p. 18. 
 
 Description. "A typical asterid with opposite ambulacralia and 
 with well-developed marginalia, therefore a true form of Phanero- 
 zonia. The strongly folded madreporite lies dorsally in an inter- 
 radius." 
 
66 
 
 BULLETIN 
 
 UNITED STATES NATIONAL MUSEUM. 
 
 l2 
 
 From the two excellent illustrations the following is made out: 
 Inframarginals conspicuous and as large as the adambulacrals. 
 Both columns finely tuberculate, with the ossicles of each alternating 
 with one another. Proximally the inframarginals of adjacent rays 
 rest on a somewhat larger axillary plate. The interbrachial areas 
 are therefore made up of single axillary ossicles (Jaekel's marginal 
 oral) and in front of these lies a pair of pointed adambulacrals, the 
 conspicuous pieces of the oral armature. These are perforated for 
 the continuation of the ring canal. The podial openings as usual 
 lie in the corners of four adjacent adambulacrals and ambulacrals, 
 
 but there is a de- 
 cided tendency to 
 restrict them to 
 only one of the am- 
 bulacral corners. 
 
 Abactinal area 
 unknown. 
 
 Remarks. This 
 genus appears to be 
 closely related to 
 Hudsonaster, but 
 
 FIG. 6.-SILT7RASTER PERFECTUS (JAEKEL'S FIGURE 3). Oj TO Og, AMBU- , -1 o, -7 , 
 
 LACRALIA OF ONE SIDE; ABOVE THESE ddi TO ddg, THE ADAMBULACRALIA, l l6 ' 1 
 
 adi AS MOUTH CORNER PIECE; dfg, PODIAL GROOVES; dpff, PODIAL OPEN- DlOrC fully WOrked 
 
 INGS; m, INFRAMARGINALIA; mo, THE SINGLE AXILLARY INFRAMARGINAL; , , n 
 
 RC, RING-CANAL IN MOUTH CORNER PLATES. Ut lt} ^ ^maUl aS 
 
 an obscure genus. 
 
 Genoholotype and only species. S. perfectus Jaekel. Ordovicic 
 (D4), Zahorzan, Bohemia. 
 
 Family PAL^ASTERID^E Gregory (emend.). 
 
 Palaeasteridae (part) MILLER, N. Amer. Geol. Pal., 1889, p. 216. GREGORY, Geol 
 Mag., dec. 4, vol. 6, 1899, p. 344 (contains Palseasterinae, Xenasterinse, and 
 Lindstromasterinse); Treat. Zool., vol. 3, Echinoderma, 1900, p. 250. 
 
 Palsecisterinas SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 1910, p. 244. 
 
 Palxgoniasteridx (part) STURTZ, Palaeontographica, vol. 36, 1890, p. 246 (contains 
 Aspidosomella and Pal&aster). 
 
 Primitive, derived, five-rayed Phanerozonia with the ambulacrals 
 slightly alternate or opposite. Interbrachial arcs incipient or some- 
 what enlarged, and occupied by single axillary marginal plates. No 
 accessory interbrachial or axillary interbrachial plates present, but 
 there are developed accessory abactinal ray ossicles. Actinal plates 
 consisting of ambulacrals, adambulacrals, and inframarginals. Mad- 
 reporite abactinal. 
 
 Contains : 
 
 Palseaster Hall. 
 Australaster, new genus. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 67 
 
 Genus PALSEASTER Hall (emend.). 
 Plate 7, figs. 1-4. 
 
 Palseaster HALL, Nat. Hist. N. Y., Pal., vol. 2, 1852, p. 247; Twentieth Rep. N. Y. 
 
 State Cab. Nat. Hist., 1868, p. 282; rev. ed., 1868=1870, p. 324. ZITTEL, 
 
 Handb. Pal., vol. 1, 1879, p. 452. 
 Palseaster NICHOLSON and ETHERIDGE (part), Mon. Silurian Foss. Girvan Dist., 
 
 Ayrshire, fasc. 3, 1880, p. 319. 
 (Not Palseaster SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 323= Uras- 
 
 terella.) 
 (Not Palseaster of most AUTHORS.) 
 
 Generic characters. Disk small and without distinct interbrachial 
 arcs. Rays five and slender. 
 
 Abactinal area of disk centrally occupied by a large plate, then a 
 ring of 5 separated, somewhat smaller, radially situated ossicles, 
 and inside the axillary pieces there are 5 subtriangular interradial 
 plates, against which lie 10 very large and conspicuous proximal 
 supramarginal plates. Between the central, radial, and interradial 
 plates are numerous small accessory pieces which separate the pri- 
 mary ossicles one from another. These accessory plates also continue 
 to crowd from the disk into the rays between the supramarginals, 
 and thus take the place of the radial columns, but are absent in the 
 distal third of the rays. Each ray has therefore 4 conspicuous 
 columns of plates, the 2 supramarginals situated inwardly of the 
 2 marginal inframarginals. The former columns terminate in 10 
 very large proximal plates situated in the axils of the disk, while the 
 inframarginals rest against the 5 very large actinal axillary margi- 
 nal pieces. All of the large plates are centrally smooth, bordered by a 
 pustulose area. 
 
 Madreporite abactinal, of medium size, circular in outline, and 
 radially striate. It lies on top of two proximal supramarginal plates 
 and the adjoining interradial plate. 
 
 Inframarginal plates thick and large, about as many in a column 
 (13) as in those of the supramarginals (13 or 14). The latter do 
 not completely overlie the inframarginals, since these bound the 
 rays both actinally and abactinally. The inframarginal plates, like 
 the plates of the abactinal area, have each a large, smooth, central 
 space encircled by a pustulose area. From their inner sides articu- 
 late short, thick, blunt spines, of which there are apparently not 
 more than 2 to each inframarginal plate. 
 
 Axillary marginal plates large, hexagonal, one in each axil and 
 common to both sides of the disk axils. 
 
 Adambulacral plates small, tumid, alternating in the main with 
 the inframarginal plates throughout the distal two-thirds of the rays, 
 but toward the mouth there are a few more adambulacrals than in- 
 framarginals. (In the type-specimen there are 13 of the latter in a 
 column to 16 of the former.) Oral armature consists of at least 5 
 pairs of drawn out and pointed basal adambulacrals. Along the inner 
 
68 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 side of each adambulacral plate there is a linear brush of from 5 
 to 7 short, slender spines. 
 
 Ambulacral grooves very narrow, tapering but very slowly. Am- 
 bulacral plates obscured by the rock but apparently very short, one 
 to each adambulacral and placed opposite one another. 
 
 GenoJiolotype (type by monotypy) and only species. P. niagarensis 
 Hall. Siluric (Rochester shale). 
 
 Remarks. To this genus has been erroneously referred a multitude 
 of Paleozoic starfishes. It is to the starfishes what Terebratula and 
 Rhynchonella used to be among the brachiopods a general dumping 
 ground for Paleozoic forms. This lack of generic conception regarding 
 Palseaster lies somewhat in the fact that Hall's original diagnosis is 
 very meagre and that he did not describe nor illustrate the abactinal 
 surface, probably the most important area amongst Paleozoic aster- 
 ids for specific and generic differentiation. Of the twenty-four Amer- 
 ican species listed under Palseaster by S. A. Miller 1 only one now 
 appears to belong there, the genotype. All others are here referred 
 to Hudsonaster, Urasterella, Mesopalseaster, Promopalseaster, Anorth- 
 aster, Devonaster, and Neopalseaster. 
 
 No new material of this genus accessible to the writer appears 
 to have been found since Colonel Jewett discovered the original 
 two specimens of Palseaster niagarensis. The writer therefore had to 
 make the most of this material, and to determine the structure of 
 the abactinal area he worked away much of the blue shale from the 
 back of the one good specimen. The finer detailed structure was then 
 revealed by cleaning with caustic potash. 
 
 In 1858 Billings proposed the genus Stenaster 2 and writes- that 
 "as it has been suggested that the two species hereinafter described 
 should be referred to Palseaster, I give the following figure of the genus 
 in order to show the difference." This figure is a good reproduction 
 of Hall's figure 27. Billings then points out that "if the large plates 
 which border the grooves in Palseaster be adambulacral, then there 
 are only five oral plates, whereas in Stenaster there are ten. But if 
 they be not adambulacral but marginal plates, then Palseaster must 
 have both marginal and adambulacral [the correct view], while 
 Stenaster has only the latter." 
 
 Hall's generic description is very meager and his figures give 
 the impression that the rays bear but a single column of marginal 
 spiniferous plates. With this evidence one can understand why 
 Billings was in doubt as to whether these plates are inframarginals 
 or adambulacrals and therefore the uncertainty as to the nature of 
 the five large axillary marginal plates. If, however, he had read 
 Hall's accurate specific description, Billings would have seen that an 
 important discrepancy -existed between the description and figures. 
 
 1 North American Geology and Palaeontology, 1889, p. 265. 
 
 2 Geol. Surv. Canada, Canadian Organic Remains, dec. 3, 1858, pp. 77, 78. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 69 
 
 Hall writes: " Lower side of arms showing two ranges of plates on 
 each side of the avenue, the outer range composed of strong hex- 
 agonal plates, with an inner range of smaller ones alternating, the latter 
 usually covered by tufts of spines." The type-specimen clearly 
 shows columns of adambulacral and inframarginals bordering the 
 ambulacral grooves and that in each axil there is a single large axillary 
 marginal plate. This matter need not here be followed further than 
 to add that Stenaster originally included two generic types, both of 
 which are widely different from Palseaster. On the other hand, Hall 1 
 is in error in regarding all of Stenaster as synonymous with Uraster- 
 ella McCoy, a name never properly defined and finally abandoned by 
 its author. Billings originally referred to Stenaster, S. salteri, and 
 S. pulcTiellus. The latter is certainly congeneric with the type of 
 Urasterella as illustrated by Salter, but the former is quite different, 
 as is pointed out elsewhere in the remarks on Stenaster, which is a 
 good genus. 
 
 Palseaster in many respects reminds one of Hudsonaster, and the 
 actinal generic characters may be regarded as alike in both. The 
 abactinal area is also similar, but in Hudsonaster there are five columns 
 with decidedly fewer plates, while in Palseaster there are no radial 
 columns. The former genus is the more primitive one and the 
 progression in differentiation toward Palseaster appears to be as fol- 
 lows: In Hudsonaster, the rays throughout are composed of five 
 columns of plates, two inframarginals, two supramarginals, and one 
 radial. In Palseaster, there are but four columns in the outer third 
 of the rays, two infra- and two supramarginals, but in the proximal 
 two-thirds where the radials are also absent, their place is occupied 
 by numerous small, irregular accessory plates. This introduction of 
 numerous supplementary plates also takes place to a far greater 
 extent on the disk, where they are crowded in between the larger 
 central and the five basal radial plates. 
 
 The primitive disk structure of Palseaster is in large part again 
 repeated in Neopalseaster, but otherwise the two genera are different. 
 
 PALSEASTER NIAGARENSIS Hall. 
 
 Plate 7, figs. 1^. 
 
 Palseaster niagarensis HALL, Nat. Hist. N. Y., Pal., vol. 2, 1852, p. 247, pi. 
 51, figs. 21-23 (not p. 352, pi. 85, figs. 8-10, possibly an undescribed 
 species). BILLINGS, Geol. Surv. Canada, Can. Org. Rem., dec. 3, 1858, p. 
 78, fig. 1. HALL, Twentieth Hep. N. Y. State Cab. Nat. Hist., 1868, p. 282; 
 rev. ed., 1868=1870, p. 324. QUENSTEDT, Petrefactenkunde Deutschlands, 
 vol. 4, 1876, p. 73, pi. 92, figs. 32, 33. HUDSON, Bull. N. Y. State Mus., 
 No. 164, 1913, pis. 9, 10, 12, 13. 
 
 Original description. "Body stellate; disk small; arms short, terete 
 with a deep avenue on the lower side, which is margined by strong 
 short spines; centre of plates (in the fossil) nearly smooth, margins 
 
 i Twentieth Rep. N. Y. State Cab. Nat. Hist., rev. ed., 1808=1870, p. 325. 
 
70 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 strongly granulate; lower side of arms showing two ranges of plates 
 on each side of the avenue, the outer range composed of strong 
 hexagonal plates, with an inner range of smaller ones alternating, 
 the latter usually covered by tufts of spines; a large pentagonal plate 
 inserted at the base of the arms, on the lower side. 
 
 "In this species, the arms are about twice as long as the width of 
 the disk. There are about 15 or 16 plates in each range from the 
 base to the apex of the arms. The range of the plates margining 
 the avenue are usually not visible, the whole being covered by the 
 short spines, which also partially fill the avenue. " 
 
 In 1870 Hall added the following important observations: 
 
 "I have distinctly recognized the two ranges, marginal and 
 adambulacral plates; but the inner ones are not shown in the figure 
 as they should have been, while the large plate at the axil of the ray 
 (though the adjacent small oral plates of the inner range are not 
 seen) is evidently part of an incomplete series, and clearly belongs 
 to the marginal range. 
 
 "The genus Palseaster has two ranges of plates on each side of the 
 ambulacral groove; marginal and adambulacral plates on the lower 
 side, besides ambulacral or poral plates. The upper or dorsal side 
 has three or more ranges of plates." 
 
 Emended description. Measurements: R=1S mm., r=5 mm, 
 Width of ray at base 5 mm. 
 
 Rays long, slender, tapering slowly; abactinally strongly convex 
 and longitudinally ridged; flat actinally. Disk comparatively large, 
 strongly convex and probably abruptly elevated above the rays 
 abactinally. There are no interbrachial arcs, but the five axillary 
 marginal plates occupy the axils and are also partially visible 
 abactinally. 
 
 Abactinal area of rays consisting of 4 columns of large, thick, 
 convex plates. These are the supra- and inframarginal columns. 
 The supramarginal plates of each ray are distally in contact with 
 one another along the mid-line, but proximally they are forced more 
 and more apart by a series of small, irregular, accessory plates. In 
 the center of the disk there is a small, convex disk plate around which 
 are situated radially 5 other small ossicles, all of which are sepa- 
 rated from each other apparently by a considerable number of minute 
 intercalary pieces. Just inside of the axils are 5 large, sub triangular, 
 uiterradial plates and adjoining these directly are 10 large and con- 
 spicuous ones, the proximal plates of. the supramarginal columns. 
 In each column there are about 13 plates, not counting the proximal 
 piece. Between all of the larger plates of the disk and for two- 
 thirds the length of the rays between the supramarginals, there are 
 numerous small, convex, irregularly shaped, accessory plates. All 
 
BEVISIOK OF PALEOZOIC STELLEROIDEA. 71 
 
 the larger ossicles of both sides are centrally smooth, surrounded by 
 a finely pustulose border. 
 
 Madreporite situated interradially and distally upon the three 
 large plates just inside an axillary marginal plate, two of which are the 
 proximal plates of supramarginal columns of adjoining rays. It is 
 circular in outline, flat, and radially striated. 
 
 Inframarginal plates occupying the outer edges of both the actinal 
 and ab actinal areas; from 13 to 15 plates hi each column. The 
 supramarginal plates are situated above and inside the inframarginals, 
 which inwardly bear short, thick, club-shaped spines. Otherwise 
 they are ornamented like the abactinal plates. 
 
 Adambulacral ossicles small, subquadrate, each one alternating 
 distally with an inframarginal plate, but proximally they are some- 
 what more numerous, there being from 17 to probably 20 in a column. 
 On these plates lie two series of spines the two short, thick, club- 
 shaped ones of each mframarginal plate while on the inner side of 
 each adambulacral there is inserted a linear brush of from five to seven 
 slender, short spines that are outwardly and laterally directed. 
 
 Ambulacral grooves very narrow, deep, and gradually tapering. 
 Ambulacral plates not well seen but apparently very short, one to 
 each adambulacral and directly opposite one another. 
 
 Axillary marginal plates five in number, very large and conspicuous 
 actmally, also showing slightly abactinally. 
 
 Locality and formation. The only good specimen was found many 
 years ago by Col. E. Jewett in the Siluric (Rochester shale) at Lock- 
 port, New York. A fragment of the ray of a much larger individual, 
 nearly twice the size of this type, was found by the same gentleman 
 at the same place. These specimens are now in the paleontological 
 museum of Cornell University (No. 7331) and were presented by 
 Hon. Ezra Cornell. Long after the study of the form was com- 
 pleted another specimen preserving two rays and showing the actinal 
 side was learned of in the University of Toronto (Walker collection, 
 No. 1008). It was found at Grimsby, Ontario. 
 
 Remarks. This species has never been well described nor figured, 
 and has accordingly led to endless generic confusion. Almost any 
 Paleozoic starfish with large marginal plates has been referred to 
 Pal&aster. This lack of generic conception was partially due, as 
 stated above, to the fact that the abactinal side remained unknown. 
 The specimen lies imbedded in blue shale showing the actinal area, 
 and the abactinal side was revealed by the writer by cutting away 
 the slab to the starfish and then developing the individual plates 
 with caustic potash. 
 
 In a general way Palseaster niagarensis resembles several species but 
 all are distinguished by generic characters. The nearest one is 
 Hudsonaster incomptus from the Cincinnatic strata, but it differs at 
 
72 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 once in having five instead of four columns of large abactinal plates. 
 There are also a far less number of the accessory plates so numerous 
 on the disk and the proximal medial areas of the rays in Palseaster 
 niagarensis. 
 
 Hall 1 refers a fragment to this species which clearly is of quite 
 another species. It is very far removed from P. niagarensis and 
 for the present need not be considered. The specimen hus not been 
 seen by the writer. 
 
 AUSTRALASTER, new genus. 
 Plate 4, fig. 4. 
 
 Palseaster ( Monaster) ETHERIDGE, jr. (part), Mem. Geol. Surv. New South Wales, 
 
 Pal., No. 5, pt. 2, 1892, p. 74. 
 
 Monaster GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 345 (not of Etheridge, jr.). 
 Australaster SCHUCHERT, Fossiliiim Catalogus, Animalia, pt. 3, April, 1914, p. 12. 
 
 Austral=sout1n.eTn and aster. A Paleozoic starfish restricted to 
 Australia. 
 
 Generic diagnosis. Animal attaining a very large size, with five 
 long; slender, almost straight-sided rays, terminating bluntly. 
 Interbrachial areas comparatively small, widely concave, and occu- 
 pied by ponderous, single, axillary marginals and inframarginal 
 plates. 
 
 Abactinal area unknown (see A. (?) stutcfiburii) . 
 
 Actinally the animal is bounded by inframarginal plates which 
 however do not appear to be present in the distal third of the rays. 
 If such plates are present in these outer regions, they are either 
 very small or gradually pass from the actinal to the abactinal area, 
 the latter condition occurring ha related genera. The inframarginals 
 in the outer third of the rays are small, subquadrangular, and rounded, 
 thence they increase rapidly in size proximally, become decidedly 
 transverse, and in the axils the columns abut against a very large 
 axillary inf ramarginal. The largest plate is the axillary marginal, orad 
 to which occur the pairs of enlarged oral armature ossicles. The 
 inframarginals appear to be nearly smooth and devoid of spines. 
 
 The adambulacrals in the distal third of the rays are numerous, 
 very short, but quite wide that is, are decidedly transverse, and 
 decrease rather rapidly hi breadth toward the tips of the rays. 
 Proximally these plates also decrease quickly in width and rapidly 
 pass inside of the inframarginals. Inside of the axillary marginals 
 the plates are again prominent and especially the pairs of oral arma- 
 ture pieces. Each adambulacral plate bears prominent tubercles 
 for the articulation of stout but short spines. The columns have 
 the pieces arranged with a decided slant outward and distally. 
 
 i Palaeontology of New York, vol. 2, 1852, p. 352 and pi. 85, figs. 8-10. 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 73 
 
 Ambulacral furrows deep, slender and tapering slowly. Ambu- 
 lacra! plates unknown. Oculars not present. 
 
 Genoholotype. Palseaster (Monaster) giganteus Etheridge, jr. The 
 specific description and the bibliographic references are included in 
 the generic diagnosis. 
 
 Kes trie ted to the Lower Marine series of the " Permo-Carbon- 
 iferous" of New South Wales. 
 
 AUSTRALASTER(P) STUTCHBURH (Etheridge, jr.). 
 
 Palxaster (Monaster) stutchburii ETHERIDGE, jr., Mem. Geol. Surv. New South 
 
 Wales, Pal., No. 5, pt. 2, 1892, p. 73, pi. 13, fig. 1. 
 Monaster stutchburii GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 346. 
 
 This species is found associated with A. giganteus and its preserva- 
 tion is such that the form is very imperfectly known. In some 
 respects it resembles that species and may prove to be a smaller 
 specimen of it, but until the disk marginals are known the differ- 
 ences will remain obscure. 
 
 If A. (?) stutchburii has the large disk marginals of Australaster, 
 it then seemingly will have the essential structure of that genus. 
 Regarding this the writer wrote Professor Etheridge in 1900 and 
 he replied that " axillary plates are not visible in the specimen". 
 
 Since the abactinal area of A. giganteus is unknown, it is desirable 
 to give here the abactinal structure in A. (?) stutchlmrii, as it may 
 prove to be congeneric with A. giganteus. 
 
 " Abactinal surface moderately convex, bearing several (five or 
 six) rows of small convex polygonal plates, inclusive of the margi- 
 nal pieces, and becoming much crowded at the apices of the rays, 
 where they form oblique rows." If these plates throughout the 
 rays are as figured by Etheridge for the distal ends, the strongly 
 quincuncial arrangement of the polygonal, closely adjoining plates 
 is another good generic character for Australaster. 
 
 PROMOPAL^ASTERID^E, new family. 
 
 Progressive Phanerozonia with distinct columns of inframar- 
 ginal plates. Interbrachial areas more or less complex, composed 
 either of inframarginals, axillary interbrachials and ambulacrals, 
 or of these with the addition of interbrachial marginals and acces- 
 sory interbrachials, or entirely of adambulacral plates. Ambu- 
 lacrals as a rule opposite, but they may also be slightly alternating. 
 Podial openings through the sutures in the lateral corners of the 
 ambulacral plates, but proximally a few alternate pores may grad- 
 ually pass medially, when there are four columns of podial openings 
 in each ambulacral furrow. 
 
 Madrsporite abactinal. 
 
 Abactinal plates very numerous, generally small, either in dis- 
 tinct columns or rows or without either arrangement. The radial 
 
74 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 and supramarginal columns may be very distinct or may be ob- 
 scured as such. Accessory ossicles always more or less abundantly 
 developed. 
 Contains : 
 
 Mesopalaeasterinae. 
 
 Promopalseas fcerinse. 
 
 Anorthasterinse. 
 
 new subfamily. 
 
 Palxocwnidde GREGORY, Treat. Zool., vol. 3, Echinoderma, 1900, p. 254. 
 Primitive Promopalseasteridse with the interbrachial areas small, 
 composed of one pair of inframarginals, single axillary infcerbra- 
 chials, and the adambulacral plates. 
 Contains : 
 
 Mesopalszaster, new genus. 
 Spaniaster Schondorf. 
 Miomaster Schondorf. 
 Devonaster, new genus. 
 
 MESOPAL^EASTER, new genus. 
 Plates 7-11. 
 
 Palseaster (part) of AUTHORS. 
 
 fArgaster HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 287: rev. 
 
 ed., 1868=1870, p. 329. 
 Mesopalseaster SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, April, 1914, 
 
 p. 24. 
 
 Meso = middle, and Palseaster. Not the largest of Palseasters of 
 authors. 
 
 Generic characters. Rays five, slender and tapering. Disk small, 
 with incipient interbrachial arcs. 
 
 Abactinal area with distinct columns of radial and supramar- 
 ginal plates, between which are inserted rows of accessory pieces, 
 one or two on each side of the medial columns. In mature specimens 
 the radial columns are less prominent proximally than distally. 
 The accessory columns proximally may also have here and there 
 inserted on each side a smaller piece, when the area between the 
 supramarginals has not only three or five columns of plates but also 
 other additional small plates. The inframarginal columns margin 
 the rays, while the supramarginals lie somewhat inside and above 
 the former. Between the two columns of marginals there may be 
 a row of accessory ambital plates. The arrangement of the plates 
 of the disk appears to be as follows: In the center there is a small 
 plate around which is a first ring of 7 pieces, followed by a sec- 
 ond ring having not less than 14 plates, and these are nearly of 
 one size. The medial ray columns terminate on the disk in 5 
 
REVISION OF PALEOZOIC STELLEROIDEA. 75 
 
 large radial plates, but inside of the proximal supramarginals there 
 is no basal interradial plate as in Hudsonaster. 
 
 Madreporite unknown. 
 
 Inframarginal and adambulacral plates as in Hudsonaster, except- 
 ing that two of the former and a single axillary plate are in each 
 interbrachial area. Oral armature so far as preserved adambulacral, 
 consisting of five pairs of basal adambulacrals. 
 
 A single, pentagonal, axillary interbrachial plate is present in 
 each area, orad to the two axile inframarginal plates. 
 
 Ambulacral grooves deep and almost closed by the adambulacral 
 columns. Ambulacral plates carinate and apparently one to each 
 adambulacral ossicle. Their relation to one another is not definitely 
 determinable, but apparently they are slightly alternate or nearly 
 opposite. 
 
 Genoholotype. Palxaster shafferi Hall. 
 
 Distribution. The species of Mesopalseaster are restricted to 
 America in the upper portion of the Ordovicic and the lower portion 
 of the Siluric. A species doubtfully referred to this genus occurs 
 hi the Lower Devonic of Germany, and another in the Upper Devonic 
 of Maryland. 
 
 The following are the species of Mesopalseaster: 
 
 M. shafferi (Hall). Middle and upper beds of the Cincinnatic 
 series. Possibly also in the Utica formation of New York. 
 
 M. intermedius, new species. Maysville formation. 
 
 M. finei (Ulrich) . Eden formation. 
 
 M. (?) lanceolatus, new species. Utica formation. 
 
 M. proavitus, new species. Eden formation. 
 
 M. (?) wilberanus (Meek and Worthen). Richmond series. 
 
 M. (?) dubius (Miller and Dyer). Upper Trenton. 
 
 M . (?) antiquus (Troost) . Upper Trenton. 
 
 M. (?) parviusculus (Billings). Siluric (Lower Arisaig). 
 
 M. (?) cataractensis, new species. Siluric (Cataract formation). 
 
 M. granti (Spencer). Siluric (Cataract formation). 
 
 M. bellulus (Billings). Siluric (Rochester shale). 
 
 M. caractaci (Gregory). Caradoc of England. 
 
 M. (?) acuminatus (Simonovitsch) . Lower Devonic of Germany. 
 
 M. (?) clarki (Clarke and Swartz). Upper Devonic (Jennings 
 formation) . 
 
 Remarks. Mesopalseaster apparently developed directly out of 
 Hudsonaster in that the single axillary marginal plates are in the former 
 genus in nearly all the species pushed inward (interbrachial) and 
 their former place occupied by the proximal plates of adjoining 
 inframarginal columns. The same generic feature also distinguishes 
 Mesopalseaster from Palseaster. Further, in Hudsonaster there are 
 no abactinal accessory ray plates, but in Mesopalseaster one or two 
 more or less completely developed columns are inserted on each side 
 
76 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 of the radial columns or, in other words, between the radials and 
 supramarginals. Between the inframarginal and supramarginal plates 
 in Mesopalseaster there are also either a few incipient accessory plates, 
 which in young specimens are wholly absent, or there is a complete 
 column of these ambital plates. The accessory and axillary inter- 
 brachial plates are additions to the generic structure of Hudsonaster 
 and Palseaster, and further distinguish Mesopalseaster from both. 
 This progression toward a greater number of columns of abactinal 
 plates attains its maximum in Promopalseaster and is most marked in 
 P. magnificus, which has not less than 28 columns at the base of a 
 ray and 5 interbrachial marginal plates in each interbrachial area. 
 The ambulacral furrows, which are very narrow in Hudsonaster, are 
 likewise so in Mesopalseaster, but are wide in Promopalseaster. Spi- 
 nosity, which is practically absent abactinally in Hudsonaster, is 
 developed in Mesopalseaster and very pronounced in some forms of 
 Promopalseaster (P. spinulosus and P. dyeri) . This is apparently also 
 true for the spines of the actinal area. 
 
 The youthful plate structure of recent species seems to be retained 
 to maturity in Hudsonaster and somewhat so also in the genotype 
 of Mesopaldeaster but in Promopalseaster the central area of the disk 
 is occupied by numerous very small plates and no definite arrange- 
 ment is discernible, though this is in large part due to their displace- 
 ment through fossilization. However, it is certain that the basal 
 radials and interradials do not increase nor maintain a relative size 
 as in Hudsonaster and in the genotype of Mesopalseaster (here 
 radials only), but must have diminished to that of the accessory 
 plates from which they are now not distinguishable. From Hudson- 
 aster through Mesopalseaster into Promopalseaster the animals are 
 constantly increasing in size, and this also continues in the species 
 of the latter genus, attaining culmination in P. magnijicus and P. dyeri. 
 
 While the generic abactinal differences between Hudsonaster and 
 Mesopalseaster are easily made out, this is not so readily accom- 
 plished between the latter and Promopalseaster. All of the abactinal 
 generic characters of Mesopalseaster are more pronounced in Pro- 
 mopalseaster excepting that in the former the ambital accessory 
 plates are almost always undeveloped as columns, while in the latter 
 these plates are always well developed in one or more columns. 
 
 When the actinal area is shown, Mesopalseaster is at once distin- 
 guished from Promopalseaster in that it has but one axillary inter- 
 brachial plate in each interbrachial area, while the latter has always 
 two or more up to five ( = interbrachial marginals) in each area. 
 
 Devonaster in some respects is closely related to Mesopalseaster 
 and may be in the line of descent from the latter. However, the disk 
 in Mesopalseaster has far fewer abactinal plates, and there are no 
 distinct interbrachial arcs with numerous small accessory plates 
 
REVISION OF PALEOZOIC STELLEROIDEA. 77 
 
 as in Devonaster. The pieces of the radial columns in Mesopalseaster 
 adjoin one another and are not separated by intercalary plates, nor 
 are these nearly so numerous between the radial and supramarginal 
 columns as in Devonaster. These accessory plates in Devonaster are 
 also irregularly disposed and not in columns as in Mesopalseaster. 
 
 The name Argaster has not been denned nor is it mentioned in such 
 a way that anyone will recognize that Hall intended it for a new genus 
 or subgenus. In addition, its genotype (Asterias antiqua = Mesopalse- 
 aster (?) antiguus) is a poorly known species. Under these circum- 
 stances, and the additional one that the name Argaster never has had 
 any standing as a genus, it should not now be rehabilitated by 
 paleontologists. 
 
 MESOPALSEASTER SHAFFER! (Hall). 
 
 Plate 8, figs. 1, 2. 
 
 Palseaster sha/eri HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 284; 
 rev. ed., 1868=1870, p. 326, pi. 9, fig. 1. MEEK, Geol. Surv. Ohio, Pal., vol. 1, 
 1873, p. 66, pi. 4, fig. 1. 
 
 Original description. "Body of about medium size composed of 
 five tapering, acutely pointed rays, which, in the specimen examined, 
 measure seven-eights of an inch from the center of the disk to the 
 extremity. The lower side of the ray is formed of two ranges of plates 
 bordering the ambulacral groove. The marginal range consists of 
 moderately convex plates which gradually decrease in size from the 
 base to the extremity of the ray, 22 or 23 in number [not more than 
 20 exist in any ray of the type-specimen], besides a small terminal 
 one at the angle of the range; each plate of the marginal range is 
 marked on its outer surface by a comparatively large cicatrix for 
 the attachment of a strong spine. The inner range of plates (adam- 
 bulacral) are somewhat smaller, about the same in number, alternat- 
 ing with those of the marginal range; the basal pair (oral plates) 
 are elongate-triangular, and slightly constricted near the middle. 
 Ambulacral a,reas narrow, composed of a double range of poral plates, 
 which at the middle of the ray are about of equal length and breadth. 
 Pores not observed. [The writer could not make out these plates in 
 the type-specimen and believes those described to be the inner sides 
 of the actinal plates.] Upper surface of the ray composed of three 
 ranges of subnodose plates, the outer ranges bearing a strong spine 
 on each plate; the central range apparently destitute of spines. No 
 spines have been observed, but the plates are strongly carinate or 
 pointed." 
 
 Emended description. The largest specimen in the Harris collec- 
 tion measures: B, = 19 mm., r 5.5 mm., R = 3.5r. Another specimen 
 of the same collection: R = 16 mm., r = 5 mm., R = 3.1r. The 
 smallest known specimen in the Vaupel collection: R = 6.5 mm., 
 
78 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 r = 2.5 mm., R = 2.6r. The type-specimen, which is the largest knowii 
 example, measures: R = 21 mm., r = 6 mm., R = 3.5r. Width of ray 
 at base in various mature examples 5 mm. to 7 mm. 
 
 Rays more or less long, slender, abactinally slightly convex, with 
 marked longitudinal ridges, actinally flat or concave. Disk of medium 
 size, abactinally convex and without interbrachial arcs. 
 
 Abactinal area of rays occupied by a central range of radial plates, 
 on each side of which there is a range of accessory ossicles which 
 however do not attain the distal portion of the rays. In mature 
 rays there are in the proximal region also inserted a few plates on 
 each side of the intercalary columns. Outside of the latter are 
 the ranges of well-defined supramarginal plates which slightly overlap 
 the inframarginals. The marginal and radial plates are most promi- 
 nent, and all are highly carinate or pointed. There is a single large 
 spine on the apex of all radial and accessory plates and several 
 smaller ones are also arranged around it. The supramarginal plates 
 have numerous granules which bore articulating spines. The plates 
 of the disk can not be clearly made out, but in a small specimen 
 somewhat distorted there appears to be a small central plate sur- 
 rounded by a first ring of 7 ossicles followed by a second ring of 
 14 plates. These pieces are all nearly of a size. The medial ray 
 columns terminate in 5 large basal radial plates, while inside of 
 the proximal inframarginals there is no large interradial plate as in 
 Hudsonaster incomptus. 
 
 Ambital area very illy defined, but in the angles between the large 
 infra- and supramarginal plates there are here and there inserted 
 tiny accessory pieces. In a young individual there are none of these 
 accessory plates. 
 
 Madreporite unknown. 
 
 Inframarginal plates distinctly granulated, completely inclosing 
 all other abactinal plates and common to both the abactinal and 
 actinal areas. In mature specimens there are from 15 to 20 plates 
 on each side of a ray. Laterally each plate has a Well-marked small 
 pit, probably the place of attachment for rather strong spines, none 
 of which however have been observed. 
 
 Interbrachial areas with single, hexagonal, axillary interbrachial 
 plates. 
 
 Adambulacral plates slightly elongate-subquadrangular, of which 
 there are from 18 to 20 on each side of a ray; distally they appear to 
 pass over and to cover completely on the actinal side the inframar- 
 ginal plates. Between the adambulacral columns there is a more or 
 less wide ambulacral furrow. Each adambulacral plate bears on its 
 inner edge a rather thick but short, slightly striate spine and several 
 minute ones. Or ad to each axillary interbrachial there is a pair of 
 prominent elongate-triangular adambulacral plates bearing spines, 
 
REVISION OF PALEOZOIC STELLEROIDEA. 79 
 
 one of the five pairs constituting a part of the oral armature. In other 
 words, the adambulacral columns of adjoining rays are continued 
 around the axillary interbrachials by two modified plates. 
 
 Ambulacral grooves deep, nearly closed by the adambulacralia. 
 Ambulacral plates not well shown but apparently carinate, one to 
 each adambulacral ossicle, and whether alternate or opposite can 
 not be stated. 
 
 Locality and formation. -In the middle and .upper stages of the 
 Cincinnatic group (Ordovicic). The type-specimen (No. 1195, 
 Amer. Mus. Nat. Hist.) was found by Mr. D. H. Shaffer at Cincin- 
 nati, Ohio, probably in the Maysville formation. Mr. Vaupel found 
 a young individual showing the abactinal area (No. 60605, U.S.N.M.); 
 another young one was secured by Mr. Faber (No. 9568, University of 
 Chicago), and Mr. George Oeh found an excellent matured individual 
 preserving the actinal area (now in the Yale Museum), all from the 
 Maysville formation on the hills back of Cincinnati. Two good speci- 
 mens and another small poor one are in the Harris collection of the 
 United States National Museum (No. 59391) and were found in the 
 Waynesville division of the Richmond formation near Waynesville, 
 Ohio. 
 
 A small asterid preserving two rays and a portion of the disk "is in 
 the United States National Museum collection (No. 23540) and was 
 found by Mr. W. P. Rust in the Utica shales one and a half miles east 
 of Rome, Oneida County, New York. It is associated with Trinucleus 
 concentricus, Dalmanella testudinaria multisecta, and other species. 
 The abactinal area only is shown, and appears to be that of Meso- 
 palseaster shafferi. It does not appear to be a Promopalseaster because 
 of the fewer columns of abactinal accessory plates, and the axillary 
 structure makes it almost certain that there is here but a single axil- 
 lary interbrachial plate. For the present it may be provisionally 
 referred to this species and attention is thus directed to it so that local 
 collectors may be on the lookout for other material. 
 
 Remarks. This species has actinally much the appearance of 
 Hudsonaster incomptus, but the latter is at once distinguished by not 
 having the five axillary interbrachial plates of Mesopal&aster shafferi. 
 M. (?) parviusculus (Billings) is smaller, with far less plates in all the 
 columns than in M. shafferi. M. (f) parviusculus and M. granti differ 
 also abactinally and ambitally in the better developed accessory 
 plates. 
 
 Cat. Nos. 60605, 59391, 23540, U.S.N.M. 
 
 MESOPAL^ASTER INTERMEDIUS, new species. 
 
 Plate 9, fig. 4. 
 
 This species is perplexing in its generic construction because of its 
 intermediate or transitional characters on the one hand (but least) 
 to Hudsonaster, and on the other (more decidedly) to Mesopalxaster 
 
 50601 Bull. 815 S 
 
80 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 and prophetic of Promopalseaster in the conspicuous ambulacral 
 furrows. 
 
 Rays long and slender, elongate-petaloid, disk small. R = about 
 14 mm., r=4 mm. 
 
 The interbrachial areas each have but a single, large, finely granu- 
 lated, axillary plate that margins the axils, and in this agree best with 
 Hudsonaster, but the rest of the known skeleton is that of Meso- 
 palaeaster. In the former genus the ambulacral furrows are always 
 very narrow and the ambulacralia are rarely seen, while in M. 
 intermedius the furrows are wide and the ossicles are rather like those 
 of Promopalseaster, though the same kind of ambulacralia is also 
 known in Mesopalseaster. Orad to the axillary plates there were two 
 small oral armature pieces that belong to the ad ambulacral columns. 
 These are not now present in the specimen, but the distinct and 
 large facet of the proximal side of the axillaries leaves no doubt on 
 this construction. 
 
 Inframarginal columns well-developed proximally, though never 
 very prominent, and becoming rapidly smaller distally. The four 
 proximal pieces are the largest, beyond which there are at least 
 14 other ossicles, and all are closely in contact and alternate with the 
 adambulacrals. Another feature of these inframarginals is that not 
 more than six can be seen from the actinal surface, while the rest pass 
 on to the sides and distally even somewhat over to the abactinal 
 area. All of the plates are finely granulated. 
 
 Adambulacral columns the most prominent of the actinal skeleton, 
 margining the distal half of the rays, and in the proximal portion 
 pass more and more inside of the inframarginals, diminishing slowly 
 in size and finally depressed beneath the axillaries. There are 22 
 plates in a column, all more coarsely granulated than the inframar- 
 ginals, largest and most transverse near mid-length of the rays, and 
 all are drawn out inwardly into blunt points that adjoin the high 
 ridges of the ambulacralia. Therefore the adambulacral and the 
 adjacent ambulacral columns have the ossicles directly opposite one 
 another, but the adjacent ambulacral rows are slightly alternating. 
 
 Ambulacral furrows conspicuous and wide, widest in the proximal 
 third but converging somewhat quickly hi the mouth area and far 
 more gradually distally. Therefore the furrows are elongate-petaloid 
 in shape. There are about 20 ambulacralia in a column. Proximally 
 the columns unite around and beneath the small adambulacral oral 
 armature pieces. Ambulacralia square to transversely rectangular, 
 each with a high L-shaped crest that laterally adjoins the points of 
 the adambulacrals and medially bends orally. Podial openings large 
 between the corners of pairs of ambulacrals and adambulacrals. 
 There is a well-developed groove down the center of the ambulacral 
 furrows. 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 81 
 
 Abactinal area unknown, but probably that of Mesopalseaster and 
 nearest to M. shafferi. 
 
 Formation and locality. The holotype was found by Faber in the 
 Maysville formation at Cincinnati, Ohio, about 350 feet above the 
 Ohio River. The type is in the University of Chicago Museum 
 (No. 9575). 
 
 Remarks. This interesting species need be compared only with M. 
 shafferi. It differs in having the axillaries in the axils of the rays 
 and not inside the basal inframarginals as in the latter form. Then 
 in M. shafferi the inframarginals are actinal in position throughout, 
 while in M. intermedius they are more on the sides. Further, in the 
 new form the ambulacral furrows are well developed with large 
 ambulacralia, while in M. shafferi the furrows are narrow and the 
 ossicles rarely seen. 
 
 MESOPAL^SASTER FINEI (Ulrich). 
 Plate 7, fig. 5; plate 9, fig. 5. 
 
 Palseaster finei ULRICH, Journ. Cincinnati Soc. Nat. Hist., vol. 2, 1879, p. 19, pi. 
 7, figs. 15-156. 
 
 Original description. "Small; rays five, of medium length, rather 
 broad, pointed and narrower where they are attached to the much 
 contracted body [probably due to distortion], than they are about 
 the center of their length. 
 
 " Dorsal side of rays composed of four [about seven, the supra- and 
 inframarginals, radials, and two intercalary columns] rows of pieces, 
 that are quite close [?] fitting, as wide as long, from 12 to 14 in each 
 row, and increase in size inward to the disk, which is composed of 
 irregularly shaped and prominent pieces some of which are smaller 
 and others larger than those composing the rays; the pieces in the 
 marginal rows [four columns infra- and supramarginals] are more 
 prominent than the two [there are three, radials and two intercalary] 
 rows between them, and have a small pit in the center, probably for 
 the articulation of a spine [all of the plates originally bore several 
 short slender spines]. Madreporiform body rather small, circular, 
 very prominent, and marked by strong striae, which become more 
 numerous toward the margin by intercalation. 
 
 "Marginal [inframarginal] pieces on the ventral surface, convex, 
 quite as long as wide, and numbering in different specimens on each 
 side from 11 to 12 [probably not more than 8 or 9]; the piece at the 
 junction of the rays is three times as large as any other of the series, 
 subcircular and very convex. [It appears that this large plate is an 
 axillary interbrachial since upon it proximally rest two basal plates 
 of the inframarginal series.] 
 
82 BULLETIN" 88, UNITED STATES NATIONAL MUSEUM. 
 
 " Adambulacral plates more prominent [less prominent than the 
 inframarginal plates], slightly wider than long, and numbering, on 
 each side, from 9 to 10 [probably not less than 16 in each column]. 
 Ambulacral pieces a little wider than long, not alternating with the 
 adambulacral plates, and each provided with a rather sharp ridge 
 across most of its width. 
 
 "There are 10 oral plates [oral armature] formed by the junction 
 of the adambulacral rows, which in form and size are scarcely dis- 
 tinguishable from the other plates of those series. 
 
 " Greatest breadth measuring between the opposite extremities of 
 the rays ; 0.7 inch; breadth of rays at their inner ends, 0.1 inch; 
 length of same, 0.3 inch; diameter of madreporiform piece, 0.02 
 inch." 
 
 Formation and locality. This small species appears to be common 
 at a very restricted horizon near the base of the Eden formation 
 (Fulton beds), exposed at low water mark in the Ohio Biver in the 
 eastern portion of Cincinnati, Ohio. 
 
 Remarks. Not one of the twenty examples seen is well preserved 
 and all the plates are more or less separated. The general structure 
 seems to be that of Mesopalseaster. The composition of the axillary 
 area is not positively ascertainable but one specimen shows what 
 appears to be a large axillary interbrachial plate (see pi. 7, fig. 5), 
 distally surmounted by two somewhat smaller inframarginals. This 
 is probably the true structure since it is so in all the smaller Meso- 
 palseasters, as M. lanceolatus, M. parviusculus, M. granti, and M. 
 proavitus. 
 
 The differences between M. finei and M. proavitus are not great. 
 The former is a smaller species with less plates in all of the ranges, 
 more prominent axillary inframarginal and axillary interbrachial 
 plates, and is also found at a lower geological horizon. M. finei 
 differs from the small species M. parviusculus of the earliest Siluric 
 in having more plates in all of the columns. M. granti is a larger 
 species and with smaller and more numerous plates than in M. finei. 
 M. lanceolatus is probably the most closely related to M. Jinei but is 
 distinguished abactinally by the diagonal arrangement of the plates 
 on each side of the radial columns. 
 
 Cat. No. 60604, U.S.N.M. 
 
 MESOPALJEASTER(P) LANCEOLATUS, new species. 
 
 Plate 4, fig. 3. 
 
 Measurements: R = 4.5 mm., r=1.3 mm., R = 3r ) . 
 
 Rays short, stout, distinctly lanceolate actinally and rapidly ta- 
 pering abactuially. Disk comparatively large, abactinally convex. 
 Interbrachial arcs distinct but small. 
 
 Abactuially the disk has a ring of large, strongly stellate plates 
 which are the basal plates of the radial and supramarginal columns. 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 83 
 
 Inside the ring the plates can not be made out, due to the small size 
 of the specimen. Rays each with a column of radials and two supra- 
 marginals between which are inserted columns of diagonally arranged 
 accessory plates. A few ambital accessory plates are probably also 
 present. The arrangement of the ossicles on the abactinal areas of 
 the rays is like that hi Promopalxaster magnificus. 
 
 Madreporite small, subconical, situated near the edge of the disk, 
 depressed between adjoining basal plates and marked by 10 or 11 
 sharp, somewhat spirally arranged ridges. 
 
 Inframarginal plates large, about six in each column proximal to 
 the very large single axillary interbrachial plate. These columns in 
 the distal half can not be seen actinally as they pass over on the dorsal 
 side. 
 
 Axillary interbrachial plates large, one in each axil, and not com- 
 pletely inclosed outwardly by the basal inframarginals. In this 
 character the form is still in the Hudsonaster stage. 
 
 Adambulacral plates small, subquadrangular, with 16 plates in each 
 column. The plates of the adambulacral oral armature are larger 
 and wedge-shaped, and are situated directly inside of the axillary 
 interbrachial plates. 
 
 Ambulacra! plates one to each adambulacral, apparently opposite 
 and with proximally converging ridges. Podial openings apparently 
 along the outer edge between the sutures of adjoining plates. 
 
 Formation and locality. Two specimens were found by the late 
 Prof. Charles E. Beecher near Rome, New York, in the Triarthrus 
 bed of the Utica formation that preserves the entire ventral anatomy 
 of these trilobites. The co types are in the Museum of Yale University. 
 Mr. W. S. Valiant in a letter states that they are common in a layer 
 2 to 3 inches above the Triarthrus bed. 
 
 Remarks. This species is most closely related to M. finei, from 
 which it is readily distinguished abactinally. Here there are more 
 and smaller plates than In M. lanceolatus, the interpolated plates are 
 arranged diagonally and not radially as in M. finei, while the basal 
 plates of the former are apparently much larger and are strongly stel- 
 late. Actinally there are in M. lanceolatus more adambulacral plates 
 in each column, although the specimens are only half the size of M. 
 finei. 
 
 MESOPAL^ASTER PROAVITITS, new species. 
 
 R=18 mm., r^about 4.5 mm. The specimens are distorted, however, 
 and no exact measurements can be given. 
 
 On the distal abactinal portion of the rays the infra- and supra- 
 marginal and radial plates closely adjoin. Proximally, however, 
 between the two marginal series there is inserted a column of inter- 
 calary plates gradually increasing in size and two other similar rows 
 of plates are placed between the supramarginal and radial columns. 
 
84 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 There are therefore at the base of the rays no less than 11 columns 
 of plates. The radial columns proximally have a tendency to become 
 less distinct and indistinguishable from the accessory pieces. The 
 plates in general are highly convex, granular and abundantly spine- 
 bearing. There are not less than 20 plates in each supramarginal 
 series. 
 
 Madreporite highly convex, broadly oval in outline and radially 
 striated. 
 
 Inframarginal plates finely granular, highly convex, subquad- 
 rangular in outline and increasing in size slowly proximally. About 
 23 in each column. 
 
 Adambulacral plates like the inframarginals but not increasing 
 much in size proximally, with about 29 in each column. As in other 
 species of this genus, each plate bears three prominent spines, two 
 laterally and one ambulacrally. 
 
 Ambulacral plates one to each adambulacral plate, and with a 
 sharp ridge which medially bends abruptly orally. Podial openings 
 as in other forms of Mesopalseaster. 
 
 Interbrachial areas occupied by single axillary interbrachial plates 
 upon each of which rest proximally two axillary inframarginals. 
 
 The specimens are not figured, as an illustration can not readily 
 be made. 
 
 Formation and locality. Three more or less entire specimens and 
 fragments of four rays were found by Dr. E. O. Ulrich in the Eden 
 shale exposed back of Covington, Kentucky, at an horizon about 
 100 feet above low water in the Ohio River. All the specimens a^e 
 now in the Herzer collection, a part of the late Prof. James HalFs 
 private collection, recently purchased by the University of Chicago. 
 
 Remarks. M. proavitus and M. granti are closely related, since 
 both have 11 columns of abactinal plates, including the marginals, 
 and they are nearly alike actinally. However, the former is twice as 
 large and appears to have more conspicuous radial and supramarginal 
 columns than the latter. These differences and the further fact that 
 one occurs in the Utica and the other in the earliest Siluric will serve 
 to distinguish the two species for the present. M. proavitus may 
 prove to bo identical with M. (?) wilberanus, which see for further 
 remarks. 
 
 MESOPAL^ASTER (?) WILBERANUS (Meek and Worthen). 
 
 Petraster wilberianus MEEK and WORTHEN, Proc. Acad. Nat. Sci., Philadelphia, 
 
 for 1861, vol. 13, 1862, p. 142. 
 Palseaster wilberanus HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, 
 
 p. 285; rev. ed., 1868=1870, p. 328. 
 
 Original description. "This beautiful starfish resembles rather 
 closely Petraster rigidus of Billings, 1 but is smaller, and has more 
 
 1 Decade 3, Org. Rem. Canada, pi. 9, fig. 3o. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 85 
 
 slender rays, with more angular spaces between. It also differs in 
 having but two ranges of plates on each side of the ambulacral 
 grooves, on the under side, instead of three. These pieces are about 
 of the same size in each row, and sometimes appear to alternate; 
 they are all rather prominent, and those of the outer range project 
 a little laterally in the form of small nodes. Toward the outer 
 extremities of the rays, however, the lateral ranges are contracted 
 behind the others, so as to be scarcely visible from below. About 23 
 of these pieces may be counted on each side of the ambulacral furrow 
 in each ray. The ambulacral furrows are very narrow, and indeed 
 seem to be closed toward the extremities of the rays, by the gradual 
 approximation of the inner rows of pieces on each side, which alter- 
 nate and appear to fit together. 
 
 "Our specimen only shows the under side, but along the outer 
 margins of two of the rays, there is some appearance either of the 
 overlapping of some of the dorsal parts by pressure, or of a slightly 
 developed disk. This part does not seem to have any distinct range 
 of marginal plates, but appears to be made up of small pieces, covered 
 with granules, or bases of small spines. 
 
 "We take pleasure in dedicating this interesting species to 
 Prof. C. D. Wilber, of the Illinois State Normal School, to whom we 
 are indebted for the use of the only specimen we have seen. 
 
 "Greatest diameter about 1 inch; smaller diameter 0.33 inch. 
 
 "Locality and position. Oswego, Kendall County, Illinois, in rocks 
 of the age of the Trenton or Hudson River Group of the New York 
 series." Probably equivalent to the Richmond beds of the highest 
 Ordovicic. The whereabouts of the type-specimen is not known. 
 
 Remarks. Hall pointed out that this species is not a Petraster 
 because P. wilberanus has but two columns of plates on each side of 
 the ambulacral groove, while Petraster has in addition "a few disk 
 plates on the ventral side." He therefore referred it to Pal&aster. 
 However, Meek and Worthen describe the abactinal area as having 
 no " distinct range of marginal plates, but appears to be made up of 
 small pieces, covered with granules, or bases of small spines." The 
 characters as far as mentioned appear to be those of Mesopal&aster. 
 Should there prove to be in P. wilberanus single axillary interbrachial 
 plates, then all of the characters will be in harmony with Mesopalse- 
 aster and M. proavitus may prove to be a synonym of it. This 
 can not be proven at present since we have not been able to locate 
 the type-specimen. 
 
 MESOPAL^ASTER (?) DUBITJS (Miller and Dyer). 
 
 Palseaster dubius MILLER and DYER, Cont. to Pal., No. 2, 1878, p. 5, pi. 4, fig. 8. 
 
 Original description. "Pentagonal; rays longer than the diameter 
 of the body, and uniformly tapering. The ambulacral groove is 
 sharply angular in the middle, formed by two series of plates having 
 
86 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 their ends together in such manner as to make an angular gutter 
 [the plates of adjoining columns are arranged practically opposite]. 
 The length of these plates is three times as great as the diameter. 
 The plates are placed with the length across the rays. There are 
 15 plates on each side of the groove in each ray, in the length of one 
 quarter of an inch [this is an error as there are about 20 plates in a 
 column]. The diameter of the body is three-tenths of an inch. 
 
 "This species is founded upon a single specimen, in Mr. Dyer's 
 collection, which shows only part of the ventral side. The ends of 
 the rays [most of the adambulacrals] and marginal plates arc destroyed 
 [each axillary area appears to bear one axillary interbrachial plate]. 
 The parts preserved seem to distinguish it from any species hitherto 
 described." 
 
 Formation and locality. In the original description the locality 
 is given as Cincinnati, Ohio, but the character of the rock shows that 
 it is from the uppermost portion of the Trenton limestone, probably 
 opposite Cincinnati, in the river quarries at Ludlow, Kentucky. 
 The type (No. 25) is in the Museum of Comparative Zoology, Harvard 
 University. 
 
 Remarks. This specimen preserves well the very wide ambulacrals 
 but almost no other plates. The adambulacrals are nearly all removed 
 and but very little is to be seen of the marginals. In three of the 
 axillary areas there are single interbrachial plates, one of the essential 
 features of Mesopalseaster. It is referred to this genus provisionally, 
 as nothing is known of the abactinal side. 
 
 MESOPAL^ASTER (?) ANTIQUTJS (Troost). 
 
 Asterias antiqua TROOST (not Hisinger 1837), Trans. Geol. Soc. Penn., vol. 1, 1835, 
 p. 232, pi. 10, fig. 9; Proc. Amer. Assoc. Adv. Sci., vol. 2, 1850, p. 59 (cat. name). 
 
 Petraster (?) antiqua SHUMARD, Trans. St. Louis Acad. Sci., vol. 2, 1866, p. 386 
 (catalogue name). 
 
 Palxaster (Argaster) antiqua HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 
 1868, p. 287; rev. ed., 1868=1870, p. 329. 
 
 Palxaster antiquus MILLER, N. Amer. Geol. Pal., 1889, p. 265 (cat. name). 
 
 Argaster antiqua GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 345 (gen. ref.). 
 
 Pal&aster antiqua WOOD, Bull. U. S. Nat. Mus., No. 64, 1909, p. 105, pi. 8, fig. 1. 
 
 Although this is the first recorded American fossil starfish, very 
 little is known about it and that little is mostly of a misleading nature. 
 The specimen lies on a limestone slab and is very badly weather- 
 worn or it may have been treated with hydrochloric acid so that now 
 it is nothing more than a polished section of a starfish. An illustra- 
 tion that will show its actual characters can not be made. 
 
 Professor Hall errs in stating that Asterias antiqua has "ambu- 
 lacral grooves occupied by a single row of subquadrate ossicula, which 
 extend across and alternate with the adambulacral plates of each mar- 
 gin. * * * It is possible that this character may prove to be 
 of generic importance." It may have been this character on which 
 
REVISION" OF PALEOZOIC STELLEROIDEA. 87 
 
 Hall thought of basing the genus Argaster, but he does not character- 
 ize it nor even mention that the name in parenthesis is intended 
 as a new term with Asterias antiqua Troost as the genotype. This 
 species, like all other Paleozoic starfishes, has double columns of 
 ambulacral plates. This the specimen clearly demonstrates on 
 the edge of the slab where the distal parts of the rays are broken 
 away. Argaster should therefore be regarded as a nomen nudum, and 
 should A. antiqua prove to be a Mesopal&aster, it should not be 
 made to displace this genus. 
 
 Asterias antiqua has about 15 inframarginal plates in each column 
 and about 32 in each adambulacral column. Two of the latter plates 
 meet as usual in a pair of triangular oral armature pieces. 
 
 Each axil is occupied by two large, quadrangular, basa] inframar- 
 marginal plates. Between these proximally there is a large, widely 
 triangular, interbrachial plate the apex of which may or may not 
 attain the margin. Proximal to each axillary interbrachial plate 
 and between the four or five pairs of axillary adambulacral plates, 
 there is in the specimen an open space in each of the five areas. 
 What additional plates, if any, occupied this area is not de terminable. 
 It may be that the axillary interbrachial plates occupied the entire 
 interbrachial areas and that the present hiatus is due to the worn 
 condition of the specimen. This appears to be the most natural 
 interpretation as it is the normal inter brachial structure of Mesopa- 
 Iseaster. In Promopalseaster there are always two, three, five, or seven 
 interbrachial marginal plates hi each area, a fact which excludes Aste- 
 rias antiqua from that genus. 
 
 The abactinal area is not visible, but many of these plates are 
 squeezed beyond the inframarginals, showing the presence of num- 
 erous small plates recalling Mesopalseaster and Promopalseaster. 
 
 Formation and locality. Troost's label reads: " Lower limestone 
 on Harpeth Kiver, Davidson County, Tennessee." His manuscript 
 reads: "It was found * * * on Harpeth Kiver, Davidson 
 County, Tennessee. Associated with Spirifer lynx [PlatystropJiia 
 l}iforata] } Cyathop7i[y]Ua [ Streptelasma] } Orthis [testudinaria], etc." 
 This is apparently the same horizon as that about the city reservoir 
 in Nashville, which is now regarded as of Upper Trenton (Catheys) 
 age. The specimen is in the United States National Museum. 
 
 Cat. No. 39914, U.S.N.M. 
 
 MESOPAL^EASTER(?) PARVIUSCULUS (Billings). 
 
 Plate 9, fig. 1. 
 
 Palseaster parviusculus BILLINGS, Canadian Nat. and Geol., vol. 5, 1860, p. 69, 
 figure. DAWSON, Acadian Geology, 2d ed., 1868, p. 594, fig. 197. HUDSON, 
 Bull. N. Y. State Mus., No. 164, 1913, pis. 1-4. 
 
 Original description. ' l The specimen is about six lines in diameter. 
 The rays are two lines in length and one and a half in width at the 
 
88 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 base, tapering at an angle of a little less than 45. The five oral 
 plates are subpentagonal, about half a line in width. The first 
 adambulacral plates of each pair of adjacent rays are in contact 
 with each other outside of the oral plates, and not completely sep- 
 arated as they are in P. niagarensis. There are six or seven adam- 
 bulacral plates on each side of the ambulacral groove in each ray, 
 and they gradually decrease in size from the oral plate outward to 
 the point of the ray. The width of the ambulacral groove is equal 
 to one-third the width of the ray and consequently the adambu- 
 lacral rows of plates are also each equal to one-third the whole width 
 of the ray. In each groove there are two rows of small and appar- 
 ently nearly square ambulacral plates, 12 or 14 in each row, and they 
 seem to be continued round on the inner margin of the oral plates; 
 the mouth is about one line wide." 
 
 Emended description. Measurements: R = 6 mm., r = 2.5 mm., 
 R = 2.4r. Width of ray at base 3 mm. 
 
 Rays short, stout, tapering rapidly. Disk comparatively large, 
 and without interbrachial arcs. 
 
 Abactinal area unknown. 
 
 Inframarginal plates at the base of the rays very large and thick, 
 highly convex, duninishing rapidly distally, usually quadrangular 
 in form and seven on each side of a ray. 
 
 Just within each axil, inside of the basal inframarginals, there is 
 a single, large, very convex, pentagonal, axillary interbrachial plate. 
 
 Adambulacral plates gradually sinking below the inframarginals 
 proximally, convex and quadrangular in form. There are 13 plates 
 in each column adjoining the very narrow ambulacral furrow, or 
 nearly two plates to each inframarginal ossicle. Two of these 
 plates (oral armature) are situated in front of each axillary inter- 
 brachial, uniting the adambulacral columns of adjoining rays. 
 
 Ambulacral plates unknown. 
 
 Locality and formation. The type-specimen, a natural mold, was 
 found by Rev. D. Honeyman in the Lower Arisaig of the Siluric 
 ( = Clinton) rocks at Arisaig, Nova Scotia. The holotype is in 
 Redpath Museum of McGill University, Montreal, Canada, and the 
 illustration is taken from a gutta-percha squeeze kindly made for 
 the United States National Museum by Sir William Dawson. 
 
 Remarks. The general actinal appearance of this little asterid 
 reminds one much of Palseaster and Hudsonaster. It differs, however, 
 at once in a little detail of considerable importance, in that each 
 axillary area has three plates, while in Palseaster and Hudsonaster 
 there is but one. In other words, the large axillary plate of those 
 genera has in M. (?) parviusculus been pushed orally and is here an 
 interbrachial plate, while the axils of the rays are occupied by two 
 basal inframarginal plates. For further remarks on this species see 
 M. granti (Spencer). 
 
REVISION OF PALEOZOIC STELLEROIDEA. 89 
 
 So long as the abactinal area of M. (?) parviusculus remains 
 unknown its generic position will be doubtful. For the present its 
 relations appear to be nearest to Mesopalseaster and to M. (?) cata- 
 ractensis. 
 
 Cat. No. 60620, U.S.N.M. 
 
 MESOPAL.EASTER (?) CATARACTENSIS, new species. 
 Plate 9, fig. 2. 
 
 The specimen of this species has been confused with M. (?) gmnti, 
 from which it differs in being smaller and in having far fewer plates 
 in the columns. The actinal side of M. (f) cataractensis alone is 
 known, while of M. (?) granti only the abactinal, but even so the 
 above comparison can still be made because the size of plates is 
 relatively about the same in species of Mesopalseaster. 
 
 Measurements: K = 9 mm., r=3 mm., R = 3r. 
 
 The species is most closely related to M. (f) parviusculus, but 
 differs in being larger with more plates in the columns. Of M. (?) 
 cataractensis only the actinal side is known, with 12 to 13 plates 
 in each inframarginal column (7 in M. (?) parviusculus) and 
 about 19 in the adambulacrals (13 in M. (?) parviusculus). Then 
 the inframarginals increase very rapidly in size proximally, while 
 in M. (?) cataractensis there is but little enlargement. 
 
 A single small, pentagonal, axillary interbrachial plate occurs 
 in each area immediately beneath the basal inframarginals. These 
 are much smaller relatively than those in M, (?) parviusculus. 
 
 Ambulacral plates unknown. Ambulacral furrows deep, nearly 
 completely closed by the adambulacral columns. 
 
 Formation and locality. in the base of the Siluric (Cataract for- 
 mation) at Hamilton, Ontario. The holotype was found by Mr. 
 Elliott near the city reservoir and is in the collection of the Hamilton 
 Natural History Society. It was loaned to the writer by the late 
 Col. Charles Coote Grant. 
 
 MESOPALJEASTER GRANTI (Spencer). 
 Plate 9, fig. 3. 
 
 Palseaster granti SPENCER, Bull. Mus. Univ. Missouri, No. 1, 1884, p. 53, pi. 7, 
 fig. 1. 
 
 Original description. "Body stellate and small with short arms, 
 about 2 centimeters across; disk less than 1 centimeter wide, and 
 apparently formed by the junction of the rays; rays 5 millimeters 
 wide at base, tapering slowly, and terminating in rounded extrem- 
 ities, at about 8 millimeters from junction of their base with the 
 disk; upper surface of rays composed of 5 [not less than 9 in mature 
 specimens at mid-length of rays] ranges of highly convex or tuberculi- 
 form plates (the marginal [supramarginal] and ventral [inframarginal] 
 
90 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 rows being the most conspicuous) and separated from each other by 
 minute plates (becoming fewer on approaching the extremities of 
 the rays) . 
 
 "The ellipsoid [supra] marginal tuberculiform plates number 
 about 12 [20 in mature examples] for each complete side of the rays, 
 and the central range [radial] is composed of a similar number, but 
 in form these plates are more circular. The disk between the ter- 
 minal central [radial] row of plates of the rays is crushed and struct- 
 ureless, except a slight elevation in the center. The terminal [proxi- 
 mal] plates of the marginal series are larger than the others of the 
 range. The madreporiform tubercle is of a spherical form and rela- 
 tively large, being nearly 2 millimeters in diameter, and is situated 
 at the axil of two rays. Both the tuberculiform plates and the 
 madreporiform tubercle have a granulated surface. 
 
 "The ventral side is unknown. 
 
 Emended description. A mature specimen measures: R=16 mm., 
 r=5 mm. ; R = 3.3r. 
 
 Rays short, stout, tapering rapidly, and with very small inter- 
 brachial arcs. 
 
 Abactinal area of disk unknown. Along the center of each ray 
 there is a radial column of small, highly convex plates bounded on 
 each side, at about the mid-length of the rays, by two columns of 
 smaller, strongly tumid, accessory plates. The radial column is, 
 however, not distinctly differentiated from those adjoining. Out- 
 side of these are the supramarginal columns, each with about 20 
 plates which are larger and more easily distinguished than the radial 
 plates. Dis tally the rays have only the ossicles of the infra- and 
 supramarginal and radial columns, with none of the accessory plates 
 as yet developed. 
 
 Ambital area with one column of very small accessory plates 
 like the marginal plates on each side of them. These accessory pieces 
 disappear before attaining the apex of the rays. 
 
 Madreporite spherical in form and relatively large, nearly 2 milli- 
 meters in diameter, and situated at the .axil of two rays between 
 two adjoining supramarginal columns. 
 
 Formation and locality. From the Cataract formation, the basal 
 deposits of the Siluric system, near the reservoir in the city of 
 Hamilton, Ontario. Col. Charles C. Grant, after whom the spe- 
 cies is named, discovered most of the specimens, which are six in 
 number, two in the Spencer collection, now destroyed by fire, one 
 in the Redpath Museum of McGill University, Montreal, another 
 in the Geological Survey of Canada at Ottawa, and two in the 
 Grant collection, one of which has generously been donated to Yale 
 University. 
 
 Remarks. This species is apparently closely related to M. bel- 
 lulus, which see for comparison. 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 
 
 91 
 
 MESOPAL^EASTER BELLULUS (Billings). 
 
 Text fig. 7. 
 
 Petraster bellulus BILLINGS, Geol. Surv. Canada, Pal. Foss., vol. 1, 1865, p. 393, 
 fig. 368. MILLER, N. Amer. Geol. Pal., 1889, p. 269, fig. 389. 
 
 Original description. "Deeply stellate, about 18 lines across; disk 
 5 lines wide; width of rays, at the base, half the width of the disk, 
 uniformly tapering to their extremities; ambulacral grooves, narrow 
 and deep, with about 30 adambulacral plates on each side. These 
 plates are strongly convex and nearly square [distally, but proximally 
 are wider than long]. Outside of these there is a row of [about 21 
 infra] marginal plates, which appear to [actually do] extend to the 
 extremities of the rays, but on this point there is some doubt, as the 
 specimen is not perfect. [The four proximal pieces increase rapidly 
 in size so that they are considerably larger than the others. All of 
 the actinal plates are granular.] There 
 appear to be one or two [there is but one 
 axillary] small disk plates between the 
 [basal adjoining infra] marginal and ad- 
 ambulacral plates just outside of the oral 
 angles. 
 
 "Locality and formation. Township of 
 Grimsby [Ontario]; in the Niagara shale 
 [ = Rochester shale]. 
 
 1 i Collector. J ohnson Pettlt, Esq. , Fi G. ?. THE ORIGINAL FIGURE OF ME- 
 
 Grimsby." The holotype is in the Vic- 
 toria Memorial Museum, Ottawa, Canada 
 (No. 2665). 
 
 Remarks. The holotype and only 
 known specimen of this species was seen 
 by the writer at Ottawa, and has now been freed from the rock so 
 that the abac tin al side can also be studied. The generic charac- 
 ters are those of Mesopalseaster and one is impressed at once by the 
 almost specific identity of the abactinal side of the specimen with 
 that of M. granti. However, as the specimens show slight differ- 
 ences and come from different Siluric formations, it is thought best 
 to recognize them as distinct species. Moreover, the actinal side 
 of M. granti is still unknown. 
 
 Abactinally all of the skeletal pieces are of about the same size, 
 small, each ossicle irregular in outline, and more or less stellate. 
 There are about 17 in the length of one-half inch. This skeleton is 
 more or less disturbed and it is impossible to clean off all the adhering 
 shale, so that it is difficult to make out the detailed arrangement. 
 The following, however, can be made out: There is no true disk as 
 in Petraster , and the parts that appear as such are either adhering 
 shale or displaced ossicles due to distortion during sedimentation, 
 
 SOPAL.EASTER BELLULUS, AFTER BlL- 
 LINGS. NATURAL SIZE. THE SPECI- 
 MEN HAS STILL TOO MUCH SHALE 
 ADHERING TO IT AND BESIDES IS CON- 
 SIDERABLY DISTORTED, PREVENTING 
 ITS BEING SATISFACTORILY PHOTO- 
 GRAPHED. 
 
92 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Distally the rays have columns of small radial pieces, and outside of 
 these are the two supramarginal rows. Proximally between these 
 primary columns there appear accessory pieces, one column of which 
 wedge in between the radials and supramarginals and from one to 
 three between the latter and the inframarginals. In this way finally 
 as many as 13 columns can be counted at the base of a ray. 
 
 The madreporite is situated near the margin between adjoining 
 supramarginal columns, and is conspicuously protruded and large 
 when compared with the small adjacent ossicles. It is a large, 
 radially striate, irregularly circular plate about six times larger than 
 the adjoining pieces. 
 
 MESOPALJ2ASTER CARACTACI (Gregory). 
 Plate 9, fig. 6; plate 11, fig. 1. 
 
 Palseaster caractaci SALTER, Cat. Foss. Mus. Practical Geology, 1865, p. 30 (nomen 
 nudum). NICHOLSON and ETHERIDGE, Mon. Silurian Foss. Girvan Disk, 
 Ayrshire, fasc. 3, 1880, p. 321 (no description). GREGORY, Geol. Mag., 
 dec. 4, vol. 6, 1899, p. 344. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., 
 Wiesbaden, vol. 63, 1910, p. 227. 
 
 Protopalxaster caractaci SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. 
 Soc. for 1913), 1914, pp. 21, 30, pi. 1, fig. 5. 
 
 Remarks. The writer was greatly pleased to receive from Dr. F. 
 A. Bather of the British Museum wax squeezes of the type-specimens^ 
 because they clearly show that the genus Mesopalseaster is present in 
 Europe. M. caractaci has its closest relationship in M. sJiafferi, the 
 genotype of Mesopald&aster. The differences are easily to be seen on 
 the abactinal side, as illustrated in this work. 
 
 Rays long and slender, abactinally flattened. R = 12.5 mm., 
 r3.S mm., R, = 3.3r. Radialia small and no larger than the pieces 
 of the accessory columns on either side of them ; the former alternate 
 in position with the pieces of the latter and all of them are more or 
 less spicular in outline. Basal radials slightly larger than the others. 
 The ossicles of the supramarginal columns large and solid, the most 
 prominent of the abactinal side, very large proximally and exceedingly 
 small distally; there are about 14 in a column. Basal inframarginals 
 most conspicuous of all abactinal plates, with each pair occupying 
 the axils, and together with the smaller basal radialia form a ring 
 bounding the disk. The disk has fallen in but still shows a few 
 small pointed plates. 
 
 " Madreporite is large, and placed close by one of the interradial 
 angles" (Gregory). 
 
 Inframarginal ossicles almost smooth, large and prominent proxi- 
 mally, decreasing rapidly in size so that not more than 9 can be 
 seen actinally, where the tiny pieces pass somewhat over to the 
 abactinal surface, or better the lateral sides; Gregory states that 
 there are 12 in a column. The basal pieces of adjacent columns do 
 not as a rule touch one another in the axils. 
 
BEVISION OF PALEOZOIC STELLEROIDEA. 93 
 
 Interbrachial areas with single, large, hexagonal, axillary inter- 
 brachial plates. 
 
 Adambulacral pieces quadrangular, fairly uniform in size for two- 
 thirds the length of the rays and then become gradually smaller 
 distally; there are about 15 in a column. A peculiarity , of this 
 species is that the ambulacralia do not continue around the axillary 
 interbrachials, but cease with the basal inframarginals. There are, 
 therefore, in M. caractaci no adambulacral oral armature pieces. 
 
 Ambulacral furrows moderately wide, with as many rectangular 
 ambulacralia as there are adambulacrals, plus probably four more 
 in each column, and these continue around the axillary interbrachial. 
 Therefore, the oral armature consists entirely of ambulacralia. All 
 of these ossicles are directly opposite one another and have high 
 medial crests that are continuous across the ambulacral furrow. 
 Podial openings large laterally between the plates and the adambu- 
 lacrals. 
 
 Locality and formation. Caradoc sandstone, Soudley quarry, 
 Church Stretton, England. The holotype, a split nodule, is in the 
 British Museum (Natural History), No. 48206; wax squeezes from 
 which the photographs have been made are in the United States 
 National Museum. Other specimens, Bather states, are in the Museum 
 of Practical Geology, London; these are from Marshbrook and occur 
 at a somewhat higher geological level. 
 
 Remarks. Gregory wrote in 1899 that "the nearest ally of this 
 species is P. matutina (Hall)," but the illustrations here presented 
 wiU show that the relationship is with Mesopaldeaster shafferi and not 
 with Hudsonaster matutinus. 
 
 Cat. No. 60606, U.S.N.M. 
 
 MESOPAL^EASTER (?) ACUMINATUS (Simonovltsch). 
 
 Asterias acuminatus SIMONOVITSCH, Sitzb. d. mat.-naturw. Classe Akad. Wiss., 
 
 Wien, vol. 64, Abt. 1, 1871, p. 100, pi. 3, figs. 2-2d. 
 Asterias acwninata SCHONDORF, Palaeontographica, vol. 56, 1909, pp. 72, 109, 
 
 pi. 11, figs. 7, 8. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, 
 
 vol. 62, 1909, p. 32, pi. 5, figs. 4, 5. 
 Roemeraster (?) acuminattis STURTZ, N. Jahrb. fiir Min., etc., 1886, vol. 2, p. 154. 
 
 Actinally this small and slender species is nearly in harmony with the 
 generic characters of Paldeaster and Hudsonaster, differing only in that 
 the axillary interbrachial plates barely extend to the margin of the 
 disk, while in those genera they are prominent and marginal in the 
 axils. In Asterias acuminatus they are as yet not crowded so far orally 
 as in most species of Mesopalseaster. It is a difference of degree, not 
 of kind; therefore this species has more the actinal character of 
 Mesopalseaster than Hudsonaster. Ambulacral plates unknown. 
 
 Abactinally Simonovitsch's species is said to have six columns of 
 tumid plates, all alike and persisting throughout the rays. If the 
 
94 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 outermost columns of each ray are regarded as the inframarginals 
 and the ones immediately inside as supramarginals, two medial 
 columns remain to be homologized with those in Mesopalseaster. If 
 Simonovitsch is correct, then by this interpretation there are two 
 columns between the supramarginals. Both can not be radials and to 
 regard one as such will leave a unilateral and apparently an unnatural 
 development. If five or seven columns of abactinal plates were present, 
 this species would be hi harmony with Mesopalxaster. Since Simono- 
 vitsch's work is of the best, we have at present the only alternative of 
 supposing that the radials in Asterias acuminatus are suppressed and 
 that its two medial columns are homologous with the intercalary 
 abactinal plates of other starfishes. Among Paleozoic asterids this 
 development is rare and is found only in Encrinaster and Palseaster. 
 In that event, A. acuminatus is not a Mesopalseaster. 
 
 A single example of this species was found in the Lower Devonic 
 (probably Upper Coblenzian) near Braubach, Germany. 
 
 In his revision of the Lower Devonic starfishes of Germany, 
 Schondorf was not able to discover the whereabouts of the type-speci- 
 men and therefore had to leave this species as determined by Simono- 
 vitsch. The former states that actinally the structure reminds one 
 of Spaniaster latiscutatus, the genotype of Spaniaster, and closely 
 related to Mesopalseaster. For further remarks see Spaniaster. 
 
 MESOPAL^ASTER (?) CLARKI (Clarke and Swartz). 
 
 Plate 10, figs. 1, 2. 
 
 Pals&aster clarki CLARKE and SWARTZ, Maryland Geol. Surv., Upper Devonian, 
 1913, p. 543, pi. 46, figs. 3,4. 
 
 Original description. "This species is represented in the collec- 
 tions by a single specimen affording a pretty sharp cast of both sides 
 of a very regular and complete individual. In general structure and 
 appearance the species is quite similar, especially on the oral surface, 
 to Palseaster eucharis Hall of the sandy Hamilton shales of central 
 New York, but the latter is a much larger form. 
 
 "The disk is small, rays long and slender, thecal plates all promi- 
 nently developed. The ambulacral surfaces are represented only by 
 a narrow linear depression beneath which the ambulacral plates are 
 concealed. These depressions are bordered by thickened and somewhat 
 elevated quadrangular or pentangular ad ambulacra. The marginal 
 plates are in single rows, much thickened, with generally quadrangular 
 outline and convex surface, each projecting on the margin of the ray. 
 At each axilla is a single pear-shaped plate with its apex outward, 
 these plates being the largest in the individual. The abactinal surface 
 is tessellated by rows of strong convex plates of similar size to the mar- 
 ginal plates. Of these there are three rows, a median row of narrow 
 oval ones between the ends of which are interlocked the edges of the 
 much larger plates of the lateral rows which are highly convex and 
 
REVISION OF PALEOZOIC STELLEROIDEA. 
 
 95 
 
 FIG. 8. SPANIASTER LATISCUTATUS, AFTER 
 SCHONDORF. SCHEMATIC ARRANGEMENT OF 
 THE ABACTINAL PLATES. C, PRESUMABLE 
 POSITION OF ANUS; Ce, CENTRAL PLATE; 
 Jn, BASAL INTERRADIALIA; mdp, PROBABLE 
 POSITION OF MADREPORITE; mo, SUPRAMAR- 
 GINALIA; RI, BASAL RADIALIA. 
 
 thickened in the center and greatly depressed to the sutures . Thus each 
 plate has a cushioned surface. Between the ends of each plate of the 
 middle row are two minute accessory plates lying in the angles at 
 which the lateral plates enter. At the base of each ray and upon the 
 disk is a single large plate whose surface rises into a high clavate node. 
 Between each two of these is one of 
 less height.. The central portion of 
 the aboral area is destroyed and no 
 trace of madrepore is seen. 
 
 "The width of this specimen from 
 tip to tip is 33 mm. 
 
 "Occurrence: Jennings formation, 
 Chemung member. Yellow sandstone 
 on the road northeast of Oakland, 
 Garrett County [Maryland], where it 
 is associated with Spirifer disjunctus. 
 
 "Collection: Maryland Geological 
 Survey." 
 
 Remarks. This clearly determined 
 species is a late survival of early 
 Paleozoic primitive asterids. The 
 characters so far as determinable in 
 the natural mold are those of Meso- 
 palseaster, but as the disk skeleton is not preserved, it is very prob- 
 able that when this feature is known the form will be seen to belong 
 to a new genus. 
 
 Genus SPANIASTER Sehondorf. 
 
 Plate 12, figs. 1, 2; text fig. 8. 
 Calaster SANDBERGER (not Agassiz 1835), Verst. d. rheinischen Schicht. Nassau, 
 
 1855, p. 381. 
 
 Spaniaster SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 60, 
 1907, p. 176; vol. 62, 1909, p. 30; Palaeontographica, vol. 56, 1909, pp. 73, 109. 
 
 Remarks. This genus with its single very small species has its 
 nearest relations with Mesopalseaster, in that it has a single axillary 
 interbrachial plate in each actinal axillary area, but differs from it 
 in that there are many more adambulacral and ambulacral plates 
 than there are inframarginals. The marked and generic difference, 
 however, is on the abactinal side, where there are but three columns 
 of plates, one radial and two suuramarginal, of large and thick ossicles 
 arranged in parallel rows, the pieces of which do not alternate with 
 one another; further, the supramarginals are almost completely 
 superposed upon the inframarginals, the two columns together, but 
 more particularly the inframarginals, bounding the rays and not the 
 inframarginals alone, and not so pronouncedly as in Mesopalseaster. 
 The disk is also more primitive in its construction, in that the central 
 
 50601 Bull. 8815 7 
 
96 BULLETIN 
 
 disk plate is encircled by a ring of but 5 small accessory disk pieces, 
 separating the former from the next ring of 10 much larger plates 
 that are the primary pieces of the radial and supramarginal columns. 
 Genoliolotype and only species. Ccelaster latiscutatus Sandberger. 
 Restricted to the Lower Devonic of Germany. 
 
 SPANIASTER LATISCUTATUS (Sandberger). 
 Plate 12, figs. 1, 2; text fig. 8. 
 
 Ccelaster latiscutatus SANDBERGER, Verst. d. rheinischen Schicht. Nassau, 1855, 
 
 p. 381, pi. 35, figs. 1, la. 
 Xenaster simplex SIMONOVITSCH, Sitz. d. mat.-naturw. Classe Akad. Wiss., Wien, 
 
 vol. 64, Abt. I, 1871, p. 97, pi. 3, figs. 1, la. 
 Spaniaster latiscutatus SCHONDORF, Palseontographica, vol. 56, 1909, pp. 73-82, 
 
 109, pi. 8, fig. 2; pi. 10, figs. 2, 9, 10; pi. 11, fig. 9 (complete synonymy given 
 
 here); Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 62, 1909, p. 31, pi. 
 
 5, figs. 1-3, text fig. 2. 
 
 The Sandberger specimen, showing only the abactinal side, was 
 found in the Lower Devonic Spiriferensandstein at Unkel, near 
 Bonn, Germany. Another specimen from the Lower Coblenzian 
 quartzite has been recently found at Bienhorntale, near Coblenz; 
 this shows both sides. Still another is from the Lower Coblenzian 
 at Oberstadtfeld in the Eifel. The holotype of X. simplex is from the 
 Upper Coblenzian at Niederlahnstein on the Rhine. 
 
 Genus MIOMASTER Sehondorf. 
 
 Plate 8, fig. 3. 
 
 Miomaster drevermanni SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, 
 vol. 62, 1909, p. 38, pi. 3, fig. 4; pi. 4, fig. 3. 
 
 Remarks. This genus is most closely related to Spaniaster, in 
 that both have the single axillary interbrachial plates and the infra- 
 marginals and supramarginals are directly superposed. They differ 
 from one another mainly on the abactinal side, though this area is so 
 poorly preserved in Miomaster that almost nothing definite can be said. 
 Sehondorf illustrates a section through .the rays that shows the 
 presence of single columns of very small accessory pieces between 
 the radialia and supramarginalia. In the description, however, he 
 states: "One can not positively determine whether the supra- 
 marginal plates are separated from the median pieces by small 
 accessory ossicles, or whether the three dorsal columns were closely 
 adjoining." The central disk area is also too much disturbed to make 
 out the skeletal arrangement. There appear to have been small 
 interbrachial abactinal areas. Under these circumstances, the genus 
 Miomaster can not be said to be well established, and its final dispo- 
 sition is dependent on finding better preserved material. 
 
 Genoholotype and only species. M. drevermanni Sehondorf (as 
 cited above). A single example was found by Drevermann in the 
 Upper Coblenzian at Miellen-on-the-Lahn, Germany. The holotype 
 is in the Senckenberg Museum, Frankfort-on-the-Main. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 97 
 
 DEVONASTER, new genus. 
 
 Plates 11 and 12. 
 Palseaster (part) of AUTHORS. 
 
 Xenaster (?) or new genus GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 346. 
 Devonaster SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, April, 1914, p. 14. 
 
 A characteristic starfish of the American Devonic. 
 
 Generic characters. Rays five, stout, tapering rapidly. Disk 
 large, with small interbrachial arcs. 
 
 Abactinal area of rays with prominent columns of radial supra- 
 marginals and less prominent inframarginal plates, all of which 
 bear numerous small pustules. The radial columns are completely 
 separated from the supramarginals by a great abundance of very 
 small, conical, irregularly arranged, accessory plates which in the 
 proximal region may also force apart single plates of these columns. 
 The supramarginal columns of adjoining rays nearly meet in the 
 axillary areas a short distance inside of the margin, at which level 
 the radial columns also cease. Inside of the area bounded by the 
 proximal plates of the radial and supramarginal columns, the disk 
 has numerous small accessory plates like those of the rays. In the 
 center of the disk is a plate somewhat more prominent than those 
 surrounding it, and just inside of the adjoining proximal supramar- 
 ginals is a small but distinct plate interradial in position. 
 
 Ambital accessory plates abundantly developed between the 
 marginal ossicles in the axillary areas. These plates are like the 
 other accessory plates and do not extend beyond the third or fourth 
 proximal inframarginal pieces, where the ambital areas cease and 
 the supramarginal ossicles come to lie more and more completely 
 over the inframarginals. 
 
 Madreporite flat or concave, situated between two proximal 
 supramarginal ossicles and outside of one of the small interradially 
 situated plates. 
 
 Inframarginal pieces lajge and thick, increasing rapidly in width 
 proximally, so that the tw.o wedge-shaped proximal plates are nearly 
 three times as wide as long. The plates are pustulose, and the proxi- 
 mal ones bear several slender spines. 
 
 Adambulacral plates more numerous than the inframarginals, 
 continuing around the axillary interbrachial plates, in front of 
 which the columns meet in two triangular and enlarged adambu- 
 lacral oral armature plates. Each piece bears two short, obtusely 
 pointed spines. 
 
 Ambulacral grooves narrow and deep, either straight or very slightly 
 petaloid. Ambulacral plates equaling in number the adambulacrals 
 and arranged in directly opposed, closely adjoining columns. Podial 
 openings in two columns through the sutures in the lateral part of 
 the furrows. 
 
98 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Axillary interbrachial plates large, a single one situated in each 
 area between the adambulacral and inframarginal columns. Each 
 bears short, thick, blunt spines. 
 
 Mouth plates (tori) minute, one situated in front of each pair of 
 oral armature plates. 
 
 Genoholotype. Palseaster eucharis Hall. 
 
 Distribution. Restricted to the Hamilton and Chemung of the 
 American Devonic. The species are: 
 D. eucharis (Hall). Hamilton. 
 D. chemungensis, new species. Chemung. 
 
 Remarks. This genus is readily distinguished from Hudsonaster 
 hi having well-developed radial and ambital accessory plates, in 
 the numerous very small plates of the disk and in the presence of 
 interbrachial axillary plates. 
 
 Devonaster differs from Palseaster in having radial columns of 
 plates and in the presence of three plates in each interbrachial area 
 against one in Palseaster. There are also other differences. From 
 Neopalseaster it differs in having ambital accessory plates and no 
 ocular plates; while the proximal supramarginals and radials are 
 very large in the former, they are small in Devonaster, particularly 
 the supramarginals, which are not readily distinguished from the 
 accessory disk plates. In Mesopalseaster and Promopalseaster the 
 accessory plates are always arranged in columns or rows and the 
 ambital accessory plates are not restricted to the axillary areas as 
 hi Devonaster. Further, in those genera (excepting in the smaller 
 forms of Mesopalzeaster) there are always from two to five inter- 
 brachial marginal plates, while Devonaster has but one axillary 
 marginal in each interbrachial area. 
 
 Devonaster greatly resembles abactinally Xenaster of the Lower 
 Devonic of Germany, but is readily distinguished actinally in that 
 the latter has more large interbrachial plates, and especially in the ad- 
 dition of numerous accessory interbrachial pieces. These differences 
 are pointed out in more detail in the remarks on Xenaster. 
 
 DEVONASTER EUCHARIS (Hall). 
 
 Plate 12, figs. 3-5. 
 
 Palseaster eucharis HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 
 287, pi. 9, figs. 3-3a (74); rev. ed., 1868=1870, p. 330, pi. 9, figs. 3-3a (74). 
 QUENSTEDT, Petrefactenkunde Deutschlands, vol. 4, 1876, p. 71, pi. 92, 
 fig. 29. ZITTEL, Handb. Pal., vol. 1, 1879, p. 452, fig. 323. COLE, Bull. 
 Geol. Soc. America, vol. 3, 1892, p. 512, pi. 15. CLARKE, Bull. N. Y. State 
 Mus., No. 158, 1912, pp. 44-45, 6 pis. 
 
 Xenaster eucharis SCHONDORP, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 
 66, 1913, pp. 87-96, pi. 3, figs. 1, 2, text figs. 1-3. 
 
 Original description. " Body rather large; the largest individual 
 being one inch and seven-eighths from the center of the body to the 
 extremities of the rays; the whole having a robust aspect; rays 
 
REVISION OF PALEOZOIC STELLEROIDEA. 99 
 
 acutely pointed at the extremity. Upper [abactinal] surface of 
 rays composed of three [radial and two supramarginal] ranges of 
 large, highly convex or tuberculiform plates which are nearly cir- 
 cular at the bases of the rays, becoming quadrate and widened to- 
 wards the extremities; separated from each other in the lower part 
 by numerous minute [accessory] plates or granules, which become 
 fewer near the middle of the ray, and before reaching the extremity. 
 The central portion of the disk is occupied by an elevated pentagon, 
 the angles of which are formed by the abrupt termination of the 
 central row of plates of each ray: the whole composed of very mi- 
 nute, highly convex plates, which vary in size, the larger ones pen- 
 tagonally arranged. The angles between the rays have a few [nu- 
 merous] small [accessory ambital] plates outside of the outer ranges 
 of tuberculose [supramarginal] plates on the upper side, uniting 
 with the inframarginal plates below [and not extending beyond 
 the third or fourth inframarginal proximal plate]. Madreporiform 
 tubercle distinct, situated lateraUy at the bases of the outer [supra- 
 marginal] range of large plates of two adjacent rays. Ventral sur- 
 face having deep ambulacral grooves, bordered by two ranges of 
 strongly tuberculose plates; the outer [infra] marginal range con- 
 sisting of 27 or 28 plates, besides a large, round [or elliptical], ter- 
 minal or axillary [interbrachial] plate; the others are wider than 
 long in the basal portion of the ray, becoming gradually shorter 
 towards the extremity where they are rounded. All the [infra] 
 marginal plates are visible from the upper [abactinal] side, and 
 usually appear as an additional range of plates on each margin of 
 the ray, making five with the three properly belonging to the upper 
 surface. Those of the inner range bordering the ambulacra (adam- 
 bulacral plates) are smaller than the marginal plates, about 38 to 
 40 in number; the basal or oral plates [oral armature] are triangular, 
 those of the adjacent rays uniting by their longer margins; and with 
 a single minute plate situated at these points. The plates of the 
 exterior surface, both upper and lower, present a granulose or stri- 
 ato-granulose surface which appears to have been produced by short 
 setae or spines; and at the angles of the rays the marginal plates 
 are armed by a few spines, which are as long or longer than the 
 transverse diameter of the plates. Ambulacra composed of a double 
 range of short, broad poral plates (ossicula), equal in number to 
 the adambulacral plates ; their outer ends excavated on the posterior 
 border, forming a comparatively large pore, just within its junction 
 with the adambulacral plate. There appears to have been [is] but 
 one range of pores in each set of ossicula, but these are large, dis- 
 tinct, and pass between [through and not between] the plates." 
 
 The following additional description is that of Mr. Cole. The 
 surface of the axillary interbrachial plate "is granulose and bears 
 
100 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 three short, thick, blunt pointed spines. The [infra] marginal plates 
 bordering each reentrant angle bear similar but more slender spines, 
 which are not 'as long as the transverse diameter of the plates.' 
 The spines are arranged in a row near the distal margin of the plates 
 and number five on the plates at the angle, the number and size 
 decreasing until they disappear at the sixth or seventh plate from 
 the angle. All the [infra] marginal plates are nearly smooth on the 
 free margin and become gradually more granulose toward the line 
 of junction with the adambulacral plates. * * * 
 
 "The adambulacral plates are apparently less numerous than 
 stated in the original description, and l the single minute plate 
 [mouth plates] ' at the points of the pairs of the oral plates [oral 
 armature] is visible in this specimen and is armed with two relatively 
 long, slender spines which are apparently but a part of the full 
 armature. The adambulacral plates, including the triangular oral 
 [armature] plates bear well-defined spines, which are shorter than 
 the diameter of the plates to which they are attached. Each plate 
 bears two spines so near to the distal margin that the impressions 
 of the short and obtusely pointed spines frequently bridge the 
 well-defined groove between the adjacent adambulacral plates and 
 terminate near the proximal margin of the next plate. The spines 
 decrease in size toward the end of the ray and a few plates show 
 only one spine. The plates of this range are thick, equaling two- 
 thirds to three-fourths the depth of the groove. The vertical angle 
 of the faces forming the lateral walls of the groove are beveled, so 
 that lateral extensions of the groove are formed between each two 
 plates on the same side. These lateral expansions are narrow and 
 shallow at the oral surface, deeper and wider inward; so that the 
 faces of the adambulacral plates near their junction with the poral 
 [ambulacral] plates are reduced to a narrow edge which projects 
 inward and nearly touches the corresponding plate on the other 
 side of the groove. The general appearance of the fossil as well as 
 the outline of the rays at the points where the broken block presents 
 a transverse section of them indicates that the plates have their 
 normal position, not having suffered distortion by pressure. 
 
 "The ambulacral plates are shown by a well-defined mold of their 
 under or external surface. The soft matrix which filled the ambula- 
 cral furrow pressed upon the membranes connecting the ambulacral 
 plates and occupying their pores, and as these membranes decayed 
 it was forced by gentle pressure into the pores and between the 
 edges of the plates. The mold of the groove is less than one-eighth 
 of an inch in width in a ray measuring five-eighths at its base. The 
 upper surface of the mold bears a narrow longitudinal median ridge 
 which marks the junction of the two ranges of ambulacral plates. 
 Similar transverse ridges, which are continuous with the lines mark- 
 
REVISION OF PALEOZOIC STELLEROIDEA. 101 
 
 ing the junction of the inner faces of the adambulacral plates, mark 
 the proximal and distal margins of the ambulacral plates. These 
 ridges do not cross at right angles to the median line, but include 
 between their proximal sides an angle of about 125. These ridges 
 indicate that the ambulacral and adambulacral plates were equal 
 in number, and that the former were united in pairs along a straight 
 median line rather than in an alternate right and left arrangement 
 along a zigzag line, as is shown in Dr. Hall's figures. The pores 
 described as being ' excavated in the posterior border of the ambu- 
 lacral plates and just within their junction with the adambulacral 
 plates' are not clearly shown on this specimen, although there are 
 irregular and inconstant markings at some of the points of the molds 
 of the lateral extensions of the groove. A series of pores near the 
 median line is indicated by a series of small rounded prominences 
 on each side of the median ridge and very close to it. These promi- 
 nences are opposite the lateral expansions of the groove, and one is 
 found on the mold of each ambulacral plate. The pores appear to 
 have perforations very near the edges of the plates, or excavations 
 in their margins." 
 
 Abnormal development. Among the 400 specimens of this species 
 recently found near Saugerties, New York, there are a few indi- 
 viduals each with but four rays, though otherwise they appear to 
 be of normal development. This is the first discovery of a four- 
 rayed starfish in the Paleozoic. 
 
 Formation and locality. In the Hamilton of the Middle Devonic 
 near Hamilton, Summit and Cooperstown, New York, Two sepa- 
 rated rays of apparently this species were found by the writer in the 
 lower third of the Hamilton near Bartletts Mills, south of Thedford, 
 Ontario. Two other fragments from the same locality are in the 
 University of Toronto (Walker collection, No. 1610H). The type 
 and other specimens are in the American Museum of Natural History, 
 one* is in Colgate University, another at Wesleyan University, and two 
 in Yale University Museum. 
 
 Recently the New York State Survey collected in the Hamilton 
 sandstone at Mount Marion, near Saugerties, New York, over 400 
 examples of this fine starfish. They occur in a limited area and 
 are often found in association with Grammysia and in such manner 
 that Doctor Clarke believes the starfishes were feeding on the bivalves. 
 This is probably the most remarkable find of Paleozoic starfishes, and 
 is certainly so for America. 
 
 DEVONASTER CHEMUNGENSIS, new species. 
 
 Plate 11, fig. 2. 
 
 Of this species only the actinal side is known, and its general 
 structure so far as can be made out is that of D. eucharis (Hall). 
 
102 BULLETIN 
 
 It differs from the latter in that each axillary interbrachial plate 
 bears one stout spine, while D. eucharis has three. Further, in 
 D. eucharis six or seven of the proximal inframarginal plates of 
 each column bear on their outer side a number of small, slender 
 spines. In D. chemungensis these spines may also be present but 
 in addition each plate bears centrally a prominent tubercle for the 
 articulation of a large spine. 
 
 Formation and locality. The type is in the Museum of Columbia 
 University, New York City (No. 6228G). It is from the Spirifer 
 disjunctus sandstone of the Chemung of " Central Pennsylvania." 
 
 NEW GENUS. 
 
 NEW SPECIES. 
 
 In the University of Chicago collection there is a specimen (No. 
 14397) collected by Professor Weller in the St. Louis limestone on 
 Fountain Creek, at Waterloo, Illinois. This five-rayed asterid is 
 small, shows only the abactinal side, and has very long but narrow 
 marginals and not over six or possibly seven in a column; the basal 
 plates of adjoining columns make the axils. Otherwise the abactinal 
 skeleton of the rays consists of many small, loosely adjoining pieces 
 whose arrangement can not be made out. Nor can the disk struc- 
 ture be determined. 
 
 The relationship of this specimen seems to be with the Promo- 
 palseasteridse, with possible nearest affinity to the genus Mesopa- 
 Ixaster. 
 
 Measurements: R = not less than 10 mm., r = 4 mm. 
 
 I'liODVJIOI'-A.ILi^E^STElRIlSr^B, new subfamily. 
 
 Progressive Promopalseasteridse with the interbrachial areas com- 
 plex and composed of the single axillary interbrachials, more than 
 one pair of interbrachial marginals, and adambulacral plates. Podial 
 openings in each ambulacral furrow mainly in two columns, Jbut 
 proximally there may be two additional ones in a length never 
 more than one-third the rays. 
 
 Contains : 
 
 Promopalseaster, new genus. 
 
 PROMOPAL^EASTER, new genus. 
 
 Plates 13 to 23, 25. 
 Palxaster (part) of AUTHORS. 
 
 Promopal&aster SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, April, 
 1914, p. 24. 
 
 Promos, chief, and aster. The largest and chief starfishes of the 
 American Ordovic. 
 
 Generic characters. Disk above medium size, with distinct and 
 angular interbrachial arcs. Rays five, slender to stout, more or less 
 long, and tapering. Some species attain a large growth. 
 
BEVISION OF PALEOZOIC STELLEROIDEA. 103 
 
 Abactinal area of rays with numerous columns of small, more or 
 less tumid, closely adjoining or reticulated, spine-bearing plates. A 
 medial radial and two lateral or supramarginal columns of plates are 
 usually more conspicuous than the accessory columns; however, the 
 radial plates may be also inconspicuous. The longitudinal arrange- 
 ment in columns is usually most pronounced, but sometimes the 
 plates on each side of the radial column may have a decided diagonal 
 arrangement. Small accessory plates are usually inserted between 
 the columns of ossicles or between the individual pieces both distally 
 and proximally. Disk with numerous small accessory plates like 
 those of the rays, with no apparent definite arrangement except 
 the supramarginal columns, which continue over the disk and unite 
 angularly in the axillary areas. The larger plates bear several 
 short articulating spines of which the one on the apex is the largest. 
 
 Ambital areas well developed, there being one or more columns 
 of small plates like the radial accessory columns both in form and 
 arrangement. 
 
 Madreporite usually conspicuous, radially striated, and situated 
 near the margin of the disk between the adjoining columns of supra- 
 marginal plates. 
 
 Inframarginal plates small and numerous distally like the adambu- 
 lacrals, but proximally they usually increase rapidly in width and 
 assist in forming the small interbrachial arcs. Each ossicle has 
 numerous small granules which probably bore short, smooth, articu- 
 lating, blunt spines. 
 
 Adambulacral plates distally like the inframarginals, increasing in 
 width proximally and continuing around the plates of the inter- 
 brachial areas. The two proximal plates of adjoining columns are 
 the paii^s of plates in the oral armature. Each adambulacral plate 
 has a more or less well-developed narrow ambiilacral extension which 
 unites with the carina of the ambulacral plates. These extensions 
 belong to the adambulacral plates, apparently always so distally, but 
 proximally they are often separated from the adambulacral plates 
 by sutures ; throughout the greater portion of the rays they are situ- 
 ated medially, but in the proximal region they are either on the distal 
 or proximal edge, each alternate plate having the extension from 
 the same corner a little longer. Each plate has more or less numerous 
 spine-bearing granules in addition to the three larger articulating 
 spines which are inserted one on the ambulacral and two on the lateral 
 edge. 
 
 Ambulacral furrows generally very wide and regularly tapering. 
 In each ray there are two columns of these plates which are slightly 
 alternating or opposite. The plates are as numerous as those of the 
 adambulacral columns, highly carinated, about as wide as long in the 
 extreme distal portion of a ray, increasing rapidly in width proximally 
 
104 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 and at the base of the rays may be four times as wide as long. The 
 podial openings, one to each plate and in single ranges, are at the 
 extreme lateral edges excavated between the sutures of adjoining 
 plates and beneath the adambulacrals. Proximally, however, every 
 other podial opening progresses inwardly with the joined carinae and 
 issues where these begin to fork. Here there are, therefore, four 
 columns of podial openings in each ambulacral furrow. This change 
 is indicated by the changed position of the adambulacral plate exten- 
 sions and also b} 7 the pairs of forked carinse of the ambulacral plates. 
 Throughout the greater portion of a ray the carinse are regular and 
 alike on each plate, but toward the mouth they change rapidly in 
 direction and soon they are arranged in forked parrs, one curving 
 distally, the other proximally, with the lateral portions of each pair 
 hi contact and uniting with the extensions of the adambulacral 
 plates. The most proximal plate of each ambulacral column is 
 usually considerably modified, longer than wide, and more or less 
 triangular in outline, between which there is sometimes inserted a 
 small quadrangular ossicle. These pieces belong to the oral 
 armature. 
 
 Interbrachial areas of medium size, with the interbrachial marginal 
 plates usually arranged in pairs but in some forms the series may be 
 terminated by single ossicles. The number of these plates in an area 
 varies in different species, there being two, three, or five inside the 
 marginal inframarginals, and all seem to be derived from the 
 inframarginal series by inward crowding. 
 
 Genoholotype. Palseaster granulosus Meek (not Hall = P. speciosus 
 Meek). 
 
 Distribution. Restricted to the Middle and Upper Ordovicic of 
 America, chiefly within a radius of 50 miles about Cincinnati, Ohio. 
 The following are the known species: 
 
 P. wilsoni (Raymond). Black River (Lowville). 
 
 P. prenuntius, new species. Trenton. 
 
 P. sp. undet. ?Young of P. speciosus Meek. Maysvillian. 
 
 P. speciosus (Meek). Maysvillian. 
 
 P. granulosus (Hall). Lower Richmond. 
 
 P. bettulus, new species. Richmond. 
 
 P. spinulosus (Miller and Dyer). Richmond. 
 
 P. exculptus (Miller). Richmond. 
 
 P. wylcqffi (Miller and Gurley). Richmond. 
 
 P. dyeri (Meek). Maysvillian. 
 
 P. magnificus (Miller). Maysvillian and Richmond. 
 
 Remarks. Eight of the ten species here referred to Promopalseaster 
 
 have been described as Palxaster. They have little direct relationship 
 
 with the latter genus in that the species are much larger, have well 
 
 developed ambital areas, numerous accessory plates, well defined 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 105 
 
 interbrachial arcs, and from two to five interbrachial marginal plates 
 in each interbrachial area. Promopalseaster is a direct development 
 from Mesopalseaster, in that it preserves the generic characters of the 
 latter, which is in turn a descendant of Hudsonaster. In Hudsonaster 
 there are no interbrachial plates, accessory or ambit al columns. In 
 Mesopalseaster the single axillan^ marginal plate of Hudsonaster has 
 been crowded orally and is no longer a marginal but an axillary 
 interbrachial. Further, the radial and both marginal columns are 
 more or less completely separated from one another by accessory 
 columns of smaller plates. In Promopalseaster this addition of 
 columns of small plates is carried to its greatest development. The 
 character, however, which is relied upon to distinguish it from Meso- 
 palseaster is that Promopalseaster always has two or more interbrachial 
 marginal plates in each interbrachial area, while the former genus 
 has one, the axillary interbrachial, and Hudsonaster has none. The 
 position and number of axillary and interbrachial marginal plates 
 will readily distinguish these genera, but if the abactinal area of a 
 new form alone is seen it will be difficult to determine whether it is a 
 Mesopalseaster or Promopalseaster. Small size and few accessory 
 columns, especially ambital, will help somewhat to distinguish 
 Mesopalseaster from Promopalseaster. 
 
 Accepting Promopalseaster as a descendant of Mesopalseaster, it is 
 seen that the axillary interbrachial plates of the latter have in P. 
 exculptus been followed by two proximal pieces of adjoining infra- 
 marginal columns. The same is probably true of P. spinulosus, but 
 here no axillary interbrachial has been observed. In P. speciosus 
 and P. bellulus, another pair of proximal inframarginals have become 
 interbrachial plates, but the axillary interbrachial is also unknown 
 in this species. In P. dyeri and P. magnificus the axillary inter- 
 brachial is present along with two pairs of interbrachial marginals. 
 In other words, there is in Promopalseaster a constant increase in the 
 size of the interbrachial area produced by the crowding of pairs of 
 proximal inframarginal plates. 
 
 P. speciosus and P. bellulus are closely related species, and so far 
 as can be determined have but two interbrachial marginal plates, 
 while our theoretic development requires three. There is, however, 
 in each area orad to the interbrachial plates a small hiatus which in 
 some cases appears to be filled by extensions from the adambulacral 
 plates. It seems therefore probable that the axillary interbrachial 
 plate may be retained, but is not now discernible on account of its 
 small size or adhering clay; it may also have dropped out or have been 
 absorbed and its place occupied by the adjoining adambulacral plates. 
 
 In a general way it can be stated that there is also a regular increase 
 in the number of accessory plates from Mesopalseaster to Promopalse- 
 aster through P. spinulosus, P. speciosus, P. bellulus, P. dyeri into 
 
106 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 P. magnijicus. It seems probable from the mature material studied 
 that the most differentiated species of Promopalseaster, P. magnificus, 
 passed through ontogenetic stages comparable to Hudsonaster, Meso- 
 palseaster granti, and Promopalxaster bellulus. 
 
 P. magnificus at present stands alone in its beautiful diagonal 
 and longitudinal arrangement of abactinal plates. 
 
 PROMOPAL^ASTER WILSONI (Raymond). 
 Plate 13, figs. 1, 2. 
 
 Palseasterf wilsoni RAYMOND, Ottawa Naturalist, vol. 26, 1912, p, 77, pi. 5, figs. 
 1-1. 
 
 Original description. " The specimen is exposed from the abactinal 
 side, and preserves the greater part of one arm, the disk, and the 
 stumps of the other four arms. The diameter of the specimen, 
 when complete, must have been about 75 mm. (3 inches), and the 
 diameter of the disk is 20 mm. This is large for a starfish from the 
 lower Ordovician. The arms are quite convex, with a gentle taper, 
 reminding one somewhat of the common recent starfish, Asterias 
 vulgaris, and as in that species, the arms were probably somewhat 
 flexible. The greater part of the abactinal side of the disk and arms 
 is covered with small convex, overlapping, V-shaped plates, which 
 are arranged with the point of the V directed toward the margins. 
 Along the crest of each arm there is a single row of larger plates 
 (radial column). These plates are quite large and hexagonal in out- 
 line near the disk, but become smaller, triangular, and alternate in 
 position farther out on the arm. There are two rows of marginals 
 [supra and infra] these plates being larger and flatter than the other 
 plates, and covered with minute tubercles, which may be spine bases. 
 Close to the disk, the supramarginals and [infra] marginals seem to be 
 of the same size, both rectangular, and the plates' of the supra- 
 marginal row directly over those of the marginal series. Farther 
 out on the arms, the plates are pentagonal, those of the two rows 
 alternating in position, and dove-tailing, and the supramarginals 
 are smaller than the marginals. One of the marginals, about half- 
 way out on the arm, is 1.25 mm. high and of about the same breadth. 
 The smaller triangular plates which cover the greater part of the 
 arm average about 0.5 to 0.6 mm. in height. On one of the arms, 
 the small triangular plates seem to be arranged in rows parallel to the 
 axis of the arm, but the plates on the longer arm seem to be more 
 irregular, although a general arrangement in rows can be seen. On 
 this arm there are a number of very small plates scattered about, 
 especially on the top of the arm, thus adding to the irregularity. The 
 triangular shape of these plates gives the arm a neat pattern, the plates 
 making diagonal rows backward and forward from the row of large 
 plates along the top of the arm. The madreporite, which is nearly 
 circular in outline, and 2 mm. in diameter, is in position, but slightly 
 
BEVTSION OF PALEOZOIC STELLEROIDEA. 107 
 
 tipped down at the inner side, in an interradius, and not far from the 
 center of the abactinal side of the disk. The surface is probably worn, 
 for it appears perfectly smooth." 
 
 In places the abactinal ossicles are removed, "disclosing the ambu- 
 lacral plates. These plates, which are long and rather thick, seem 
 to be alternate in position. Two of the plates seem to be pierced by 
 pores near their proximate ends, two pores piercing each plate ver- 
 tically. Near the outer end of the more perfect arm there is a space 
 where a few of the small triangular plates are missing, and here also 
 the ambulacral plates can be seen from the upper side. Each plate 
 has a narrow keel on that side. Other details of the plates of the 
 actinal side are unknown." 
 
 Formation and locality. In the Lowville limestone at City View, 
 near Ottawa, Canada, where this interesting asterid was found by 
 Miss A. E. Wilson, in whose collection the holotype now is. 
 
 Remarks. It is interesting to note that this fully developed 
 Promopalseaster, one closely related to P. magniiicus of the highest 
 Ordovicic, occurs in much older rocks; that is, in the Black River 
 formation. This occurrence again brings out the fact often noted 
 by the writer, that Paleozoic asterids are slow to change in characters 
 accessible to the paleontologist. 
 
 P. magniiicus, like P. wilsoni, Raymond states, "has two rows 
 of large marginals and a row of large plates along the top of each 
 arm, while the greater part of the surface is covered with small 
 convex triangular plates. Miller found the plates to be spine-bearing, 
 a point which can not be definitely decided in the present species. 
 From the photograph (submitted by Schuchert) it appears that there 
 are spaces between the small triangular plates on the abactinal sur- 
 face in Pals&aster f magniiicus, while in P. ? wilsoni these plates actually 
 overlap each other." 
 
 PROMOPAL^EASTER PRENUNTIUS, new species. 
 Plate 13, fig. 3; plate 15, fig. 5. 
 
 Remarks. This species is represented by a good specimen showing 
 the actinal side, the other adhering to the limestone. R = somewhat 
 less than 30 mm., r = 7 mm. Width of ray at base about 9 mm. 
 
 P. prenuntius is closely related to P. speciosus, but is distinguished 
 therefrom by the smaller size, less pustulose ornamentation of the 
 plates, and the lower position in the geological column. The plates 
 of the axial area are also more regular in size and there are in the 
 proximal region nearly always two adambulacrals to each inframar- 
 ginal; at about mid-length of the rays the plates of each of the two 
 columns are about equal in number, but every now and then there 
 is some duplication among the adambulacrals. P. prenuntius is 
 equally as spinose as P. speciosus and the former is undoubtedly the 
 ancestor of the latter. 
 
108 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Formation and locality. The holotype was collected by Mr. Wendt 
 near Frankfort, Kentucky, apparently in the Lower Trenton. The 
 writer's attention was called to it by Prof. Arthur M. Miller, who 
 has it in his charge at the State University of Kentucky at Lexington. 
 
 PROMOPAL^ASTER, species undetermined. 
 Plate 14, figs. 1, 2. 
 
 Asterias primordialis ANONYMOUS, two lithographic figures sent out by the Western 
 Academy of Sciences previous to 1872 without description or known author. 
 
 Nothing more is known of this species than the two good original 
 illustrations reproduced here. These figures were sent to F. B. Meek 
 on May 18, 1872, by Mr. D. H. Shaffer, of Cincinnati, Ohio, with the 
 following comment (they were found in the Meek correspondence 
 kept in the United States National Museum): "The lithograph in- 
 closed of this Asterias was found here, and in the possession of 
 Joseph Clark (deceased). I saw it, and this is a faithful picture of it. 
 I think the fossil is either in the possession of his nephew or in the 
 cabinet of Maxwell's Female Seminary, which now is the owner of 
 Mr. Clark's cabinet. I think it is worthy a place with Palseaster 
 shafferi in the illustrations of the Ohio Geological Survey." 
 
 From the illustration one sees that this form had on the abactinal 
 side of the rays about nine columns of ossicles. Of these the radial, 
 supra- and inframarginals are largest. Between the marginals there 
 is a single column of tiny ambital pieces, while on each side of the 
 radials are two columns of small accessory pieces. The structure of 
 the disk pieces can not be made out. 
 
 The interbrachial areas are small and do not appear to have more 
 than two inwardly crowded inframarginals, but there may also be 
 present single very small axillary pieces. 
 
 The adambulacral and inframarginal columns appear to have not 
 more than 20 ossicles hi a column. Of ambulacrals there are some- 
 what more, about 25, and these alternate slightly with one another. 
 
 "Asterias primordialis" appears to be the young of Promopalse- 
 aster speciosus (Meek), and the differences can all be explained as due 
 to incomplete development; that is, the former has fewer ossicles and 
 fewer secondary columns of plates. 
 
 Formation and locality. From the hills of Cincinnati, in the Mays- 
 ville formation. The present whereabouts of this fine specimen is 
 unknown. A still smaller and younger specimen is in the Faber 
 collection of the University of Chicago (No. 9567), and was collected 
 at 350 feet above the Ohio River at Cincinnati. It has but a single 
 axillary plate in each interbrachial area, and about 15 adambulacrals 
 in a column. It is interesting to note that in these young individuals 
 of Promopalxaster, the smaller they are the more they approach 
 Mesopalseaster and suggest Hudsonaster. 
 
EEVISIOST OF PALEOZOIC STELLEKOIDEA. 109 
 
 PROMOPAL^ASTER SPECIOSUS (Meek). 
 Plate 14, figs. 3, 4; plate 15, figs. 1-4. 
 
 Asterias antiquata LOCKE (not A. antiqua Troost), Proc. Acad. Nat. Sci., Phila- 
 delphia, for 1846-47, vol. 3, 1848, p. 32, fig. on p. 33. 
 
 Palseaster antiquata HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, 
 p. 286. 
 
 Palssaster antiquatus HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., rev. ed., 
 1868=1870, p. 328. 
 
 Palseaster granulosus MEEK (not Hall 1868), Amer. Journ. Sci., ser. 3, vol. 4, 1872, 
 p. 276; Geol. Surv. Ohio, Pal., vol. 1, 1873, p. 60, pi. 4, figs. 3a-c. 
 
 Palseaster speciosus MEEK, Amer. Journ. Sci., eer. 3, vol. 4, 1872, p. 277 (name at 
 end of description); Geol. Surv. Ohio, Pal., vol. 1, 1873, p. 61 (name at end 
 of description). 
 
 Also see Promopalxaster, sp. undet., page 108. 
 
 Original description by Meek (1873). " Attaining a large size; 
 rays (as a little depressed by accident) slightly more than twice as 
 long as their breadth at their inner ends ; and tapering regularly from 
 the disk to their free ends, which are rather acutely angular; breadth 
 of the disk a little less than that of the inner ends of the rays. Mar- 
 ginal pieces convex [bearing numerous small spines], nearly or quite 
 as long as wide, numbering on each side, in the whole length of each 
 ray (1.40 inch), 31. Adambulacral pieces, a size smaller, as long as 
 wide, convex, and numbering on each side 39 to 40; like those of the 
 [infra] marginal series, each bearing a small spine [several spines], 
 the largest of which are each about 0.14 inch in length and 0.02 inch 
 in thickness [between each two adambulacral plates just above the 
 podial opening is inserted a large and thick spine], Ambulacral 
 pieces very short, or nearly three times as wide as long, apparently 
 not alternating with the adambulacral pieces, and each provided 
 with a rather sharp ridge across nearly its entire breadth. Dorsal side 
 of disk and rays composed of small tuberculiform pieces, of which 
 about 16 rows may be counted at about half way between the inner 
 and outer ends of each ray, along the middle of which those of two 
 [always two] or three of the rows are a little larger than the others; 
 each dorsal piece bearing a minute, very short spine [they are nume- 
 rous and like those of the marginal plates]. Surface of all the pieces 
 minutely granular, one of the central granules always being somewhat 
 larger than the others for the articulation of a spine [all of these 
 granules bear spines]. Oral pieces and madreporiform body un- 
 known." 
 
 Emended description. Rays regularly tapering. R = 44 mm., 
 r= 11 mm., R = 4r. Width of ray at base 14 mm. 
 
 Abactinal area of rays covered by small, highly convex, tuber- 
 culated plates, each bearing numerous short slender spines. These 
 ossicles are arranged in longitudinal columns, of which there a?e 
 15 on each ray at about its mid-length. The plates of one or 
 
110 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 two median columns are larger and more convex than the three 
 columns immediately on each side, while the pieces of the fourth 
 column are again more pronounced than those on each side of it, and 
 probably represent the supramarginals. Between the supramarginals 
 and the inframarginals are from one to three columns of ambital 
 plates, and between these are inserted here and there some small 
 extra pieces. The extra pieces are mainly developed beside the supra- 
 marginal columns. Plates of the disk like those of the rays, but their 
 arrangement is unknown. 
 
 Madreporite unknown. 
 
 Inframarginal plates very convex, about as wide as long except- 
 ing near the base of the columns where they are about twice as wide 
 as long. There are about 31 of these ossicles in a column, and they 
 have numerous small, slender, sharp spines articulating on well- 
 developed tubercles. 
 
 Adambulacral plates greatly resembling the inframarginals. 
 They are largest near the mid-length of each ray, diminish in size 
 distally, but proximally they hold their width and decrease in length 
 and therefore are more numerous. There are 43 plates in each 
 column besides those in the oral armature. Ambulacrally each 
 adambulacral plate has a short attenuate extension which articulates 
 with the crests of the ambulacral plates. Between all the adam- 
 bulacral ossicles there is inserted in the suture facing the ambulacral 
 groove a single large, thick spine, excepting for a short distance 
 proximally where such are inserted in every other suture. The 
 lateral surface of the adambulacral plates in the distal half of the 
 columns bears numerous small spines like those of the inframarginal 
 series, but proximally these spines are gradually displaced by two 
 or possibly more larger ones like those on the ambulacral face. 
 
 Ambulacral furrows wide and deep. Ambulacral plates of adjoin- 
 ing columns opposite, two or three times as wide as long, and slightly 
 overlapping proximally. Upon each plate there is a high median 
 ridge which arises at the inner end of the plate and abuts against 
 the short extension of the adambulacral plate. The podial open- 
 ings are between the plates and beneath the sutures of the adam- 
 bulacral plates, excepting near the base of the rays, where they 
 occur in every other suture. The ridges here are sigmoid and not 
 straight, as they are more distally. There appear never to be more 
 than two rows of podia in an ambulacrum. 
 
 In each axillary area inside of two large inframarginal plates and 
 between the converging adambulacral columns are inserted two 
 pairs of wedge-shaped interbrachial marginal plates ornamented 
 like the inframarginals. 
 
 Formation and locality. The holotype and only known specimen 
 was collected by Mr. Charles B. Dyer in the Maysvillian at Gin- 
 
REVISION OF PALEOZOIC STELLEROIDEA. Ill 
 
 cinnati, Ohio. It is now in the Dyer collection, Museum of Com- 
 parative Zoology (No. 22), Harvard University. The original of 
 Astcrias antiquata Locke was found at Cincinnati, but the specimen 
 appears to be lost. 
 
 Remarks. Meek (1873) in describing this specimen, provisionally 
 referred it to Palseaster granulosus Hall and commented as follows: 
 
 "Although this fine Star-fish agrees pretty well in most of its 
 characters with the description of Palseaster granulosus of Hall (which 
 has not yet been figured) , I am far from being entirely satisfied that it 
 is really the same, as it seems to differ in some important respects. 
 For instance, the rays of P. granulosus are described as being 'obtusely 
 rounded at the extremities'; while in the form under consideration 
 they are rather acutely rounded, if not angular. Again, instead of 
 having 25 of the marginal pieces on each side, in a space of one inch 
 and a quarter from the apex of each ray, and 42 or 43 of the adam- 
 bulacral, it shows in this space 28 marginal and only 32 adambula- 
 cral pieces. The number of the latter being about 10 less on each 
 side in the same space a rather decided difference, showing the 
 inner row to consist of proportionally larger pieces. Its ambulacral 
 ossicula seem to have the same proportional breadth and length as in 
 the type of P. granulosus and also have each a similar ridge across 
 the middle; but these ridges do not show the zigzag arrangement 
 mentioned in the description of P. granulosus. Prof. Hall does not 
 say how many rows of pieces are seen on the dorsal sides of the rays 
 of his species; but he states that it is probably the same species that 
 the Western Academy of Sciences sent out lithographs of under 
 the name Asterias primordialis. One of these lithographs, now 
 before me [reproduced here on plate 14, figs. 1, 2], represents from 
 8 to 10 rows of these dorsal pieces, which is 6 or 8 less than may be 
 counted near the middle of the rays of our specimen. 
 
 "In noticing this form in the Am. Jour. Sci., vol. 3 (3d series), 
 p. 277, I proposed, in case it should be distinct from P. granulosus, 
 to call it P. speciosus. J) 
 
 With such marked differences between P. granulosus and P. speci- 
 osus, and since the type-specimen of the former can not be located 
 to determine the interbrachial structure, it is deemed advisable to 
 adopt Meek's name P. speciosus for the specimen described above. 
 
 In the upper portion of the Ordovicic in the Richmond formation 
 occurs another closely related species, P. ~bellulus, which is dis- 
 tinguished from P. speciosus in having more slender rays and usually 
 a greater number of plates in the actinal columns. The greatest 
 difference, however, is that it has seven pairs of adjoining adam- 
 bulacral plates proximal to the interbrachial plates, while in P. 
 speciosus there are but two or three pairs of adambulacrals. In 
 other words, the adambulacral oral extensions are far longer in 
 P. bellulus than in P. speciosus. 
 
 50601 Bull. 8815 8 
 
112 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 The illustration of Asterias antiquata Locke referred to above by 
 Meek is very poor, and yet it seems to be the same species which 
 the latter described as P. granulosus Hall = P. speciosus Meek. 
 This, however, can not now be established since the whereabouts 
 of Locke's specimen is unknown. Both specimens are from Cin- 
 cinnati and are of about the same size. Hall comments on this 
 species (1870) as follows: 
 
 "This species was noticed by Dr. Locke, as cited above, but with- 
 out specific description, and expressing a doubt whether it was or 
 was not identical with the Asterias antiqua of Troost. The figure 
 would indicate a distinct species from that of Dr. Troost." 
 
 PROMOPAL^EASTER GRANULOSUS (Hall). 
 
 
 
 Palxaster granulosa HALL Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, 
 
 p. 285. 
 Palseaster granulosus HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., rev. ed., 
 
 1868=1870, p. 327. 
 
 Original description. "Body of medium size, five rayed; rays a 
 little more than twice as long as their breadth at base; obtusely 
 rounded at the extremities. Upper surface of rays composed of 
 numerous very small tuberculose or subspinose plates; the madre- 
 poric tubercle large, quite distinct, situated laterally at the base of 
 two of the rays. Under surface of rays composed of a [infra]marginal 
 range of small tuberculose plates, about 25 on each, side in a ray 
 measuring one inch and a quarter from base to apex; and an inner 
 (adambukicral) range of smaller plates, of which about 42 or 43 can 
 be counted on the same ray; the terminal or oral [armature] plates 
 are small, elongate, subtriangular, in pairs at the base of the adjacent 
 rays. Ambulacral areas composed of a double series of short, broad, 
 slightly curved poral plates (ossicula) , each plate marked by a sharply 
 elevated ridge along its entire breadth, commencing on the one plate 
 at the outer posterior angle and terminating on the anterior inner 
 angle, and running in the opposite direction on the adjacent plate. 
 When the outer ridged surface of the poral plate is ground away, 
 the narrow openings or pores are visible between the plates, apparently 
 in two rows in each series, making four ranges of pores in each ambu- 
 lacral area.' (The marginal ranges of pores are obscure, and may 
 only be apparent [there is probably an error here in regarding the 
 inner openings as podial openings].) On the under surface, near the 
 bases of the rays, the tubercles bear short spines some of which are 
 still in place." 
 
 ' * Some figures of a Palssaster, closely allied to or identical with this 
 one, from Cincinnati, Ohio, have been circulated by the Natural 
 History Society of that place, under the name of Asterias primordialis; 
 but no description of it has ever been published, so far as I know, nor 
 
EEVISION OF PALEOZOIC STELLEKOIDEA. 
 
 113 
 
 do I find it at all recognized in the catalogues." These original 
 figures are here reproduced as Promopalseaster, sp. undet. (pi. 14, 
 figs. 1, 2). The specimen is probably an immature individual of 
 P. speciosus. 
 
 Formation and locality. The holotype was found by Mr. J. Kelly 
 O'Neall in the Lower Richmond formation near Lebanon, Ohio, and 
 was loaned to Hall for description. The whereabouts of the specimen 
 can not now be located. Some years ago the writer asked the late 
 Professor Whitfield about it and he answered that Halt had returned 
 it to O'Neall, but the latter in turn wrote (Aug. 27, 1896) that he 
 had not received it. 
 
 Remarks. This species seems to be distinguished by the smaller 
 number of plates in the inframarginal columns, as the following table 
 shows. However, until the nature of the interbrachial areas is known, 
 the relationship of P. granulosus to other Paleozoic forms can not 
 be stated. 
 
 
 Inframar- 
 ginals. 
 
 Adambu- 
 lacrals. 
 
 Inter- 
 brachials. 
 
 Adambu- 
 lacrals 
 orad to 
 inter- 
 brachials. 
 
 P granulosus (Hall) 
 
 25 
 
 42-43 
 
 
 
 P speciosus (Meek) . * 
 
 31 
 
 43 
 
 4 
 
 4 
 
 P bellulus new species . 
 
 31-38 
 
 48-55 
 
 4 
 
 8 
 
 P. magnificus (Miller) . 
 
 45 
 
 50-52 
 
 5 
 
 5-6 
 
 
 
 
 
 
 PROMOPAL^ASTER BELLULUS, new species. 
 Plate 15, figs. 6-8; plate 16, fig. 1; plate 18, figs. 4, 5. 
 
 R = 36 mm., r= 10 mm., R = 3.6r. Width of ray at base, 11.5 mm. 
 
 A first view of this species gives the impression of P. speciosus 
 (Meek). Of the latter but a single specimen is known and it is now 
 lost, while of P. bellulus there are numerous examples, all of which 
 have the same specific characters. The specimens preserved in lime- 
 stone have the rays more slender, while those from soft shale are as 
 stout as in P. speciosus. 
 
 In the holotype of P. bellulus from limestone there are 55 adam- 
 bulacral and 38 inframarginal plates in each column, while in 
 P. speciosus there are 43 and 31 plates, respectively, in the same 
 columns. Shale specimens of P. lellulus have less plates in a column. 
 One of these, a somewhat smaller specimen than the holotype, has 
 31 inframarginal plates, the same number as in P. speciosus, and 
 about 48 adambulacrals in each column. P. bellulus has therefore 
 from 31 to 38 inframarginal plates and from 48 to 55 adambulacral 
 plates in each column. 
 
114 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 A more important distinguishing character exists in the inter- 
 brachial areas. In P. lellulus and P. speciosus there are two pairs 
 or four inter brachial marginal plates, while the number of adjoining 
 adambulacral plates is greater. In the latter there are four of these 
 on each side, while in the former there are eight. In other words, 
 the interbrachial areas in P. lellulus are much more elongated orally 
 than in P. speciosus and the interbrachial arcs are also greater. 
 
 Abactinally on the rays the arrangement and number of columns 
 of plates appear to be very much like those in P. speciosus. The 
 individual plates are, however, less convex, cruciform, more like those 
 of P. spinulosuSj and have stronger and more abundant spines. The 
 spines in P. bellulus are very numerous, short, and slender, and are 
 inserted one on the apex of each plate and a number around the sides 
 in the angles between the radial extensions. In P. speciosus the spines 
 are grouped over the convex area of the plate and around the larger 
 central spine. The arrangement of the plates of the disk appears to 
 have no marked pattern and consists of very numerous small plates 
 like those of the rays. 
 
 The adambulacral plates each bear three spines as in P. speciosus 
 and increase in size toward the base of the rays. One is inserted on 
 the inner or ambulacral face of the plate and the two closely adjoining 
 ones immediately above and laterally on the rounded surface. 
 
 Ambulacral plates as in P. speciosus. 
 
 Madreporite of medium size, subcircular in outline, with numerous 
 straight, sharp, radiating ridges. It is inserted proximally between 
 two adjoining columns of supramarginal plates. 
 
 A development occurring only in this species of Promopalseaster 
 is a single plate oral to the proximal adambulacrals. This plate 
 has been seen in four axillary areas. It may be a modified ambu- 
 lacral and may correspond to a similar plate, which is an ambulacral, 
 hi P. exculptus. 
 
 Formation and locality. Of this species quite a number of speci- 
 mens were secured by Mr. Harris in the Waynesville beds of the 
 Richmondian. They are all in the United States National Museum. 
 One excellent specimen (the holotype) showing the actinal area, 
 and two smaller poorer specimens are attached to limestone, while 
 eleven fair specimens and fragments of eight other individuals are 
 from a soft blue shale associated with Zygospira modesta and Ptilo- 
 dictya sliafferi (upper form). All were secured in the vicinity of 
 Waynesville, Ohio. The shale specimens were exhumed from one 
 small area, showing that probably many starfishes could be similarly 
 secured by collectors, since these soft specimens in weathering out 
 are broken up and lost; more asterids will be found when they are 
 dug or quarried for. Another good specimen is in the Gurley col- 
 lection of the University of Chicago (No. 10983) and was found at 
 Versailles, Indiana. 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 115 
 
 Remarks. The similarity and difference between P. bellulus and P. 
 speciosus are pointed out above. Another related species is P. spinu- 
 losus, which has the same kind of abactinal plates and madreporite 
 as P. bellulus. In the former the rays are far longer and narrower, 
 with fewer ambital plates and columns between the supramarginals. 
 Actinally P. spinulosus is at once distinguished from P. bellulus 
 in the much smaller interbrachial areas, in that it does not have 
 more than two interbrachial marginal plates while P. bellulus has 
 four. In the latter species there are also far more adambulacral 
 plates around the interbrachial pieces. 
 
 It will always be difficult to distinguish fragments of P. bellulus, 
 P. speciosus, and P. spinulosus from one another, even with good 
 material, since at least two specimens of P. bellulus were identified 
 as Palseaster granulosus Hall = Promopalseaster speciosus (Meek) . 
 
 Cat. No. 40879, U.SJST.M. 
 
 PROMOPAL^EASTER SPINULOSUS (Miller and Dyer). 
 Plate 16, fig. 2; plate 17, figs. 1, 2; plate 18, figs. 1-3. 
 
 Compare with Promopalseaster exculptus (Miller). 
 
 Palseaster spinulosus MILLER and DYER, Journ. Cincinnati Soc. Nat. Hist., vol. 
 
 1, 1878, p. 32, pi. 2, figs. 12-126. 
 Palxaster longibrachiatus MILDER, Journ. Cincinnati Soc. Nat. Hist., vol. 1, 1878, 
 
 p. 102, pi. 3, fig. 4. 
 
 Original description (of Palseaster spinulosus). "Pentagonal; 
 rays longer than the diameter of the body; marginal plates globular 
 near the apices of the rays, but lengthened toward the junction 
 with the body. Six of these plates measure from the body on a ray 
 three- tenths of an inch. Two wedge-shaped plates form the junc- 
 tion of the marginal plates with the body. 
 
 " Adambulacral plates a little smaller [in width] than the margi- 
 nal pieces, and possessed of two or three [four or more] spines to 
 each plate. These spines taper to a fine point, and are longer than 
 the diameter of the plates. The oral pieces are not determined 
 [they are like those in P. exculptus]. The ambulacral plates have 
 their greatest length across the rays, and are possessed of a sharp 
 ridge in the middle which seems to be [is] connected at one end with 
 the adambulacral pieces. [The entire number of plates in each 
 range can not be given, since the rays are imperfect.]- 
 
 "The dorsal side is covered with plates united by angular exten- 
 sions. They are of unequal size, and strongly tuberculated or spi- 
 nous. 
 
 "The madreporiform tubercle on its upper face is an oblate sphe- 
 roid, much depressed, and marked by fine radiating stride, which 
 become more numerous by intercalation, without bifurcation. 
 [This plate is interpolated between the proximal plates of two ad- 
 
116 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 joining columns of supramarginal ossicles and about medially be- 
 tween the margin and the center of the disk.]" 
 
 Supplementary description. II unknown, r=7 mm. Width of 
 ray at base 9 mm. 
 
 Abactinal area of rays margined by inframarginals, above and 
 inside of which are columns of large, bipyriform, multispinous, su- 
 pramarginal plates of which there are five in 5 mm. at the base of a 
 ray. The columns of adjoining rays unite in the axillary areas. 
 Inside of the supramarginal columns the rays and disk have numer- 
 ous smaller accessory plates, usually triangular in outline or vari- 
 ously stellate. They lie upon or against each other, each ossicle 
 bearing at least one small spine, and leave between them numerous 
 abactinal openings. Outside of the supramarginal plates in the 
 ambital areas are spicular ambit al plates which cover the abactinal 
 side of the inframarginals. 
 
 Description of the type of Palseaster longibrachiatus. 11 = 38 mm., 
 r = 7 mm., R = 5.4r. Width of ray at base 9 mm. 
 
 Rays large, slender, tapering slowly; actinally somewhat convex 
 at their outer ends, but elsewhere concave. 
 
 Abactinal area unknown. 
 
 Inframarginal plates granular, large, decreasing gradually in size 
 dis tally, highly convex, in outline tetragonal or pentagonal and 
 common to both the abactinal and actinal areas. From 28 to 30 
 plates in a column on each side of a ray. 
 
 Axillary areas occupied by the proximal plates of adjoining infra- 
 marginal columns, and in the interbrachial areas there are two sub- 
 quadrangular or sub triangular interbrachial marginal plates. There 
 may be an additional small single plate in each area. 
 
 Adambulacral plates greatly resembling the inframarginal ossicles. 
 Distally they progressively overlap the inframarginal plates con- 
 siderably, while proximally they gradually increase in size and are 
 entirely inside and depressed beneath the plane of the marginal 
 columns. Orally the columns of adjoining rays unite in two wedge- 
 shaped modified adambulacrals (oral armature pieces) . 
 
 Ambulacral furrows deep and gradually tapering. Ambulacral 
 plates unknown. 
 
 Formation and locality. The type of Palseaster spinulosus (No. 16, 
 Mus. Comp. Zool.) is said to have been found at Cincinnati, Ohio. 
 This is probably an error, since il/s color and preservation indicate 
 the Richmond formation and that it comes from some locality 
 considerably to the north of Cincinnati. The only other known 
 specimen, the type of P. longibrachiatus, was found in the Richmond 
 formation near Clarksville, Ohio, and is in the Harris collection, 
 United States National Museum. 
 
 Remarks. The type-specimen of Palseaster spinulosus, which is 
 free, preserves but the disk and a small proximal portion of the rays. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 117 
 
 Comparing it with the actinal area of P. longibrachiatus Miller, it 
 is evident that both forms are identical. In the latter the rays are 
 complete, very long and slender, and there is nothing to show that 
 they were dissimilar in P. spinulosus Miller and Dyer. Both types 
 are nearly of the same size and the actinal plates are identical in form 
 and arrangement. The abactinal area in P. longibrachiatus is not 
 known, but since its actinal structure is that of Promopalseaster 
 spinulosus it is safe to assume that the abactinal structure is alike 
 in both. 
 
 P. spinulosus actinally is also closely related to P. exculptus (Miller). 
 The latter appears to have shorter and more rapidly tapering rays 
 and in general seems to be a more robust species. Another character 
 by which these species can be separated is that the interbrachial 
 areas in P. spinulosus have two, while P. exculptus has three inter- 
 brachial marginal plates. It is possible that the former species 
 also has three interbrachial marginal plates, but as yet the small 
 single piece of each area has not been observed, while in P. exculplus 
 it is distinctly present in each of the five areas. Should P. spin- 
 ulosus also prove to have three interbrachial plates, it would be diffi- 
 cult to distinguish it actinally from P. exculptus. 
 
 P. dyeri and P. magnificus are far larger species and have five 
 interbrachial marginal plates in each area. 
 
 Cat. No. 40881, U.S.N.M. 
 
 PROMOPAL-EASTER EXCULPTUS (Miller). 
 
 Plate 18, fig. 7; plate 20, fig. 2. 
 
 Compare with Promopalasaster spinulosus (Miller and Dyer). 
 Palseaster exculptus MILLER, Journ. Cincinnati Soc. Nat. Hist., vol.4, 1881, p. 69, 
 pi. 1, fig. 1. 
 
 Original description. " Pentagonal; rays a little longer than the 
 diameter of the body; diameter of the body, about 0.93 inch; length 
 of ray measuring to the center of the body or disk, about 1J inches; 
 breadth of a ray at the junction with the body, about 0.57 inch; rays 
 obtusely pointed. 
 
 "The [infra-] marginal range consists of somewhat quadrangular 
 plates, having a width a little greater than the length; the first 8 
 of these have a length of one-half inch, and there are about 18 in 
 the length of an inch, and not far from 25 in each range, though the 
 specimen does not permit us to make the count with certainty. The 
 surface is strongly tubercular, and was probably spinous [originally 
 covered with numerous small spines]. 
 
 "The adambulacral range consists of about 28 [25] plates, on each 
 side of a ray; they are narrower than the marginal plates, but have 
 about the same length. Each plate [has a short ambulacral exten- 
 sion conforming with the ridge of the ambulacral plates and] bore 
 
118 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 strong spines, and some of them, preserved on our specimen, have 
 a length greater than the length of a plate. * * * 
 
 "The ambulacral plates have their greatest length across the rays, 
 thus providing a wide ambulacral furrow. Each plate is furnished 
 with a sharp ridge in the middle, that curves slightly outward, from 
 the center toward the adambulacral range, increasing in height 
 until it approaches or abuts against the adambulacral plate. * * * 
 The appearance of having been carved out, which is presented by 
 the ambulacral plates, suggested the specific name. [The plates of 
 adjoining columns are opposite one another or slightly alternate.] 
 
 "The dorsal side and madreporiform tubercle unknown." 
 
 Supplementary description. R = 37 mm., *r=12 mm., R = 3.1r i . 
 The specimen is very much flattened and the exact width of a ray 
 can not be given but appears to have been about 10 mm. at the base. 
 
 In the axils of the rays the proximal inframarginal plates of adjoin- 
 ing rays rest against each other, inside of which are two wedge-shaped 
 interbrachial marginal plates. Orad to these and adjoining the pairs 
 of proximal adambulacrals (oral armature pieces) is situated a single 
 subquadrate ossicle, making three interbrachial marginal plates in 
 each interbrachial area. 
 
 The podial openings in the ambulacral grooves are between the 
 sutures of adjoining adambulacral and ambulacral plates along the 
 line where these two columns adjoin. The proximal ambulacral 
 plates orad to the axial adambulacrals are considerably modified 
 and are to be considered as parts of the oral armature. A single 
 rather large plate is here partially wedged between the pair of termi- 
 nating adambulacrals, and on each end of it abuts a single broadly 
 triangular plate, a modified ambulacral, completing the oral ends of 
 the ambulacral columns (see drawing, pi. 20, fig. 2). 
 
 Formation and locality. In the Richmond formation near Waynes- 
 ville, Ohio. The holotype and only specimen is in the Harris collec- 
 tion of the United States National Museum. 
 
 Remarks. This species is near P. spinulosus, but apparently had 
 wider, shorter, and more rapidly tapering rays. There appear to be 
 but two interbrachial marginal plates in P. s-pinulosus, while P. 
 exculptus has three in each area. Should the former species also prove 
 to have three plates, a possibility, P. exculptus will be actinally 
 identical with P. spinulosus. The wider and more rapidly tapering 
 rays of P. exculptus can then be explained by the fact that the type- 
 specimen is considerably distorted, since the adambulacrals and infra- 
 marginals now lie wholly outside of the ambulacrals, which are com- 
 pletely exposed, an unnatural condition. So long as the abacti- 
 nal area of P. exculptus remains unknown the species had best be 
 retained. 
 
 Cat. No. 60608, U.S.N.M. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 119 
 
 PROMOPAL^ASTER WYKOFFI (Miller and Gurley). 
 Plate 18, fig. 6; plate 19, fig. 2. 
 
 Palxaster wykoffi MILLER and GURLEY, Bull. No. 12, Illinois State Mus. Nat. 
 Hist., 1897, p. 46, pi. 3, fig. 27. 
 
 Original description. " Species medium size [R = 26 mm., r = 8 mm. 
 Width of ray at base 10 mm.] Rays pateliform; length about one 
 and a half tunes the diameter of the body; breadth of a ray at the 
 place of junction with the body, about two-thirds the diameter of 
 the body; obtusely pointed. 
 
 "Marginal [inframarginal] plates wider than long and numbering 
 about 15 in the length of half an inch from the body [or about 28 
 in a complete column]. The [infra] marginal plates curve regularly 
 around the tips of the rays. The adambulacral range curves around 
 the ends of the rays within the marginal plates and consists of sub- 
 quadrate plates, wider than long. They are a little shorter than the 
 marginal plates, so that there are about 18 in the length of half an 
 inch [about 35 in a complete column]. There are 10 oral plates [oral 
 armature] at the junction of the adambulacral rows, which present 
 triangular extensions toward the center of the ventral cavity. A 
 single irregular axillary plate rests between the terminal marginal 
 plates and the angle formed at the junction of the adambulacral 
 plates [this description is inadequate, see beyond for the detail]. 
 The ambulacral plates have their greatest length across the rays, 
 thus providing a wide ambulacral furrow. Each plate is furnished 
 with a sharp ridge in the middle, extending from the middle furrow 
 to the adambulacral plates. 
 
 "Our specimen exposes only the ventral side and no spines are 
 preserved. It is a well-marked and beautiful species." 
 
 Formation and locality. Found in the Richmond formation "near 
 Madison, Indiana, by Charles W. Wykoff, in whose honor we have 
 proposed the specific name." The holotype is now in the Gurley 
 coUection of the University of Chicago (No. 6066). 
 
 Remarks. Each interbrachial area begins orally with a pair of 
 elongate triangular basal adambulacrals (the oral armature pieces) 
 dis tally to which there are two pairs of adjoining adambulacrals 
 followed by a single axillary ossicle and usually one but also more 
 or less of a second pair of interbrachial marginal plates. P. wylcoffi 
 is therefore distinguished from P. exculptus in that it has orally to 
 the single interbrachial plate two pairs of proximal adambulacrals 
 instead of one as in the last-named species. These differences are 
 not decided, and it may eventually be seen when more well-preserved 
 material is at hand that they are either individual variations or due 
 to differences in age. 
 
120 BULLETIN" 88, UNITED STATES NATIONAL MUSEUM. 
 
 P. wykoffi also greatly resembles Anorfhaster miamiensis, but the 
 interbrachial areas in the latter are entirely composed of adambu- 
 lacral plates, there being no interbrachial marginals present. While 
 both species attained a similar size, another -difference is that the 
 former has a greater number of plates in the adambulacral and 
 inframarginal columns. 
 
 PROMOPAL^EASTER DYERI (Meek). 
 
 Plate 18, fig. 8; plate 20, figs. 3-6; plate 25, fig. 1. 
 
 Palseaster dyeri MEEK, Amer. Journ. Sci., ser. 3, vol. 3, 1872, p. 257; Geol. Surv. 
 Ohio, Pal., vol. 1, 1873, p. 58, pi. 4, figs. 2a-2/. 
 
 Original description (1873). "Among the specimens loaned to me 
 for study and description by Mr. Dyer, there is a very imperfect 
 example of one of the largest known species of Silurian Starfishes. 
 When entire, it could scarcely have measured less than 5 inches in 
 diameter [R = probably 3 inches, or 75 mm.] across from end to end 
 of the rays on opposite sides; and it presents a breadth of disk (as 
 flattened by pressure) of about 2 inches [r = probably seven-eighths 
 inch, or 22 mm.]. Its state of preservation is, unfortunately, such as 
 not to admit of systematic description, but I think enough of its 
 character can be given to enable the student to identify it, by the 
 additional aid of figures. 
 
 "The dorsal side of both disk and rays is composed of numerous 
 small pieces [with stellate extensions], with the pores between them 
 apparently so large that these pieces only seem to touch at three to 
 four salient points of each, so as to form a kind of reticulated struc- 
 ture; while they each bear a little central tubercle, with a minute pit in 
 its top for the articulation of small, short [blunt] spines, generally 
 about 0.07 to 0.09 inch in length, and about 0.02 to 0.03 inch in 
 thickness. [Each plate bears but one of these spines and there appear 
 to be no other smaller spines.] 
 
 "In one of the axilla between two of the rays the so-called madri- 
 poriform body can be seen near the margin of the disk. It is nearly 
 flat, of an obtusely subtrilobate form [probably cruciform], with a 
 breadth or transverse diameter of 0.30 inch, and a diameter at right 
 angles to the same of 0.24 inch [not less than 10 mm.]. Its lobed 
 edge is directed inward toward the middle of the disk, and its middle 
 lobe is largest, and shows the little divisions between the slits or 
 furrows, diverging and bifurcating inward like the nervation in the 
 pinnules of some kind of ferns; while in the smaller lateral lobes these 
 markings diverge outward. 
 
 "The ventral side is also much obscured by the adhering matrix, 
 and numerous detached and confusedly mingled spines. A row of 
 comparatively small, tumid, nearly square [infra] marginal pieces, 
 
REVISION OF PALEOZOIC STELLEROIDEA. 121 
 
 however, can be seen in places, on each side of the ambulacral 
 furrows, and alternating with a row of similar but slightly smaller 
 adambulacral pieces, the number of pieces in each side of these being 
 about the same. [In the proximal portion of a ray there are 19 
 marginal plates in 40 mm.]. The marginal pieces seem each to 
 connect with the adjacent range of dorsal pieces, at places in the 
 rays, by a little central salient point only, while those of both series 
 are roughened by numerous comparatively coarse granules [all of 
 which bear small spines], and each piece (especially [only] of the 
 marginal row) also shows a small central pit for the articulation of 
 a spine. These spines are larger than those connected with the 
 dorsal pieces, being generally about 0.22 inch in length and 0.05 inch 
 in thickness; they are smooth, straight, rounded, slightly thickened at 
 the attached end, and tapering at the free end to a slightly blunted 
 point. [The adambulacral plates also possess these large spines, 
 which are inserted on the distal inner edge of each plate.]" 
 
 In each interbrachial area there are two pairs of wedge-shaped 
 pieces and a single diamond-shaped interbrachial marginal plate. 
 There are at least 4 (and may be as many as 10) pairs of adam- 
 bulacral plates orally or in the actinal interbrachial areas, the terminal 
 pair being of the oral armature. 
 
 Ambulacral plates much wider than long, increasing rapidly in 
 width toward the mouth. Each plate is carinated as in P. sped- 
 osus and proximally as in P. magnificus, with the podial openings 
 confined to the extreme outer edge of the ambulacral furrows. 
 
 Formation and locality. Found at Cincinnati, Ohio, in the Mays- 
 ville beds, about 200 feet below the top of the hills. The ,holo type 
 is in the Dyer collection of the Museum of Comparative Zoology, 
 Harvard University (No. 13). Another specimen from near the top 
 of the Maysville at Cincinnati, preserving only the disk and showing 
 best the actinal area, is in the Gurley collection of the University 
 of Chicago (No. 10989). Originally this individual appears to have 
 been larger than the holotype. 
 
 Remarks. The relationship of this species is with P. spinulosus, 
 but the larger size, greater development of both dorsal and ventral 
 spines, absence of columnar arrangement of the abactinal plates, 
 and the presence of five instead of two or three interbrachial marginal 
 plates will readily separate P. dyeri from the latter species. Even 
 though this form appears to have attained a larger growth than 
 P. magnificus, which it resembles in some characters, it differs in 
 being more ponderous in its skeleton and in the far stouter and 
 longer actinal spines. 
 
 Regarding the generic position of Palseaster dyeri, Meek wrote: 
 
 " Possibly I should have called it Petraster dyeri, for if the apparent 
 presence of a few disk plates on the ventral side between the mar- 
 
122 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 ginal pieces and the adambulacral, is not deceptive, it would, in 
 that respect, conform to the structure of that group, and differ 
 from Palseaster, as now understood; though I am inclined to think 
 this appearance due to the accidental displacement of the parts at 
 the point where there are some indications of a few disk pieces." 
 These pieces are not to be correlated with the accessory interbrachial 
 plates of Petraster, for in this genus accessory plates consist of two 
 short columns situated between the adambulacral and marginal 
 plates and uniting in the axillary areas. In P. dyeri, however, the 
 four interbrachial marginal plates are continuous with the infra- 
 marginal columns and evidently were derived from that series, 
 and are not accessory interbrachials. It is true that all interbrachial 
 plates increase the size of the disk, but in one they are derived from 
 the inframarginal series, by crowding and in the other they are 
 interpolated, newly developed plates that force apart the columns 
 of plates in the rays sometimes almost to the distal ends. 
 
 PROMOPAL.EASTER MAGNIFICUS (Miller). 
 
 Plate 21, fig. 1; plate 22, fig. 1; plate 23, figs. 1-3. 
 
 Palseaster magnificus MILLER, Journ. Cincinnati Soc. Nai. Hist., vol. 7, 1884, 
 p. 16, pi. 4, figs. 3, 3a. 
 
 Original description. "The diameter or breadth of the disk is 
 one and one-fourth niches, and the distance from the point of one 
 ray to the point of the opposite one, if the rays were wholly preserved 
 in the specimen under examination, would be fully 6 inches. * * * 
 
 "The plates upon the dorsal side are very convex, and part of 
 them, at least, were spine-bearing, though it would seem that there 
 was not more than one spine upon any single plate. The arrange- 
 ment of the plates on the dorsal side of the rays is very ornamental. 
 A single series of highly convex or conical plates, larger than the 
 others, and each evidently bearing a central spine, occupies the 
 middle of each ray; on either side near the margin of each ray there 
 is a similar series, and the two intervening spaces are filled with 
 smaller, convex plates arranged in rows which are directed diagonally 
 forward from the plates of the side series to the plates of the central 
 series, forming angles with each plate in the central series occupying 
 an angle. This disposition of the plates on the dorsal side of the 
 rays will, so far as known, serve to distinguish this species from any 
 hitherto described. 
 
 "The plates covering the dorsal side of the body or disk have been 
 so much disturbed in our specimen that one can not correctly define 
 them. 
 
 "The ambulacral furrows are wide. The marginal plates are 
 hexagonal, about the size of the larger plates on the dorsal side of 
 
KEVISION OF PALEOZOIC STELLEKOIDEA. 123 
 
 the rays, and separated from the side series by intervening smaller 
 plates. Each bore several small spines, as shown by the small pits 
 for their articulation. * * * 
 
 "The adambulacral plates are hexagonal and much wider than 
 long. They are more numerous than the marginal plates near the 
 disk, but toward the apices of the rays they interlock alternately 
 with the marginal plates. The number on each side of a furrow hi 
 a complete ray would be 50 or more. The pits for the articulation 
 of the spines are as numerous as they are on the marginal plates. 
 These two series on the ventral side of the species, with numerous 
 spines upon each plate, are in striking contrast with the plates on 
 the dorsal side of the rays, where no plate bears more than a single 
 spine. 
 
 "The ambulacral plates have their greatest length across the 
 rays, and seem to be about as numerous as the adambulacral ones. 
 An angular depression marks the center of each ambulacral furrow, 
 upon each side of which a sharp ridge arises upon each ambulacral 
 plate, and curving forward and outward abuts against an adambula- 
 cral plate. " 
 
 Emended description. The largest specimen, the holotype, meas- 
 ures R = (about) 67 mm., r = 17 mm., R = nearly 4r. Another speci- 
 men: 11 = 58 mm., 3* =15 mm., R= nearly 4r. 
 
 Abactinal surface very ornamental. Medially along each ray there 
 is a radial column of highly convex plates, and two columns of similar 
 plates, the supramarginals, are situated near the margin. Between 
 the inframarginal, supramarginal, and radial columns are very nu- 
 merous diagonal rows of smaller conical or angular plates, from 2 at 
 the apex of the ray to 14 at base of same in each row on each side of 
 the radial column. This may be stated in another way. Between 
 the radial and supramarginal columns and again in the ambital area, 
 or between the supramarginals and inframarginals, the diagonal rows 
 have from one to seven plates in each area. These rows are directed 
 diagonally and distally across the rays from the sides to the median 
 column, the apex of the angle thus formed being occupied by the 
 larger plates of the radial column. All of these smaller plates appar- 
 ently bore a single short spine. Between all of the diagonal rows 
 are inserted both proximally and distally numerous minute, conical, 
 irregular-shaped plates. The supramarginal columns continue across 
 the disk and those of adjoining rays unite in the axillary areas. The 
 radial columns also extend over the disk but do not attain the center, 
 and the diagonal arrangement of the small plates ceases near the 
 proximal portion of the rays. The pattern arrangement of the disk 
 plates can not be made out since their original position is disturbed. 
 
 Madreporite quite large, quadri-lobate in outline, depressed, convex 
 and very finely radiately striate. It is situated in one of the axillary 
 
124 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 areas, less than 4 mm. from the margin. Against it rest two columns 
 of supramarginal plates. 
 
 The inframarginal plates, of which there are at least 45 in each 
 column, are distally small and subquadrate but proximally increase 
 rapidly in size and at the base of the columns are three to four times 
 as wide as long. These plates bear numerous pitted pustules upon 
 which articulated short, sharp, smooth spines. The columns of ad- 
 joining rays meet in the axils and continue into the interbrachial 
 areas. 
 
 The adambulacral plates are like the inframarginals but do not 
 increase so rapidly in width as those plates and are somewhat more 
 numerous, there being in a complete ray about 52 in a column. 
 Proximally some of the large plates are broken into two or three 
 often very convex ossicles. In addition to the small spines like those 
 of the inframarginals, each plate bears on its ambulacral edge a prom- 
 inent socket in which articulated a long, thick, smooth spine. The 
 adambulacral plates in the proximal third of the rays each have a 
 small, more or less wedge-shaped, carinated, accessory adambulacral 
 plate. In this region these ossicles separate the adambulacrals from 
 the ambulacrals and beneath the accessory adambulacral plates are 
 the podial openings. Five or six adambulacral plates of each column 
 abut against the interbrachial marginal plates, while five or six pairs 
 continue orally, the terminating pieces being of the oral armature. 
 
 Ambulacral furrows wide, increasing in width proximally. An 
 angular median sinus marks each ambulacral furrow. Ambulacral 
 plates short but wide, slightly overlapping proximally, and one to 
 each adambulacral plate. All of the plates are strongly carinated, 
 the carina in the distal two-thirds converging medially and proximally. 
 In the proximal third the carinse gradually are changed in form and 
 are there arranged in forked pairs. In other words, the carinae adjoin 
 the accessory adambulacrals, are arranged in pairs, continuing ad- 
 joining and straight for a short distance, and then diverge in broad 
 curves, terminating near the center of the ambulacral groove. This 
 arrangement produces in the proximal portion of the ambulacral 
 furrows four columns of ovoid pits, all terminating laterally into 
 podial openings. Every other podial opening belongs to the same 
 column, one series beneath the adambulacrals, the other gradually 
 passing medially in the ambulacral grooves. In the distal two-thirds, 
 however, the podial openings are arranged in single columns, one to 
 each ambulacral plate and issuing from underneath the adambulacrals. 
 
 Interbrachial areas with seven plates, each composed of two prox- 
 imal inframarginals, beneath which are two pairs of interbrachial 
 marginals and a single diamond-shaped axillary marginal plate. All 
 bear similar spines and ornamentation on the inframarginals. Some- 
 times one of the distal interbrachial marginals may be divided and 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 125 
 
 the arrangement of the interbrachial plates made irregular. In a 
 specimen from Jefferson County, Indiana, there are 3 pairs of inter- 
 brachial marginals instead of 2 as in the Ohio individuals. There- 
 fore there are also more adambulacrals here, 14 pairs against 10 in 
 the typical specimens. 
 
 Formation and locality. Two free specimens of this magnificent 
 starfish were found in the Richmond formation near Waynesville, 
 Ohio. Originally pieces of these two individuals were glued together 
 as one specimen, which is the cause of our figures being less perfect 
 than Mr. Miller's. Fragments of seven other individuals were found 
 in the vicinity of Waynesville. In the University of Chicago col- 
 lection (No. 10981) there is a specimen from Jefferson County, 
 Indiana, apparently of this species. Mr. Vaupel secured the distal 
 portion of a ray of an apparently young example of this species in 
 the Maysville beds on Rons Hill, Cincinnati, Ohio, and Mr. Ulrich 
 has fragments of four individuals from the Maysville strata about 
 Cincinnati, and Covington, Kentucky. 
 
 Remarks. This species is readily separated from the other species 
 of Promopalxaster by the marked diagonal rows of abactinal plates. 
 Actinally P. magnificus is readily distinguished from P. exculptus and 
 P. spinosus in having five instead of three interbrachial marginal 
 plates in each area, in the rapidly increasing size of the plates in the 
 inframarginal and adambulacral columns, and in the proximal am- 
 bulacral plates. P. speciosus differs at once from P. magnificus in that 
 its abactinal plates are arranged in regular longitudinal columns, 
 are far less numerous, larger and are all nearly of a size. 
 
 This is one of the largest and best preserved of American Paleozoic 
 starfishes. P. dyeri may be a larger species but is distinguished abac- 
 tinally not only by the arrangement and difference in the forms of 
 the plates but also by the short, thick, blunt spines which now ap- 
 pear to have no definite arrangement, while P. magnificus has all of 
 its very fine spines arranged in diagonal rows like the plates. 
 
 Cat. Nos. 40883, 60621, 60622, U.S.N.M. 
 
 new subfamily. 
 
 Aberrant Promopalaeasteridae with the axillary and interbrachial 
 areas composed entirely of adambulacral pieces. 
 Contains : 
 Anorihaster. 
 
 ANORTHASTER, new genus. 
 
 Plate 13, fig. 4; plate 20, fig. 1. 
 Anorthaster SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, April, 1914, p. 11. 
 
 A + orihos + aster = out of the regular, in reference to the completely 
 adambulacral na-ture of the interbrachial areas. 
 
126 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Generic characters. Disk small, with apparently small interbrachial 
 arcs. Rays five, of moderate length and tapering at first slowly 
 and then rapidly distally. 
 
 Abactinai area unknown. 
 
 Inframarginal plates small, the columns not attaining the axils, 
 but resting upon the second enlarged axillary adambulacral plate. 
 
 Adambulacral plates distally like the inframarginals, increasing 
 in size slowly proximally until near the axillary region, where four 
 plates suddenly attain great width, terminating in the axils of the 
 rays and here suppressing the inframarginal plates. Eight inter- 
 brachial adambulacrals of varying form are situated orally to the two 
 large axillary adambulacral plates, and at first give one the impression 
 of slender interbrachial areas of the same nature as in Promopalszaster. 
 These plates, however, are not interbrachial marginals, as in other 
 genera, and derived by the oral crowding of proximal inframarginals. 
 They are distinctly adambulacral ossicles, forming slight interbrachial 
 areas, and, with the axillary adambulacrals, form small arcs. For the 
 shape and position of these plates see figure 1, plate 20. 
 
 Ambulacral plates alternating, slightly carinated, and very short 
 but wide. In the distal region they are as long as the adambulacral 
 plates, but proximally decrease in length where there are nearly two 
 of them to one adambulacral ossicle. Podial openings between every 
 other plate through the sutures of adjoining pieces at their outer 
 edge and immediately beneath the inner edge of the adambulacral 
 ossicles. The proximal plates of each column are modified into oral 
 armature pieces that are slightly tumid, as long as wide, and sub- 
 triangular in outline. Between the proximal ambulacrals and orad 
 to the proximal interbrachial adambulacrals are situated additional 
 single, very small, quadrangular oral armature plates. 
 
 Genoholotype and only species. Palseaster miamiensis Miller. 
 
 Distribution. Ordovicic, Richmond formation, near Waynesville, 
 Ohio. 
 
 Remarks. The suppression of the inframarginal plates in the axils 
 of the rays by two of the adambulacral plates of each column and 
 the oral continuation beneath the latter of four pairs of adambulacral 
 plates holding an interbrachial position distinguish this genus 
 fromPromopalseaster, to which it otherwise seems very closely related. 
 This character also distinguishes it from all other associated genera. 
 
 The interbrachial structure of Anorthaster appears abnormal. In 
 Mesopalseaster and Promopalseaster the proximal inframarginal plates 
 are crowded orally and form interbrachial areas; in Anorthaster their 
 formation is effected in the opposite way, not by the inframarginals, 
 but by the adambulacrals. This character is seen in a single speci- 
 men, but it is so regularly developed and well preserved as to indicate 
 a normal and not a pathologic or abnormal condition. 
 
KEVISION OF PALEOZOIC STELLEROIDEA. 127 
 
 ANORTHASTER MIAMIENSIS (Miller). 
 
 Plate 13, fig. 4; plate 20, fig. 1. 
 
 Palseaster miamiemis MILLER, Journ. Cincinnati Soc. Nat. Hist., vol. 3, 1880, 
 p. 143, pi. 4, fig. 3. 
 
 Original description. " Pentagonal; rays about one and a half 
 times the diameter of the body, or about nine-tenths of an inch; 
 diameter of the body about six-tenths of an inch; breadth of a ray 
 at the point of junction with the body a little more than half the 
 diameter of the body, or about seven-twentieths of an inch; rays 
 obtusely pointed. 
 
 "Marginal plates wider than long, and numbering about 12 in 
 the length of half an inch from the body. Two marginal plates 
 form the junction of the rays. Ambulacral furrow wide, the plates 
 being more than twice as long as wide. There are about 18 ambu- 
 lacral plates in a length of one-half inch, and each one is provided 
 with an angular ridge taperingfrom the marginal plates to the furrow." 
 
 Emended description. R = 23 mm., r = 7 mm., R = 3.2r. Width of 
 rays at base 8 mm. 
 
 Rays tapering very slowly in the proximal half, but more rapidly 
 
 distally. 
 
 Abactinal area unknown. 
 
 Inframarginal plates about 16 in each column and subquadr angular 
 in outline. These ossicles do not continue into the axils, but rest 
 upon the second large axillary adambulacral plate. 
 
 Adambulacral plates about 18 in each column, like the infra- 
 marginal pieces, increasing in size proximally, while the two axillary 
 ones are suddenly enlarged, extend to the margin of the disk, and have 
 the position of marginal ossicles. Orally to the latter the adambu- 
 lacral plates continue as interbrachial ossicles. The distal pair is 
 large and both are wedge-shaped, followed by two pairs of quite 
 small quadrangular plates and a final pair of long and narrow plates; 
 in all there are, therefore, 22 adambulacral plates in each column. 
 The interbrachial adambulacral plates are terminated by a single 
 quadrangular oral plate wedged in between the proximal ambu- 
 
 a ILbulacral furrows very wide, broadly gutter-shaped. Ambu- 
 lacral plates about 30 in a column, slightly alternating, decidedly 
 wider than long proximally, increasing in length distally, and finally 
 becoming about as wide as long near the apex of a ray. Each plate 
 is slightly carinated, the ridges crossing the plates from the lateral 
 distal edge to the medial proximal edge. The proximal ambulacral 
 plates are modified, conspicuous, and subtriangular in outline 
 Podial openings between two adjoining plates in alternate sutures at 
 
 50601 Bull. 8815 9 
 
128 BULLETIN- 88, UNITED STATES NATIONAL MUSEUM. 
 
 their extreme outer edges and immediately inside of the adambu- 
 lacral plates. 
 
 Formation and locality. In the Richmond formation, near Waynes- 
 ville, in Montgomery County, Ohio. The holotype is in the Harris 
 collection of the United States National Museum. 
 
 Eemarks. -This species has a general resemblance to some of the 
 Promopalseasters, particularly P. ~bellulus and P. wylcoffi, but the 
 peculiar arrangement of the axillary and interbrachial adambulacral 
 plates will distinguish it not only from them but from all other 
 Ordovicic asterids. 
 
 Cat. No. 40880, U.S.N.M. 
 
 Family XENASTERID^E Schondorf. 
 
 Xenasteridx GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 346; Treat. Zool., vol. 3, 
 
 Echinoderma, 1900, p. 250. 
 
 Palsegoniasteridse STURTZ, Palaeontographica, vol. 36, 1890, p. 247 (not opp. 246). 
 Xenasteridse SCHONDORF, Palaeontographica, vol. 56, 1909, p. 105; Jahrb. nassau- 
 
 isch. Ver. Naturk., Wiesbaden, vol. 62, 1909, p. 25; vol. 63, 1910, pp. 244, 250. 
 
 Progressive Phanerozonia having the general characters of the 
 Promopalseasterinse, with the addition of accessory interbrachials. 
 The ambulacral and adambulacral plates are directly opposite one 
 another and do not waver between the slightly alternate and opposite 
 arrangement in the Promopalaeasteringe. Podial openings in two 
 columns in each ambulacral furrow, the apertures lying between 
 each four adjoining plates, that is, between two adambulacrals and 
 two ambulacrals. 
 Contains : 
 
 Xenaster Simonovitsch. 
 
 Agalmaster Schondorf. 
 
 Khenaster Schondorf. 
 
 Eifelaster Schondorf. 
 
 Trimeraster Schondorf. 
 
 Schondorf defines the family as follows (leaving out much of his 
 detail) : 
 
 Lower Devonic starfishes with well-developed supramarginals and 
 usually still larger inf ramarginals ; the latter are somewhat more numer- 
 ous than the former, causing them to be unequally superposed. Ambu- 
 lacra opposite one another and opposite the adambulacrals; podial 
 openings in two rows. Actinally each interradius has either three or 
 five interbrachial plates; abactinally this area is filled with small 
 accessory plates and margined only by inframarginals. Disk skeleton 
 consisting of small separated pieces, a central disk plate, five primary 
 radialia, five primary interradialia, and more or less of accessory disk 
 
KEVISION OF PALEOZOIC STELLEEOIDEA. 129 
 
 ossicles. Eays with three columns of plates, one radial and two 
 supramarginal, that may or may not be separated from one another 
 by small accessory pieces. Madreporite dorsal and interradial. 
 
 Genus XENASTER Simonovitsch emend. Sehondorf. 
 
 Plate 24. 
 
 Archseasterias MULLER, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 12, 1855, pp. 
 6, 8 (Archxasterias founded in error). 
 
 Xenaster SIMONOVITSCH, Sitzb. mat.-naturw. Classe Akad. Wiss., Wien. vol. 64, 
 Abt. 1, 1871, p. 88. SCHONDORF, Palseontographica, vol. 56, 1909, pp. 42, 
 105 (complete synonymy given here); Jahrb.nassauisch. Ver. Naturk., Wies- 
 baden, vol. 62, 1909, p. 26. 
 
 Generic characters. Xenaster has its nearest relationship in 
 Devonaster. No detailed description need be given, since the splendid 
 illustrations of Sehondorf give all the necessary characters. It 
 differs from Devonaster as follows: 
 
 In Devonaster there is but a single interbrachial plate in each 
 actinal axil, the axillary interbrachial, while in Xenaster there are 
 two pairs of interbrachial marginals and a single axillary inter- 
 brachial plate; in other words, five interbrachial plates instead of 
 one (1+2+2). In addition to these plates in Xenaster, the interbra- 
 chials are more or less surrounded by small accessory pieces, and then 
 other similar plates separate the inf ramarginal and adambulacral col- 
 umns to near the outer third of the rays. The inf ramarginal plates in 
 Xenaster do not increase so rapidly in width proximally as do these 
 plates in Devonaster, and while the interbrachial areas are of about 
 the same size in both genera, the space occupied by the additional 
 interbrachial marginal and accessory interbrachial ossicles in the 
 former is taken up in the latter genus by the increased size of the 
 inf ramarginal pieces. 
 
 Abactinally Xenaster has the generic characters of Devonaster. 
 The plates in all the columns of the former genus are more prominent 
 and rounder, particularly the accessory plates, of which there appear 
 to be less than in Xenaster. The center of the disk in both genera 
 is occupied by a small central disk plate, but there are many more 
 accessory plates around it in Devonaster than in Xenaster. In both 
 genera the supramarginal columns converge proximally, producing 
 small disk areas between the infra- and supramarginal plates occu- 
 pied by ambital accessory plates. 
 
 Madreporite large and striate in Xenaster. 
 
 Genotype. X. margaritatus Simonovitsch. 
 
130 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Distribution. Restricted to the Lower Devonic of Germany. 
 The species are: 
 
 X. margaritatus Shnonovitsch. 
 
 X. dispar Schondorf. 
 
 X. elegans Schondorf. 
 
 X. (?) rhenanus (Miiller). 
 
 Remarks. Miiller in his description of Asterias rtienana, 1 the geno- 
 type of Archseasterias , notes that the adambulacral plates of adjoining 
 columns alternate and that the ambulacral columns ' ' have the appear- 
 ance also of alternating/' which if established would be very remark- 
 able, and would justify the creation of a distinct genus Archseasterias 
 for this asterid of the Rhine grauwacke. Schondorf shows that 
 these statements of Miiller' s are very faulty and further that the 
 genus Archseasterias has not been denned so as to be recognizable. 
 Under these circumstances it was best for Simonovitsch to disre- 
 gard Archseasterias and to establish a new generic name for his species 
 margaritatus. There is no Paleozoic genus of starfishes better 
 described or illustrated than this one by Simonovitsch, and should 
 it ever prove that Asterias rhenana Miiller is identical with Xenaster 
 margaritatus, a possibility, the latter should not be made to give 
 way to the former on the ground of priority. It is an injustice to 
 extend the law of priority indiscriminately to all work, and to reject 
 Archseasterias is no reflection on the work of Miiller, as his material 
 was very poor and his work of early date in paleontology. He pub- 
 lished at a time when it was very desirable to learn anything what- 
 ever about Paleozoic starfishes. 
 
 As pointed out above, Xenaster has much of the structure of 
 Devonaster, yet it differs in the important character of having 
 numerous accessory interbrachial plates. This feature seemingly 
 relates it with forms like Palasterina which have a great abundance 
 of accessory interbrachials, yet in no interbrachial area of this genus 
 are there axillary interbrachials or interbrachial marginals. In other 
 words, the Palasterina type of disk is made by the intercalation of 
 accessory plates between the inframarginals and adambulacrals, 
 whereas hi Devonaster it is accomplished by the greater width of the 
 inframarginals and by the oral crowding of a plate which in primitive 
 forms is an axillary marginal. Devonaster although from younger 
 strata is more primitive than Xenaster because of its simpler inter- 
 brachial actinal structure. If it were not for the accessory inter- 
 brachials, Xenaster would be closely related to Promopalseaster which 
 also has a number of proximal inframarginals crowded into the inter- 
 brachial areas. It is the Promopalseaster stock out of which Xenaster 
 probably developed, while Devonaster apparently came through 
 Mesopalseaster. 
 
 * Verb, naturh. Ver. preuss. Rheinl., etc., vol. 12, 1855, pp. 6, 8. 
 
REVISION" OF PALEOZOIC STELLEROIDEA. 131 
 
 XENASTER MARGARITATUS Simonovitsch emend. Schondorf. 
 
 Plate 24, figs. 1,2. 
 
 Xenaster margaritatus (part) SIMONOVITSCH, Sitzb. mat.-naturw. Classe Akad. 
 Wiss., Wien, vol. 64, Abt. 1, 1871, p. 88, pis. 1, 2. SCHONDORF, Palseon- 
 tographica, vol. 56, 1909, pp. 43, 106, pi. 7, figs. 1, 3, 4; pi. 8, fig. 1; pi. 11, 
 figs. 2, 3, 10, 11 (complete synonymy given here); Jahrb. nassauisch. Ver. 
 Naturk., Wiesbaden, vol. 62, 1909, p. 26, pi. 2, figs. 1, 2. SPENCER, Mon. 
 Brit. Pal. Asterozoa, pt. 1 (Palaeontogr. Soc. for 1913), 1914, p. 30. 
 
 This species is one of the best described and illustrated of Paleozoic 
 starfishes and does credit to its author, and to its subsequent reviser, 
 Schondorf. It occurs rarely in the Lower Devonic (Upper Coblen- 
 zian) as natural molds at Niederlahnstein on the Rhine, Germany. 
 
 XENASTER DISPAR Schondorf. 
 
 Xenaster margaritatus (part) SIMONOVITSCH, Sitzb. mat.-naturw. Classe Akad. 
 
 Wiss., Wien, vol. 64, 1871, Abt. 1, pi. 2, figs. 2, 2a, 26. 
 Xenaster dispar SCHONDORF, Palaeontographica, vol. 56, 1909, pp. 50, 84, 106, 
 
 pi. 9, fig. 1; pi. 11, fig. 13; Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 
 
 62, 1909, p. 28, pi. 3, fig. 3. 
 
 From the Upper Coblenzian at Niederlahnstein, and Miellen, 
 Germany. 
 
 XENASTER ELEGANS Schondorf. 
 
 Xenaster margaritatus FOLLMANN (not Simonovitsch) , Jahrb. naturh. Ver. preuss. 
 
 Rheinl., etc., vol. 48, 1891, p. 150. 
 Xenaster elegans SCHONDORF, Palseontographica, vol. 56, 1909, pp. 53, 107, pi. 9, 
 
 figs. 2, 3; pi. 11, figs. 4, 12; Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 
 
 62, 1909, p. 40, pi. 4, figs. 6, 7. 
 
 From the Lower Devonic (Coblenz quartzite) at Konigstuhl, near 
 Rhens, Germany. 
 
 XENASTER (?) RHENANUS (Muller). 
 
 Asterias (Archseasterias} rhenana MULLER, Verh. naturh. Ver. preuss. Rheinl., 
 
 etc., vol. 12, 1855, p. 6, pi. 1, figs. 4-6. 
 Xenaster (?) rhenana SCHONDORF, Palaeontographica, vol. 56, 1909, pp. 55, 107, 
 
 text fig. 2 (complete synonymy given here); Jahrb. nassauisch. Ver. Naturk., 
 
 Wiesbaden, vol. 62, 1909, p. 28. 
 
 This species is based upon incomplete material and can not be 
 made out fully. It seems probable that it is a species of Xenaster 
 and closely related to X. margaritatus Simonovitsch. The examples 
 are in the Berlin Museum and were found in the Lower Devonic at 
 Winningen, near Coblenz, and Kemmenau, near Ems, Germany. 
 
 Genus AGALMASTER Schondorf. 
 
 Text fig. 9. 
 
 Agalmaster SCHONDORF, Palseontographica, vol. 56, 1909, pp. 58, 107; Jahrb. 
 nassauisch. Ver. Naturk., Wiesbaden, vol. 62, 1909, p. 29. 
 
 Original remarks. Agalmaster differs from Xenaster in the following 
 characters: Forms larger, broader rayed, with flat actinal but highly 
 arched abactinal plates. Supramarginals much stronger than the 
 large inframarginals and projecting considerably beyond these. 
 
132 BULLETIN 88, UNITED STATES NATIONAL MUSEUM.. 
 
 \ 
 
 Abactinal interbrachial area small, and occupied in the main by two 
 
 axillary inf ramarginals ; actinally this area has the same structure as 
 
 Xenaster. Madreporite dorsal. 
 
 Genoholotype (the writer here selects the first species). A. miel- 
 
 lensis Schondorf. Other species are A. grandis Schondorf and A. 
 
 intermedius Schondorf, both from the Lower Devonic of Germany. 
 / \ Remarks. The only 
 
 / \ character that may be 
 
 of generic value and 
 that at present distin- 
 guishes Agalmaster from 
 Xenaster is that in the 
 former genus the supra- 
 marginals margin the 
 rays instead of the in- 
 f ramarginals, as is the 
 case in the latter genus. 
 In a second species (A. 
 grandis) the small ac- 
 cessory interbrachials 
 crowd in between all the 
 pairs of interbrachial 
 
 FIG. 9. AGALMASTER MIELLENSIS, AFTER SCHONDORF. SCHEMATIC marginals and further 
 
 ARRANGEMENT OF ABACTINAL PLATES. R* AND -R 3 , SECOND AND , . ' 
 
 THIRD PROXIMAL RADIAUA; Jn, PRIMARY INTERRADIALIAJ Cdp, tllCre &TQ J&T ID.OTG OI 
 
 CENTRAL PLATE; mdp, MADREPORITE; mo, SUPRAMARGINALIA; ^ggQ pieces between 
 mu, INFRAMARGINALIA; Pifm, PRIMARY INTERRADIALIA. 
 
 the inframargmals and 
 
 adambulacrals; in fact, there are three to four columns of these in- 
 stead of one (as in A. mieUensis). 
 
 AGALMASTER MIELLENSIS Schdndorf. 
 
 Text fig. 9. 
 
 Agalmaster mieUensis SCHONDORF, Palseontographica, vol. 56, 1909, pp. 58, 107, 
 text fig. 3; pi. 8. fig. 4; pi. 9, fig. 4; pi. 11, figs. 1, 5; Jahrb. nassauisch. Ver.' 
 Naturk., Wiesbaden, vol. 62, 1909, p. 29, pi. 3, fig. 2; pi. 4, figs. 1, 2. 
 
 A single specimen with the rays about 43 mm. long was found in the 
 Lower Devonic (Upper Coblenzian) at Miellen-on-the-Lahn, Germany. 
 
 AGALMASTER GRANDIS Schdndorf. 
 
 Xenaster margaritatus SIMONOVITSCH (part), Sitzb. mat.-naturw. Classe Akad. 
 
 Wiss., Wien, vol. 64, Abt. 1, 1871, pi. 2, figs. 3, 3a. 
 Agalmaster grandis SCHONDORF, Palseontographica, vol. 56, 1909, pp. 62, 108, 
 
 pi. 9, fig. 5; Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 62, 1909, p. 29, 
 
 pi. 3, fig. 1. 
 
 One specimen (Xenaster margaritatus Simonovitsch, part) from 
 the Lower Devonic (Upper Coblenzian) at Niederlahnstein on the 
 Rhine, Germany. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 
 
 133 
 
 AGALMASTER INTERMEDIUS Schflndorf. 
 
 Agalmaster intermedius SCHONDORF, Palaeontographica, vol. 56, 1909, pp. 82, 
 108, pi. 11, fig. 14; Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 62, 
 1909, p. 30. 
 
 From the Upper Coblenzian at Miellen-on-the-Lahn, Germany. 
 
 Genus RHENASTER Sehondorf. 
 Text fig. 10. 
 
 Rhenaster SCHONDORF, Palseontographica, vol. 56, 1909, pp. 65, 108, pi. 8, fig. 3; 
 pi. 10, figs. 1, 4. 
 
 Remarks. Rhenaster is a small form and differs from Xenaster, 
 Agalmaster, and Devonaster in the complete absence of all abactinal 
 accessory plates, allow- 
 ing the radial and supra- 
 marginal pieces to ad- 
 join one another closely. 
 Dorsal axillary disk ~7=TP?^O g V\C\ 
 
 T i I /I )s~*\-/ sr?~^ ^-' /\S. \V 
 
 areas not completely 
 but almost absent, 
 supramarginals in the 
 main lying wholly upon 
 the inframarginals and 
 the two columns of 
 plates together margin- 
 ing the rays. There 
 also are no accessory 
 plates of any kind on 
 the actinal side. Other- 
 wise the generic struc- 
 ture is that of Xenaster, except that in Rhenaster the first pair of 
 interbrachial marginals are not yet pushed so much orally and they 
 almost take part in margining the axils. Madreporite unknown. 
 
 Genoholotype and only species (one specimen). R. schwerdi Schon- 
 dorf, from the Lower Devonic (Upper Coblenzian) at Dorrbachtal, 
 near Coblenz, Germany. 
 
 Genus EIFELASTER Sehondorf. 
 
 Etfelaster SCHONDORF, Palaeontographica, vol. 56, 1909, pp. 70, 108, pi. 10, figs. 
 
 7,8. 
 
 Remarks. This genus is very closely related to Rhenaster and 
 differs only in that there are small dorsal interbrachial areas between 
 the adjoining proximal portions of the supramarginal columns, and 
 these are filled with a small number of accessory ambital pieces. 
 The outer portion of these ambital areas is made up of the two basal 
 inframarginals that occupy the axils of the ventral side. 
 
 
 FIG. 10. REENASTER SCHWEKDI, AFTEK SCHONDORF. SCHEMATIC 
 ARRANGEMENT OF ABACTINAL PLATES. SYMBOLS AS IN FIG. 9. 
 
134 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 The genoholotype and only species, E. fottmanni, occurs in the 
 Lower Devonic (Lower Coblenzian) at Landscheid, near Wittlich, 
 in the Eifel, Germany. Plastotypes of the holotype were made for 
 the writer by Professor Jaekel, of Greifswald, and these are now in 
 the Yale University collection. 
 
 Genus TRIMERASTER Schondorf. 
 
 Plate 19, fig. 1. 
 
 Trimeraster SCHONDORF, Palaeontographica, vol. 56, 1909, pp. 68, 108, pi. 7, 
 fig. 2; pi. 10, figs. 5, 6. 
 
 Remarks. Trimeraster is a small form, very closely related to 
 Xenaster, and can be distinguished generically only in that the former 
 has inside of the inframarginals but one. pair of interbrachial margi- 
 nals and a single axillary interbrachial in each interbrachial field 
 instead of the five plates of the latter genus. 
 
 Genoholotype and only species (one specimen). T. parvulus Schon- 
 dorf, from the Lower Devonic (Coblenz quartzite) at Konigstuhl, 
 near Khens, Rhine Valley, Germany. 
 
 NEOPAL^ASTERIDJE, new family. 
 
 Progressive Phanerozonia without interbrachial arcs. The columns 
 of supra- and inframarginal plates wholly superposed. Madreporite 
 abactinal. Well-developed ocular plates present. Ambulacrals alter- 
 nating. Disk with a ring of large plates of basal, radial, and inter- 
 radial ossicles. 
 
 Contains : 
 
 Neopalseaster, new genus. 
 
 The origin of this family is uncertain, but it seems to be related to 
 the Promopalseasteridse, since its essential characters are those of the 
 Mesopalaeasterinse. In the latter the supramarginals do not com- 
 pletely overlie the inframarginals making one consolidated column as 
 in Neopalseaster. It is, so far as known, the oldest family developing 
 ocular plates. This fact is of considerable importance for it means 
 that the oculars were originally basal radialia, and that they have 
 progressively wandered from the disk and then remained at the tip 
 of the rays. 
 
 NEOPALSEASTER, new genus. 
 
 Plate 13, fig. 5; pi. 23, fig. 4. 
 Neopalseaster SCHUCHERT, Fossilium Catalogue, Animalia, pt. 3, April, 1914, p. 26. 
 
 Generic characters. Disk of medium size, without interbrachial 
 arcs. Eays five, short and tapering rapidly. 
 
 Abactinally the disk has a small central plate surrounded by 
 numerous smaller plates. Bounding the smaller accessory disk 
 
KEVISION OF PALEOZOIC STELLEEOIDEA. 135 
 
 plates is a ring of very large, thick, tumid, variously shaped, radial 
 and interradial plates. Of the latter there may be one plate inside 
 of the basal supramarginals of adjoining columns, or this plate may 
 be divided, when the pieces appear as inwardly crowded supramar- 
 ginals. Laterally and distally upon the interradials are situated the 
 large basal radial plates. The rays are bounded laterally by columns 
 of large, thick, subquadrate, tubercular supramarginals terminated dis- 
 tally by single ocular plates. These plates appear to be common to 
 both the actinal and abactinal areas and must therefore be the united 
 infra- and supramarginal columns. Between the supramarginals dis- 
 tally appear single small isolated plates which proximally become 
 larger and continuous, forming an inconspicuous column of radial 
 ossicles. On each side of this column are inserted a number of appar- 
 ently irregularly arranged small accessory plates which are like those 
 of the disk. All of the plates of the abactinal area are finely tuber- 
 culose, these points being for the attachment of very fine, short spines. 
 
 Madreporite small, rounded, not very convex, very finely radially 
 striated and resting directly upon two basal supramarginal plates of 
 adjoining rays. 
 
 Ocular plates small but distinct, one terminating each ray and rest- 
 ing against the distal marginal plates. 
 
 Supra- and inframarginal plates large and conspicuous, apparently 
 firmly united and indistinguishable laterally as separate columns. 
 Abactinally the supramarginal plates are wider and overlie more or 
 less the adambulacrals. 
 
 Adambulacrals smaller than the inframarginals but otherwise 
 resemble the latter. 
 
 Ambulacral grooves narrow. Ambulacra! plates alternating, about 
 as numerous as the adambulacrals, 1 -shaped, with the podial open- 
 ings between adjoining plates. 
 
 All other actinal characters unknown, 
 
 Genoholotype and only Jcnown species. Palseaster crawfordsvillensis 
 Miller. From the Keokuk crinid beds near Crawfordsville, Indiana. 
 
 Remarks. Neopalseaster retains a very primitive abactinal plate 
 structure and calls to mind Hudsonaster, Palseaster, and typical 
 Mesopalseaster. It is distinguished from these early Paleozoic genera 
 by the complete consolidation of the supra- and inframarginal plates 
 into one column, and the presence of ocular plates. The inter- 
 brachial area is unknown in Neopalseaster, but its abactinal structure 
 seems to indicate a single interbrachial plate in each area bounded 
 distally by two basal inframarginal plates. If this interpretation is 
 correct, then this character will further distinguish Neopalseaster from 
 Hudsonaster and Palseaster. 
 
136 BULLETIN" 88, UNITED STATES NATIONAL MUSEUM. 
 
 NEOPAL^EASTER CRAWFORD SVILLENSIS (Miller). 
 
 Plate 13, fig. 5; plate 23, fig. 4. 
 
 Palseaster crawfordsmllensis MILLER, Journ. Cincinnati Soc. Nat. Hist., vol. 2, 
 1880, p. 256, pi. 15, fig. 3; N. Amer. Geol. Pal., 1889, p. 265, fig. 379. 
 
 Original description. "This species is founded upon the dorsal 
 view of a single specimen. The rays are longer than the diameter of 
 the body, and not of uniform size. They are flattened or depressed 
 in the middle, as is also the central part of the body. Many of the 
 plates possess a central tubercle or small spine, and probably all of 
 them did. 
 
 "The marginal plates are large ; somewhat elliptical in outline, and 
 have their shorter diameters in the direction of the length of the 
 rays. There are about 12 plates on each side of a ray, and they 
 come together at about the eighth plate from the body, though in 
 the ray opposite the madreporiform tubercle they come together at 
 the seventh. The space between the marginal plates of each ray 
 is filled with smaller plates; three of these unite the larger plates at 
 the body, but they diminish in number toward the apex of the ray, 
 and cease at the eighth plate. In addition to the two large plates 
 which form the junction of the rays with the body, a few large plates 
 cover the outer part while the central part is covered by smaller 
 plates. The madreporiform tubercle is supported by three plates, 
 two of them are large marginal plates, which form a junction between 
 two rays, and the other is a large plate within, forming part of the 
 covering of the body." 
 
 Emended description. The type-specimen measures: R, = 22 mm., 
 r=7 mm., K, = 3.1r > . Width of rays at base 7 mm. Another speci- 
 men in the Museum of Comparative Zoology has rays 3 mm. longer. 
 
 Rays short, tapering rapidly. Disk rather large for a small species. 
 
 Abactinally the disk has a central circular plate surrounded by 
 numerous small, conical, irregularly disposed, accessory plates, among 
 which are a few larger pieces usually adjacent to the large interradial 
 plates. Outside of the small disk plates is a ring of very large, irregu- 
 larly shaped, radial and interradial plates. Five of these are inter- 
 radial in position, and are situated just within the basal plates of 
 adjoining supramarginal columns. These plates may remain normal 
 as a single plate or may be divided into two plates, when they some- 
 what resemble inwardly crowded supramarginals. Upon these 
 laterally and distally rest five large radial pieces, the basal plates 
 of the radial columns. It is very probable that the radial columns 
 are continuous from the basal plate to near the distal portion of the 
 ray, where a few of these plates are much reduced in size and are 
 
EEVISIOIST OF PALEOZOIC STELLEEOIDEA. 137 
 
 separated and wedged in between the adjoining four supramarginal 
 ossicles. There appear to be 10 or 11 of these in a column. On each 
 side of the radial columns in the proximal half of each ray are a number 
 of small accessory plates arranged in irregular columns. All of the 
 abactinal plates are more or less convex and bear numerous small 
 pustules clustered around a larger central one, all of which bore small 
 spines. 
 
 Supramarginal plates very conspicuous, subquadr angular in out- 
 line, generally a little wider than long, with numerous small pustules, 
 among which toward each lateral edge is a large one upon which 
 probably articulated prominent spines. There are from 11 to 13 of 
 these plates in each column. In the distal third of a ray both 
 columns approximate and adjoin each other closely. Each supra- 
 marginal plate lies wholly and directly over an inframarginal and the 
 pieces appear as one consolidated plate with the abactinal side convex 
 and the actinal nearly flat. The supramarginals are the widest and 
 extend in part over the adambulacrals. 
 
 Madreporite small, circular in outline, slightly convex and very 
 finely radially striated. It lies directly upon two basal supramar- 
 ginal plates of adjoining rays and directly outside of one of the large 
 interradial plates. 
 
 An ocular plate terminates each ray. 
 
 Inframarginals apparently like the supramarginals excepting 
 distally, where they are nearly twice as long as wide. 
 
 Adambulacral plates smaller than the inframarginals, nine in 
 the space occupied by five of the latter, somewhat wider than long, 
 convex, and covered with numerous small pustules. 
 
 Ambulacral grooves very narrow in the distal region. The ambu- 
 lacral plates appear to be as numerous as the adambulacrals, and are 
 h- -shaped, with the podial openings between the plates in about the 
 mid-width of the column. 
 
 All other actinal characters are unknown, since the two specimens 
 expose the abactinal area, though one has portions of the plates 
 removed, revealing the actinal characters described. 
 
 Formation and locality. The type-specimen is in the Harris 
 collection of the United States National Museum, and another 
 specimen is in the Dyer collection of the Museum of Comparative 
 Zoology (No. 4). Both were found in the crinid beds of the Keokuk 
 group of the Lower Carboniferous at Crawfordsyille, Indiana. 
 
 Remarks. There is no Carboniferous asterid with which Neopalse- 
 aster crawfordsvillensis can be confounded. 
 
 Cat. No. 60607, U.S.N.M. 
 
138 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Family PALASTERINID^E Gregory (emend.). 
 
 Pateasterinidse GREGORY (part), Geol. Mag., dec. 4, vol. 6, 1899, p. 348 (contains 
 Palasterina, Schaenaster, and Schuchertia)} Treat. Zool., vol. 3, Echinoderma, 
 1900, p. 250. 
 
 Lindstromasterinss GREGORY (part), Geol. Mag., dec. 4, vol. 6, 1899, p. 346 (contains 
 Lindstromaster and Uranaster). 
 
 Palseasterinidse STURTZ, Palaeontographica, vol. 36, 1890, p. 246. 
 
 Progressive Phanerozonia developing large interbrachial arcs. 
 Ambulacral plates more or less alternate. Madreporite abactinal. 
 Disk large, pentagonal, and the rays separated by well-developed 
 interbrachial arcs. The inframarginal plates bound the animal and 
 are separated from the adambulacrals more or less completely by a 
 varying number of interbrachial plates. 
 
 Abactinal surface with longitudinal columns of radial, supra- 
 marginal and accessory columns of plates, or the radial columns 
 may be reduced or even replaced by transverse rows of small accessory 
 pieces. The central region of the disk may retain a ring of larger 
 basal radial and supramarginal pieces. 
 Contains: 
 
 Pet raster Billings. 
 
 Lindstromaster Gregory. 
 
 Palasterina McCoy. 
 
 Uranaster Gregory. 
 
 Palxostella Stiirtz. 
 
 Pseudopalasterina Stiirtz. 
 
 Genus PETRASTER Billings. 
 
 Plates 23, 26, 27. 
 
 Petraster BILLINGS, Geol. Surv. Canada, Can. Org. Rem., dec. 3, 1858, p. 79. 
 HALL, Twentieth Rep. N. Y. State Cab.. Nat. Hist., 1868, pp. 283, 294; rev. 
 ed., 1868=1870, pp. 325, 337. 
 
 Palseaster (part) ZITTEL, Handb. Pal., vol. 1, 1879, p. 452. 
 
 PalsRosterina of some AUTHORS. 
 
 Generic characters. Disk and interbrachial arches more or less 
 large. General shape pentagonal. Rays five, short and slender or 
 stout and tapering rapidly. 
 
 Abactinal area of rays distally with one medial radial, two supra- 
 marginal and two inframarginal columns of plates. Between the 
 radial and supramarginal columns proximally are inserted columns 
 of accessory plates' In P. speciosus there are five on each side of 
 the radial column. Between the supramarginal and iinVaniarginal 
 columns in the axillary and basal ray regions are inserted columns 
 of ambital plates. In P. speciosus there are three. The plates 
 are more or less stellate, with numerous subcircular openings in the 
 angles between adjoining plates. 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 139 
 
 Inframarginal plates bounding the entire outer edge of the animal, 
 conspicuous, closely adjoining, not stellate and common to both the 
 actinal and abactinal areas. 
 
 Madreporite radially striate, abactinal. 
 
 Adambulacrals closely adjoining the inframarginals in the distal 
 portion of the rays but proximally the former are separated from the 
 latter by more or less numerous, small, accessory interbrachial plates. ' 
 The adambulacrals may be of nearly the same size, or considerably 
 wider than long in the mid-length of the column. The adambula- 
 crals of adjoining columns meet orally in a pair of larger triangular 
 plates, the oral armature. 
 
 Interbrachial areas more or less large and the space between the 
 inframarginal and adambulacral columns filled with a variable 
 number of accessory interbrachial plates. 
 
 Ambulacrals slightly alternating, about as numerous as the adam- 
 bulacrals, each with an L-shaped, proximally converging carina. 
 Podial openings through the outer proximal corner of the plate and 
 proximal to the carina. Grooves narrow, regularly tapering. 
 
 GenoJiolotype (type by monotypy). Petraster rigidus Billings. The 
 above diagnosis is based on the genotype and Pal&asterina spedosa 
 Miller and Dyer. 
 
 Distribution. Ordovicic of North America, Siluric of Australia. 
 
 The species are: 
 
 P. rigidus (Billings). Trenton. 
 
 P. speciosus (Miller and Dyer). Maysville, Kichmond. 
 
 P. (?) americanus (D'Orbigny). Maysville. 
 
 P. smythi McCoy. Siluric of Australia. 
 
 'Remarks. While Billings has correctly pointed out the diagnostic 
 characters of Petraster, yet the genus has been very imperfectly 
 understood. This may partly be accounted for in that he later also 
 included a specimen of Hudsonaster matutinus (Hall), which of course 
 fails to have' the essential generic character of Petraster, namely, the 
 interbrachial accessory plates. The following is Billings' original 
 description: 
 
 "This genus has both marginal and adambulacral plates, with a 
 few disk-plates on the ventral side. The general form is deeply 
 stellate, and the rays long and uniformly tapering. A single specimen 
 has been collected, and as it shows the underside only, the characters 
 of the dorsal surface can not be given. The structure of the mouth 
 is also unknown. Generic name from petra, a stone. 
 
 "It differs from Palasterina by the presence of large marginal 
 plates outside of the disk-plates [that genus has small marginals], 
 and still more from Stenaster, which has neither disk nor marginal 
 plates. It is allied to Astropecten." 
 
140 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Professor Hall at first recognized the distinctness of Petraster, since 
 he wrote as follows (1870): 
 
 "The character of Petrasier here described, and illustrated in the 
 figure (3a, pi. 9), gives an intercalated partial range of disk-plates, 
 between the adambulacral and marginal plates, which will separate 
 these forms from any of the Palaeasters in my collection.' 7 
 
 On a later page, after an examination of the genotype, he added 
 a "Note on the genus Petraster" in which he concludes that the 
 specimen was injured during life, as shown by the unequal distribu- 
 tion of the accessory interbrachial plates, and further that one ray 
 is "without intercalated plates on either side.' 7 He adds: "This 
 yiew is sustained by the fact that the other parts have the ordinary 
 structure of Palseaster, and in all other respects the specimen agrees 
 with the typical Palseaster matutina." The genotype was studied 
 at Ottawa by the present writer and found to be as described by 
 Billings. The accessory interbrachial plates, though somewhat 
 irregular in development in different areas in the type species of 
 Petraster, are normal in position and a similar but more complete 
 development also appears in Lindstromaster and Palasterina. 
 
 Petraster is distinguished from Palasterina as follows: The most 
 important feature is that the inframarginal plates of the former 
 are prominent, closely adjoining and short but wide, while in Palas- 
 terina they are small, not conspicuous, and globular, or subquadrate. 
 The next important difference is on the abactinal disk, where in 
 Palasterina there is an irregular ring of prominent basal radial, 
 and supramarginal plates. These are absent in Petraster. The acces- 
 sory interbrachial ossicles in the latter genus never attain the distal 
 region of the rays as in Palasterina where these pieces are also more 
 numerous. Palasterina is also more abundantly spinose than 
 Petraster. 
 
 Schuchertia has no inframarginals as marginal plates, which at 
 once distinguishes it from both Petraster and Palasterina. It is 
 true that in Schuchertia inframarginals are also present but they are 
 usually not well developed and remain adjoining the adambulacrals. 
 These two columns are therefore not separated from one another by 
 accessory interbrachial plates as in Petraster and Palasterina. 
 
 The primary structure of Petraster is that of Hudsonaster. So many 
 of the generic characters are common to both that the former genus 
 appears almost certainly to have been derived through the latter. 
 It is true that the central abactinal area of the disk in Petraster is 
 devoid of the large basal plates, a marked character in Hudsonaster, 
 but the other generic characters are all present in the former. Petras- 
 ter adds more or less numerous columns of radial accessory ambital 
 and accessory interbrachial plates, none of which are present in 
 Hudsonaster. It is these accessory ossicles which differentiate these 
 
OF PALEOZOIC STELLEKOIDEA. 141 
 
 genera and show the line of development from the deeply stellate 
 primary form to the pentagonal genera with well-developed inter- 
 brachial arcs. 
 
 PETRASTER RIGIDUS (Billings). 
 Plate 27, fig. 5. 
 
 Palasterina rigidus BILLINGS, Geol. Surv. Canada, Rep. of Progress, 1853-1856, 
 
 1857, p. 291. 
 Petraster rigidus BILLINGS, Geol. Surv. Canada, Can. Org. Hem., dec. 3, 1858, 
 
 p. 80, pi. 10, fig. 3a (not fig. 3bHudsonaster matutinus} . WRIGHT, Mon. 
 
 British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palaeontogr. Soc. for 1861), 
 
 1862, p. 29. HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 
 
 294; rev. ed., 1868=1870," p. 337. 
 
 Description of 1858. "This species has much the aspect of an 
 Astropecten; the disk is one-fourth the whole diameter, the rays 
 rather slender and uniformly tapering, the angles between the bases 
 of the rays rounded. The plates [of the actlnal side] which appear to 
 be adambulacral [increase very little in size from the tips of the rays 
 toward the mouth], are quadrate and a little convex; [the adambula- 
 cral columns terminated in the mouth area by a pair of pointed 
 oral plates and not by a single plate as shown in the original illustra- 
 tion], the marginal [inframarginal] plates oblong, and also convex 
 [certainly not less than 16 and probably 20 in each column, increasing 
 rapidly in size toward the axils, whsre there is a single large axillary 
 plate] ; the disk plates [accessory interbrachials] consist of three at 
 each angle [one orally and two distally], and a single row [of not more 
 than seven plates] on each side of the ray, but extending only one- 
 third or one-half of the length of the ray; they all lie between the 
 [infra] marginal and adambulacral plates. [Abactinal side unknown.] 
 The specimen figured was about 2 inches [or 50 mm.-] in diameter 
 when perfect ; width of disk half an inch, and of rays at the base about 
 three lines." 
 
 Formation and locality. Trenton limestone, Ottawa, Canada. 
 Holotype No. 140 la is in the Victoria Memorial Museum, Ottawa. 
 The species has also been identified by Springer in the Lower Trenton 
 (Kirkfield) at Kirkfield, Ontario. 
 
 Remarks. Hall and Billings discussed their asterid genera and 
 species at different times and finally the former examined Billings' s 
 material. In this connection Hall showed that figure 3& of Petraster 
 rigidus was based on the actinal side of Hudsonaster matutinus. 
 Regarding figure 3a, which is the holotype of this species, he in 1870 
 wrote as follows: 
 
 "The specimen illustrated in figure 3a has a few small intercalated 
 plates between the marginal and ambulacral [adambulacral] ranges 
 in two of the axils of the rays, and there are a smaller number of gran- 
 ules in a similar position but unequally distributed on one side of 
 
142 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 another axil, while two of the axils do not show any such intercalated 
 plates or granules. In one of the rays, at least, the ambulacral, adam- 
 bulacral, and marginal plates are distinctly visible, without inter- 
 calated plates on either side. 
 
 "The presence of these unequally distributed plates or granules 
 is apparently an abnormal structure, probably the result of accident 
 during the growth of the animal; and this view is sustained by the 
 fact that the other parts have the ordinary structure of Palseaster, 
 and in all other respects the specimen agrees with the typical Palse- 
 aster matutina" 
 
 The holotype was examined by the writer and although imperfect 
 was found to have a normal development, with the plates in their 
 proper places in at least two of the rays and axils. It certainly is not 
 an abnormal development of "Palseaster matutina" but represents 
 a normal individual of a distinct genus and species diverging from 
 Eudsonaster matutinus toward the forms with large disks and great 
 axillary areas, as in Lindstromaster and Palasterina. Hall seemingly 
 was led to make the erroneous remarks above quoted through the 
 fact that Billings had also included in his description a'nd illustration 
 (36) an individual of Hudsonaster matutinus, an error due to the 
 undoubtedly close relationship of this form with Petraster rigidus. 
 
 PETRASTER SPECIOSUS (Miller and Dyer). 
 
 Plate 23, figs. 5-7; plate 26, fig. 1; plate 27, figs. 1-4. 
 
 Palssasterina spedosa MILLER and DYER, Journ. Cincinnati Soc. Nat. Hist., vol. 1, 
 1878, p. 30, pi. 1, fig. 7. MILLER, N. Amer. Geol. Pal., 1889, p. 266, fig. 381. 
 
 Paldeasterina approximata MILLER and DYER, Journ. Cincinnati Soc. Nat. Hist., 
 vol. 1, 1878, p. 30, pi. 1, fig. 8. 
 
 Original description of Palseasterina spedosa. "Pentagonal; rays 
 obtuse at their apices; greatest distance from point to point about 
 2J inches; breadth of body between rays about 1J inches, and dis- 
 tance from tip of ray to next adjoining tip on either side about 1J 
 inches. 
 
 "The [infra] marginal plates are small and somewhat hemispher- 
 ical near the termination of the rays, they gradually enlarge and 
 become square, and then rectangular as they approach the disk, until 
 at the narrowest part of the disk or body of the fossil they are twice 
 as long as wide. There are about 50 marginal plates between the 
 apex of one ray and the next one adjoining, or, in a perfect specimen 
 of this size, about 250. 
 
 "The back or dorsal side is covered with numerous plates (prob- 
 ably in a complete specimen of this size there would be 1,000 or more), 
 which are very prominent in the center or somewhat conical, and 
 seem to have been joined together with deeply serrated edges. 
 The plates have from three to eight of these indentations,, which 
 give them a beautiful starlike appearance. 
 
KE VISION" OF PALEOZOIC STELLEROIDEA. 143 
 
 "The ambulacral grooves are narrow and deep, as shown by the 
 sharp ridges on the back of the specimen. The small dorsal plates 
 which cover the ambulacral pieces are exfoliated in some places, 
 and show two rows of ambulacral plates coming evenly together 
 and forming the sharp ridge.'' 
 
 Original description of Palseasterina approximate, . " Pentagonal; 
 rays more slender than in P. speciosa; greatest distance from point 
 to point in the specimen figured 1.15 inches and breadth of the 
 body one-half inch; another specimen from the collection of Mrs. 
 M. P. Haines, of Richmond, Ind., measures from point to point 2.5 
 inches, and has a breadth of body of nine-tenths inch. 
 
 "The [infra] marginal plates have about the same form, and are 
 about as numerous as they are in P. speciosa. The adambulacral 
 plates are arranged with their length across the rays. The oral 
 plates are very prominent. [This statement is somewhat in error. 
 The five prominent points around the mouth are each formed of one 
 large interbrachial plate and a pair of proximal adambulacrals.] The 
 space between the [infra] marginal plates and the oral ones [adambu- 
 lacrals] is filled with numerous small [accessory interbrachial] pieces. 
 The ambulacral grooves are narrow. Ambulacral ossicles unknown. 
 
 "The dorsal side is covered with small conical pieces, which give 
 it a coarsely granular appearance. The madreporiform tubercle 
 is prominent, conical, and longitudinally striated. 
 
 "This species is distinguished from P. speciosa by its narrower 
 rays, more contracted body, and smaller dorsal plates." 
 
 Emended description. The holotypo of P. speciosa measures: 
 R = 33 mm., r 18 mm. The holotype of P. approximata measures: 
 R = 15 mm., r = 6.5 mm. 
 
 Rays in young specimens slender distally, but with age they 
 become obtuse and very wide proximally and here merge into the large 
 disk. Interbrachial arcs very large. 
 
 The abactinal area of disk and rays is bounded by columns of very 
 prominent inframarginal plates. Beginning at the apex of each ray 
 they are very small and globular, soon they become quadrate and 
 gradually shorter but wider, so that near the middle of each interbra- 
 chial arc they have a crowded appearance. In a full-grown specimen 
 there are about 50 and hi a half-grown example about 45 of these 
 plates between the distal ends of adjoining rays. In the distal region 
 these plates are rounded and nearly smooth but gradually become 
 granular and strongly convex, each with one prominent point for an 
 articulating spine, none of which, however, have been observed. On 
 the actinal side these inframarginals are also very prominent and 
 pustulose but here are flat. They are most prominent near the center 
 of the interbrachial arcs. 
 
 50601 Bull. 88 15 10 
 
144 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 The supramarginal columns begin at the very apex of the rays 
 and for more than one- third of their length adjoin the inframarginals 
 where ambital plates begin to appear. The supramarginal columns 
 are continuous over the disk in a broad curve, with about 18 to 20 
 in a column, or from apex to apex of adjoining rays there are from 
 35 to 40 of these plates. In the axillary areas they are separated 
 from the inframarginals by three or four rows of ambital plates. At 
 the apex of the rays the supramarginals are highly convex and 
 nearly circular in outline but soon pass into more and more dis- 
 tinctly stellate plates. This is the form of all the abactinal plates 
 inside of the inframarginals ; they are stellate, highly convex, each 
 with a central node for an articulating spine and a few granules 
 that are the bases for smaller spines. 
 
 Each radial column appears immediately beneath the two terminal 
 or rather distal supramarginal plates and then continues as a column 
 to near the center of the disk. They are more prominent than the 
 other columns excepting the marginals and have not less than 25 
 plates in each one. On each side of the radials are five columns of 
 radial accessory plates which appear to continue as columns over the 
 disk in broad curves joining those of the next ray. Between these 
 columns in the axillary areas are additional accessory plates. These 
 columns of accessory plates appear singly, first on one side and later 
 on the other, and not in pairs simultaneously, one on each side of the 
 radial columns. 
 
 Ambital areas well developed in the axillary region, where there 
 are about three columns of these plates. The columns pinch out 
 rapidly dis tally and none are present in the outer third of the rays. 
 
 The plate arrangement of the central part of the disk can not be 
 made out. 
 
 Madreporite of medium size, highly conical, and conspicuous, 
 with numerous sharp single or bifurcating ridges; on the under side 
 are seen two outwardly directed spiral cones (the white lines of the 
 drawing representing the spiral tubes in the madreporite), reminding 
 one of the brachia in Atrypa (pi. 27, fig. 4). 
 
 Adambulacral plates depressed, convex, subquadrangular in out- 
 line in young specimens, but in fully grown individuals a number of 
 these in the central region of the column are much drawn out laterally 
 and are here two or three times as wide as long. In a half-grown 
 individual there are about 20 of these plates in a column, but in a 
 mature specimen there appear to be not less than 26. These plates 
 end inwardly in an apex, against which terminate the ridges of the 
 ambulacral plates. The adambulacral and inframarginal columns 
 are closely adjoining in the distal two-thirds of the rays but proxi- 
 
REVISION OF PALEOZOIC STELLEROIDEA. 145 
 
 mally they are separated from each other by numerous accessory 
 interbrachial plates, of which there appear to be not less than 30 in 
 each area. The apexes of these interbrachial areas form the oral 
 armature and each consists of two adambulacral plates, back of 
 which is a rather large interbrachial plate. 
 
 Ambulacra! grooves narrow, tapering, and deeply V-shaped. 
 Ambulacral plates slightly alternating, about as long as wide, and 
 proximally superposed, with about 26 in each column. Each plate 
 has an L-shaped ridge with the point proximally directed. The 
 podial openings are situated in the outer proximal corner of the 
 plates and between the inner angles of two adambulacrals. 
 
 Formation and locality. Richmond and Maysville formations of 
 the Upper Ordovicic. The holotype of P. speciosa was found by 
 Mr. W. C. Barnhart, on Twin Creek, near Winchester, in Preble 
 County, Ohio, and is now in the Dyer collection of the Museum of 
 Comparative Zoology, Harvard University (No. 14). Four other 
 less well-preserved specimens are in the Harris collection of the 
 United States National Museum and were found in the vicinity of 
 Waynesville, Ohio. The holotype of P. approximata and another 
 similar-sized specimen but not so well preserved are also from the 
 vicinity of Waynesville, Ohio. The first is in the Dyer collection 
 of the Museum of Comparative Zoology (No. 15), and the other in 
 the United States National Museum. There is a slab with two 
 young individuals much etched with acid but otherwise excellent, 
 showing the actinal side, in the Gurley collection of the University 
 of Chicago (No. 10979). Finally there are two fine specimens, not 
 fully grown, showing well the actinal and abactinal sides, in the 
 Haines collection of the same university (Nos. 10839 and 10840), 
 found near Hamilton, Ohio; these are apparently from the very top 
 of the Maysville formation. 
 
 Remarks. P. speciosa is described by Miller and Dyer from the 
 abactinal side and P. approximata from the actinal side. These 
 writers point out that the rays are more slender and the disk more 
 contracted in the latter, but when one considers that it is less than 
 half the size of the former and that during growth these forms con- 
 tinually add accessory plates, this difference hi form is seen to be 
 one of growth. The ' 'smaller dorsal plates" noted by these writers in 
 Mrs. Haines's specimen of P. approximata are a character which the 
 present writer does not regard as of value unless they be constant 
 at this lower geologic horizon (Maysville at Hamilton), in which event 
 this specimen can later on be distinguished by another specific name. 
 
 Cat. No. 60609, U.S.N.M. 
 
146 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 PETRASTER (?) AMERICANTJS (D'Orbigny). 
 Plate 26, fig. 2. 
 
 Asterias GRAHAM, ANTHONY, and JAMES, Amer. Journ. Sci., eer. 2, vol. 1, 1846, 
 
 p. 441, figure but no description. 
 Ccelaster americanus D'ORBIGNY, Prodr. de Paleont., vol. 1, 1849, p. 22 (name 
 
 proposed). 
 Asterias anikonii DANA, Manual Geol., ed. 1, 1863, p. 221, with figure but no 
 
 description. 
 Palasterina (tyjamesi DANA, Amer. Journ. Sci., ser. 2, vol. 35, 1863, p. 295; Manual 
 
 Geol., ed. 2, 1864, p. 221, with figure but no description. 
 Palseaster jamesi HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 286; 
 
 rev. ed., 1868=1870, p. 329. MEEK, Geol. Surv. Ohio, Pal., vol. 1, 1873, 
 
 p. 62, pi. 4, fig. 4. 
 
 Meek's description. " Through the kindness of Mr. U. P. James, 
 of Cincinnati, the discoverer of this fossil, I have now before me the 
 original typical specimen, which I found not in a condition to be 
 fully and systematically characterized, nor perhaps to afford the 
 means of determining, beyond doubt, its generic affinities. It 
 evidently attained a large size, and has a comparatively large disk, 
 with its five rays rather broad at their inner ends, somewhat rapidly 
 tapering, and apparently longer than the diameter of the disk. It 
 evidently lies [does lie] in the matrix in such a manner as to show the 
 ventral side [the inner dorsal aspect of the ventral plates], but pre- 
 sents the appearance of having the marginal and disk plates of this 
 side removed [they are present]. The five pairs of oral pieces [proxi- 
 mal adambulacral plates] are seen in place, and proceeding outward 
 from these can be seen a row of adambulacral pieces on each side 
 of each of the rather wide [narrow] ambulacral furrows. These 
 latter pieces are [proximally] nearly three times as long as their 
 diameters in the direction of the length of the rays, and quite promi- 
 nent at their inner ends, where they are articulated together by little 
 processes and corresponding sockets or sinuses; while the outer 
 two-thirds of each is flattened and distinctly more depressed than 
 their inner ends. Outside of, and alternating with, the outer flat- 
 tened ends of these adambulacral pieces, a row of [inframarginal] 
 nearly square, or more or less oblong pieces, may be seen all along the 
 margins of the rays, and connecting at their axilla in such a manner 
 as to leave room for several disk [or interbrachial] plates between 
 them and the oral and inner adambulacral pieces." 
 
 In each interbrachial area there are inserted between the infra- 
 marginals and adambulacrals interbrachial plates as follows: Proxi- 
 mally one hexagonal plate upon which rest two similar plates mar- 
 gined by the inframarginals. 
 
 "At some places within the [narrow] ambulacral furrows, remains 
 of ambulacral ossicula can be seen deeply interlocking with the 
 inner ends of the adambulacral pieces, but their exact form, and the 
 
REVISION OF PALEOZOIC STELLEROIDEA. 147 
 
 position and arrangement of the ambulacra! pores, can not be 
 clearly made out in the specimen studied. 
 
 "The two oral pieces [proximal adambulacrals] of each of the 
 five pairs are separated by deep sutures, and have an irregular form, 
 being longer than wide, and, like the adambulacral pieces, which 
 they somewhat exceed in size, flattened and depressed at their outer 
 ends, and elevated into crestlike prominences farther in, with a 
 lateral process or thickening on the outer side of each, in which a more 
 or less distinct pit may be seen." Between the pairs of oral adam- 
 bulacral plates are inserted small, single, sub quadrangular plates, 
 the proximal plate of each pair of ambulacral ossicles. Orad to 
 each pair of oral armature plates are situated single hemispheric 
 plates. 
 
 "The surface, and the arrangement of the dorsal parts, are un- 
 known; but they were probably armed with short spines, as some 
 remains of little spines are seen in the matrix at the margin of the 
 disk, at one place. 
 
 "As the extremities of none of the rays can "be clearly seen, the 
 exact breadth of the whole fossil, between the ends of opposite 
 rays, can not be exactly given, but it is evident that the length of 
 one of the rays, measuring from the middle of the disk, must have 
 been a little more than 2 inches, and consequently that the diam- 
 eter across from the extremities of opposite rays could not be less 
 than about 4 inches. The breadth of the disk is 1.20 inches; 
 and that of the rays at their inner ends, 0.70 inch." 
 
 Formation and locality. The single specimen was found in the 
 Maysville formation (Ordovicic), by Mr. U. P. James, on or near 
 Vine Street hill, Cincinnati, Ohio, and is now in the James collection 
 of the Walker Museum of the University of Chicago. 
 
 Remarks. This large species is quite distinct from any other star- 
 fish in having three rows of interbrachial plates, one piece in the proxi- 
 mal, two in the medial, and five or possibly more in the distal row. 
 While the arrangement of these interbrachial plates is different than 
 hi the other species of Petraster, their position is that of this genus. 
 Therefore this species is for the present referred to Petraster. The 
 preservation of this specimen is such that its generic and specific 
 characters will remain hi obscurity until other material is found. 
 It lies with the actinal side buried in the limestone while all of the 
 abactinal plates have been worn away. What one sees is therefore 
 the inner or dorsal aspect of the ventral skeleton. 
 
 PETRASTER SMYTHI McCoy. 
 
 Petraster smythi McCoy, Geol. Surv. Victoria, Prodr. Pal. Victoria, dec. ], 1874, 
 p. 41, pi. 10, figs. 1-16. 
 
 Original description. "Five broad semielliptical lobes meeting 
 at slightly rounded reentering angles, leaving the length and the 
 
148 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 width at base of the rays nearly equal and less than the width of the 
 disk. The upper surface is covered with crowded irregularly polyg- 
 onal tumid plates. Madreporiform tubercle very large (1J lines in 
 diameter), irregularly porous, and rugged with branching vermicular 
 ridges, excentric toward base of the two posterior rays. Ambulacral 
 groove very narrow, bordered with a row of large transversely oblong 
 adambulacral plates, wider than long, about 6 in 2 lines at middle 
 of ray; margin of the rays bordered with a rather smaller row of 
 similar marginal plates; between the row of adambulacral and mar- 
 ginal plates an intercalary row of small irregular plates. Width of 
 disk between the rays, 7 lines; from tip to tip of rays, about 1 inch 2 
 lines; length of ray, about 5 lines. 
 
 " Very rare in the fine sandy Upper Silurian rocks of Moonee Ponds, 
 Flemington, a little north of Melbourne [Australia]. ' ' 
 
 Remarks. The holotype exposes the abactinal side, but the plates 
 of two of the rays are absent, exposing the actinal skeleton, which is 
 therefore seen from its inner side. So far as one can judge of the 
 description and illustration, the species is a small but genuine Petras- 
 ter. Abactinally the rays have conspicuous radial and supramar- 
 ginal columns, each with about 17 ossicles, that are tumid and are 
 all closely adjoining. Outside of these in the distal portion of the 
 rays are the equally conspicuous inframarginals, and they margin 
 not only these parts but the entire animal; proximally the inframar- 
 ginals separate more and more from the supramarginals, forming 
 small ambital areas, occupied by a number (can not be determined) 
 of rounded plates that now appear not to have been closely adjoining. 
 
 Madreporite large, radiately striate, situated in an interradius and 
 well inside the ambital area. 
 
 Ambulacralia large, about 12 in a column, and opposite one another. 
 Adambulacrals smaller, about 14 in a column. Interbrachial struc- 
 ture unknown. 
 
 Genus LINDSTROMASTER Gregory. 
 
 Lindstromaster GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, pp. 344, 346. 
 Hisingeraster STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 pp. 224, 225 (same genoholotype as for Lindstromaster). 
 
 Original description. "Palseasterinidae with flat pentagonal disk 
 and five short blunt rays. 
 
 ''The plates of the disk are large, polygonal, tuberculate, and 
 crowded into a close tessellate pavement, which completely covers 
 the interradial areas. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 149 
 
 "Marginal [inframarginal] plates well developed and conspicuous, 
 and but slightly smaller than the adambulacrals. Both supra- and 
 inframarginals appear to be present. 
 
 "The abactinal [actinal] furrows are large and subpetaloid. They 
 are bounded by large tuberculate adambulacral plates. The ambu- 
 lacral plates are boot-shaped [and slightly alternating]. The pores 
 for the podia are large, and occur on the suture between the adam- 
 bulacrals and ambulacrals. 
 
 "The adambulacral elements in the oral armature are prominent, 
 and consist of five pairs of subtriangular plates. 
 
 "Type-species: Asterias antiqua, Hisinger 1837. Silurian: Got- 
 land." No other species of this genus is known. 
 
 Remarks. Of this genus only the actinal side is known and the 
 published figure from a drawing by Mr. George Lilejevall is one of 
 the best of Paleozoic starfishes. Lindstromaster differs from Petras- 
 ter in but one generic character, if it be a generic one, in that the 
 ambulacral furrows are large and subpetaloid in the former and 
 narrow and slowly tapering in Petraster. However, since the abac- 
 tinal area is unknown in Lindstromaster there probably will be dis- 
 covered in this area differences distinguishing it from Petraster. It 
 is also probable that the marginals in Lindstromaster which Gregory 
 thinks are "both supra- and inframarginals" lying directly super- 
 posed are only inframarginals. In Siluric starfishes these plates 
 have not attained the superposed position so marked in recent genera. 
 The supramarginals are here never true marginals and always lie 
 more or less inside the inframarginals, which are the true marginals of 
 these early genera. For other remarks see Palseostella. 
 
 The name Hisingeraster was published after Gregory's name and 
 is based on the same genotype. 
 
 When more material is obtained and the genus is restudied, com- 
 parisons should also be made with Palasterina primseva, as the two 
 forms appear to have much in common. 
 
 LINDSTROMASTER ANTIQUT7S (Hisinger). 
 
 Asterias antiqua HISINGER, Lethsea Suecia, 1837, p. 89, pi. 26, fig. 6. 
 Lindstromaster antiqua GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, pp. 343, 347, 
 
 pi. 36, figs, la, 16 (complete synonymy given here). SCHONDORF, Jahrb. 
 
 nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 225. 
 
 A single specimen is known from "Bed C," Mount Hoburg, Got- 
 land, corresponding to the Wenlock of England. It is in the Angelin 
 collection of the Mineralogical Museum at Copenhagen. 
 
150 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Genus PALASTERINA McCoy. 
 
 Palasterina McCoY, British Pal. Foss., 1851, p. 59 (not defined). SALTER, Ann. 
 Mag. Nat. Hist., ser. 2, vol. 20, 1857, pp. 324, 327. BILLINGS (part), Geol. 
 Surv. Canada, Can. Org. Rem., dec. 3, 1858, p. 76. ZITTEL, Handb. Pal., 
 vol. 1, 1879, p. 453. STURTZ (part), Palseontographica, vol. 36, 1890, p. 226; 
 (part), Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 43, 60. 
 SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, 
 p. 220. 
 
 Palxasterina GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 349 (complete 
 synonymy here). 
 
 The term Palasterina was used by McCoy in the following words: 
 "Before I was aware Prof. Forbes had described them [the three 
 species named below] it seemed to me that the U [rasterella] ruthveni 
 and U. Jvirudo, as well as the similar American species, might be easily 
 separated from the great starfishes forming the recent genus Uraster, 
 by their small size and much more simple skeletons, and I had named 
 the genus Urasterella in my manuscript. The U. primdevus I thought 
 generically distinct from the other two, as the rays were not contracted 
 at base, etc.; and I had named it Palasterina, from its resemblance 
 to the recent genus Asterina." 
 
 The three species mentioned by McCoy had been described by him 
 in manuscript, but on learning that descriptions had been previously 
 published by Forbes, the former, in his "British Palaeozoic Fossils/' 
 adopted the names of Salter. In writing of these three forms, as 
 above quoted, he uses the generic name Palasterina (not Palseasterina, 
 the generally accepted form), and while a type-species is selected, yet 
 McCoy did not point out a single generic character of present value. 
 His statement that "the rays were not contracted at base" is a 
 feature which at that time distinguished Palasterina from Urasterella, 
 but now many Paleozoic genera are known having rays "not con- 
 tracted at base." 
 
 While McCoy does not strictly propose the generic name, Salter is 
 the first to accept and define Palasterina, which he does in the following 
 words : 
 
 "Pentagonal, depressed, the arms a little produced, with three or 
 five principal rows of tubercles above, combined with a plated disk 
 which fills .up the angles ; ambulacra rather shallow, of subquadrate 
 or slightly transverse ossicles, bordered by a single row of squarish 
 large plates, the lowest of which (ad-oral adambulacral plates, Huxley; 
 angle-ossicula, Forbes) are large and triangular, bearing combs of 
 spines (Upper Silurian)." 
 
 Recently Gregory, in a paper entitled "On Lindstromaster and the 
 classification of the Palseasterids" (1899), redefines the genus, basing 
 his definition largely on P. lonneyi. In this connection he writes: 
 
 "The species [P. lonneyi] is of interest, as the structure is better 
 preserved than in the type of the genus [P. primseva], and thus we are 
 
KEVISION OF PALEOZOIC STELLEKOIDEA. 151 
 
 largely dependent upon it for our knowledge of the generic charac- 
 ters " (p. 350). 
 
 Emended description. Disk large, with moderately developed inter- 
 brachial arches. Rays five, short, and tapering more or less rapidly. 
 U R about twice as great as r." 
 
 Abactinal area of rays distally with one medial column of large, 
 thick, and subquadrangular radial plates, on each side of which are 
 similar columns of supramarginal and inframarginal pieces. In this 
 region the columns adjoin and the ossicles are crowded, but 
 proximally between the radial and supramarginal and between the 
 latter and the inframarginal columns (ambital areas) are inserted 
 numerous accessory smaller plates. The latter are most numerous 
 in the ambital areas and at the base of the rays. The ossicles are 
 packed into a tessellate pavement. In the center of the disk there 
 seems to be a prominent central disk piece and at the bases of the 
 rays there is a somewhat disconnected ring of ten most prominent 
 plates, the five basal pieces of the radial and five interradial that 
 give rise to the ten supramarginal columns. Inside of this ring there 
 are probably numerous, very small pieces with no definite arrange- 
 ment. A number of the proximal plates of both the radial and 
 supramarginal columns may be separated from one another by small 
 accessory pieces. 
 
 Madreporite abactinal. 
 
 Inframarginal plates bounding the entire outer edge and common to 
 both sides of the animal. These plates are, however, small (smaller 
 than the adambulacrals) and bear tufts of small spines. 
 
 Adambulacrals subquadrangular, and closely adjoining, each plate 
 bearing on its outer lateral edge a tuft of three spines. Oral armature 
 consists of five pairs of triangular adambulacral plates which have 
 slender spines on the inner edges. 
 
 Interbrachial areas extending to near the distal ends of rays and 
 occupied by numerous "isolated rounded or subangular [accessory 
 interbrachial] plates bearing [single] small spines." 
 
 Ambulacrals slightly alternating and about as numerous as the 
 adambulacrals. Each plate has an L-shaped ridge, posteriorly 
 directed. The podial openings are on the sutures between the 
 ambulacrals and adambulacrals. 
 
 Genoholotype. Uraster prims&vus Forbes. The above diagnosis is, 
 however, based largely upon Palasterina bonneyi Gregory. Dr. 
 Bather sent the writer a number of wax squeezes of the genoholo- 
 type, and while the parts preserved are clear and sharp, yet the speci- 
 mens are not complete enough to work out the generic characters. 
 Therefore, for the present, P. bonneyi is taken as the genoholotype. 
 
 Distribution. Ludlow shales (Upper Siluric) of Great Britain. 
 
152 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Contains : 
 
 P. primseva (Forbes). Ludlow of England. 
 P. bonneyi Gregory. Ludlow of England. 
 P. (?) ramseyensis Hicks. Tremadoc of Wales. 
 
 For other remarks see Palseostella. 
 
 Since the foregoing was written, Schondorf 's work cited above has 
 come to hand. He studied wax squeezes of P. primseva and deter- 
 mined that the genotype is devoid of marginalia, and therefore refers 
 Palasterina to the Cryptozonia. He writes: " Special marginalia ap- 
 pear not to be present, at least the marginal rows are in no way dis- 
 tinguishable from the other intermediary [accessory interbrachial] 
 plates. Accordingly Palasterina primseva Forbes sp. does not belong 
 as stated by Gregory (p. 349) to the asterids with distinct marginal 
 plates, the Phanerozonia, but with the asterids having inconspicuous 
 or no marginalia, the Cryptozonia' 7 (p. 222). 
 
 The present writer holds that there are inframarginalia present all 
 along the edge of the interbrachial areas and the rays, and that they 
 are most typical along the distal portion of the rays. Here the 
 inframarginalia are ontogenetically youngest and less affected by 
 subsequent growth displacement and alteration than are the older 
 ones in the interbrachial areas. In the latter region it is true that 
 the marginalia are not conspicuous, but so long as one can make 
 them out to be inframarginalia, size alone can not be the criterion 
 that will permit of the conclusion that no marginalia are present in 
 Palasterina. However, the difference in interpretation between 
 Schondorf and the writer is not a great one, as neither lays great 
 taxonomic value on whether the marginalia are prominent or u not 
 prominently developed" (p. 223). So long as the inframarginalia are 
 more or less prominent, one of the generic characters of Palasterina, 
 a phanerozonian, is present, and when they are so inconspicuous as 
 not to be made out among the other ossicles, we have one of the 
 generic characters of Schuchertia, a cryptozonian. 
 
 Schondorf also states that the ambulacralia, and the adambulacralia 
 as well, are all opposite and do not alternate with one another. The 
 present writer states that the ambulacrals are " slightly alternating, " H 
 and throughout this work he has given the arrangement of these 
 ossicles his special attention. In a great many cases, and especially 
 in the Ordovicic species, he has had difficulty in ascertaining what 
 was their actual position in the living animals, for nearly all the 
 fossils have been squeezed more or less. He has always given their 
 arrangement as they impressed him in the fossil when no evident dis- 
 tortion could be seen. The writer would not lay special stress upon 
 slight alternation among the ambulacralia, for in many Ordovicic 
 species there is some variation in each ray from opposite to slightly , 
 alternate. Of course, when the alternation or opposite arrangement 
 
REVISION' OF PALEOZOIC STELLEROIDEA. 153 
 
 is complete and fixed throughout the rays, he would lay great value 
 on the character. It may be said that in the earliest Asteroidea the 
 chronogenetic tendency is from slight alternation to complete and 
 fixed opposite arrangement among the amhulacral ossicles. 
 
 PALASTERINA PRIM^EVA (Forbes). 
 
 Uraster primxvus FORBES, Mem. Geol. Surv. Great Britain, vol. 2, pt. 2, 1848, 
 p. 463; Mem. Geol. Surv. United Kingdom, dec. 1, 1849, p. 2, pi. 1, figs. 
 2a, 26; in McCoy, Brit. Pal. Foss., 1851, p. 60. MURCHISON, Siluria, 1854, 
 p; 221, fig. 39. 
 
 Palasterina primxvus McCoy, Brit. Pal. Foss., 1851, p. 59 (nomen nudum). 
 SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 327, pi. 9, figs. 2a-2c. 
 WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palseontogr. 
 Soc. for 1861), 1862, p. 26, fig. 16a. QUENSTED, Petrefactenkunde Deutsch- 
 lands, vol. 4, 1876, p. 74, pi. 92, fig. 35. STURTZ, Verh. naturh. Ver. preuss. 
 Rheinl., etc., vol. 50, 1893, p. 44; vol. 56, 1900, pp. 214, 224. SCHONDORF, 
 Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 220. 
 
 Palszasterina primseva GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 349. SPEN- 
 CER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. for 1913), 1914, pp. 
 37, 38, fig. 30. 
 
 Formation and locality. A common species in the Ludlow rocks. 
 Underbarrow, Kendal, Westmoreland, and Leintwardine, Shropshire, 
 England. 
 
 Remarks. Dr. Bather furnished the author with wax squeezes of 
 specimens Nos. E4990-E4993 (E61 is quite another species and 
 abactinally more closely related to Eudsonaster) in the British 
 Museum (Natural History). They are from the Lower Ludlow at 
 Kendal, Westmoreland. These show little of value abactinally, but 
 actinally are well preserved along the ambulacra. Unfortunately, 
 however, none of the marginals are present and but little of the 
 interbrachial areas. When better material is at hand a comparison 
 should be made also with Lindstrb'master antiquus (Hisinger), as the 
 two look suspiciously alike. 
 
 PALASTERINA BONNEYI Gregory. 
 
 Palseasterina bonneyi GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, pp. 349, 350, 
 text figs. 1-3, and pi. 16, figs. 2a, 26. SCHONDORF, Jahrb. nassauisch. Ver. 
 Naturk., Wiesbaden, vol. 63, 1910, p. 223. 
 
 "This species has hitherto been included in P. primseva, the type- 
 species of the genus, from which it differs by having shorter and 
 blunter rays, more numerous actinal interbrachial plates, and more 
 adambulacral plates in each series ; the character of the abactinal ray 
 plates is also different in the species, the longitudinal series being 
 widely separated at the proximal end of the rays in P. bonneyi" 
 (Gregory). 
 
 Formation and locality. Ludlow shales. Leintwardine, Shrop- 
 shire. Types in British Museum (Natural History). 
 
154 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 PALASTERINA (?) RAMSEYENSIS Hicks. 
 
 Palasterina ramseyensis HICKS, Quart. Journ. Geol. Soc. London, vol. 29, 1873, 
 p. 51, pi. 4, figs. 21-23. WOODWARD, Geol. Mag., dec. 2, vol. 1, 1874, p. 96. 
 
 This starfish needs to be restudied in the light of modern knowl- 
 edge. The specimens represented by Hicks's figures 21 and 22 seem 
 to be referable to Petraster rather than to Palasterina, while that of 
 figure 23 appears to be nearer Mesopalseaster. 
 
 Formation and locality. Said to be from the Tremadoc, but the 
 development of the starfish seems to be in harmony with Upper 
 Ordovicic time. The specimens are from Ramsey Island and St. 
 Davids, Wales, and are in Mr. Lightbody's collection. 
 
 Genus URANASTER Gregory. 
 
 Uranaster GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 347. SCHONDORF, Jahrb. 
 nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 225. 
 
 The name is "from Uranus, the grandfather of Pluto; the starfish 
 resembles the living genus Plutonaster." 
 
 Generic description. Animal deeply pentagonal, above medium size, 
 with well-developed interbrachial arches, and five long slender rays. 
 
 Inframarginal plates marginal, large, and elongated in the direction 
 of the rays. These plates are apparently common to both the actinal 
 and abactinal areas. Abactinally adjoining the inframarginals is 
 another column of large submarginal plates ( ?supramarginals) 
 alternating with the former, and sometimes there are smaller acces- 
 sory pieces between these columns in the angles of the plates. The 
 rays have no medial or radial columns of prominent plates, but the 
 entire space between the submarginal columns is occupied by numer- 
 ous closely fitting, convex, or tubercular plates which are arranged 
 in alternate transverse rows, each having from three to four pieces 
 on each side of a ray. 
 
 Interbrachial accessory plates numerous, polygonal, and, according 
 to Baily 's figure of U. Tcinahani, arranged in crescentic rows conforming 
 to the shape of the disk margin. These plates do not appear to 
 extend between the marginals and adambulacrals beyond the mid- 
 length of the rays. 
 
 Adambulacral plates tubercular, subquadrangular in outline, and 
 widest transversely in the medial third of the column. 
 
 Ambulacral furrows very narrow, deep, and tapering gradually. 
 Ambulacra! plates traversed by strong transverse ridges. 
 
 Madreporite unknown. 
 
 GenoJiolotype. Palasterina Icinahani Baily. Upper Ordovicic. A 
 second species is U. elizse, Spencer, also from the Ordovicic of Great 
 Britain. 
 
 Remarks. Uranaster differs from Petraster, Palasterina, and 
 Lindstromaster in having the abactinal area of the rays between the 
 
REVISION OF PALEOZOIC STELLEROIDEA. 155 
 
 two pairs of marginal columns filled with small tuberculate plates 
 arranged in transverse rows. The other genera have the plates in 
 longitudinal columns. 
 
 URANASTER KINAHANI (Baily). 
 
 Palasterina kinahani BAILY, in KINAHAN, Man. Geol. Ireland, 1878, pp. xv, 26, 
 pi. 2, fig. 1; Mem. Geol. Surv. Ireland, Expl. Mem. Sheets Nos. 169, 170, 
 180, 181, 1879, pp. 58, 59, fig. 6. 
 
 Uranaster kinahani GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 348. SCHONDORP, 
 Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 225. 
 
 This species occurs abundantly as natural molds in the Caradoc 
 (Upper Ordovicic), near Ballymadder Point and Bannow, Wexford, 
 Ireland. A specimen is in the British Museum (Natural History), 
 No. E 194. 
 
 URANASTER ELIZAS Spencer. 
 
 Uranaster elizx SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palaeontogr. Soc. .for 
 1913), 1914, pp. 18, 20, 23, figs. 18, 23. 
 
 From the Ordovicic of Great Britain. 
 
 Genus PAL^OSTELLA Stiirtz. 
 
 Palxostella STURTZ, Palseohtographica, vol. 36, 1890, p. 230, pi. 31, figs. 42, 43; 
 
 Verb, naturb. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 42, 58, pi. 1, figs.5^8, 
 Palsenectria STURTZ, Verb, naturb. Ver. preuss. Rbeinl., etc., vol. 50, 1893. 
 
 p. 12 (genoholotype the second specimen of Palseostella solida). 
 
 Description. Animal attaining a large size, with large pentagonal 
 interbrachial arcs. Rays five, stout. Ambulacral grooves wide and 
 apparently regularly tapering. 
 
 Abactinally the inframarginals are also the marginals for this 
 area. Near the distal ends of the rays the supramarginals adjoin 
 and lie either partially over or inside of the inframarginals and 
 continue nearly to the axillae. There also seems to be a single radial 
 column, confined, however, to the distal third of the rays. Other- 
 wise the abactinal skeleton consists of very numerous, small, irregu- 
 larly shaped, loosely interlocking plates without definite arrangement. 
 
 Madreporite abactinal. 
 
 Actinally the animal is bounded by subquadrate, numerously 
 spine-bearing, inframarginal plates which increase rapidly in size 
 towards the axillae, where they are ponderous and nearly twice as 
 wide as long. Ambulacral plates alternating, L-shaped, with single 
 columns of podial openings. Adambulacrals subquadrate, prominent, 
 increasing regularly in width proximally and bearing spines like 
 the marginals. Interbrachial areas large, reaching to near the 
 distal ends of rays, widely separating the inframarginals from the 
 adambulacrals in the axillary region, and the space occupied by 
 very numerous, small, spine-bearing, apparently irregularly dis- 
 posed plates. 
 
156 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Genoholotype and only species. P. solida Stiirtz. Two speci- 
 mens are known from the Lower Devonic roofing slates, Bundenbach, 
 Germany. 
 
 Remarks. The starfishes from the Bundenbach roofing slates are 
 at best but poor fossils and were it not for the great skill of Mr. 
 Stiirtz in cleaning them out of the matrix their systematic position 
 could not well be determined. At best they are compressed to almost 
 paper thickness and distorted during solidification and shortening or 
 elongation of the slates. Under these circumstances it appears 
 best to redescribe the detailed abactinal characters as given by 
 Stiirtz. He mentions numerous paxillae and finds many characters 
 common to both Palseostella and the living Nectria. 
 
 Palseostella is closely related to Palasterina, also to Lindstromaster , 
 and may be a descendant of the latter. The actinal structure in 
 Lindstromaster and Palseostella is nearly alike, both having large 
 inframarginals and adambulacrals, but the interbrachial areas in 
 the former are occupied by large closely adjoining plates, while in the 
 latter these are small and somewhat loosely interlocking. Abac- 
 tinally they can not be compared, since that side is unknown in 
 Lindstromaster. The greatest difference between Palasterina and 
 Palseostella is that the former has small inframarginals while in the 
 latter they are very large. Then the supramarginal and radial 
 columns in Palasterina are better developed and comparatively 
 larger, while in Palseostella they are shorter and most prominent in 
 the distal half of the rays. In the latter genus the central region 
 of the disk has no ring of fifteen basal radial and supramarginal 
 plates as in Palasterina. 
 
 From this evidence it seems probable that the line of descent is 
 from Petraster to Lindstromaster to Palseostella in marntaining promi- 
 nent columns of inframarginals, while the line from Petraster to 
 Palasterina tends toward the reduction or elimination of these plates 
 as a conspicuous skeleton element. 
 
 Palsenectria is based on the second specimen, and the genus is 
 described as follows: " Should the described starfish [the second 
 specimen of Palseostella solida Stiirtz] prove not to be identical with 
 Palseostella, which is possible, even though not probable the other 
 specimen is in the British Museum I propose for it the new name 
 Palsenectria devonica." Unless the author takes the time to work 
 out his new forms, or decides the problem presented for himself, he 
 should not expect some one else to do this for him. Under these 
 circumstances the genus and species are regarded as not defined. 
 
 Genus PSEUDOPALASTERINA Sturtz. 
 
 Pseudopalasterina STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 pp. 219, 224. 
 
 Genoholotype and only species. Palasterina follmanni Sturtz. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 157 
 
 PSEUDOPALASTERINA FOLLMANNI (Sttirtz). 
 
 Palasterina follmanni STURTZ, Paleeontographica, vol. 36, 1890, p. 226, pi. 29, 
 
 figs. 29-31a. 
 Pseudopalasterina follmanni STURTZ, Verb, naturh. Ver. preuss. Rheinl., etc.. 
 
 vol. 56, 1900, pp. 219, 224. 
 
 Actinally this species has ambulacrals and narrow adambulacrals 
 and outside of the latter the interbrachial and abactinal areas consist 
 of a membrane with small spine-bearing plates. It has no inframar- 
 ginal nor radial and supramarginal columns, features characterizing 
 Palasterina. 
 
 Formation and locality. Lower Devonic of Bundenbach, Germany. 
 
 NEW GENUS. 
 
 NEW SPECIES. 
 
 Prof. Weller got on Fountain Creek, at Waterloo, Illinois, in the 
 St. Louis limestone, a small pentagonal asterid (No. 14396, Univer- 
 sity of Chicago collection) showing only the actinal side, that differs 
 from all other known forms of the large-disked genera. The five rays 
 are completely within the pentagon, with the interbrachial areas large 
 and straight-sided. These areas are made up of a few large tesselate 
 plates, of which it seems that seven compose the interbrachial mar- 
 gins and inside these there seem to be transverse rows, each with five, 
 three, two, and one ossicles. It could not be made out whether the 
 inframarginals and supramarginals are directly superposed, but this 
 may be so. 
 
 Ambulacral furrows exceedingly narrow, a mere line. These are 
 bounded by columns of large, very ornate adambulacrals, each with 
 seven ossicles. Those of opposite columns alternate decidedly with 
 one another and on its outer side each bears two short but dis- 
 tinct spines. 
 
 Adambulacral oral armature in five very prominent pairs of pieces, 
 long and pointed, and about twice as long as any other adambulacrals. 
 
 Measurements: R = 8.5 mm., r = 7 mm. 
 
 Family LEPIDASTERIME Gregory (emend.). 
 
 Lepidasteridse GREGORY (part), Geol. Mag., dec. 4, vol. 6, 1899, p. 352 (includes 
 Lepidaster&n&Etheridgaster)', Treat. Zool., vol. 3, Echinoderma, 1900, p. 255. 
 
 Helutnihasterinse GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 258. 
 
 Helianihasteridse STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 p. 204. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 1910, p. 235. 
 
 Primitive multi-rayed Phanerozonia apparently with the general 
 structure of Pabeasteridse, but with as many as 24 rays. Madreporite 
 known only in Helianthaster, where it is interbrachial and on the 
 
158 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 edge of the disk, more actinal than abactinal. Inframarginals or 
 supramarginals bounding the rays. 
 Contains : 
 Lepidaster Forbes. 
 Eelianthaster Koemer. 
 Lepidaster ella, new genus. 
 
 Remarks. For a discussion as to why there are multi-rayed that 
 is, more than the normal five-rayed asterids, see the family Palse- 
 
 osolasteridse. 
 
 Genus LEPIDASTER Forbes. 
 
 Lepidaster FORBES, Mem. Geol. Surv. United Kingdom, British Org. Hem., 
 dec. 3, 1850, p. 1, pi. 1, figs. 1-3. WRIGHT, Mon. British Foss. Echinod., 
 Oolitic, vol. 2, pt. 1 (Palseontogr. Soc. for 1861), 1862, p. 35. WOODWARD, 
 Geol. Mag., dec. 2, vol. 1, 1874, p. 9. ZITTEL, Handb. Pal., vol. 1, 1879, 
 p. 454. STURTZ, Palseontographica, vol. 36, 1890, p. 222, pi. 28, figs.19-20; 
 Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 52, 72. 
 
 Generic description. Disk very large, over 50 mm. in diameter, 
 and apparently composed of heavy, closely set, polygonal plates. 
 Rays 13 in number, fairly stout, not slender, and tapering fairly 
 rapidly in the distal half. R = 52 mm. , r = 25 mm. A little more than 
 half the length of the rays extends beyond the disk. 
 
 Actinally, the rays are bounded on each side of the very narrow 
 ambulacral furrow by two columns of strong, tumid, closely ad- 
 joining, transversely oblong, adambulacral and inframarginal plates. 
 The latter are also the marginals for the abactinal side. The adam- 
 bulacrals are tuberculate and probably bore small spines; there 
 are 25 ossicles in each column. Ambulacrals unknown, but the 
 arrangement of the adambulacrals indicates that they were slightly 
 alternate. 
 
 Madreporite and interbrachial areas unknown. 
 
 Abactinally little is known. The rays are described as having 
 " numerous small polygonal nearly flat ossicula, closely set, and of 
 various sizes." To judge by similar rays in other genera, it would 
 appear that Lepidaster may have had radial and supramarginal 
 columns of ossicles. 
 
 Genoholotype and only species. L. grayi Forbes. The holotype 
 was found in the quarries of Wenlock limestone in the Castle Hill at 
 Dudley, England. 
 
 Observations. Forbes's illustration leads the writer to believe 
 that the abactinal plates have been deranged and that originally 
 the larger pieces were arranged in supramarginal columns, while the 
 smaller ones composed the radial row of ossicula. This type of 
 structure generally goes with the actinal arrangement as here seen in 
 Lepidaster , a duplicate of the same structure in Hudsonaster } Poise- 
 aster, and Mesopalseaster. Stiirtz compares the abactinal skeleton of 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 159 
 
 Lepidaster with the recent ScytJiaster, which is made up of plates of 
 various sizes without regular arrangement. It seems more natural 
 to compare Lepidaster with Siluric and Ordovicic genera than with 
 recent forms, and particularly when nearly identical structures are 
 found in the genera mentioned. 
 
 Forbes also describes Lepidaster as having the ambulacral grooves 
 " towards the extremity, in some instances partially filled up by small 
 polygonal intervening plates." His figures show a few of these 
 plates arranged in single columns. This anomalous structure is 
 undoubtedly best explained by accepting Stiirtz's conclusion, that 
 they are the separated ambulacral pieces, since otherwise none of 
 these plates appear to be present. As a fifth actinal, or a single 
 ambulacral column, the structure is out of all* harmony with star- 
 fishes. 
 
 Genus HELIANTHASTER Roemer. 
 
 Eelianthaster ROEMER, Palseontographica, vol. 9, 1863, p. 147, pi. 28. QUENSTEDT, 
 Petrefactenkunde Deutschlands, vol. 4, 1876, p. 82, pi. 93, fig. 32. ZITTEL, 
 Handb. Pal., vol. 1, 1879, p. 453. STURTZ, N. Jahrb. fur Min., etc., 
 1886, vol. 2, p. 148; Palaeontographica, vol. 32, 1886, p. 81; vol. 36, 1890, 
 p. 218, pi. 27; Verb, naturh. Ver. preuss. Eheinl., etc., vol. 50, 1893, pp. 12, 
 30. GREGORY, Treat. Zool., vol. 3, Echinoderma, 1900, p. 258. CLARKE, 
 Bull. N. Y. State Mus., No. 121, 1908, p. 61, pi. 10. SCHONDORF, Jahrb. nas- 
 sauisch. Ver. Naturk., Wiesbaden, vol. 62, 1909, p. 34. 
 
 Generic characters. Disk large; rays 14 to 16 in the genotype. 
 Interbrachial actinal areas well developed but not over-large for a 
 many-rayed asterid, either integumentary or granular, distally con- 
 cavely cut out and margined by several small inframarginals, about 
 seven on each side of a larger axillary piece. 
 
 Madreporite marginal, large, more actinal than abactinal, radi- 
 ately striate, interbrachial, and situated immediately outside of the 
 inframarginals. In the fossils it appears to be of the actinal surface. 
 
 Rays long and slender, protruding beyond the disk more than 
 twice the length inside the disk. Adambulacrals opposite one 
 another, with small lateral spines, prominent and large, wider than 
 long, bounding the rays, and terminating proximally in pairs of 
 modified pieces. These make the adambulacral parts of the oral 
 armature. Ambulacral grooves narrow, ambulacral ossicles not 
 seen but probably arranged opposite one another. 
 
 Abactinally the disk appears to have a scale-like covering. The 
 rays have median columns of radialia, outside of which are stout 
 columns of supramarginal ossicles. 
 
 GenoJiolotype (type by monotypy). H. rhenanus Roemer (citations 
 as above). Lower Devonic of Bundenbach, Germany. The above 
 definition is based on the illustrations of Stiirtz. There is a second 
 species in Germany, and H. filiciformis occurs in England. 
 
 50601 Bull. 8815 11 
 
160 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 HELIANTHASTER FILICIFORMIS Woodward. 
 
 Helianthaster filiciformis WOODWARD, Geol. Mag., dec. 2, vol. 1, 1874, pp. 7-10, 
 fig. on p. 8. 
 
 A natural mold in sandstone measuring about 45 mm. in total 
 diameter. Has 11 rays. The disk "must have measured 10 
 mm. in breadth. The arms are 17 mm. in length, and near their 
 junction with the body are 5 mm. broad. " The specimen needs to 
 be restudied and modernized. 
 
 The holotype is from the Upper Devonic at Great Inglebourne, 
 Harberton, South Devon, England, and is now in the collection of 
 Mr. Champ ernowne. 
 
 LEPBDASTERELL.A, new genus. 
 
 Plate 25, fig. 2. 
 Lepidasterella SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, April, 1914, p. 23. 
 
 Much like Lepidaster, but with 24 rays instead of 13 as in that 
 genus. Rays extending considerably beyond the disk. The abac- 
 tinal side only is known, but it shows that the rays have slender radial 
 columns, the ossicles of which are disposed alternatingly with the 
 larger and more prominent supramarginals. Outside of these in 
 some rays may be seen the edges of the inframarginalia, and these 
 have well developed but slender, rather long spines. 
 
 There appear to be no ambital areas, as the inframarginals of 
 adjoining rays meet and at their junction begins the disk. The 
 disk appears to have been made up of more or less closely adjoining 
 polygonal plates whose arrangement is not discernible in the specimen. 
 
 The madreporite and its position are unknown. 
 
 Actinal area unknown. 
 
 Genoholotype and only species. L. babcocki, new species. 
 
 Remarks. The essential difference between Lepidaster and Lepid- 
 asterella is that the former has 13 rays while the latter has 24. 
 
 LEPIDASTERELLA BABCOCKI, new species. 
 
 Plate 25, fig. 2. 
 
 Helianthaster, new species CLARKE, Fifty-ninth Rep. N. Y. State Mus., 1906, p. 37, 
 
 and plate. 
 Helianthaster gyalum CLARKE (part), Bull. N. Y. State Mus., No. 121, 1908, p. 61 
 
 (not pis. 12, I3=Pal3eosolaster (?) gyalum}. 
 
 Description. Rays, 24. Length of best preserved ray in the 
 holotype, 28 mm. Width of ray at base, 3 mm. Width of disk, 
 probably not less than 20 mm. 
 
 Rays slender and regularly tapering. Their structure is only 
 known abactinally, from a natural mold in a fine sandstone. Medi- 
 ally there is a narrow but high column of radial plates, each one of 
 
KEVISION OF PALEOZOIC STELLEROIDEA. 161 
 
 which alternates with those of the supramarginal plates. The 
 latter are slightly tumid, subquadrate in outline, regular in size, 
 but decreasing gradually distally. Outside of these and margining 
 the rays may be seen a little of the inframarginalia, which bear pairs 
 of short, slender, and finely striated spines. There are from 31 to 
 33 closely adjoining plates in each one of the abactinal columns; 
 there appear to be no accessory plates of any kind in the rays. 
 
 Disk circular in outline, somewhat tumid and covered by small 
 many-sided plates that originally appear to have been closely adjoin- 
 ing. 
 
 Remarks. As this is the only American starfish with more than 
 five rays, it is readily distinguished from all others. The abactinal 
 arm structure is practically that of Hudsonaster, with the difference 
 that in L. labcocki the inframarginals do not project beyond the 
 supramarginals and are therefore not seen as a rule from the dorsal 
 side in the natural casts. 
 
 Locality and formation. The holotype, an excellent specimen, was 
 found in the lower part of the Upper Devonic, near Ithaca, New 
 York, by Mrs. G. W. Babcock, after whom the species is named; 
 it is in her possession. The writer's attention was called to this 
 interesting specimen by Prof. H. S. Williams of Cornell University. 
 Some years after this starfish was described in manuscript, Clarke 
 directed attention as above cited to two others found in the Cashaqua 
 shales of the Portage in Hunt's quarry, at Interlaken, New York. 
 
 Cat. No. 60627 (cast), U.S.N.M. 
 
 FAMILY, unknown. 
 Genus ASTROPECTEN Link. 
 
 The genus Astropecten is based upon living species, and it is not 
 probable that the Devonic forms are identical. 
 
 ASTROPECTEN (?) SCHLUTERI Sturtz. 
 
 Astropecten schluteri STURTZ, Palaeontographica, vol. 32, 1886, p. 87, pi. 10, figs. 1, 
 16, 2, 2a; Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 51, 71. 
 
 In the roofing slates of the Lower Devonic at Bundenbach, Ger- 
 many. A single very much distorted and compressed example is 
 the basis of this species. 
 
 Genus ATAXASTER Jaekel. 
 Ataxa.ster JAEKEL, Zeits. geol. Gesell., vol. 55, 1903, Protokol, p. 14 (106). 
 
 Genoholotype and only species. A. pygmseus Jaekel. Ordovicic 
 (DJ, St. Benigna, Bohemia. 
 
 Description. "A small asterid whose ambulacrals in the distal 
 parts are alternate, but in the proximal are opposite." 
 
 Remarks. The above is all that is known about Ataxaster, and 
 for the present the genus has no value. 
 
162 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 CRYPTOZONIA Sladen. 
 
 Specialized Asteroidea without true marginal plates. In other 
 words, there are no large and conspicuous marginal plates bordering 
 the animals, but in primitive forms large adambulacrals do margin 
 the species. In other primitive forms more or less of the infra- 
 marginals may be present, but if so they remain adjoining the adam- 
 bulacrals. 
 
 Ambulacrals alternating or directly opposite one another. 
 Oral armature generally with the adambulacral elements the most 
 conspicuous; more rarely the ambulacral elements are most promi- 
 nent. 
 
 Contains the following families: 
 
 Stenasteridae. Schuchertiidse. 
 
 Monasteridae. Palasteriscidae. 
 
 Urasterellidae. Schcenasteridae. 
 
 Calliasterellidae- Palaeosolasteridae. 
 
 Compsasteridae. 
 
 Remarks. This widely accepted order, which appears as if founded 
 in nature on a single grand phylum, probably has no such value. 
 In other words, asterids without either one or both of the marginal 
 columns bounding the animal developed several times. Therefore, 
 the absence of these ossicles is no indication of direct phyletic 
 relationship, but such are simply cases of parallel development. As 
 long as asterids retain the primitive characters of few columns of 
 rather strong ossicles and the adambulacral type of oral armature, 
 they are clearly Phanerozonia, but when the ponderous skeleton 
 breaks up into a more flexible one of small pieces, then the marginal 
 and abactinal columns vanish as such in the mass of small plates. 
 On the other hand, ponderosity may even be retained with the loss 
 of the inframarginals alone. In all of these Paleozoic forms, the 
 adambulacral type of oral armature is the rule. 
 
 Among the Paleozoic "Cryptozonia" it seems certain that at least 
 the families Stenasteridae, Urasterellidae, Schuchertiidae, and Palaeo- 
 solasteridae had independent origins in Phanerozonia stocks. The 
 Urasterellidae and Calliasterellidae apparently had a single origin in 
 the Phanerozonia subfamily Mesopalaeasterinae by the adoption of 
 marked flexibility. On the other hand, the families Stenasteridae 
 and Monasteridae retained rigidity and primitive characters, and 
 more probably arose in the Hudsonasteridae through the loss of the 
 iriframarginals alone. The Schuchertiidae also had their origin 
 directly in some Phanerozonia stock and one naturally looks for it 
 in forms developing large interbrachial areas as in the Palasterinidae. 
 In this family, however, the accessory plates are introduced between 
 the adambulacrals and inframarginals, while in the former family they 
 
KEVISION" OF PALEOZOIC STELLEROIDEA. 163 
 
 are introduced outside of the inframarginals and the entire abactinal 
 skeleton is broken up into an abundance of tiny pieces. Therefore, one 
 must go back for their origin at least as far as the Palaasteridse. In 
 this case it was not primarily flexibility that led to this supposed 
 ordinal change, but it was due to increase of body cavity and enforced 
 enlarging of the skeleton in the interbrachial and ambital areas, 
 making the more or less pentagonal disk. It is probable that the 
 Palasteriscidas were their descendants, while the Schoenasteridse may 
 have been the final Paleozoic representatives of the same phyletic line. 
 The PalasosolasteridaB seemingly arose in the Phanerozonia family 
 LepidasteridaB by the adoption of a flexible skeleton. 
 
 It would, therefore, seem that the Paleozoic families of supposed 
 Cryptozonia construction are to be grouped as follows: 
 
 Superfamily Stenasteracea, new. 
 
 Includes families Stenasteridse and Monasteridse. 
 Superfamily Urasterellacea, new. 
 
 Includes families Urasterellidse, Calliasterellidse, and Compsasteridse. 
 Superfamily Schuchertiacea, new. 
 
 Includes families Schuchertiidse, Palasteriscidee, and Schcenasteridae. 
 Superfamily Palseosolasteracea, new. 
 
 Includes family Palaeosolasteridse. 
 
 STENASTERIDSE, new family. 
 
 Rigid, small, primitive, five-rayed Cryptozonia, with rapidly taper- 
 ing or petaloid rays. Ambulacrals few in number and opposite in 
 arrangement. Interbrachial areas consisting of the single pairs of 
 large basal adambulacral oral armature plates. 
 
 Abactinal skeleton unknown, but in some forms seemingly integu- 
 mentary. No spines as yet known. It is probable that this family 
 will be referred to the Auluroidea. 
 
 Contains: 
 
 Stenaster Billings. 
 
 Tetraster Nicholson and Etheridge. 
 
 Genus STENASTER Billings (emend.). 
 Plate 32, fig. 1. 
 
 Stenaster BILLINGS, Geol. Surv. Canada, Can. Org. Bern., dec. 3, 1858, p. 77. 
 STURTZ, Palseontographica, vol. 36, 1890, p. 220. GREGORY, Geol. Mag., 
 dec. 4, vol. 6, 1899, p. 352. SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 
 (Palseontogr. Soc. for 1913), 1914, p. 22. 
 
 Urasterella STURTZ (not McCoy), Verb, naturh. Ver. preuss. Rheinl., etc., vol. 
 50, 1893, pp. 40, 41, 56. 
 
 Generic characters. Small rigid asterids, the largest example having 
 11 = 20 mm., / = 4.5 mm. Disk small, without interbrachial arcs. 
 Rays five, short, stout, lanceolate or petaloid. 
 
 Abactinal area devoid of a preservable skeleton. For this reason 
 when this side is at hand it is nearly always mistaken for the actinal, 
 so nearly alike are the two. 
 
164 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Madreporite unknown. 
 
 Adambulacral plates with granular surfaces, few in number, never 
 more than 17 hi a column, subquadr angular and thick, greatest width 
 about the middle of the rays, rapidly diminishing in size distally and 
 making the margin of the rays and disk. The great proximal adam- 
 bulacrals are the orals, occupying the axils in pairs, acutely triangular, 
 more or less pointed, and terminating orally. 
 
 Ambulacral plates large, directly opposite one another and the 
 adambulacrals as well, h- -shaped, with the widest portion in the per- 
 radial center of the rays; there are as many as 16 or 17 ambulacrals 
 in a column. Laterally each plate is more or less excavated, both 
 distally and proximally, thus leaving very large, subcircular podial 
 openings. 
 
 Spines of any kind are so far unknown. 
 
 Genoholotype (the first species and the one selected by subsequent 
 workers). Stenaster salteri Billings. 
 
 Remarks. This genus has not had a good standing, due largely 
 to the fact that Palseaster Hall was poorly known when Billings 
 described Stenaster and further because he included two distinct 
 generic types in his genus. A careful reading of Stenaster, however, 
 reveals that Billings actually based his genus on S. salteri, the first 
 form following the generic description, and this selection has been 
 followed since. Later on, McCoy applied the name Urasterella in 
 a loose manner to the second species (Palseaster pulcJiellus) , and 
 although it is a form of this genus it is not the genotype. Hall (1 868) 
 directed attention to this work of McCoy, but erroneously assumed 
 that all of Stenaster was synonymous with Urasterella. It is true, 
 as stated by Hall, that Billings's second species is congeneric with 
 Urasterella, but the first species and genotype is certainly quite dis- 
 tinct from McCoy's genus. Sttirtz (1890) also points out the same 
 thing and gives a short and emended diagnosis of " Urasterella 
 (Stenaster)." In 1893 the same writer applied McCoy's name 
 Urasterella to Stenaster salteri and made S. pulchellus the genotype 
 of Urasterella, a proceeding that violates the rules of nomenclature. 
 
 Stenaster as here restricted differs from Urasterella in being more 
 decidedly rigid and not so flexible as the latter, while the rays are 
 far shorter and petaloid in form. For these reasons, Stenaster has 
 comparatively few adambulacrals and ambulacrals, while there are 
 many more of these ossicles in Urasterella. Finally, the former 
 reveals no abactinal plates or spines of any kind, while the latter 
 has a skeleton of small plates that terminate in long inarticulate 
 spines or rods. 
 
 Actinally Stenaster is closely related to Tetraster, and the only 
 marked difference is that the former has petaloid rays and more 
 pronounced adambulacral oral jaws. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 165 
 
 There would be no need to point out here the difference between 
 such distinct genera as Stenaster and Palseaster were it not that 
 Hall regarded the former as a synonym of the latter. In Stenaster 
 the rays are petaloid and not slender and regularly tapering, as in 
 Palseaster. The most marked distinction, however, is the fact that 
 these two genera belong to different orders, for Palseaster has columns 
 of iirframarginals that are completely absent in Stenaster. Further, 
 in the last-named genus, the interbrachial areas are made up each 
 of two pairs of oral armature pieces, while in Palxaster there are, 
 distaUy to these, additional large single axillary interbrachials. 
 
 Stenaster and the related genus Tetraster are very primitive in 
 construction. Actinally they are seen to have the structure of 
 Hudsonaster minus the inframarginal columns and the single axillary 
 interbrachials. It is this difference that makes the former genera 
 members of the order Cryptozonia, while Hudsonaster is the most 
 primitive of Phanerozonia. Until the abactinal area is known ha 
 Tetraster and Stenaster, positive phyletic relationship can not be 
 stated, but in a number of specimens of the latter genus the evidence 
 at hand indicates decided specialization through the complete removal 
 of the heavily plated skeleton of Hudsonaster. 
 
 Distribution. Ordovicic of America. The following are the 
 known species: 
 
 8. salteri Billings. Black River and Trenton. 
 
 8. (?) oUusus (Forbes). Bala of Ireland and Wales. 
 
 S. (?) coronella (Salter) . May Hill oandstone (Siluric) of England. 
 
 S. (?) confluens Trautschold. Upper Carboniferous of Russia. 
 
 STENASTER SALTERI Billings. 
 
 Plate 32, fig 1. 
 
 Stenaster salteri BILLINGS, Geol. Surv. Canada, Can. Org. Rem., dec. 3, 1858, 
 p. 78, pi. 10, figs, la, 16. WRIGHT, Mon. British Foss. Echinod., Oolitic, 
 vol. 2, pt. 1 (Palseontogr. Soc. for 1861), 1862, p. 28, fig. 15 (2) on p. 24. 
 
 Original description. "This species has rather short, broad rays, 
 which are narrower where they are attached to the very contracted 
 body than they are at about the center of their length. In conse- 
 quence of this form, the sides of the rays are not parallel, but a little 
 curved outward. As however only two specimens have been col- 
 lected, and both appear to be a little flattened by vertical pressure, 
 it may be that this leaflike shape of the rays is accidental [an 
 abundance of specimens show this form to be the natural one]. 
 * * * The adambulacral plates are oblong [granular and from 7 
 to 17 in each column in the smallest and largest examples], and 
 the sutures between them are nearly at right angles to the ambu- 
 lacral grooves; those next the body are a little sloping outward. 
 
166 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Their length is about twice their breadth, and they are so disposed 
 that the greater dimension is transverse or at right angles to the 
 groove; the extremities which lie next to the grooves are angular, 
 and some of them appear to have the contiguous pores partly exca- 
 vated in them. The oral plates [adambulacrals] are acutely triangu- 
 lar, the sharpest angle being toward the mouth [and form the inter- 
 brachial areas]. The plates are smooth [the adambulacrals are all 
 distinctly granular]. The ambulacral pores are very large, and the 
 ossicles are much contracted in the middle and greatly expanded 
 along the median line of the bottom of the groove." These plates 
 are directly opposite one another and the adambulacrals, and in 
 number equal those of the latter. 
 
 The type-specimen figured by Billings measures: R = 14 mm., 
 r=3.5 mm., R = 4n Width of a ray at base about 4 mm., at about 
 mid-length 5 mm. The largest specimen: K- = 20 mm., r 4.5 mm. 
 
 In the University of Toronto there is a specimen that in every 
 way, except one, has the characters of Stenaster salteri. It was 
 found associated with many other individuals at Kirkfield. It 
 differs from its associates in having what appears to be a distinct 
 disk, rather large, with concave sides, filling in the spaces between the 
 rays. One looks in vain, however, for plates or spines, as the inter- 
 brachial areas are nothing more than an amorphous mass of cal- 
 cium carbonate. These areas are very distinct and stand out prom- 
 inently, but because they do not reveal any plated or spinif erous struc- 
 ture the writer regards them as false characters, produced during the 
 permineralization of the specimen. This conclusion is further sup- 
 ported by the fact that otherwise the characters are those of S. 
 salteri. 
 
 Formation and locality. Three specimens (the type, No. 1398, and 
 two fragments) are from the Trenton limestone at Belleville, Ontario, 
 and are now in the Museum of the Canadian Survey. Another 
 specimen in that museum is on the same slab with Petraster rigidus 
 and has been labeled Palseaster matutina. In Mr. Ulrich's collection 
 there are four isolated rays of this species obtained by him from the 
 Black River limestone at Curdsville, Kentucky. A further specimen 
 preserving two rays, from Government House Bay, Ottawa, was found 
 by Mr. Walter R. Billings. In the Museum of Comparative Zoology 
 there is still another individual which appears to be of this species; 
 it was found by Mr. J. B. Perry at Pant on, Vermont. Finally, an 
 abundance of material was obtained in the Black River limestones 
 at Kirkfield, Ontario; there are more than twenty specimens from 
 this locality in the Walker collection of the University of Toronto, 
 gathered by Mr. Townshend. 
 
 Cab. No. 60628, U.S.N.M. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 167 
 
 STENASTER (?) OBTUSUS (Forbes). 
 
 Asterias primseva SALTER and SOWERBY, Quart. Jour. Geol. Soc. London, vol. 
 
 1, 1845, p. 8, 20 (table) (rumen' nudum). 
 Uraster obtusus FORBES, Mem. Geol. Surv. Gt. Britain, vol. 2, pt. 2, 1848, p. 463; 
 
 Mem. Geol. Surv. United Kingdom, dec. 1, 1849, p. 2, pi. 1, fig. 3. MURCHI- 
 
 SON, Siluria, 1854, p. 182, fig. 17. 
 Palxaster obtusus SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 326. 
 
 WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Paleeontogr. 
 
 Soc. for 1861), 1862, p. 24. SALTER, Mem. Geol. Surv. Gt. Britain, vol. 3, 
 
 1866, p. 289, pi. 23, fig. 1. 
 Stenaster (?) obtusus STURTZ, N. Jahrb. fur Min., etc., 1886, vol. 2, p. 153; Verh. 
 
 naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 41, 56. 
 Stenaster obtusus SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. for 
 
 1913), 1914, pp. 22, 23, 31, text fig. 21, pi. 1, figs. 6, 7. 
 
 The little that is known of this species appears to be in harmony 
 with the characters of Stenaster as here defined. It occurs in the 
 Caradoc beds (Ordovicic) at Drumcannon, Waterford, Ireland, and 
 in the Bala rocks west of Bala Lake (Moel-y-Garnedd) , North Wales. 
 
 STENASTER (?) CORONELLA (Salter). 
 
 Palxaster coronella SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 326. 
 WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palseontogr. 
 Soc. for 1861), 1862, p. 25. 
 
 Stenaster (?) coronella STURTZ, N. Jahrb. fur Min., etc., 1886, vol. 2, p. 153. 
 
 The description of this species is very short and almost nothing is 
 known of its characters. It occurs in the May Hill sandstone (Siluric) 
 at Gunwick Mill, Malvern, England. 
 
 STENASTER (?) CONFLUENS Trautschold. 
 
 Stenaster conftuens TRAUTSCHOLD, Nouv. Mem. Soc. Imp. Nat. Moscou, vol. 14, 
 1879, p. 11, pi. 2, fig. 5. SCHONDORF, Palseontographica, vol. 56, 1909, p. 337. 
 
 Based on a fragment of the distal part of a ray. Appears to be 
 a crj^ptozonian. Generic position unknown. From the Upper Car- 
 boniferous (Moscovian) of Moscow, Russia. 
 
 Genus TETRASTER Nicholson and Etheridge (emend.). 
 
 Plate 33, fig. 4. 
 
 Tetraster NICHOLSON and ETHERIDGE, Mon. Silurian Foss. Girvan Dist., Ayrshire, 
 fasc. 3, 1880, p. 324, pi. 21, figs. 3-8 (not figs. 1-2= Eudsonaster batheri, and 
 9-10== Urasterella girvanensis) . 
 
 The name has reference to the four columns of actinal plates of 
 the rays. 
 
 Remarks. The authors of Tetraster distinguished their genus from 
 Palseaster on the ground that it had on the actinal side but four 
 columns of plates, while that genus as typified by P. matutinus } now 
 Hudsonaster matutinus, has six. In this definition they are correct, 
 but they complicated their good intentions not only by referring to 
 
168 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Tetraster another Cryptozonia form (Urasterella girvanensis, new 
 species), but also by confusing with their genotype specimens that 
 certainly have the character of Palseaster so far as six columns of 
 actinal ossicles are concerned. This latter admixture the writer has 
 taken out of the genotype and has described it in this work as Hudson- 
 aster ~batheri. The adjusting of this matter has been made possible 
 through the kindness of Dr. Bather, who made for this work wax 
 squeezes of the various specimens. After seeing these and the other 
 material originally referred to Tetraster by Nicholson and Etheridge, 
 their various drawings became clear. Their figures are fairly good, 
 but in places do not bring out 'all the characters, but it was the 
 mixture of three generic forms under Tetraster that made it for a time 
 impossible to determine on what the genus should stand. 
 
 Emended description. Small, five-rayed asterids, E, = about 5 mm., 
 r= about 2 mm. Abactinal side unknown. Actinally convex and 
 in its general expression reminding much of living species with large 
 marginals, but in Tetraster the comparatively massive margining 
 plates are adambulacralia. 
 
 Adambulacrals compose the entire outer actinal areas of Tetraster 
 and margin the entire annual. Distally the pieces are small and the 
 12 ossicles of each column increase rapidly in size with the largest 
 basal pieces of adjoining columns making the prominent interbrachial 
 areas. Ambulacrally all are somewhat excavated, stand high above 
 the furrow and each ossicle terminates in a ridge that joins those of 
 the ambulacrals. All of these plates are abundantly granular. 
 
 Ambulacral furrows not wide but rapidly becoming very deep 
 proximally, with excavated adambulacral sides. The columns meet 
 in front of the two largest interbrachial adambulacrals. Podial 
 openings are large and issue deeply from beneath the adambulacrals 
 and between the lateral sutures of the ambulacralia. The pieces of 
 the ambulacral columns are as many as there are adambulacrals and 
 are placed directly opposite one another. Medially the ambulacralia 
 are elevated, roof-like, and without a central gutter. 
 
 While the ab actinal area is unknown, it appears that the adambu- 
 lacrals also margin this side of the animal. The nature of the skele- 
 ton inside of these columns may be of small pieces as hi Urasterella, 
 or, what seems more probable, consist of large radial and supramar- 
 ginal ossicles, without accessory pieces. 
 
 Spines of any kind are unknown. 
 
 Genoholotype. Tetraster wyville-thomsoni Nicholson and Etheridge 
 as above emended. T. (?) imbricatus (Salter) is also placed under 
 this genus for the present. 
 
 Tetraster as now defined is so distinct in its great adambulacral 
 development that it will not be confused with any other Paleozoic 
 genus except Stenaster. Both genera, so far as the actinal area is 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 169 
 
 concerned, are closely related. The differences, however, are worthy 
 of generic rank. In Stenaster the rays are petaloid, with the adambu- 
 lacrals largest at the mid-length of the rays, while in Tetraster the 
 rays are triangular, with the greatest ossicles in the axils. 
 
 At first the genotype looks as if one had a direct representative of 
 living Phanerozonia, but a little study quickly shows that the large 
 actinal margining plates are not marginals or inframarginals, but 
 adambulacrals, and therefore indicate a cryptozonian form. For a 
 while it seemed that these large plates must be inframarginals, but 
 then adambulacrals should be present, and they were looked for 
 along the ver'tical ambulacral walls, but even here there are no 
 diminutive pieces of these columns. Among Paleozoic asterids the 
 writer has not seen a form without adambulacrals, and when there are 
 but four actinal columns it is always the inframarginals that are 
 diminutive or absent. 
 
 This species may be identical with T. (?) inibricatus (Salter), 
 which see for further remarks. 
 
 Distribution. Restricted to the Upper Ordovicic at Thraive, Gir- 
 van, Scotland. The specimens occur as very sharp natural molds in 
 a micaceous sandstone, from which good wax squeezes can be made, 
 revealing all the skeletal characters. The originals are in the collec- 
 tion of Mrs. Robert Gray, Edinburgh, Scotland. 
 
 TETRASTER (?) IMBRICATUS (Salter). 
 
 Palseaster imbricatus SALTER, Mem. Geol Surv. Gt. Britain, vol. 3, 1866, p. 
 289, pi. 23, fig. 8. 
 
 Original description. "P. rigidus, uncialis. Radii breves conici, 
 nee ad basin valde expansi, subcarinati, tuberculis seu jugis obliquis 
 remotiusculis asperi. 
 
 "Ray conical, its length about five lines, its breadth at base less 
 than two lines. Only two rays are preserved; these are convex, 
 slowly tapering, somewhat carinate above (we do not see the lower 
 side), and ornamented by tubercles gathered into curved oblique 
 rows, which run forward from the avenues toward the carina above, 
 and are separated from each other by a space little more than their 
 own breadth. 
 
 " Locality: Caradoc rocks, Llanfyllin, Montgomeryshire [Wales]. 
 The specimen is in the collection of Mr. Prosser." 
 
 Remarks. As the writer has not seen the holotype, his conclusions 
 are based on the lithographic figure, which adds but little knowledge 
 to that in the description. As there are but two columns of dorsal 
 ray plates, it hardly seems that the species is a phanerozonian. In 
 general it looks most like Tetraster, but as the dorsal side of this 
 form is unknown, no direct comparisons can be made between them. 
 On the other hand, the imbrication of the plates, their large size, 
 
170 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 and completely opposite arrangement suggest that T. (?) imbricatus 
 may be an auluroid. Until the original specimen is restudied no 
 definite assignment can be given it. 
 
 MONASTEKID^E, new family. 
 
 Progressive but primitive five-rayed Cryptozonia, with massive 
 plates, especially the adambulacrals, which are common to the actinal 
 and abactinal areas. Ambulacrals opposite. Interbrachial areas con- 
 sist of a number of pah's of adambulacrals crowded orally Abacti- 
 nally the radial and supramarginal columns consist of large, closely 
 adjoining plates, and are similar to those of Hudsonaster. 
 
 Contains : 
 
 Monaster Etheridge. 
 
 Genus MONASTER Etheridge. 
 
 Palseaster (Monaster} ETHERIDGE, jr. (part), Mem. Geol. Surv. New South Wales, 
 
 Pal., No. 5, pt. 2, 1892, pp. 70, 71. 
 Etheridgaster GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 353 (genoholotype, 
 
 Palxaster clarlcd). 
 
 Emended description. Animal large, very stout, with five thick 
 petaloid rays. Disk very large, with marked ray angles. 
 
 Abactinal area of rays with prominent radial, and supramarginal 
 columns of large, contiguous, strongly convex, hexagonal plates, 
 densely covered with small granules radially arranged. The ossicles 
 of the radial columns alternate with those on each side and are largest 
 in the mid-length of the rays, decreasing in size both distally and 
 proximally, but most rapidly distally. This growth gives the ray 
 columns a decided petaloid form. Outside of the supramarginals the 
 animal is bounded by single columns of prominent, short, but very 
 wide plates, which are the abactinal aspect of the actinal adam- 
 bulacrals. These plates bear numerous spiniferous tubercles. The 
 ossicles of the axillary disk region are not determinable. In the center 
 of the disk there appear to be five distinct radials and a central disk 
 plate, and around these probably were numerous small accessory 
 pieces. 
 
 Madreporite abactinal, large, oval, radially striate, and situated 
 near the axillary margin. 
 
 Actinally the rays consist almost entirely of the adambulacrals, 
 which are numerous, abundantly tuberculate, short, and very wide. 
 These columns increase rapidly in width, join and form angular 
 axillse, and leave between themselves deep petaloid ambulacral 
 grooves. The interbrachial areas consist of the oral extensions of 
 adjoining columns of adambulacrals, of which there are a great num- 
 ber of pairs, terminating in the mouth in five small pairs, the oral 
 armature. 
 
KEVISION OF PALEOZOIC STELLEEOIDEA. 171 
 
 Ambulacrals in two columns, opposite, short but wide, and about 
 as numerous as the adambulacrals. Podia! openings unknown. 
 
 Genoholotype. Palseaster darlcei De Koninck. This is also the only 
 species of Monaster and occurs in the "Upper and Lower Marine 
 series" of the " Permo-Carbonif erous " of New South Wales. 
 
 Remarks. Mr. Etheridge proposed Monaster as a subgenus of 
 Palseaster, from which it differs so radically as to give it easily the 
 rank of a genus. He defines the group as follows : In Palseaster " the 
 adambulacral plates, bordering the ambulacral avenues, are small 
 and quadrangular, followed by large transverse marginal plates. In 
 our Permo-Carboniferous species, on the contrary the adambulacral 
 plates are transversely elongated, and occupy nearly the whole of 
 the actinal surface on each side the avenues. The marginal plates 
 [having reference to the plates along the margins which consist of 
 adambulacrals, and also form part of the abactinal skeleton], in con- 
 tradistinction to those of Hall's Silurian species, are here smaller and 
 subdorsal in position. The question now presents itself, of what value 
 in a classificatory sense is this character ? Hall lays particular stress 
 on the position of these plates on the actinal side of Palseaster. He 
 says it 'has two ranges of plates on each side of the ambulacral 
 groove; marginal [inframarginal] and adambulacral plates on the 
 lower side, besides ambulacral or poral plates. The upper or dorsal 
 side has three or more ranges of plates/ In the case of our specimens, 
 only one set of plates, excepting those of the ambulacral grooves, 
 are, as before stated, absolutely actinal; the marginals [same usage 
 as before] are strictly so, or, at the least sub-dorsal. Under these cir- 
 cumstances, I purpose distinguishing our Australian species under 
 the subgeneric name of Monaster (from the one or single row of 
 adambulacral plates on each side of an ambulacral avenue) ." 
 
 The original definition is here given at length to show that it can 
 only apply to the structure in Palseaster darkei De Koninck, which 
 is also the first species following the generic discussion. The author 
 in the same work describes a new species which he also refers to 
 Monaster, Palseaster (Monaster) giganteus, but its structure is radi- 
 cally different and does not conform with the subgeneric definition 
 by Etheridge. Elsewhere in this work it is taken as the genotype of 
 the new genus Australaster . Gregory in the serial above cited takes 
 as the genotype of Monaster the last named species, the third of 
 Etheridge, and transposes the former as the genotype to his new 
 genus Eiheridgaster. This the writer holds can not be done even 
 though Etheridge selected no genotype for Monaster. That author's 
 genotype, as the name implies, refers to a species with but a single 
 column of plates on each side of the ambulacrum. The species selected 
 by a subsequent author should have the structure implied in the 
 
172 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 original generic definition and when none actually applies, then the 
 first species following the generic diagnosis. That Gregory fully 
 appreciated the structural difference between Palseaster clarkei and 
 P. (M.) giganteus is shown in his reference of the former to the order 
 Phanerozonia and the latter to the Cryptozonia. Our disagreement 
 is not as to structure but in the interpretation of the rules of nomen- 
 clature. Under these circumstances P. clarkei is retained as the geno- 
 type of Monaster, since it appears that P. giganteus has both infra- 
 marginals and adambulacrals on the actinal side, a structure quite 
 different from that described for and present in Monaster Etheridge. 
 
 After the above was written in 1900, the writer explained by letter 
 to Professor Etheridge what Gregory had done. Etheridge replied 
 under date of June 6, 1900: "The laws of zoological nomenclature 
 should have guided Doctor Gregory to have selected the first species 
 described, as the subgeneric type, in the absence of any statement to 
 the contrary on my part. As you say, Eiheridgaster is certainly a 
 synonym of Monaster." 
 
 Monaster is most like Hudsonaster. It retains the primitive pon- 
 derous skeleton of the latter, but curiously has lost the inframarginal 
 columns of ossicles, although the supramarginals are present. 
 
 MONASTER CLARKEI (De Koninck). 
 
 Palseaster clarkei DE KONINCK, Mem. Soc. roy. Sciences, Liege, ser. 2, vol. 2, 1877, 
 p. 166, pi. 7, figs. 6, 6a; (David), Mem. Geol. Surv. New South Wales, Pal. 
 No. 6, 1898, p. 127, pi. 7, figs. 6a, 66. 
 
 Palseaster (Monaster) clarkei ETHERIDGE, jr., Mem. Geol. Surv. New South Wales, 
 Pal. No. 5, pt. 2, 1892, p. 71, pi. 14, figs. 1, 2; pi. 15, fig. 4. 
 
 Etheridgaster clarkei GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 353. 
 
 Of this species three natural molds have been found in the "Upper 
 Marine " and "Lower Marine' 7 series (Carboniferous) of Northum- 
 berland County, New South Wales. The holotype in the Clarke 
 collection was destroyed by fire. 
 
 The species attained a large size, the rays from the center of the 
 disk to their extremities are not less than 5 cm., and in another 
 specimen are 6.5 cm. 
 
 URASTERELLID^E, new family. 
 
 Txniasteridse GREGORY (part), Geol. Mag., dec. 4, vol. 6, 1899, p. 351 (includes 
 
 Tseniaster, fStenaster, Urasterella, Protasteracanthion, Salteraster). 
 Roemerasterinx GREGORY, Treat. Zool., vol. 3, Echinoderma, 1900, p. 255. 
 
 Specialized Cryptozonia, with alternate ambulacra, and with adam- 
 bulacral type of oral armature. Rays five, rather flexible, long and 
 gently tapering, proximally united without forming interbrachial 
 areas. No inframarginals discernible as such at maturity, the actinal 
 margin being occupied by well-developed adambulacrals. Abactinal 
 area composed of numerous small plates arranged in columns and 
 
KEVISION OF PALEOZOIC STELLEKOIDEA. 173 
 
 quincunx. The radial and supramarginal columns may be dis- 
 cernible in somewhat larger plates. Adambulacrals many, like coins 
 set on edge. * 
 
 Contains: 
 
 Urasterella McCoy 
 
 Genus URASTERELLA McCoy (emend.). 
 Plates 27 to 30. 
 
 Urasterella McCoY, British Pal. FOBS., 1851, p. 59 (not defined). HALL, Twentieth 
 Kept. N. Y. State Cab. Nat. Hist., 1868, p. 289; rev. ed., 1868=1870, p. 332. 
 McCoY, Geol. Surv. Victoria, dec. 1, 1874, p. 42. ZITTEL, Handb. Pal., 
 vol. 1, 1879, p. 453. STURTZ, N. Jahrb. fur Min., etc., 1886, vol. 2, p. 152; 
 Palseontographica, vol. 36, 1890, p. 219. GREGORY, Geol. Mag., dec. 4, vol. 6, 
 1899, p. 352. 
 
 Stenaster BILLINGS (part), Geol. Surv. Canada, Can. Org. Rem., dec. 3, 1858, 
 p. 77. STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, 
 pp. 40, 56. 
 
 Eoemeraster STURTZ, Palaeontographica, vol. 32, 1886, p. 85 (genoholotype, Asterias 
 asperula Roemer); vol. 36, 1890, p. 220; Verh. naturh. Ver. preuss. Rheinl., 
 etc., vol. 50, 1893, pp. 52, 73. 
 
 Protasteracanthion STURTZ, Palseontographica, vol. 32, 1886, p. 90 (genoholotype, 
 P. primus Stiirtz= Asterias asperula Roemer); Verh. naturh. Ver. preuss. 
 Rheinl., etc., vol. 50, 1893, pp. 54, 75. 
 
 Palasteracanthion STURTZ, N. Jahrb. fur Min., etc., 1886, vol. 2, p. 153 (genoholo- 
 type, "A, primus "= Asterias asperula Roemer). STURTZ, Verh. naturh. Ver. 
 preuss. Rheinl., etc., vol. 50, 1893, p. 75. 
 
 Salteraster STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 
 43, 60 (genoholotype, Palseaster asperrima oalter). 
 
 fEoactis SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. for 1913), 
 1914, p. 30 (genoholotype, E. simplex Spencer=? Urasterdla girvanensis). 
 
 Generic characters. Disk very small, without interbrachial arcs. 
 Rays five, very long and slender at maturity, but shorter and rapidly 
 tapering when immature. 
 
 Abactinal side with very numerous small stellate plates, all of 
 which, excepting one or three medial columns, are drawn out into 
 more or less long, blunt, stout, erect, nonarticulating rods. The disk 
 is occupied by a central plate and a first ring with five plates, which 
 in some species are seen to be the basal radial plates, followed by a 
 second ring with 1 5 plates. Five of the latter are the second proximal 
 radial plates, and 10, basal plates of the supramarginal columns. 
 Between the central plate and the first ring there may be inserted a 
 few accessory, much smaller pieces. These disk ossicles may remain 
 more prominent throughout life or may have the size of the other 
 abactinal plates, in which case their arrangement is not plainly made 
 out. In the center of the ray the adial column may be the more 
 conspicuous throughout life or it may be more or less completely 
 suppressed when the supramarginals adjoin and these may then 
 
174 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 be the more prominent columns. Or the entire abactinal area of the 
 rays may be composed of ossicles arranged in columns and in 
 quincunx when the plates are of nearly equal size. The number of 
 columns varies with age and in different species, the greatest number 
 observed being 13 at the base of a ray. 
 
 Ambital plates often not readily distinguishable at maturity from 
 the radial and supramarginal columns. The growing distal tips of 
 the rays of Urasterella have no ambital plates, but shortly after their 
 introduction they begin to develop the rodlike extension so charac- 
 teristic of this genus. Of these columns there may be as many as 
 four at the base of a ray on each side of the supramarginals. 
 
 Inframarginals, as such, usually not distinguishable at maturity 
 from the ambital plates. Their position is rather abactinal than 
 actinal. At the distal end of rays, however, these plates lose their 
 ambital character, passing over somewhat to the actinal side, and 
 closely adjoin the adambulacrals. In the young of U. ulrichi the 
 inframarginals are well developed in the axillary regions and here 
 there is also a single interbrachial marginal plate. More dis tally, 
 however, the inframarginals have the character of the ambital plates. 
 In none of the mature specimens have been seen well-developed or 
 larger axillary inframarginals or interbrachial marginal plates. In 
 U. asperula the axils have actinally single plates which may be 
 remnant inframarginals. 
 
 Madreporite abactinal, of medium size, slightly convex, depressed 
 and granules triate. 
 
 Adambulacral plates very numerous, coin-shaped, and arranged on 
 edge with the actinal surface pustulose. Each plate on its actinal 
 surface bears two or three short, thick spines, and on its ambulacral 
 side there is another similar spine. Along the outer edge of these 
 plates toward the abactinal side there is another row of spines, in 
 pairs, which are long and slender, flat, and longitudinally grooved 
 on two sides. The adambulacral columns terminate in small tri- 
 angular plates of the oral armature. In the young of U. ulrichi five 
 very stout, short, pointed spines (tori) are inserted inside of the plates 
 of the oral armature. 
 
 Ambulacral columns with the ossicles generally slightly alternating, 
 but they may also be opposed, one plate to each adambulacral piece, 
 more or less wedge- or club-shaped, and those of each column par- 
 tially overlapping. Medially the columns loosely adjoin. Each 
 plate is excavated laterally, along the proximal edge, leaving a more 
 or less long, slender podial opening between adjoining plates. 
 
 Genoholotype. Uraster ruihveni Forbes. The above diagnosis, 
 however, is based on Stenaster grandis Meek, a form thought to be 
 in generic harmony with the genotype. 
 
KEVISION OF PALEOZOIC STELLEKOIDEA. 175 
 
 Distribution. The species occur in North America and Europe and 
 range from the Ordovicic to the Upper Carboniferous. The following 
 are the known species: 
 
 U. pulcJiella (Billings). Trenton. 
 
 U. grandis (Meek). Richmond. 
 
 U. fiuxleyi (Billings). ?Chazy. 
 
 U. ulrichi, new species. Lowville. 
 
 U. girvanensis, new species. Upper Ordovicic of Scotland. 
 
 U. (?) asperrima (Salter). Bala of Wales. 
 
 U. (?) constellata (Thorent). Siluric of France. 
 
 U. ruthveni (Forbes). Ludlow of England. 
 
 U. Jiirudo (Forbes). Ludlow of England. 
 
 U. selwyni McCoy. Siluric of Australia. 
 
 U. asperula (Roemer). Lower Devonic of Germany. 
 
 U. } new species. Ithaca beds. Upper Devonic. 
 
 U. montana (Stschurowsky). Upper Carboniferous of Moscow, 
 
 Russia. 
 
 Remarks.- McCoy in suggesting the name Urasterella did it in the 
 following words: 
 
 11 Before I was aware Prof. E. Forbes had described them it seemed 
 to me that the U. [raster] RutJiveni and U. Hirudo, as well the similar 
 American species, might be easily separated from the great star- 
 fishes forming the recent genus Uraster, by their small size and much 
 more simple skeletons, and I had named the genus Urasterella in my 
 manuscript." 
 
 This is all that McCoy did to establish the genus Urasterella, 
 abandoning his manuscript definition on learning that Forbes had 
 described the species as those of Uraster. Salter 1 in 1857 paid no 
 attention to this name, although he was the first to recognize and 
 define Palasterina, which McCoy proposed at the same time and in 
 the same manner. It seems that Hall (1868, p. 332) was the first 
 to revive the name Urasterella and regarded Billings's Stenaster as a 
 synonym by taking his second species, 8. pulchella, as the genotype. 
 Hall's remarks are as follows: "Mr. Salter, apparently overlooking 
 my description of Pal&aster niagarensis, has placed both the above- 
 cited European species [ Uraster rutTiveni and U. Jiirudo] under Palae- 
 aster, as defined by himself; but as it has been shown that this genus 
 has two ranges of plates on each side of the ambulacral groove, these 
 forms can not with propriety be arranged with typical Palseasters. 
 
 " There was the same reason for adopting the generic term Uras- 
 terella as for adopting Palasterina, both of which were proposed by 
 McCoy at the same time, and the typical forms of each were specified. 
 Mr. Salter has for some reason recognized the genus Pabea,ster pro- 
 
 iAnn. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 326. 
 50601 Bull. 88 15 12 
 
176 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 posed by me a little earlier, but probably published after that of McCoy; 
 and has given the two species of Urasterella to that genus. Now 
 that there seems no reason for continuing them under that generic 
 term, they should be restored to their proper position as indicated 
 above. The two species of Forbes must either be placed under 
 Urasterella as proposed by McCoy, or fall under the later genus 
 Stenaster of Billings. Were the latter genus of my own proposing 
 I should nevertheless return to Urasterella, and I have no doubt 
 that Mr. Billings will accord with this view." 
 
 Palseaster pulcJiellus is a true Urasterella, but this does not make 
 the genus Stenaster a synonym of Urasterella, since S. salteri Billings 
 has quite another structure and is here accepted as the genotype of 
 Stenaster. 
 
 Meek 1 also recognizes McCoy's name, but because of certain pecul- 
 iarities in S. salteri, which he recognizes as the genotype, and also 
 since he had not seen the dorsal side of McCoy's S. grandis, he prefers 
 to retain Stenaster for the latter. 
 
 McCoy returned to his genus in 1874, after going to Australia, and 
 described a new form, U. selwyni. It is important to quote here 
 his remarks : 
 
 " Genus Urasterella (McCoy )= Stenaster (Billings). 
 
 "Gen. Char.: Small starfishes, with five moderate rays, narrowed 
 at the base, and without disk. Ambulacral grooves narrow, bor- 
 dered on the under side, with only one row of large (adambulacral) 
 plates; no marginal plates. Upper surface with numerous rows of 
 small tubercular plates. Confined to Silurian rocks. 
 
 "The late Mr. Salter and Mr. Billings refer the starfishes of this 
 type to the subsequently published genus Pateaster of Hall; but, 
 as Prof. Hall objects that his genus Palseaster has ambulacral, adam- 
 bulacral, and marginal plates, and the types of my genus U. ruthveni 
 and U. Jiirudo of the English Ludlow rock, like our Australian species 
 and the American Pals&aster or Stenaster pulchella, have only one row 
 of plates on each side of the ambulacral groove, I return to the use 
 of my old generic name." 
 
 Zittel 2 says that Stenaster is a synonym for Urasterella and defines 
 the latter genus. Stiirtz 3 points out the errors in the diagnosis of 
 Billings and that of Zittel, redefines the genus, and correctly states 
 that Stenaster Billings contains species of two genera, that is, Sten- 
 aster salteri, the genotype of Stenaster, and S. pulchella, which he refers 
 to Urasterella. In this way the genus Urasterella has come to be 
 recognized. 
 
 The figure and description of Uraster ruthveni given by Forbes* 
 appears to be of a species generically identical with the American 
 
 1 Pal. Ohio, vol. 1, 1873, p. 67. s Palseontographica, vol. 36, 1890, p. 219. 
 
 2 Handb. Pal., vol. 1, 1879, p. 453. * British Org. Rem., dec. 1, 1849, p. 1, pi. 1, fig. 1 . 
 
REVISION OF PALEOZOIC STELLEROIDEA. 177 
 
 Stenaster pulchellus Billings and this is the general consensus of opinion. 
 The writer unfortunately had no material of the genotype of Uras- 
 terella for study. However, since U. grandis is closely related to U. 
 pulchella and shows so much more detail, it is here accepted as the 
 genotype for the time being. 
 
 Professor Hall (1870) wrote: " In Stenaster = Urasterella, however, 
 we have the absence of adambulacral plates." This is nevertheless 
 not the case, for the corn-shaped marginal series in S. pulchellus are 
 the ambulacral plates, since weU-developed inframarginal plates, as 
 in Palseaster, are absent in mature Urasterella. The inframarginals 
 are, however, seen to be present in U. pulchella or in the distal ends 
 of the rays in other species, though proximally they are so modified 
 as not to be readily distinguishable from the ambital plates. In the 
 axils of the young of U. ulrichi the inframarginals are well developed, 
 along with single interbrachial marginal plates, but in mature speci- 
 mens of other species none have been seen. 
 
 Of Roemeraster the writer has seen three excellent specimens skil- 
 fully prepared by Sttirtz which clearly show that this genus has the 
 generic structure of Urasterella. Stiirtz 1 describes this genus as 
 having "strong marginal plates" inside of the "small, cornered adam- 
 bulacrals." Our specimens do not show such plates, and if present 
 they can not be adambulacrals. This fact can be demonstrated 
 in a well-preserved distal end of a ray, where two columns are present 
 on each side of the ambulacrals. The innermost column of closely 
 adjoining plates increase in size, retain iheir position beside the ambu- 
 lacrals, and become the most prominent of the entire animal, while 
 the outermost column soon change in aspect, the plates become 
 separated and assume the characters of the ambital pieces. This 
 is likewise true in the young of U. ulrichi where the axillary areas 
 also have distinct interbrachial marginal and two larger proximal 
 inframarginal plates. Passing distally, the latter also soon change 
 then- form, are separated one from another and are not distinguish- 
 able from the ambital plates. Stiirtz further describes and figures 
 five interbrachial ossicles in mature Urasterella asperula which are 
 also well developed in the young of U. ulrichi. Urasterella is an 
 easily recognized genus and the triangular ambital plates drawn out 
 into short blunt erect rods are peculiar to it, a character again re- 
 peated in Roemeraster. Under these circumstances the latter appears 
 to be indistinguishable from Urasterella. For other remarks see 
 U. asperula. On the other hand, Gregory regards Roemeraster as a 
 good genus and places it erroneously among the ophiuridlike asterids 
 in the family Tseniasteridse. 
 
 i Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, p. 52. 
 
178 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 In regard to Protasteracanthion Stiirtz, see remarks under Uras- 
 terella asperula, and for Salteraster Sturtz see U. asperrima. 
 
 Urasterella differs from Stenaster as redefined in this work in having 
 long, slender, flexible rays which are never short and petaloid as in 
 the latter genus. Again, the adambulacral pieces of Urasterella are 
 very numerous, thin, and coin-shaped, while in Stenaster they are few 
 in number and comparatively thick; the ambulacral plates are 
 wholly different. 
 
 The long, slender and flexible rays, the apparent absence of in- 
 framarginal columns, and the absence of distinct interbrachial 
 plates (these are not the same as the single axillary pieces seen in 
 U. asperula) at maturity readily distinguish this genus from all other 
 Paleozoic genera. 
 
 For the origin of Urasterella see U. ulrichi. 
 
 Eoactis. After this book was completed appeared the work of 
 Spencer, with the new genus Eoactis. It is probable that the genus 
 is good and can be distinguished from Urasterella, but the necessary 
 comparisons can not now be made. 
 
 URASTERELLA PULCHELLA (Billings). 
 
 Plate 28, figs. 3, 4; plate 30, fig. 5. 
 
 Palseaster pulchellus BILLINGS, Geol. Surv. Canada, Rep. Progress for 1853-1856, 
 
 1857, p. 292. 
 Stenaster pulchellus BILLINGS, Geol. Surv. Canada, Can. Org. Hem., dec. 3, 1858, 
 
 p. 79, pi. 10, fig. 2. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, 
 
 pt. 1 (Palaeontogr. Soc. for 1861), 1862, p. 28. 
 Urasterella (Stenaster) pulchellus HALL, Twentieth Rep. N. Y. State Cab. Nat. 
 
 Hist., 1868, p. 289; rev. ed., 1868=1870, p. 332. 
 
 The largest specimen from Middleville, New York (Hall collection), 
 measures: 11 = 52 mm., r=ll mm., R = 4.8r. An individual of the 
 usual size from Trenton Falls, New York (Mus. Comp. Zool., No. 31), 
 measures: R = 30 mm., r = 4. mm., R = 7.2r. One from Ottawa 
 (Geol. Surv. Canada collection) measures: R = 25 mm., r = 4 mm., 
 R = 6.1r. The smallest specimen seen (Mus. Comp. Zool., No. 36) 
 measures: R = 7 mm., r = 1.5 mm., R = 4.7r. Width of rays at 
 base in mature examples from 4.5 mm. to 7 mm. 
 
 Original description. " Diameter, 2J inches; rays subcylindrical, 2J 
 lines in width at the base, with a length of 1 inch; disk 3J lines in 
 diameter; grooves narrow, bordered throughout by narrow oblong 
 plates, nine in the length of two lines; the length of these plates in a 
 direction transverse to the rays is about 1 line; near the disk there 
 appears to be but one row of marginal plates." 
 
 Formation and locality. Restricted to the Trenton limestone. 
 Most abundant at Trenton Falls, New York. From this locality 
 
REVISION OF PALEOZOIC STELLEROIDEA. 179 
 
 there are two specimens in the New York State Museum and six 
 in the Museum of Comparative Zoology, Harvard University, col- 
 lected by Dr. C. D. Walcott (Nos. 31-36). The American Museum 
 of Natural History has one specimen from Canajoharie, New York 
 (No. 660) ; in the Hall collection, Albany, there is a specimen from 
 Middle viUe, New York. At Hull, Canada, Mr. W. R. Billings col- 
 lected two specimens; the type and another specimen were found 
 by E. Billings at Ottawa, Canada; these are now in the Museum of 
 the Geological Survey of Canada at Ottawa. 
 
 Remarks. This graceful species has the essential structure of 
 U. grandis and will therefore not require a detailed description. 
 U. pulchella is from a lower geological horizon, is probably the an- 
 cestor of U. grandis and has far less numerous abactinal plates, 
 which on the disk reveal a primitive arrangement reminding one of 
 Hudsonaster. In the center of the disk there is a single plate around 
 which is a first ring of 5 basal radial plates followed by another with 
 15 plates. The plates of the second ring are a little more conspicu- 
 ous than any other abactinal plates and are disposed as follows: 
 Five are radial in position and are the second basal plates of the 
 5 radial columns, while the other 10 are disposed interradially in 
 pairs immediately on each side of the second basal radials. The 
 plates interradial in position are the basals of the supramarginal 
 columns. Between the central ossicle and first ring there appear 
 to be a few small accessory plates. 
 
 The arrangement of the disk pieces above described is plainly 
 preserved in a very young example (No. 36, MILS. Comp. Zool.). 
 The radial columns remain the most prominent while the supra- 
 marginals a little distally from the base of the rays are not readily 
 distinguishable from the other columns. Here and there an accessory 
 piece may be inserted between the radials and supramarginals but 
 the greater width of the rays is attained by increasing the size of 
 these columns and by the introduction of ambital columns outside 
 of the supramarginals. In a mature ray on each side of the radials 
 proximally, there appear to be not more than four columns of plates 
 but it is possible that a few pieces of a fifth column may be developed. 
 The form and spinosity of the abactinal plates is as in U. grandis, 
 except that the nonarticulating spines are less long in U. pulchella. 
 
 Inframarginal columns at first view do not appear to be present 
 but a careful examination near the distal end of a ray reveals two 
 columns of nearly equal-sized plates on each side of the ambulacral 
 furrow. Here these plates closely adjoin, the adambulacrals are 
 elongate subquadrangular and the inframarginals quadrangular in 
 shape. Proceeding proximally the former become more prominent 
 and wider but remain throughout closely adjoining. The inframar- 
 ginals, however, gradually pass over to the abactinal side although 
 
180 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 they remain beside the adambulacrals, become more and more 
 spinose, longer than wide, and eventually stellate in form and then 
 are inseparable from the abactinal plates. There are about 42 adam- 
 bulacrals in each column. 
 
 U. pulchella is readily distinguished from U. ulricJii and U. grandis 
 in being smaller, with more slender and graceful rays, and in its fewer 
 columns of plates. From U. Jiuxleyi it is distinguished by the less 
 convex rays and the far smaller number of plates. 
 
 Cat. No. 60610, U.S.N.M. 
 
 URASTERELLA GRANDIS (Meek). 
 
 Plate 27, figs. 6-8; plate 28, figs. 1, 2; plate 30, figs. 1-4. 
 
 Stenaster grandis MEEK, Amer. Journ. Sci., ser. 3, vol. 3, 1872, p. 258; Geol. Surv. 
 
 Ohio, Pal., vol. 1, 1873, p. 66, pi. 3 bis, figs. 7a-7c. MILLER, N. Amer. Geol. 
 
 Pal., 1889, p. 283, fig. 432. 
 
 Urasterella grandis MEEK, Geol. Surv. Ohio, Pal., vol. 1, 1873, p. 67. 
 Palseaster harrisi MILLER, Journ. Cincinnati Soc. Nat. Hist., vol. 2, 1879, p. 117, 
 
 pi. 10, figs. 2, 2<z. 
 
 Original description. "Attaining a very large size, with the body 
 or disk comparatively small, or only of the breadth of the united 
 inner ends of the five rays. Rays long, slender, gradually tapering, 
 and very flexible, widest at their immediate connection with the 
 body, where they seem to be more or less depressed, but becoming 
 more nearly terete farther out. Dorsal side of body and arms com- 
 posed of numerous subtrigonal pieces that rise into pointed tubercles, 
 or sometimes assume almost the character of short spinules, and 
 are arranged hi quincunx, so as to form about eight rows near the 
 middle of the rays; those of the outer two rows being a little larger 
 than the others. Dorsal pores apparently rather large, and passing 
 through between the concave sides of contiguous pieces. Ventral 
 side of body unknown. That of the rays composed of the usual single 
 row of transverse adambulacral pieces on each side of the well 
 defined, rather deep, and moderately wide ambulacral furrows. 
 Adambulacral pieces rather more than twice as long as wide, with 
 their longer diameters at right angles to the ambulacral furrows, 
 and rounding over from end to end so as to be most prominent in 
 the middle; while they do not connect with each other by flat sides, 
 but have little projecting processes, and corresponding sinuses, 
 apparently for the purpose of imparting greater flexibility to the 
 rays." 
 
 Emended description. The largest specimen being doubled over 
 actinally does not permit of exact measurements, but it is, as near 
 as can be determined, as follows: R = 93 mm., r = 9 mm., R = 10.3r. 
 Another specimen spread flatly measures: 11 = 49 mm., r=6.5 mm., 
 11 = 7.67-. The smallest specimen (holotype of Palseaster Jiarrisi] 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 181 
 
 measures: R = 10 mm., r = 2.5 mm., R = 4r. Width of rays at base 
 in mature examples from 7 mm. to 8.5 mm. 
 
 Rays at maturity very long, depressed subcylindrical in outline, 
 slender and tapering slowly. Disk very small, formed by the united 
 inner ends of the rays. 
 
 Abactinal area reticular, consisting of very numerous, highly 
 conical, stellate plates, the radial columns and the plates of the disk 
 most prominent, while the other ray plates (supramarginal and 
 ambit al) are smaller and irregularly triangular in form. All plates 
 are more or less drawn out into stout, blunt, nonarticulating spines 
 which are best preserved along the sides of the rays. On the disk 
 the ossicles are arranged in a few concentric rows while on the rays 
 they are in columns and in quincunx. Near the base of a ray in the 
 largest specimen there are about 13 columns, diminishing to about 
 4 at the distal ends. 
 
 Madreporite of medium size, lobate, radially crenulostriate, situ- 
 ated between two adjoining rays and about midway between the 
 margin and center of disk. 
 
 Adambulacral plates slightly overlapping the ambulacral columns, 
 diminishing in size distally, coin-shaped, arranged on edge, and vary- 
 ing in different specimens from 60 to 110 in each range. In the 
 youngest known example there are about 20 plates in a column. 
 Each piece bears three or four short, finger-shaped, articulating 
 spines, two or three outwardly disposed, and one placed near the 
 inner base between adjoining plates. Along the outer margin of 
 the adambulacral plates and abactinally to the thick finger-shaped 
 spines there is a row of long, slender, flattened and longitudinally 
 grooved spines, two to each ossicle. Orally the coin-shaped adam- 
 bulacral plates are somewhat modified, stand less erect and terminate 
 in pairs of subquadrangular oral armature pieces. 
 
 Ambulacral grooves wide, shallow, and furrowed medially by a 
 narrow angular gutter. Ambulacral plates of adjoining columns 
 opposite or very slightly alternating, the pieces narrow, equaling 
 in number the adambulacrals, slightly overlapping each other 
 proximally and partially interlocking in the medial gutter. The 
 ambulacral plates continue in undiminished size to the compara- 
 tively small mouth, are highly convex and club-shaped, with the 
 attenuated ends laterally disposed. The podial openings are between 
 the attenuated ends of adjoining plates. 
 
 Locality and formation. In the Richmond formation at Richmond, 
 Indiana (type-locality), and in the vicinity of Waynesville, Ohio, 
 where Mr. Harris secured six more or less mature and three young 
 individuals, besides numerous fragments. A ray of this species 
 was found by Mr. U. P. James near Dayton, Ohio. In the Gurley 
 collection of the University of Chicago there is a young specimen 
 (No. 10978) from near Ridgeville, Warren County, Ohio. 
 
182 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Remarks. The type-specimen of Palseaster Jiarrisi Miller is undoubt- 
 edly a Urasterella, and there are no characters other than size by 
 which this individual can be separated from U. grandis. Of about 
 the same age are three specimens in the Harris collection and another 
 in the University of Chicago, and all were originally referred to 
 P. Jiarrisi. One of these is nearly again as large as the type, is about 
 one-half the size of U. grandis, and measures 49 mm. along the greater 
 radius. The only marked difference between P. Jiarrisi and U. 
 grandis is the smaller number of adambulacral plates in the former, 
 a feature common to the young of many fossil starfishes when com- 
 pared with the adults of the same species. In fact, the variation in 
 the number of these plates in the two largest examples (64 and 110) 
 is nearly as great as between the type of Palseaster Jiarrisi (22) 
 and the smaller of the two largest specimens of U. grandis (64). 
 
 U. grandis is closely related to U. pulchella (Billings) of the 
 Trenton limestone. These species are, however, easily distinguished, 
 not only by the different geological occurrences, but in that U. grandis 
 attains a much larger and more robust growth. The latter has also 
 many more abactinal ossicles with longer nonarticulating spines, 
 and the adambulacral columns have from 60 to 110 plates, instead 
 of from 36 to 60 as in U. pulchella. U. grandis appears to be a 
 direct descendant of the latter and has varied only in attaining a 
 larger size and a greater number of plates. 
 
 U. grandis is also closely related to U. ulrichi, and both are nearly 
 of one size. The latter, however, has the rays highly convex abac- 
 tinally, the plates are smaller but as strongly, spinose, and there are 
 two columns of larger central plates, instead of one as in U. grandis. 
 In the latter in the mid-length of the ray there are about 9 plates 
 in a column in 10 mm., while in U. ulrichi there are from 11 to 12 in 
 the same space. 
 
 Cat. Nos. 40885, 40887, U.S.N.M. 
 
 URASTERELLA HUXLEYI (Billings). 
 Plate 29, fig. 2. 
 
 Stenaster huxleyi BILLINGS, Geol. Surv. Canada, Pal. Foss., vol. 1, 1865, p. 213, 
 fig. 197. 
 
 E = 58 mm., r = 5.5 mm., 11 = 10. or. Width of ray at base, 6 mm. 
 
 Original description. " Deeply stellate, 4 or 5 inches across; body 
 small, less than half an inch in diameter; rays long; flexuous, sub- 
 cylindrical, apparently angulated along the medium line on the upper 
 side, uniformly tapering to an acute point. On the dorsal side the 
 rays are covered by a multitude of small subangular plates, each 
 from one-fourth to one-third of a line wide. The central part of the 
 body is not well preserved in the only specimen collected; but it is 
 
REVISION OF PALEOZOIC STELLEROIDEA. 183 
 
 evident from a view of the plates which remain that they are here 
 larger and more convex than those of the rays. 
 
 " Diameter of the body, five lines. Length of each ray, If inches. 
 Width of the rays at their junction with the body, 3 lines. Depth 
 of the rays from the dorsal to the ventral side of the body apparently 
 somewhat less than the width. The total breadth of the specimen, 
 if the rays were straightened out, would thus be about 4J inches. 
 
 "From the manner in which the rays are curved, it is evident that 
 they possessed a considerable amount of flexibility. The specimen 
 is somewhat distorted by pressure, but a small portion of one of the 
 rays near the body seems to retain its natural shape, and it is here 
 obtusely angulated along the median line. The transverse section 
 of the ray should be, therefore, subpentagonal. There is still, how- 
 ever, some doubt on this point. The under side is unknown. " In 
 places where the specimen is broken the adambulacrals are seen to 
 be as in other species of Urasterella; there appear to be about 60 or 
 more of these plates in each column. 
 
 Locality and 'formation. The only specimen of this species was 
 found by Mr. J. Richardson in strata of Chazy age (bed I of the 
 Newfoundland section) at Point Rich, Newfoundland. The holotype 
 (No. 554) is in the Museum of the Geological Survey of Canada, at 
 Ottawa, which has furnished the photograph illustrating the specimen. 
 
 Remarks. The holotype was seen at Ottawa and the original 
 illustration found to be a fairly accurate reproduction of the charac- 
 ters of the fossil. The abactinal side of the disk has a central disk 
 plate that is large and tumid. Around it is a circle of six smaller, 
 highly convex plates, and at the base of each ray medially there is 
 another single large tumid plate, the basal radial. The abactinal 
 side of the rays is highly convex and somewhat angulated medially. 
 The ossicles are small and distinctly arranged in quincunx, of which 
 there are about six plates in each diagonal row near the base of a ray. 
 In other words, the abactinal characters of U. huxleyi are very much 
 like those of U. ulrichi, with the differences that in the latter species 
 the prominent disk plates are smaller and there are more columns 
 of smaller ossicles on the stouter and longer rays. Further, in U. 
 ulrichi there are two columns of larger abactinal plates along the 
 central area of the rays, while in U. huxleyi all the ray ossicles are 
 of equal size. 
 
 TJ. pulchellus has less convex and more slender rays, and far fewer 
 abactinal plates. 
 
 URASTERELLA ULRICHI, new species. 
 Plate 29, fig. 1; plate 30, figs. 6, 7. 
 
 The smallest specimen measures: R = 14 mm., r = 4 mm., R = 3.5r. 
 The best preserved specimen measures: R = 45 mm., r = 7.5 mm., 
 R = 6/*. The largest specimen measures: R = 78 mm., r=12 mm., 
 
184 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 R = 6.5r. Width of ray at base in the different individuals 4, 7.5, 
 and 9 mm., respectively. 
 
 Rays short and tapering rapidly when young but at maturity very 
 long, highly convex abactinally, and tapering very slowly. Disk 
 comparatively large in the young but small at maturity and formed 
 by the united ends of rays. 
 
 Abactinal area of disk and rays composed of numerous small, tumid, 
 or highly spinose plates which in the rays are arranged distinctly 
 in columns and in quincunx. In the angles between all of the 
 plates are left subcircular small openings. On the rays medially 
 there are two columns of large convex plates, variously stellate and 
 not produced into short, blunt rods. These are the supramarginals, 
 and between them are a few widely separated plates of the radial 
 columns. In the young the two proximal radial plates are sepa- 
 rated from each other by from one to three supramarginals, while 
 the third plate is separated from the second by three or four supra- 
 marginals. In a mature specimen there appear to be about eight 
 of these radial plates on each ray and distally they are separated 
 from one another by five supramarginal ossicles. On each side of the 
 supramarginal columns are from one (distally) to five (proximally) 
 columns of smaUer or accessory ambital plates. In a full-grown 
 specimen there are 11 to 12 in 10 mm., triangular in outline, and 
 drawn out into short, stout, blunt rods. In the center of the disk 
 in the youngest specimen (probably also at maturity) there is a 
 single large depressed plate around which is a first circle with 6 
 plates followed by a second having 16 pieces. Of the latter, 5 are 
 basal radials, 10 basal supramarginals, and 1 the madreporite. 
 All of the disk plates are variously stellate, and are the largest plates 
 of the abactinal area, the size gradually diminishing distally along 
 the rays. 
 
 Madreporite concentrically striate, somewhat smaller than the basal 
 supramarginals, between two of which it is placed. 
 
 Adambulacral plates seen only in the young specimen, very strong, 
 carinated, subquadrate, wider than long, and about 19 or 20 in each 
 column 10 mm. long, not counting the oral armature pieces, which are 
 subtriangular in outline. Inside of each pair of oral armature plates 
 is placed a very stout but short subcircular spine which has not been 
 observed in other species. No other spines are preserved. 
 
 Ambulacral furrows very narrow and deep, concealing the ambu- 
 lacral plates. 
 
 In the axils of the youngest specimen, outside of the adambulacrals, 
 are situated three prominent plates, the proximal one being the 
 smallest. On each side of these along the ray is a single column of 
 plates which rapidly diminish in size and separate with increasing 
 interspaces distally. Their number can not be made out, but they 
 appear to continue to the tips of the rays, where plates occur that 
 
REVISION OF PALEOZOIC STELLEROIDEA. 185 
 
 are not ambital. In the mid-length of the ray, however, these plates 
 greatly resemble the ambitals. Judging from the manner in which 
 they appear distally, their form and constant position beside and 
 outside the adambulacrals leads to the conclusion that they are the 
 inframarginals. Whether the inframarginals and interbrachial mar- 
 ginals are present at maturity cannot be determined. 
 
 Formation and locality. Three specimens from the top of 'the Black 
 River limestone immediately beneath the Black River shale, or from 
 the Vanuxemia bed of the Black River (Mohawkian) group at Minne- 
 apolis, Minnesota. The specific name is after the distinguished 
 paleontologist, Dr. E. O. Ulrich, who found all the specimens. They 
 are in the United States National Museum. 
 
 Remarks. This species is distinguished from other Ordovicic 
 Urasterellas by the few and widely separated plates of the radial 
 columns, and by the prominence of the supramarginal columns, 
 which in the other species are not distinguishable from the ambitals. 
 The convexity of the rays abactinally is also greater than in the 
 other species excepting U. Jiuxleyi, but that species is further dis- 
 tinguished in that it has smaller plates, there being from 7 to 10 in 
 5 mm., while in U. ulrichi there are only 5 to 6 in the same space. 
 
 U. ulrichi and U. grandis attained a similar large size. The former, 
 however, is from a much lower horizon, has very convex rays abac- 
 tinally, two columns of larger central plates (supramarginals) instead 
 of one (radial), and the plates are smaller and therefore more 
 numerous. 
 
 The young of this species are very interesting in that they show 
 distinctly the presence of large inframarginal and interbrachial 
 marginal plates in the axils. In U. pulchella none of these plates 
 have been seen in the axils, but the inframarginals are believed to 
 be present in the very small plates which are indistinguishable from 
 the ambital pieces situated along the greater length of the rays out- 
 side of the adambulacrals. The same appears to be true for U. grandis. 
 The young of U. ulrichi in its general structure reminds one much 
 of Mesopalseaster sJiqfferi, and it is probable that Mesopalseaster and 
 Urasterella are derived from the same stock, which also gave rise to 
 Hudsonaster. The latter retains throughout life the primitive plate 
 structure, while Mesopalseaster, and particularly Urasterella, develop 
 in various ways an abundance of accessory plates. 
 
 The best preserved specimen of U. ulrichi (pi. 29, fig. 1) has two 
 nearly fully grown rays and three short stumps. One of these short rays 
 is so well preserved as to indicate that this condition is not due to poor 
 preservation, but is apparently a case of accidental loss of parts 
 during life. The wound has been healed, but no regeneration of lost 
 parts has taken place, as is so common in similar losses among the 
 living starfishes. 
 
 Cat. No. 60612, U.S.N.M. 
 
186 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 URASTERELLA GIRVANENSIS, new species. 
 Plate 28, fig. 5. 
 
 Tetraster, sp. ind., NICHOLSON and ETHERIDGE, Mon. Silurian Foss. Girvan Dist., 
 
 Ayrshire, fasc. 3, 1880, p. 325, pi. 21, figs. 9, 10. 
 ? Eoactis simplex SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palaeontogr. Soc. for 
 
 1913), February, 1914, p. 30, pi. 1, fig. 4. 
 Urasterella girvanensis SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, April, 
 
 1914, p. 44. 
 
 Description ~by N. and E. "Body stellate, with slowly tapering 
 arms, which increase little in width throughout their whole length [the 
 distal ends being unknown]; upper surface unknown, but the body 
 was convex and probably granular. [The pieces of the disk are seen 
 through the mouth and consist of many tiny plates arranged in more 
 or less regular circles about the slightly larger central ossicle.] Ave- 
 nues of the arms broad, and not bridged over by any of the plates [this 
 is a slip of the pen, for the ridged ambulacralia lie horizontal and 
 deep in the grooves and are directly opposite one another; the podial 
 openings are fairly large and in the usual position laterally]; marginal 
 ambulacral plates [ = adambulacrals] moderately convex, trans- 
 versely elongated, or oblong in form, and less in width than the 
 ambulacral plates; those in the angles of the rays are the largest, and 
 somewhat more elongated than the others; oral plates not visible." 
 The interbrachial areas are structurally very interesting because in 
 each one there is a single narrow but long axillary interbrachial 
 ossicle that distaily margins the axil, and in front of this is a minute 
 pair of ad ambulacral oral armature pieces. On either side of the 
 axillary interbrachial are the most prominent adambulacrals, about 
 five in number, being larger than the other distal ones, which are 
 considerably narrower and of fairly uniform size throughout the rays. 
 
 Formation and locality. A single specimen from the Upper Ordo- 
 vicic at Thraive Glen, Girvan, Scotland. A good wax squeeze of the 
 holotype was furnished by Doctor Bather. The original is in the col- 
 lection of Mrs. Robert Gray, at Edinburgh, Scotland. 
 
 Remarks. This species is clearly a Ur aster ella, a fact which was 
 also noted by Nicholson and Etheridge, as they state: "In some of 
 its characters it approaches very closely to T. (?) asperrimus, Salter, 
 sp." In its interbrachial skeleton U. girvanensis retains youthful 
 generic characters, seen in the well-developed interbrachial axillary 
 ossicles. After the above was written appeared Spencer's paper 
 above cited. Before the writer was aware of this work he had pro- 
 posed the name U. girvanensis. If we are treating of the same 
 species Spencer's name takes precedence. 
 
 Cat. No. 60611, U.S.N.M. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 187 
 
 URASTERELLA (?) ASPERRTMA (Salter). 
 
 Palseaster asperrima SALTER, Ann. Mag. Nat. Hist.,ser. 2, vol. 20, 1857, p. 325, 
 
 pi. 9, fig. 1. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 
 
 (Palseontogr. Soc. for 1861), 1862, p. 24, fig. 15 (1). 
 Palseaster asperrimus SALTER, Mem. Geol. Surv. Gt. Britain, vol. 3, 1866, p. 289, 
 
 pi. 23, fig. 2. 
 
 Palseaster (?) asperrimus STURTZ, Palseontographica, vol. 32, 1886, p. 91. 
 fTetraster asperrimus NICHOLSON and ETHERIDGE, Mon. Silurian Foss. Girvan 
 
 Dist, Ayrshire, fasc. 3, 1880, pp. 320, 321, 324. 
 Salteraster asperrimus STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 
 
 1893, pp. 43, 60. 
 
 Nicholson and Etheridge wrote of this species as follows: It 
 "is an unsatisfactory species. The specimens in the Museum of 
 Practical Geology have the large transverse ossicles very apparent; 
 but as to whether there is a row inside or outside these, or both, 
 we are by no means certain. It appears, however, to have possessed 
 only four rows." Under Tetraster they compare this species with 
 their "T. sp. ind.," which is a true Urasterella (U. girvanensis) . 
 
 It seems best under these circumstances to refer this species to 
 Urasterella, it being apparently near U. grandis. It is found in the 
 Caradoc or Baia sandstones (Ordovicic), near Welshpool, North 
 Wales. Should it prove to be generically different from Urasterella , 
 then the name Salteraster Stiirtz can be revived, as he names P. asper- 
 rimus as the genoholotype. 
 
 URASTERELLA (?) CONSTELLATA (Thorent). 
 
 Asterias constellata THORENT, Me"m. Soc. ge"ol. de France, vol. 3, 1838, p. 259, 
 pi. 22, fig. 7. 
 
 The original figure of this species does not permit of determining 
 its generic position. It is described as having but one range of plates 
 on each side of the ambulacral grooves, and the figure seems to 
 indicate the presence of a large disk with well-defined interbrachial 
 arcs. It seems to have more of the characters of Urasterella than 
 of any other genus. 
 
 The specimen was found in the Siluric ( ? Lower) strata in northern 
 France (Mondrepuis, L'Aisne). 
 
 URASTERELLA RUTHVENI (Forbes). 
 
 Uraster ruthveni FORBES, Mem. Geol. Surv. Gt. Britain, vol. 2, pt. 2, 1848, p. 436; 
 
 Mem. Geol. Surv. United Kingdom, dec. 1, 1849, p. 1, pi. 1, fig. 1; in McCoY, 
 
 British Pal. Foss!, 1851, p. 59. MURCHISON, Siluria, 1854, fig. 39-3. 
 Palxaster ruthveni SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 326. 
 
 WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palaeontogr. 
 
 Soc. for 1861), 1862, p. 25. 
 Urasterella ruthveni FORBES, in McCoY, British- Pal. Foss., 1851, p. 59. 
 
 This, the genotype of Urasterella, is unfortunately not well known, 
 but appears to be congeneric with U. grandis and U. pulchella. It 
 occurs in the Upper Ludlow beds (Siluric), near Kendal, Westmore- 
 land, England. 
 
188 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 URASTERELLA HIRUDO (Forbes). 
 
 Uraster hirudo FORBES, Mem. Geol. Surv. Gt. Britain, vol. 2, pt. 2, 1848, p. 464; 
 
 Mem. Geol. Surv. United Kingdom, dec. 1, 1849, p. 3, pi. 1, fig. 4; in McCoy, 
 
 British Pal. Foss., 1851, p. 59. MURCHISON, Siluria, 1854, p. 221, fig. 39-2. 
 Palxaster hirudo SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 326. 
 
 WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palseontogr. 
 
 Soc. for 1861), 1862, p. 25. 
 Urasterella hirudo FORBES, in McCoy, British Pal. Foss., 1851, p. 59. 
 
 This small species has much the appearance of being the young 
 of U. ruthveni. The form is said to be gregarious and is associated 
 with that species. 
 
 URASTERELLA SELWYNI McCoy. 
 
 Urasterella selwyni McCoy, Geol. Surv. Victoria, Prodr. Pal. Victoria, dec. 1, 
 1874, p. 42, pi. 10, figs. 2, 2a, 3, 3a. 
 
 Original description. " Kays five, elongate, gradually tapering from 
 a little beyond the base, which is slightly contracted, angulated on 
 the upper side by a prominent ridge along the middle of each ray, 
 having a row of conical tubercular plates (about eight in two lines), 
 each side sloping on the dorsal aspect from the middle with about 
 three rows of conical tubercular plates rather smaller than the middle 
 row. The five axil plates small, ovate, triangular, very tumid. 
 Adambulacral plates large, extending to the tubercular margin, 
 transversely oblong, about twice as wide as long (about nine in two 
 lines). Ambulacral plates small, in a deep ambulacral groove. 
 Length of ray from mouth to tip, six lines; greatest width near base, 
 1J lines. Surface of plates granular. 
 
 "This beautiful species is easily known by its strongly angulated 
 rays on the dorsal side. The traces of oral plates are so very minute 
 and indistinct that I can not give their character. 
 
 "This is the first fossil starfish seen in Australia, and I dedicated 
 it to my old friend Mr. Selwyn, formerly Director of the Geological 
 Survey of Victoria, and now Director of the Geological Survey of 
 Canada, who collected it. 
 
 "This species is most nearly related to the Uraster ruthveni of 
 Forbes from the Upper Silurian grits of Kendal in Westmoreland. 
 
 "Common in the fine sandy Silurian beds of range on E. side of 
 commonage reserve, Kilmore." 
 
 Remarks. This is clearly a species of UrastereTla. ActinaUy it 
 has in each axil one fairly large axillary interbrachial and in this 
 recalls the same structure in U. girvanensis, new species. 
 
 URASTERELLA ASPERULA (Roemer). 
 
 Asterias asperula ROEMER, Palaeontographica, vol. 9, 1863, p. 146, pi. 24; pi. 26, 
 
 fig. 6; pi. 27. 
 
 Roemeraster asperula STURTZ, Palseontographica, vol. 32, 1886, p. 85, pi. 9, figs. 4, 5. 
 Protasteracanthion primus STURTZ, Palseontographica, vol. 32, 1886, p. 90, pi. 11, 
 
 figs. 3, 3a. 
 
 Remarks. Of this species there are two specimens in the United 
 States National Museum purchased of Stiirtz, and two more are 
 
REVISION OF PALEOZOIC STELLEROIDEA. 189 
 
 in the Tale Museum Collection. These show both sides of the species. 
 U. asperula is said to be common in the roofing slate of the Lower 
 Devonic at Bundenbach, Germany. 
 
 There can be no doubt that Asterias asperula Roemer is a true 
 UrastereTla. All the generic characters are shown, even the longi- 
 tudinally grooved spines and the rodlike extensions of the ambital 
 plates. For further remarks on this species see generic discussion. 
 
 The abactinal structure of Roemeraster asperulus reminds one much 
 of UrastereTla pulcJiella of the Trenton, which is the least specialized 
 species of the genus. The single interbrachial plate retained to 
 maturity reminds one of the young of U. ulrichi. In this character 
 U. asperula appears to be primitive. In the proximal third of the 
 rays in U. asperula the radial columns are the most marked and the 
 plates continue to increase in size toward the disk. The supramar- 
 ginals are also well developed proximally, but the two or three 
 proximal plates are smaller and depressed, so that the ten basals 
 along with the five radials do not make so prominent a ring of large 
 ossicles as in U. pulcJiella or in the young of U. ulrichi. Distally 
 the rays in U. asperula have the plates of nearly equal size, although 
 the columnar and quincuncial arrangement is retained. The center 
 of the disk is occupied by a prominent central disk-plate and the 
 first ring consists of five radial plates as in U. pulcJiella. 
 
 Cat. No. 59382, U.S.N.M. 
 
 URASTE3ELLA, ne\7 species. 
 
 In the paleontological museum of Cornell University there is a 
 large slender-rayed specimen having the general form and structure 
 of Urasterella. There is, however, so little of the actinal detail pre- 
 served that nothing more can be done than to indicate the presence 
 of this species. 
 
 The specimen was found by Mr. J. B. Woodworth at Brookton, 
 near Ithaca, New York, in the Upper Devonic. 
 
 URASTERELLA MONTANA (Stschurowsky). 
 
 Palseaster montanus SCHONDORF, Palseontographica, vol. 56, 1909, p. 324, pi. 23, 
 fig. 1; pi. 24, figs. 20-22 (complete bibliography cited here). 
 
 In general this form recalls U. grandis but is somewhat smaller and 
 stouter. The actinal side alone is known, showing a wide ambu- 
 lacral furrow bordered by stout columns of narrow adambulacrals. 
 All of the ossicles of the ambulacrals and adambulacrals are opposite 
 one another. Oral armature decidedly adambulacral in composition. 
 Interradial areas described as having "a few plates." A section 
 through a ray (Schondorf s fig. 22) shows that abactinally on each 
 side of the radialia there are four columns of ossicles, or nine in all. 
 
 Dimensions, about: E, = 35 mm., r = 6-7 nun., R 6r. Width 
 of ray at mid-length about 6 mm. 
 
190 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Formation and locality .The holotype is from the oldest Upper 
 Carboniferous (Moscovian) of Mjatschkowa, near Moscow. The 
 specimen is now in the Bergakademie at Berlin, Germany. 
 
 CALLIASTERELLID^E, new family. 
 
 Calliasteridse SCHONDORF, Jahrb. nassaulsch. Ver. Naturk., Wiesbaden, vol. 63, 
 1910, p. 251. 
 
 Cryptozonia with ophiurid expression; a small disk with primitive 
 plate arrangement and five long, very flexible rays, with radialia 
 and supramarginalia. No interbrachial areas. Ambulacrals oppo- 
 site. 
 
 Contains : 
 
 CalliastereUa, new name. 
 
 Genus CALLIASTERELLA, new name. 
 Plate 31, fig. 3, text fig. 11. 
 
 Calliaster mirus TRAUTSCHOLD (not Calliaster Gray 1840, Echinoderma), Nouv. 
 
 Me"m. Soc. imp. Nat. Moscou, vol. 14, 1879, p. 108, pi. 13, figs. 3a-3ft, 4. 
 
 SCHONDORF, Palaeontographica, vol. 56, 1909, p. 327, pi. 23, figs. 2-5; pi. 24, 
 
 figs. 1-18; text fig. on p. 328. 
 CalliastereUa SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, April, 1914, 
 
 p. 14- 
 
 A cryptozonian asterid with the general expression of the ophiurid 
 Ony chaster. 
 
 Description. Disk relatively small, primitive, with rather large, 
 decidedly spiculate ossicles. Rays five, long and slender, round 
 in section. R = about 120 mm., r = 30 to 35 mm., R = 4r. Width 
 of ray at mid-length about 15 mm. 
 
 Abactinal disk plates in form and position as in figure 11. There 
 is a small central five-rayed plate with the rays in the position of the 
 five arms. Around the central plate is a first ring of five larger basal 
 radial plates. Then comes a second ring of ten plates, five of which 
 are the second basal radialia; the other five are interradial in posi- 
 tion and give rise hi the next ring to the ten basal inframarginal 
 ossicles. The third ring has five radialia and ten basal inframargi- 
 nals. All of the ossicles in the three rings are variously six-rayed, 
 with large rounded openings between the adjoining spicular ends. 
 Between each pair of basal inframarginals are inserted single elon- 
 gate interradial disk plates. 
 
 Madreporite unknown. 
 
 The rays abactinally have a medial column of transverse radialia, 
 and alternating with these on either side are columns of supra- 
 marginals. These ossicles are of peculiar construction, enabling 
 the rays to flex about as in Onychaster. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 191 
 
 Ambulacralia small, adambulacralia larger, both very numerous 
 in each column and in their disposition opposite one another. There 
 are no inframarginals. 
 
 Oral armature of Cryptozonia construction and very much as hi 
 living Asterias glacialis. 
 
 Ocular plates probably not present. 
 
 Genoholotype and only species. C. mirus (Trautschold) (cita- 
 tions as above). The holotype and three other fragments are from 
 
 \ 
 
 R 
 
 FIG. ll.-*-THE PLATES OF THE DISK OF CALLIASTERELLA MIRA. SCHEMATIC. AFTER SCH&NDORF. 1, CEN- 
 TRODORSAL; 2, BASAL RADIALIA; 3, SECOND RADIALIA; 4, THIRD RADIALIA; 5, BASAL INFRAMARGINALS; 6, 
 PAIRED INFRAMARGINALS; a, POSSIBLE POSITION OF ANUS; mdp, PROBABLE POSITION OF MADREPORITE. 
 
 the Upper Carboniferous (Moscovian), at Mjatschkowa, near Moscow. 
 The holotype is in the University of Petrograd. 
 
 Remarks. There is no other Paleozoic asterid worked out in such 
 detail as is Calliasterella. Not only is the gross skeleton known, but the 
 detailed construction of all of the essential ossicles and spines as 
 well. Quarto pages of text and two plates are devoted to the skeleton. 
 
 The dorsal skeleton retains primitive construction, and although 
 the ossicles are much modified, their general orientation is that of 
 the older Phanerozonia. 
 
 COMPSASTERIM;, new family. 
 
 Specialized Cryptozonia with decidedly spicular abactinal skele- 
 ton, recalling that of Asterias. Ambulacra opposite or slightly 
 
 50601 Bull. 8815 - 13 
 
192 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 alternating. Rays five, long, thick, and rounded in section. Disk 
 not large. 
 
 This family contains: 
 Jaekelaster Sturtz. 
 Compsaster Worthen and Miller. 
 
 Genus JAEKELASTER Sturtz. 
 
 Jaekelaster SitfRTZ, Verb, naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, pp. 
 235-236, pi. 4, figs. 13-16. 
 
 Generic characters. Rays five, thick and long, 55 mm. in length, 
 16 mm. in greatest breadth, rounded distally. Disk large. Both 
 rays and disk devoid of marginal plates. 
 
 Abactinally without columns of plates, entire surface decidedly 
 and abundantly covered with "paxillae." Madreporite small, 
 subcentral, radiately stria te. 
 
 Ambulacral furrows wide, widest at about mid-length and nar- 
 rowing both distally and proximally. Two col mns of podial 
 openings. Ambulacralia narrow, L-shaped, slightly overlapping 
 and slightly alternating proximally. Adambulacrals small, di- 
 rectly opposite the ambulacrals. Outside of the rays the integu- 
 ment bears spines and "paxillae" abundantly. 
 
 Genoliolotype and only species. J. petaliformis Sturtz (citations 
 as above). Lower Devonic of Bundenbach, Germany. 
 
 Remarks. This genus is most closely related to Compsaster , 
 in fact the general appearance of the two is very much alike. 
 
 Genus COMPSASTER Worthen and Miller. 
 
 Plate 31, figs. 1, 2. 
 Compsaster WORTHEN and MILLER, Geol. Surv. Illinois, vol. 7, 1883, p. 327. 
 
 Original description. "Body stellate; central area or disk com- 
 paratively small; rays large, long, more or less fusiform; grooves 
 deep and bordered by numerous thin, subcircular, adambulacral 
 plates. The ventral side of the typical species shows about six 
 rows of plates upon each side of the ambulacral furrows, which 
 have a regular, transverse as well as longitudinal arrangement. 
 
 "This genus is distinguished from all others in the family [their 
 Palseasteridse] by the number and form of the adambulacral plates, 
 by the great number of disk plates upon each side of the ambula- 
 cral furrows, and by the general form of the body and rays." 
 
 GenoTwlotype. C. formosus Worthen and Miller. It is also the 
 only named species of the genus. 
 
 The adambulacral plates in Compsaster appear to be much as 
 in UrastereUa and both genera agree in having no distinct inframar- 
 
REVISION OF PALEOZOIC STELLEROIDEA. 193 
 
 ginal plates. The ambit al plates are very numerous, showing a dis- 
 tinct progression to far more numerous columns of plates than in 
 Urasterella. They also appear like those in this genus. It is prob- 
 able that the abactinal area when it is known will be seen to have 
 spicular ossicles like those of the ambital areas. 
 
 COMPSASTER FORMOSUS Worthen and Miller. 
 
 Plate 31, figs. 1, 2. 
 
 Compsaster formosus WORTHEN and MILLER, Geol. Surv. 111., vol. 7, 1883, p. 327, 
 pi. 31, figs. 2a, 26. 
 
 Original description. "Body deeply stellate; central disk com- 
 paratively small; rays rigid, large, fusiform, more than twice as long 
 as the diameter of the central disk, and terminating abruptly in an 
 obtuse point. The typical specimen furnishes the following meas- 
 urements: Diameter of the body, 0.72 inch; length of ray from cen- 
 tral part of disk, 1.78 inches; diameter of the ray at its junction with 
 the body, 0.41 inch. 
 
 "Ambulacral grooves deep; ossicles rather small; adambulacral 
 plates very numerous, and consisting of series of thin plates upon 
 each side of the ambulacral furrows, which are rounded upon the 
 exterior, prolonged below, and each bear a short, sharp spine on the 
 upper part of the inner side, directed toward the apex of the ray. 
 There are about eighty adambulacrak upon each side of the furrows, 
 and they dimmish very slowly in size toward the apex, after passing 
 the fusiform enlargement of the ray. 
 
 "The disk-plates abut upon the adambulacrals in a straight line; 
 they are subquadrangular, or polygonal, and each bears a strong 
 central spine. Six longitudinal rows appear on the ventral side on 
 each side of the ambulacral furrows; they are somewhat uniform in 
 size, arranged in transverse, as well as longitudinal order, and are 
 about two-thirds as numerous in a longitudinal row as the plates in 
 an ambulacral series. 
 
 "Oral plates, madreporiform tubercle, and dorsal side unknown, 
 except so far as we may judge of the spinous character of the plates 
 from those visible on the ventral side. 
 
 "This large and beautiful species is so distinct from any hitherto 
 described that no comparison is necessary for the purpose of identifi- 
 cation. 
 
 "Position and locality. Okaw bluffs, between Chester and Kaskas- 
 kia, Randolph county, Illinois; from the second division of the Chester 
 limestone. 
 
 "Illinois vState coUection of 1880, by A. H. Worthen, No. 2476." 
 
 The writer has not been able to consult the type-specimen. 
 
194 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 COMPSASTER, new species. 
 
 Professor Weller collected an excellent asterid at Fountain Creek, 
 Waterloo, Illinois (No. 14395, University of Chicago collection), 
 showing the entire actinal side of a form that is nearest to O.formosus. 
 It is, however, a smaller and more slender species, but until the 
 abactinal surfaces of both species are known, one can not say that 
 they are certainly of the same genus. 
 
 Measurements : R = 20.5 mm., r = 4.5 mm. 
 
 SCHUCHERTIID^E, new family. 
 
 Specializing Cryptozonia with well-developed pentagonal inter- 
 brachial arcs. Inframarginals well developed in the proximal regions 
 where they remain adjoining the adambulacrals. Interbrachial 
 and abactinal areas composed of small, more or less closely adjoining 
 plates without regular arrangement. 
 
 Madreporite unknown. 
 
 Contains : 
 
 Schuchertia Gregory. 
 
 Remarks. This family is the most ancient and primitive of all 
 large-disked or pentagonal starfishes devoid of marginals. In 
 Schuchertia the first appearing inframarginals are retained through- 
 out life and remain adjoining the adambulacrals in the axillary 
 regions. These columns distally become less distinct and in the 
 outer third of the rays are not distinguishable as inframarginals 
 from the other smaller ossicles of the interbrachial areas. This 
 therefore indicates that during the growth of Schuchertia the infra- 
 marginals are in the process of elimination and in later forms seem 
 to be completely disguised or lost. Then the plates of the inter- 
 brachial and abactinal areas, while small, are usually strong, rarely 
 spicular or stellate but never decidedly so, while in later genera the 
 ossicles either break up into smaller and smaller plates, even into 
 granules, or are spicular or thorny pieces. Even the adambula- 
 crals which are well developed in Schuchertia may become greatly 
 modified and almost eliminated. 
 
 In seeking for an ancestor for this family, it is plain that it came 
 from a stock like Hudsonaster. This genus actinally has columns 
 of ambulacral, adambulacral, and inframarginal plates; abactinally, 
 inframarginal, supramarginal, and radial columns of plates. In 
 addition there are five axillary marginals, and on the disk a ring of 
 five basal radial and five interradial plates giving rise to the radial 
 and supramarginal columns. The first step from Hudsonaster toward 
 Schuchertia would be a form of the former genus introducing small 
 ambital plates. This type is as yet unknown, but is suggested in 
 UrastereTla. The progressive introduction of ambital plates and no 
 
REVISION OF PALEOZOIC STELLEROIDEA. 195 
 
 development of small interbrachial pieces will tend to keep the 
 inframarginals beside the adambulacrals. This is the case in Schuch- 
 ertia where the axillary marginals are also retained, but this genus 
 has progressed considerably beyond this stage, since the inframar- 
 ginals fail to develop in the later growth, while the supramarginals 
 and radials, as columns, are no longer distinguishable as such in 
 any part of the individuals. The tendency of departure from Hudson- 
 aster therefore seems to be toward the breaking up and elimination 
 of its essential structure into a mass of variously arranged small 
 pieces, except the ambulacrals, which remain as columns of stout 
 
 plates. 
 
 Genus SCHUCHERTIA Gregory. 
 
 Plates 32 and 33. 
 
 Palasterina BILLINGS (part, not McCoy or Salter), Geol. Surv. Canada, Can. Org. 
 
 Rem., dec. 3, 1858, p. 76. 
 
 Schuchertia GREGORY, Geol. Mag., dec. 4, vol. 6, August, 1899, p. 351. 
 Trentonaster STURTZ, Verb, naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, pp. 
 
 224, 225 (based on same genoholotype as Schuchertia). 
 
 Original description. "Palseasterinidse with tessellate exoskeleton; 
 the rays are short and the general shape is pentagonal. R: r as 2:1. 
 Interradial plates numerous, polygonal. Adambulacral plates large 
 and hexagonal. Ambulacral furrow tapering uniformly toward the 
 distal end. 
 
 " Allied to Palseasterina by the general form of the body and the 
 absence of the marginal plates." 
 
 Emended description. Rays five, short and slender. General 
 form pentagonal. Disk large, with well-developed interbrachial 
 arcs. 
 
 Abactinal area composed of very numerous, small, tumid, non- 
 stellate plates which are arranged in quincunx or columns. There 
 are no radial, supramarginal, or ambital plates recognizable as such, 
 nor is the margin bounded by columns of inframarginals. 
 
 Madreporite indistinguishable amongst the abactinal plates. 
 
 Actinally the ambulacral furrows are very narrow, bounded by 
 columns of adambulacral plates. Adjoining these in the proximal 
 regions are distinct " axillary marginals" and inframarginals, the 
 latter distally becoming smaller, and these continue either closely 
 adjoining or are separated from one another by increasing interspaces. 
 In the latter case they are not readily distinguished from the inter- 
 brachial accessory plates. 
 
 Interbrachial areas occupied by numerous small accessory plates 
 and like those of the abactinal area with which they are continuous. 
 
 Ambulacral plates apparently slightly alternating. 
 
 Genoliolotype (of both Schuchertia and Trentonaster). Palasterina 
 stellata Billings. The generic description is, however, largely based 
 on S. laxata, new species. 
 
196 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Distribution. Ordovicic and Siluric of North America. Con- 
 tains the following species: 
 
 S. stellata (Billings). Trenton, Ottawa, Canada. 
 
 8. laxata, new species. Richmond of Ohio. 
 
 S. ordinaria, new species. Basal Siluric.* Girardeau lime- 
 stone, Alexander County, Illinois. 
 
 Remarks. Schuchertia need only be compared with Petraster and 
 Palasterina. The former differs in that the incomplete columns of 
 inframarginals adjoin the adambulacrals and are not separated from 
 them by interbrachial accessory plates as in the other two genera. 
 Petraster is readily distinguished by the prominent columns of infra- 
 marginals bounding the entire animal and abactinally by the distinct 
 columns of radial, supramarginal, and ambital plates. In Schuchertia 
 the plates of the abactinal and interbrachial areas are alike and 
 not distinguishable into the kinds of columns just mentioned for 
 Petraster. 
 
 The fact that in ScJiuchertia the " axillary marginals 7 ' and infra- 
 marginals remain beside the adambulacrals seems to indicate its 
 origin in forms like Hudsonaster. The generic structure of the latter 
 is retained in Schuchertia, to which is added along the margin (mainly 
 axillary) a series of interbrachial accessory plates. The generic 
 structure of Hudsonaster is also retained in Petraster, but here, unlike 
 those in Schuchertia, the interbrachial accessory plates are developed 
 between the inframarginals and adambulacrals, forcing these columns 
 apart. The phylum starting in Schuchertia is not a prolific one, but 
 the other, Palasterinidse, whose inframarginals are true marginals, 
 is not only more prolific in genera but also has a longer geological 
 range. Beginning in Petraster of the Ordovicic, it is continued in 
 the Siluric in Lindstromaster and Palasterina. 
 
 SCHUCHERTIA STELLATA (Billings). 
 Plate 32, fig. 2; plate 33, fig.l. 
 
 Palasterina stellata BILLINGS, Geol. Surv. Canada, Rep. Progress for 1853-1856, 
 1857, p. 290; Geol. Surv. Canada, Can. Org. Rem., dec. 3, 1858, p. 76, pi. 9, 
 figs, la, 16. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1, 
 (Pakeontogr. Soc. for 1861), 1862, p. 27, fig. 16 on p. 26. QUENSTEDT, Petre- 
 factenkunde Deutschlands, vol. 4, 1876, p. 74, pi. 92, fig. 34. 
 
 Trentonaster stellata STURTZ, Verb, naturh. Ver. preuss. Rheinl., etc., vol. 56, 
 1900, pp. 217, 224, 225. 
 
 Description of 1858. "Pentagonal; disk about one-half of the whole 
 diameter; ambulacral grooves narrow and deep, bordered on each 
 side by a row of small, nearly square adambulacral plates; a second 
 row consisting of disk plates extends nearly to the end of each ray, 
 the remainder of the disk covered with smaller plates. All of these 
 plates are solid and closely fitted together; the disk plates in the 
 
KEVISION OF PALEOZOIC STELLEKOIDEA. 197 
 
 angles in contact with the oral plates are much larger than any of 
 the others. 
 
 "In the only specimen in the collection the length of the rays 
 measured along the ambulacral grooves is three lines; number of 
 adambulacral plates on each side of the grooves sixteen; the rays 
 diminish somewhat rapidly in size, and terminate in a rounded point; 
 diameter of the disk four lines. The plates are all a little worn, so 
 that the character of their surfaces can not be observed; they were 
 probably nearly smooth." 
 
 Emended description. Measurement of the immature type-speci- 
 men: R = 6 mm., r = 3 mm. Larger specimen: R = 9 mm., r=4 mm. 
 
 Abactinal area composed of a series of plates which are more or 
 less closely adjoining and on the rays are arranged in distinct but 
 twisted columns. This twisting is due to the insertion of new columns 
 of plates, always on the right side, crowding the older ones to the left. 
 The plates on the rays are subquadrangular to elongate subquad- 
 rangular, increasing in size proximally, and on the disk are largest 
 and generally subcircular in outline, or faintly stellate. The plates 
 appear to be smooth. At the apex of the ray are two somewhat 
 larger plates followed by three columns and on each side of these 
 there are two other columns of ossicles. Near the beginning of the 
 interbrachial arcs the rays have from se^en to eight columns of plates. 
 
 Madreporite not distinguished among the abactinal plates. 
 
 Actinally the most conspicuous columns are the adambulacrals 
 bounding the very narrow ambulacral grooves. These ossicles are 
 subquadrangular in outline near the base of the column, but become 
 wider than long distally; there are about 15 in a column, terminating 
 proximally in two larger, prominent, wedge-shaped plates of the 
 oral armature. Interradially upon each pair of oral pieces is placed 
 a large, single, pentagonal plate (holds the position of axillary 
 interbrachials), against which rest two diverging inframarginal 
 columns, each with 13 or 14 ossicles, and these columns continue 
 adjoining the adambulacrals. Before attaining the distal ends of the 
 rays they gradually become smaller and pass over to the abactinal 
 side. Other actinal disk plates are also present, but apparently are 
 arranged in quincunx, and are smooth like those of the abactinal side. 
 
 Ambulacrals unknown. 
 
 Formation and locality. Ordovicic. The holotype (No. 1399, Geol. 
 Surv. Canada collection) showing the actinal area was found by Mr. 
 E. Billings, at Ottawa. Another specimen, also in the Museum of 
 the Geological Survey of Canada, and showing the abactinal area, was 
 found by Mr. J. S. Stewart on Governor General Bay, near New 
 Edinburgh, Canada. 
 
 Remarks. This little Ordovicic asterid is distinguishable from 
 other species with large interbrachial arcs in that it is devoid of all 
 marginal and radial columns of plates. From S. laxata it is differ- 
 
198 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 entiated by its smaller size, less numerous plates, and by the rela- 
 tively greater size of the disk ossicles. 
 
 SCHUCHERTIA LAXATA, new species. 
 
 Plate 32, fig. 3* plate 33, figs. 2, 3. 
 
 The best specimen measures: R = 18 mm., r= 6 mm., R = 3r. The 
 University of Chicago individual: R = 23 mm., r= about 8 mm. 
 R = 2.8r. Other specimens indicate a growth twice as large as the 
 former one. 
 
 Rays short and slender. Disk and interbrachial arcs large but not 
 nearly so large as in Petraster speciosus. Six specimens are known, 
 four of which are poorly preserved and but a jumble of plates. The 
 specific name is given to indicate the generally separated condition 
 of the plates. 
 
 Abactinal areas of rays and disk composed of very numerous, 
 small but irregularly sized, subquadrate or diamond-shaped, slightly 
 pustulose plates. The arrangement is mainly in quincunx but a 
 columnar arrangement is also noticeable. 
 
 Madreporite not distinguishable amongst the abactinal plates. 
 
 Ambulacral furrows very narrow, hardly revealing the carinated 
 ambulacral plates. The podial openings are between the plates 
 along their lateral corners. 
 
 Adambulacral plates very convex, a little wider than long, with 
 the inner edge more or less pointed, against which terminates the 
 carina of the ambulacral pieces. There are about 15 of the former 
 plates in 15 mm. along the base of the columns. Actinally the adam- 
 bulacral columns are the most conspicuous, since the inframarginals 
 beyond the mid-length of the former columns appear not to be 
 separable from the adjoining interbrachial pieces. The inner side of 
 the adambulacrals bears tufts of short blunt spines. 
 
 Inframarginals recognizable as such only within the axils where 
 they adjoin the ad ambulacral columns. Just within each axil there 
 is a large single plate (axillary marginal) against which rest the infra- 
 marginal columns. These plates decrease rapidly in size distally and 
 are soon separated from one another so that the tenth piece from the 
 axil is indistinguishable in shape and size from the interbrachials. 
 
 Interbrachial accessory plates very numerous, smallest in the 
 inner axillary areas and thence increasing rapidly to a size maintained 
 throughout the interbrachial areas. In form they are either diamond- 
 shaped or subquadrate, centrally tumid, and each plate seems to have 
 borne one central and two or three lateral spines. 
 
 Formation and locality. Five specimens are in the Harris collec- 
 tion, all from the Richmond (Waynesville) , in the vicinity of Waynes- 
 ville, Ohio. A fine specimen showing the abactinal area (University 
 of Chicago collection, No. 10982) was found 7 miles north of Hamilton, 
 
REVISION OF PALEOZOIC STELLEROIDEA. 199 
 
 Ohio. Another fragment was found by Mr. E. H. Vaupel at Oxford 
 in the same State. 
 
 Remarks. The only Upper Ordovicic species with which Schu- 
 cTiertia laxata can 136 confounded is Petraster speciosus. However, 
 there is one fundamental difference between them, so that even 
 fragments can be distinguished. In P. speciosus the inframarginals 
 are very conspicuous and bound the outer margin of the entire animal, 
 while in S. laxata there are no columns of marginal plates, since 
 the inframarginals closely adjoin the adambulacrals. In other 
 words, in the former species the interbrachial accessory plates are 
 between the adambulacrals and inframarginals, while in the latter 
 form these pieces, which are also far more numerous, are all outside 
 of the inframarginals. The generally disjointed condition of the plates 
 in S. laxata will probably always distinguish it from P. speciosus. 
 
 Cat. Nos. 60613, 60623, U.S.N.M. 
 
 SCHUCHERTIA ORDINARIA, new species. 
 
 A regular species of Schuchertia. 
 
 The holotjTpe shows the abactinal side only. R = 1 1 mm., r = about 
 6.3 mm. 
 
 This species is most closely related to S. laxata, but is smaller and 
 with a comparatively larger disk. Therefore the rays do not protrude 
 beyond the disk so far as in the latter form. Abactinal skeleton con- 
 sists of minute tumid ossicles that are more cut along their edges 
 than in S. laxata, and therefore more spicular. 
 
 The specimen can not be freed of the adhering clay sufficiently to 
 make an instructive photograph, and is therefore not illustrated. 
 
 Formation and locality. The holotype is from the basal Siluric 
 Girardeau limestone, Alexander County, Illinois. It is in the Gurley 
 collection of the University of Chicago (No. 10992). 
 
 Family PALASTEBISCID^E Gregory. 
 
 Palssbrisingidx STURTZ, Palaeontographica, vol. 36, 1890, p. 246. 
 Palsechinasteridse STURTZ, Palaeontographica, vol. 36, 1890, p. 246, also p. 247. 
 Palasteriscidse GREGORY, Treat. Zool., vol. 3, Echinoderma, 1900, p. 257. 
 
 Specialized Cryptozonia with very large interbrachial arcs. Abacti- 
 nal and interbrachial areas either with a smooth membrane or granu- 
 lar and thorny. No radial or supramarginal columns of ossicles. 
 Inframarginals not present in any position. Madreporite probably 
 always actinal. Ambulacrals alternating or opposite; adambulacrals 
 more or less modified, but remain adjoining the ambulacrals. 
 Contains : 
 
 Palasteriscus Sturtz. 
 Echinasterella Stiirtz. 
 Loriolaster Sturtz. 
 Cheiropteraster Sturtz. 
 For remarks on the course of development, see Schuchertiidse. 
 
200 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Genus PALASTERISCUS Sturtz. 
 
 ' Palasteriscus STURTZ, Palaeontographica, vol. 32, 1886, p. 95, pi. 14, fig. 1; vol. 36, 
 1890, p. 223, pi. 28, figs. 23-236; pi. 29, fig. 24; Verh. naturh. Ver. preuss. 
 Rheinl., etc., vol. 50, 1893, pp. 44, 61. 
 
 This genus differs from Loriolaster in being more decidedly stellate, 
 with longer and more slender rays and less extensive interbrachial 
 arcs. The abactinal and interbrachial areas are made up of innumer- 
 able, small, variously shaped, loosely interlocking, stellate plates. 
 These areas in Loriolaster appear to be smooth. 
 
 Madreporite very large, actinal. 
 
 The genoholotype, P. devonicus (same citations as above), is the 
 only species and is very rare in the Lower Devonic roofing slates of 
 Bundenbach, Germany. 
 
 Cat. No. 59389, U.S.N.M. 
 
 Genus ECHINASTERELLA Sturtz. 
 
 Echinasterella STURTZ, PalseontograpMca, vol. 36, 1890, p. 225, pi. 28, figs. 26, 26a, 
 27; Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 53, 73. 
 
 This form seems to be closely related to Palasteriscus , and without 
 material for examination it is difficult to point out the differences 
 supposed to be generic. Sturtz describes the ambulacrals as oppo- 
 site, but his figures 26 and 27 show that they are slightly alternating. 
 
 The genoholotype, of which three imperfect examples are known, 
 is E. sladeni (same citations as above). It is from the Lower Devonic 
 of Bundenbach, Germany. Another form which probably belongs 
 here is E. (?) darwini Clarke, from the Devonic of Brazil. 
 
 ECHINASTERELLA (?) DARWINI Clarke. 
 
 Echinasterella ? darwini CLARKE, Monog., I, Serv. Geol. Min. Brasil, 1913, p. 315, 
 pi. 27, figs. 9-12; Bull. N. Y. State Mus., No. 164, pi. 34, figs. 1-3. 
 
 Original description. "Of this fine starfish the collections con- 
 tain two specimens, one, that from which our illustrations are taken, 
 a sharp cast of an oral surface with the arms extended, in a shale 
 sufficiently compact to permit a squeeze to be made of the entire ex- 
 posure. The other is a considerably distorted individual also chiefly 
 with oral exposure. I have placed the species only provisionally with 
 Sturtz's genus EchinastereUa, which was described from the Bunden- 
 bach slates, feeling that in all probability both this species and its 
 associated Aspidosomaf pontis will be found on close analysis by 
 expert students of the Asteroidea to pertain to other genera. The 
 structural features presented by E.f darwini are as follows: The 
 oral surfaces of the arms are very broad, the ambulacral grooves 
 narrow, and the plates arranged opposite each other. The ambulacral 
 plates are turned obliquely inward and are broadened at their inner 
 ends. As preserved these show only their upper edges except where 
 
REVISION OF PALEOZOIC STELLEROIDEA. 201 
 
 turned somewhat more obliquely along the food groove. At the 
 edges of these very broad ambulacral areas the adambulacral plates 
 project in a single row on each margin, as rounded nubs or thickened 
 elongated ridges, from each of which project not less than two and 
 probably three spines. In no place is the aboral surface of the starfish 
 presented, but the madrepore plate is distinctly shown in one of the 
 axillae, indicating its ambulacral position. This plate is round, con- 
 vex, obscurely radiopunctate, and somewhat ridged. The oral appara- 
 tus is indicated by thickened plates at the axillae, but their structure 
 in detail can not be made out. The example serving as the type of this 
 species has a radial length from center of mouth to tip of longest arm 
 of 54 mm." 
 
 Formation and locality. From the Devonic of Ponta Grossa, 
 Brazil. 
 
 Genus LORIOLASTER Sturtz. 
 
 Loriolaster STURTZ, Palaeontographica, vol. 32, 1886, p. 94, pi. 12, figs. 3, 3a, 4; 
 pi. 13, figs. 1, la, 2, 2a; vol. 36, 1890, p. 208, pi. 26, figs. 36, 4a; Verh. naturh. 
 Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 47, 63. 
 
 Generic description. Animal large, five-rayed, widely pentagonal, 
 with very large interbrachial arcs entirely inclosing the rays. No 
 marginal plates and seemingly with a parchment-like integument on 
 the abac tin al side and in the large interbrachial areas. The plates 
 seen on the abactinal side resemble the aspect of the actinal plates. 
 
 Madreporite unknown. 
 
 Ambulacral plates alternating, numerous, considerably wider than 
 long, with the podial openings indeterminate. 
 
 Adambulacrals about as numerous as the ambulacrals, sickle- 
 shaped, greatly elongated laterally and bearing club-shaped carinse 
 (the regular arrangement of the latter seems to preclude their being 
 articulating spines) which have on their outer lateral ends needle-like 
 spines. 
 
 Oral armature pieces large, described as ambulacral. 
 
 The only known species is L. mirdbilis Sturtz (same citations as 
 above), from the Lower Devonic of Bundenbach, Germany. It is 
 not a common species. 
 
 Cat. No. 59380, U.S.N.M. 
 
 Remarks. All of the Bundenbach material has been subjected to 
 great pressure so that nearly all of the finer details have been obliter- 
 ated and obscured by the adhering slate. However, L. mirabilis 
 can not be confounded with any of the associated species because of 
 the constant absence of the marginal plates and the smooth abactinal 
 and interbrachial membrane. The latter may have been made up of 
 very small calcareous pieces now obliterated by the great pressure to 
 which these fossils have been subjected. Also see Cheiropteraster. 
 
202 BULLETIN" 88, UNITED STATES NATIONAL MUSEUM. 
 
 Genus CHEIROPTERASTER Sturtz. 
 
 Cheiropteraster STURTZ, Palaeontographica, vol. 36, 1890, p. 228, pi. 29, fig. 33; 
 pi. 30, fig. 32; Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 49, 68. 
 
 This genus has its nearest relationship in Loriolaster, from which 
 it differs in having a far larger oral opening and markedly different 
 ambulacral columns. These are small plates, in shape like the 
 vertebrae in teleost fishes, which alternate in adjoining columns and 
 do not closely adjoin medially. Podial openings unknown. 
 
 Madreporite small, actinally situated near the mouth. 
 
 Abactinal and interbrachial integument granular and thorny. 
 
 Oral armature pieces small, described as ambulacral. 
 
 GenoTiolotype and only species. C. giganteus Sturtz (same citations 
 as above). This large species is very rare in the Lower Devonic 
 roofing slates of Bundenbach, Germany. 
 
 Cat. No. 59381, U.S.N.M. 
 
 SCHOENASTERID^:, new family. 
 
 Specialized Cryptozonia with well-developed interbrachial arcs. 
 Abactinal area reticular, composed of numerous small plates. Inter- 
 brachial areas with distinctly imbricating plates. Oral armature 
 adambulacral. Adambulacrals well developed in the form of a rope 
 (hence the name, from schoinos, a rope). Ambulacral plates and 
 madreporite unknown. 
 
 Contains : 
 
 Schcenaster Meek and Worthen. 
 
 Genus SCHCENASTER Meek and Worthen. 
 Plates 32, 33, 35. 
 
 Schcenaster MEEK and WORTHEN, Proc. Acad. Nat. Sci. Philadelphia, vol. 12, 
 1860, p. 449; Geol. Surv. Illinois, vol. 2, 1866, p. 277. ZITTEL, Handb. Pal., 
 vol. 1, 1879, p. 453. 
 
 Original description. " Animal consisting of a flattened pentagonal 
 disk, with the angles more or less produced in the form of rays or 
 arms, and the margins between the rays concave in outline, and 
 fringed with short, flattened, spine-like appendages, which are also 
 continued part of the way out along the lateral margins of the rays. 
 Upper side of rays composed of a number of alternating solid plates, 
 with the dorsal pores passing between them, while the angles between 
 the rays are filled with similar plates, forming the upper side of the 
 disk. Under side of the disk composed of numerous small plates, 
 very distinctly imbricating inward and laterally toward the ambu- 
 lacra. Ambulacral furrows (in the typical species) wide, deep, with 
 on each side a single row of comparatively stout, squarish, or oblong 
 adambulacral pieces, having an obliquely outward, imbricating 
 arrangement, so as to present somewhat the appearance of a twisted 
 
REVISION OF PALEOZOIC STELLEROIDEA. 203 
 
 cord, as seen from below ; farther out these become the marginal pieces 
 of the free rays. There is ; however, no regular row of marginal 
 pieces to the disk between the rays. [In other words, there are no 
 infra- or supramarginals.] Oral pieces ten, anchylosed ( ?) in pairs, so 
 as to look like five pieces merely emarginate at the outer and inner 
 ends. (Other characters unknown.) 
 
 "Of course it is not possible to give a systematic diagnosis of a 
 genus like this, of which only imperfect fossil species are known. 
 All that can be done, in cases of this kind, is to give such of the more 
 prominent characters as happen to be visible in the particular speci- 
 mens accessible; while we can not always be sure, until better speci- 
 mens are obtained, and other species known, whether some of the 
 characters given may not be merely specific, or in other cases of 
 more than generic importance. At the same time, we have to regret 
 our inability to give any information in regard to some of the more 
 delicate parts that would be the first to claim the attention of the 
 zoologist in describing existing starfishes. 
 
 "In first publishing a description of the beautiful species forming 
 the type of this genus, we referred it provisionally to McCoy's genus 
 Palasterina, under the subgeneric name Schcenaster. Later com- 
 parisons, however, have satisfied us that it can not properly be retained 
 in that genus; and as it seems to present equally important differ- 
 ences from all the other established genera known to us, we now 
 propose to separate it as a distinct genus, under the name Schoenaster. 
 It is probably most nearly allied to the Silurian genus, Palasterina, 
 but differs in the peculiar oblique, outward, imbricating character 
 of its row of plates on each side of the ambulacral furrows, and the 
 distinct inward imbricating character of the minute, scale-like plates 
 covering the under side of the disk. There are likewise differences 
 in the arrangements of the plates and pores of the dorsal side of the 
 free arms, as seen in our figure 7&, pi. 19. 
 
 "As the disk is not seen in the specimen from which figure 7d, 
 of the plate just alluded to, was drawn, it presents so different an 
 appearance from fig. 7a of the same plate, showing the upper side 
 of the fossil, that, looking at these figures alone, doubts might arise 
 whether or not they belong to the same type. An examination, 
 however, of the upper side of the same specimen from which 7d was 
 drawn, as well as of other fragments, shows them to be the same. A 
 fragment of the same specimen from which fig. Id was drawn also 
 shows portions of the under side of the disk. 
 
 "Another species, apparently of this genus, from the Burlington 
 limestone, with much narrower ambulacral furrows 1 , shows numerous 
 
 i "We should explain here, that the ambulacral furrow of the enlarged ray, represented by fig. 7c of 
 plate 19, is proportionally too broad, in consequence of the accidental flattening of the specimen, and in 
 part to the adambulacral pieces being represented proportionally too small. These furrows are more 
 nearly natural in fig. 7d, but even in that specimen they are proportionally wider than in undistorted 
 examples." 
 
204 BULLETIN" 88, UNITED STATES NATIONAL MUSEUM. 
 
 little, short, flattened, spine-like appendages protruding from these 
 furrows, with an outward imbricating arrangement or inclination 
 towards the extremities of the rays. There may have been other 
 little spines over the outer surface, in addition to those fringing the 
 margins of the disk, though the specimens retain no traces of them." 
 
 Genoholotype. S . fimbriatus Meek and Worthen. Lower Carbonif- 
 erous (St. Louis) of Illinois. 
 
 The other three species referred to ScTmnaster probably do not be- 
 long in this genus. The specimens have not been studied. 
 
 SCHCENASTER FIMBRIATUS Meek and Worthen. 
 
 Plate 35, figs. 1-4. 
 
 Palseasterina (Schoenaster} fimbriata MEEK and WORTHEN, Proc. Acad. Nat. Sci., 
 
 Philadelphia, vol. 12, 1860, p. 449. 
 Schcenaster fimbriatus MEEK and WORTHEN, Geol. Surv. Illinois, vol. 2, 1866, 
 
 p. 278, pi. 19, figs. 7a-7d. 
 
 Original description. "Body regularly pentagonal star-shaped, 
 with the rays produced into rather acutely pointed arms, which are 
 convex above, and about equal in length to the diameter of the disk. 
 Plates of the upper side of the arms and disk, convex, or even tumid ; 
 near the disk those of the rays hexagonal, heptagonal, or irregular 
 in form, alternating, and consisting of about five or six longitudinal 
 rows, with a few much smaller intermediate pieces. Farther out 
 the rays, they gradually pass into two mesial ranges of oblong, alter- 
 nating pieces, with their longer diameter parallel to that of the rays; 
 while on each side of these, minute irregular pieces fill the space 
 between them and the marginal pieces. Toward the extremities 
 of the rays, these little intermediate pieces diminish in size and at 
 last become obsolete, leaving only the two middle and outer, or adam- 
 bulacral rows. Ambulacral furrows, in apparently undistorted 
 specimens, deep and nearly or quite twice as wide as the row of 
 pieces on either side; adambulacral pieces rather thick and strong, 
 and liable to present considerable differences in their obliquity and 
 breadth of surface exposed, in consequence of the compression or 
 distortion of the specimen. Plates of the under side of the disk, very 
 much smaller than the adambulacral, closely crowded together, 
 and owing to their imbricating arrangement, presenting much the 
 appearance of the scales of a fish; immediately on each side of the 
 rays, they imbricate toward the latter, but near the middle of the 
 space between any two ambulacra, the imbrication is inward toward 
 the mouth, so that in tracing the rows parallel to their longer diam- 
 eter, across between the rays, they are found to describe a nearly 
 semicircular curve, with a slight angularity near the middle. 
 
 "Near the extremities of the rays, the dorsal pores are seen to 
 pass between the ends of the two mesial ranges of oblong pieces, 
 
REVISION OF PALEOZOIC STELLEROIDEA. 205 
 
 but farther in toward the disk they are more irregularly dis- 
 tributed. Our enlarged figure 7&, pi. 19, represents these pores 
 and the dorsal plates, as seen in one of the rays, with the convex 
 outer portion of the plates ground away, in which condition the pores 
 probably appear larger than natural. In specimens with the tumid 
 portion of these plates unremoved, the pores are not readily seen, 
 and the whole dorsal side then seems to be made up of solid, close- 
 fitting pieces. Greatest diameter across between the extremities of 
 the opposite rays, about 2.37 inches; diameter of disk, 1 inch; breadth 
 of ambulacral furrows, about 0.10 inch; length of little flattened 
 marginal spines, near 0.08 inch. 
 
 " Locality and position. St. Clair County, Illinois; in the St. Louis 
 division of the Subcarboniferous series." 
 
 The specimen has not been studied. 
 
 SCHCENASTER (?) WACHSMUTHI Meek and Worthen. 
 Plate 33, fig. 6. 
 
 Schcenaster wachsmuthi MEEK and WORTHEN, Proc. Acad. Nat. Sci., Philadelphia, 
 vol. 18, 1866, p. 259; Geol. Surv. Illinois, vol. 3, 1868, p. 499, pi. 17, fig. 4. 
 
 Original description. "Body flattened or much depressed, with 
 a regular, distinctly pentagonal outline, the angles being produced 
 into five rather attenuated rays, which are a little convex above, 
 and apparently as much as two-thirds as long as the diameter of 
 the disk, if not more. Disk concave in outline on the margin be- 
 tween the rays, and imparting a slightly alate character to the 
 latter by extending a little along their margins; like the dorsal side 
 of the rays, composed above of numerous bmall, slightly convex 
 plates. Dorsal pores moderately distinct between the plates. 
 Plates of the under side of the disk about as large as those of the 
 dorsal side, but flattened, scalelike, crowded, and having the inward 
 imbricating character of the genus strongly marked. Ambulacra 
 (as seen in a compressed specimen) very narrow, their marginal 
 plates moderately large, oval-oblong, comparatively thin, and very 
 strongly imbricating outward. Between these, two rows of short, 
 flattened, spinelike scales are seen arising from the ambulacral 
 furrow, and all inclining outward or toward the extremities of the 
 rays. (Other characters unknown.) 
 
 "Diameter of disk, 1.32 inches; rays apparently extending as much 
 as 0.90 inch or more beyond the margins of the disk. 
 
 "This species will be readily distinguished from our 8. fimbriatus, 
 of the St. Louis limestone, the only other species of the genus known 
 to us, by its smaller and less convex plates on the dorsal side, as well 
 as by its much thinner, less oblique, and more strongly imbricating 
 row of plates along each side of the ambulacra, and particularly 
 by its much narrower ambulacral furrows. We have not seen any 
 
206 BULLETIN 
 
 traces of the row of short, flattened, marginal spines seen around the 
 disk of S. fimbriatus, in the form under consideration; nor have 
 the similar little appendages arising in a double row from the am- 
 bulacra of the latter been seen in S. fimbriatus. These, however, 
 may be rather generic than specific characters, and consequently 
 be found common to both species. 
 
 "The specific name is given in honor of Mr. Charles Wachsmuth, 
 of Burlington, Iowa, the discoverer of the only specimen we have 
 seen." 
 
 Formation and locality. Burlington limestone, Burlington, Iowa. 
 The specimen has not been seen; it is in the Museum of Compara- 
 tive Zoology, Harvard University (No. 7). 
 
 SCHCENASTER (?), new species. 
 
 In the Gurley collection of the University of Chicago there is a 
 small specimen (No. 10993) from the Chester formation of Pope 
 County, Illinois. According to the older classification it would be 
 referred to Schwnaster, but until this genus is thoroughly revised 
 nothing of generic value can be done with these Carboniferous 
 asterids. The specimen under discussion seems to be most closely 
 related to S. (?) wachsmuthi. 
 
 Measurements: R = about 10 mm., r = about 3.5 mm. 
 
 SCHCENASTER (?) LEGRANDENSIS Miller and Gurley. 
 
 Plate 32, figs. 4-6. 
 
 Schcenaster legrandensis MILLER and GURLEY, Descr. new gen. and ep. Echinod., 
 
 1890, p. 56, pi. 9, figs. 7-9. MILLER, Sixteenth Rep. Geol. Surv. Indiana, 
 
 1891, p. 371, pi. 9, figs. 7-9; N. Amer. Geol. Pal., App. 1, 1892, p. 682, fig. 1246. 
 
 Original description. "Body thin, regularly pentagonal, sides 
 concave, with long, nanow, gradually tapering convex arms. Plates 
 on the dorsal side of the disk in our specimen apparently anchylosed, 
 and spines, if any belonged to the margin, broken away. Ventral 
 side depressed and flat between the arm furrows, where it consists 
 of very small plates, and if they imbricate inward the overlap must 
 be very slight. Ambulacral furrows wide, deep; two rows of sub- 
 quadrangular, ambulacral plates form the bottom of each furrow, 
 on each side of which there is a row of oblong adambulacral plates, 
 having an obliquely inward imbricating arrangement, presenting 
 somewhat the appearance of a twisted cord; these are continued to 
 the ends of the arms with the same obliquely inward imbricating 
 arrangement. Five pairs of oral plates. 
 
 "This species is small in comparison with the two heretofore 
 described, has sides less convex, and narrower arms." 
 
 Formation and locality. Kinderhook limestone at Le Grand, 
 Iowa. The specimen has not been seen; it may be in the Gurley 
 collection of the University of Chicago. It is certainly not a form 
 of Schcenaster. 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 207 
 
 SCHCENASTER (?) MONTANUS Raymond. 
 
 Plate 33, fig. 5. 
 
 SdiMnaster f montanus RAYMOND, Ottawa Naturalist, vol. 26, 1912, p. 80, fig. 
 3 on p. 81. 
 
 Original description. "Animal small, about an inch in diameter. 
 Rays short, slender, extending about one-half their length beyond 
 the disk. Disk large, pentagonal, the margin slightly concave 
 between the rays. The five proximal plates of the adambulacral 
 series function as orals, while on the arms beyond the disk the adam- 
 bulacrals become marginals. The adambulacral plates are rather 
 small, oval, placed with the long axis diagonal to the axis of the arm. 
 On the most perfect arm there are 16 of these plates on each side of 
 the groove, not counting the proximal and distal plates. 
 
 "The ambulacral ossicles are small, arranged alternately. On 
 this specimen they are mostly displaced. The plates on the disk 
 between the rays are few and small. The marginals are small, 
 rounded, and do not appear to bear spines, but this appearance may 
 be due to poor preservation. 
 
 " Locality. This species is described from a single specimen col- 
 lected by the writer in the Madison limestone at Spring Canyon in 
 the Ruby Mountains, near Alder, Montana. The type is in the 
 Carnegie Museum, Pittsburgh, Pennsylvania." 
 
 PAL^EOSOLASTERID^E, new family. 
 
 Specialized multiradiate Cryptozonia with as many as 29 rays, 
 large disk, and actinal madreporite. Ambulacralia opposite or slightly 
 alternating. 
 Contains : 
 
 Palseosolaster Stiirtz. 
 Echinasterias Sttirtz. 
 Echinodiscaster Delage and Herouard. 
 Echinostella Stiirtz. 
 Medusaster Sttirtz. 
 
 How rays are introduced in multi-rayed asterids. For paleontologic 
 purposes it is not necessary to go deeply into this matter, 'but it is 
 desirable to know when, where, and how the supernumerary rays are 
 introduced in living forms so that we may be guided in our generic 
 studies. 
 
 Ritter and Crocker 1 have recently summed up what is known on 
 this subject, and to their paper the reader is referred for further 
 study. 
 
 In nearly all cases the multi-rayed forms have the rays of equal 
 development, and for this reason it is the general belief that 
 
 i Ritter and Crocker, Multiplication of rays and bilateral symmetry in the 20-rayed starfish, Pycnopodia 
 kelianthoides (Stimpson), Proc. Washington Acad. Sci., vo . 2, 1900, pp. 247-274. 
 50601 Bull. 8815 14 
 
208 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 adults have the full complement of rays characteristic of a species. 
 In some forms there are individuals with smaller immature arms, 
 but it is not certain that these are newly introduced rays, or that 
 "this disparity in size is due to the regeneration of the halves of 
 automatically bisected animals 77 (p. 248). It is true that certain 
 species start with the full complement of rays and introduce none 
 hi later growth. Others certainly deviate from this rule, and a 
 species with as many as 37 rays has one small specimen with only 
 24 plus 2 young sprouting rays. It is therefore plain that "in 
 Heliaster rays are added until far in adult life, 77 and it is also probable 
 that "they are added in pairs 77 (p. 249). In Labidiaster as many as 
 six new rays may bud simultaneously at intervals around the entire 
 circumference of the disk. 
 
 An adult Pycnopodia has from 20 to 24 rays, and "this variation 
 does not depend upon the size of the specimen. * * * The 
 number is generally even, * * * but a few specimens with 21 
 have been found 77 (p. 250). The smallest specimen had six equal 
 arms and two much smaller budding rays, one larger than the other. 
 Between these two extremes all intervening stages occur. At least 
 the original five and probably six rays are of larval origin, all the 
 others being postlarval. When the sixth ray is introduced is un- 
 known; the rest as a rule appear in bilateral order that is, in pairs. 
 They are all developed "in a budding area adjacent to I and II 77 
 on the side toward the sixth ray until late in adult life. When the 
 arms are of unequal number it is due to the suppression of a ray. 
 In Pycnopodia, therefore, ray multiplication goes on through a con- 
 siderable part of adult life, but not the whole of it, and is variable 
 with the individuals. All of the rays, whether of larval or post- 
 larval origin, have the same structural characters. 
 
 Finally, it seems that the sixth ray in Pycnopodia has its origin 
 in, or at least "is in some intimate way related with the larval organ 
 of the embryo 77 (p. 268). Therefore multiradiation among asterids 
 has its origin in late larval life. 
 
 In Heliaster , Clarke states, 1 "the formation of new rays is funda- 
 mentally different from that in Pycnopodia." They do not develop 
 hi distinct generations, but appear entirely independently of each 
 other. "A considerable number may develop at approximately the 
 same time, often as many as six or seven and sometimes eight or 
 nine in H. polybrachius, but they show no definite relation to each 
 other. 77 
 
 The evidence seems "to show that they tend to arise in all four 
 quadrants of the circumference of the starfish about equally, but 
 successively rather than simultaneously. 77 
 
 i H. L. Clarke, Bull. Mus. Comp. Zo61., vol. 51, 1907, pp. 25-76. 
 
KEVISION OF PALEOZOIC STELLEROIDEA. 209 
 
 In Heliaster the original number is five, and the new rays are not 
 as a rule disposed bilaterally (pp. 63-66). 
 
 Verrill (1914) states that Heliaster and allied living forms strikingly 
 resemble Helianfhaster of the Devonic, " and may indicate a con- 
 tinuous descent from these ancient forms'* (p. 13). He also says, "I 
 am inclined to believe that the increase in number of rays has been 
 due more to the advantage gained in holding their food securely, and 
 in opening bivalves, than for holding to the rocks, though both go 
 together' 7 (p. 16). 
 
 Genus PALvEOSOLASTER Sturtz. 
 Plate 34. 
 
 Palseosolaster STURTZ, Verb. nat. Ver. preuss. Rheinl., etc., vol. 56, 1900, pp. 
 
 226-229, pi. 2, figs. 1-3. 
 Helianthaster CLARKE (part), Bull. N.Y. State Mus., No. 121, 1908, p. 64, pi. 11. 
 
 Generic characters. Disk very large, with ' 27 to 29 rays in the 
 genotype, which project one-third their length beyond the disk. 
 Animal large, up to 190 mm. in greatest diameter. Disk and rays 
 without marginalia. Length of rays 95 mm., width of rays 7 mm. 
 
 Abactinal area decidedly and abundantly spinous and devoid of all 
 columns of plates. 
 
 Actinally the great disk is also decidedly spinous. Rays slender, 
 with wide ambulacra; ambulacral plates very narrow, seemingly 
 alternating, but more probably opposite, h- -shaped, with large podial 
 openings in two rows in each ambulacrum. The rays are bounded 
 by narrow columns of small adambulacral ossicles that bear spines 
 on their outer sides. Mouth circular and very large. The nature of 
 the stout oral armature can not be made out. 
 
 Madreporite actinal, placed near the mouth, interbrachial, very 
 large, striate, more or less oval, about 34 mm. in greatest width. 
 
 The general aspect is said to be much like the living Solaster affinis 
 Brandt. 
 
 GenoJiolotype. P. gregoryi Sturtz (citations as above). Lower 
 Devonic of Bundenbach, Germany. Another species occurs at this 
 locality and a third is found in the Upper Devonic of New York. 
 
 Remarks. For present purposes we may state that Palseosolaster 
 has from 25 to 29 rays and that the ambulacralia are arranged opposite 
 one another; the other Sturtz genera, Echinasterias, Ec7iinodiscaster } 
 and Echinostella, are so much like Paldeosolaster that they may be 
 disregarded. 
 
 Clarke recently erroneously referred another very well preserved 
 species of this genus to Helianthaster (H. roemeri Clarke), but it 
 plainly has no direct relationship with H. rhenanus. This is seen 
 in the greater disk, larger number of rays, decidedly actinal position 
 
210 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 of the madreporite and the absence of interbrachial inframarginals. 
 It is clearly a Palseosolaster. 
 
 PAL^JOSOLASTER (?) GYALUM (Clarke). 
 
 Plate 34, fig. 1. 
 
 Helianthaster gyalum CLARKE, Bull. N. Y. State Mus., No. 121, 1908, p. 63, pis. 
 12, 13. 
 
 Original description. The New York specimens, i i Helianthaster 
 gyalum nov. are smaller than H. rhenanus. The arms are more 
 numerous and appear to be quite uniformly 24-25. Compared to 
 H. rhenanus they are relatively short, but very long compared with 
 the size of the disk, which is much suppressed, and on none of the 
 specimens, all showing the oral surface, is any distinct evidence of 
 it visible, so deeply do the arms cut into it and so closely do they 
 lie together. Notwithstanding this apparent retreat of the disk the 
 madreporiform plate is very large. This organ is preserved in but one 
 example, but here it overlaps two adjoining interbrachial angles and 
 the mouth parts pertaining thereto. Instead of being a flat or 
 concave elongate plate, as in H. rhenanus, it is highly convex and 
 circular; its surface markings less distinct and coarse in that species. 
 
 "The great oral aperture is margined by a series of pronounced 
 ' jaws' or sharp projecting elevated angles the sides of which take 
 origin from the margins of adjoining arms. These oral projections 
 are slightly expanded at their tips into blunt points comparable to 
 but smaller than the 'Hocker' of H. rhenanus, but like them carry 
 small spines projecting inward. The solidity and strength of these 
 mouth parts is indicated by their prominence and elevation as shown 
 in figure. * * * The reentrant angle at the base of each arm is 
 narrow, long, and acute, much more extreme in these respects than 
 in H. rhenanus and very much more elevated." 
 
 Actinally the rays have two columns of plates of which the ambu- 
 lacrals are by far the most prominent, are opposite one another or 
 slightly alternate, and occupy the comparatively wide ambulacral 
 furrows. The adambulacrals are narrow columns and apparently as 
 many in number as the ambulacrals. Laterally each adambu- 
 lacral bears several spines. 
 
 Locality and formation. A slab with three individuals from the 
 Portage (Upper Devonic) at EaiTs quarry, Ithaca, New York, is now 
 in Cornell University. 
 
 Remarks. The writer has not seen these specimens, but the illus- 
 trations seem to indicate that the " pronounced jaws" are made up 
 of small ossicles of which there are at least five in each column. 
 Further, that these ossicles are more probably the continuation of 
 the narrow adambulacrals than of the ambulacral columns into the 
 great oral area, and that proximally to these lie the minute pairs of 
 oral armature pieces. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 211 
 
 The madreporite in P. (?) gyalum, as in the forms of Palseosolaster, 
 is very large, actinal in position, and placed even closer to the mouth 
 than in any other species. Not only this, but it lies completely cov- 
 ering one proximal ambulacral furrow and across parts of two adja- 
 cent rays. Its general position and size are in harmony with Palseo- 
 solaster and not at all with Helianihaster. 
 
 That P. (?) gyalum can not be referred to Helianihaster is therefore 
 seen in the different position of the madreporite, the greater number 
 of rays, the wider ambulacral furrow, and the improbability of its 
 having three columns of abactinal ray plates in place of an integument 
 bristling with spines. All of these differences are in harmony with 
 Palseosolaster. Further, if P. (?) gyalum had interbrachial inframar- 
 ginals as does Helianihaster, they should show somewhere on these 
 five specimens, all of which preserve the actinal side. While these 
 differences may not appear to be great, they make of Helianihaster a 
 phanerozonian and of Palseosolaster a cryptozonian. 
 
 PAL^EOSOLASTER ROEMERI (Clarke). 
 Heliarthaster roemeri CLARKE, Bull. N. Y. State Mus., No. 121, 1908, p. 64, pi. 11. 
 
 From the Lower Devonic of Bundenbach, Germany. The holo- 
 type is in the New York State Museum. 
 
 Genus ECHINASTERIAS Sturtz. 
 
 Echinasterias STURTZ, Verh. nat. Ver. preuss. Rheinl., etc., vol. 56, 1900, p. 230, 
 pi. 2, fig. 4; pi. 3, fig. 5. 
 
 The genotype has 25 rays, but otherwise appears to have all the 
 generic characters of Palseosolaster. 
 
 Genoholotype and only species. E. spinosus Sturtz (citations as 
 above) . Lower Devonic of Bundenbach, Germany. 
 
 Genus ECHINODISCASTER Delage and Herouard. 
 
 Echinodiscus STURTZ (not Echinodiscus Worthen and Miller 1883, Echinoidea), 
 Verh. nat. Ver. preuss. Rheinl., etc., vol. 56, 1900, pp. 231-233, pi. 3, figs. 
 6-10. 
 
 EcMnodiscaster DELAGE and HEROUARD, Trait6 de Zoologie Concrete, 1904. 
 
 Echinodisdtes SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, 1914, p. 15. 
 
 
 
 One of the specimens has 29 rays and a greatest diameter of 160 
 mm. The writer fails to see how this genus is to be distinguished 
 from Palseosolaster. It may be more abundantly spinose, and the 
 madreporite is somewhat smaller and more coarsely striate, but these 
 characters can hardly be of generic value. 
 
 Genoholotype and only species. Echinodiscus multidactylus Sturtz 
 (citations as above). Lower Devonic of Bundenbach, Germany. 
 
 Cat. No. 59386, U.S.N.M. 
 
212 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Genus ECHINOSTELLA Sturtz. 
 
 Echinostella STURTZ, Verb. nat. Ver. preuss. Rheinl., etc., vol. 56, 1900, pp. 
 233-235, pi. 3, fig. 11; pi. 4, fig. 12. 
 
 The only specimen has 28 or 29 rays and a greatest diameter of 
 150 mm. Abactinally the rays and the central area of the disk 
 stand out rounded above the remainder of this side of the animal, 
 which is not the case in Palseosolaster; otherwise the two genera aie 
 very much alike. 
 
 GenoJiolotype and only species. E. traquairi Sturtz (citations as 
 above). Lower Devonic of Bundenbach, Germany. 
 
 Genus MED US ASTER Sturtz. 
 
 Medusaster STURTZ, Palseontographica, vol. 36, 1890, p. 229; pi. 31, figs. 34,35; 
 Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 54, 73. 
 
 A form with from 12 to 15 rays. Thought to have relationship 
 with living Solaster. 
 
 GenoJiolotype and only species. M. rhenanus Sturtz (citations as 
 above). Lower Devonic, Bundenbach, Germany. 
 
 Cat. No. 59385, U.S.N.M. 
 
 PALEOZOIC OPHIURIDS. 
 
 A great deal has been written about these animals, but in general 
 the true structure of some of them was not known until very recently. 
 Authors have described these delicate and generally poorly pre- 
 served fossils in such broad terms that a complete restudy of all of 
 the material is required before it can be said that most of the genera 
 or even the species are established. The way has been successfully 
 blazed by Schondorf in Europe, and his methods of study and results 
 need to be applied to the American fossils. It was the writer's hope 
 to do this, but it is now plain that his present duties will prevent his 
 doing so. 
 
 In general it may be said that but few Paleozoic so-called ophiurids 
 are true Ophiuroidea. They are ophiurid-like animals, with open 
 ambulacral furrows, but without the essential characters of the 
 Asteroidea. Nor are they transitional in structure between the 
 Asteroidea and Ophiuroidea. Therefore Schondorf has separated 
 them under the term Auluroidea. It seems to the writer that they 
 originated in the Asteroidea early in the Ordovicic in some crypto- 
 zonian stock near Urasterella, with large and square ambulacralia. 
 (Stenaster and Tetraster are probably true aulurids.) Out of the Aulu- 
 roidea, probably in late Devonic time, arose the true Ophiuroidea. 
 
 The essential differences between the Auluroidea and Ophiuroidea 
 will become plainer to the student after a study of the text and 
 figures presented in this work. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 
 
 213 
 
 Subclass AULUROIDEA. 
 
 Auluroidea SCHONDORF, Palaeontographica, vol. 67, 1910, p. 60; Jahrb. nassauisch. 
 
 Ver. Naturk., Wiesbaden, vol. 63, 1910, pp. 234, 247, 251. SPENCER, Mon. 
 
 Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. for 1913), 1914, pp. 24,48. ' 
 Protophiuroidea and Euophiuroidea SOLLAS and SOLLAS, Philos. Trans. Roy. Soc. 
 
 London, ser. B, vol. 202, 1912, pp. 214,222. 
 
 Auluroidea are Paleozoic brittle-stars, with a more or less well- 
 developed central disk, whose border between the rays is more often 
 concave than convex ; in other words, 
 star-shaped. The rays appear al- 
 ways to be five in number, simple, 
 long and slender, and more or less 
 sharply marked off from the disk as 
 appendages. This means that the 
 body cavity does not extend from 
 the disk into the rays as in Aster- 
 oidea. On the actinal side the rays 
 have open ambulacral furrows with 
 the ambulacralia never anchylosed 
 into vertebrae ; they are arranged in 
 two columns, the pieces of which 
 are either alternate or opposite one 
 another. 
 
 Original definition. "The ambu- 
 lacral water-vascular system lies in 
 a circular canal that is situated wholly within the ambulacralia medi- 
 ally between the adjoining columns of ossicles. From it diverge short 
 side branches that either partially penetrate the substance of the 
 
 individual ambulacrals, or lie in the suture 
 between adjoining ambulacrals; in either 
 case they extend into the ventrally open, 
 broad ambulacral furrow. Ambulacrals free, 
 not coossified, those of adjoining columns 
 either alternate or opposite, but always di- 
 rectly opposite the adambulacrals. Ambu- 
 lacrals ventrally composed of a medially 
 situated, internally concavely hollo wed-out 
 body, which, as the plates of the two columns 
 are normally united, forms the medial ambu- 
 lacral canal; and of a lateral process extend- 
 ing to the adambulacrals, with depressions 
 on both sides of it in the ventral surfaces of 
 the ambulacrals and adambulacrals [see fig. 
 14]. [These large lateral depressions are not podial openings through 
 or between the plates as in asterids, but appear to be cavities for the 
 ampullae or for these and podial insertions. Dorsally the ambulacrals 
 
 FlG. 12. A SECTION THROUGH THE ABM OF AN 
 ASTEKID, AFTEK SCHONDORF. A , AMBULACRA- 
 LIA; Ad, AD AMBULACRALIA; Amp, AMPULLA; 
 D, DORSAL SKELETON; F, PODIA; ipl, ACCES- 
 SORY OSSICLES; Mo, ATTACHMENT FOR UPPER 
 
 LONGITUDINAL MUSCLES; Mo 1 , UPPER TRANS- 
 VERSE MUSCLE ; Mu, ATTACHMENT FOR LOWER 
 LONGITUDINAL MUSCLE; Mv>, LOWER TRANS- 
 VERSE MUSCLE; Mv, VERTICAL MUSCLE ; Bo, 
 UPPER MARGINALIA; Ru, LOWER MARGINALIA; 
 
 Wr, RADIAL WATER- VESSEL. 
 
 FlG. 13. A SECTION THROUGH THE 
 ARM OF A TRUE OPHIURID, AFTER 
 SCHONDORF. Bs, VENTRAL SHIELD; 
 
 C^CUTIS; F, PODIA; L, BODY CAV- 
 ITY; N, NERVE-RING; oZm, uZm, 
 
 UPPER AND LOWER INTERMEDIARY 
 VERTEBRAL MUSCLES; Rs, DORSAL 
 
 SHIELD; Ss, LATERAL SHIELD; W, 
 
 VERTEBRA; Wr, RADIAL WATER- 
 VESSEL. 
 
214 
 
 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Ad. 
 
 FIG. 14. A SECTION THBOUGH THE ARM OF AN AULUBID, 
 WITH ALTERNATING AMBULACEALIA, AFTEE SCHON- 
 DOEF. A, AMBULACEALIA OF THE DOESAL AND VEN- 
 TRAL SKELETON; A 1 , VENTEAL EXTENSION OF THE 
 AMBULACEALIA; Ad, AD AMBULACEALIA = LATERAL 
 
 SHIELDS OF OPHIUEIDS; F, PODIA, ON LEFT THE CANAL 
 PASSES THBOUGH THE PLATE, ON EIGHT THE PLATE IS 
 DISSECTED DOWN TO THE CANAL; Wr, INTEESKELETAL 
 EADIAL WATEE- VESSEL. 
 
 are covered with spines and tubercles.] Disk with concave, or con- 
 vex ( ?) margins, with or without marginal ossicles. When the latter 
 are present, they never extend along the rays, but are wholly re- 
 stricted to the disk. The rays on both sides are margined by the 
 adambulacrals. Ventrally the rays have broad open ambulacral fur- 
 rows, bounded laterally by the 
 adambulacrals. A typical mad- 
 reporite [probably always] lies 
 in one of the ventral interradii. 
 "The group [subclass] is re- 
 stricted to the older Paleozoic." 
 Remarks. This subclass of 
 Stelleroidea appears to be an in- 
 dependent development whose 
 structure partakes of that of 
 the Asteroidea and the Ophiu- 
 roidea, though more like the 
 latter. The Auluroidea agree 
 with the asterids in having open 
 ambulacral furrows, and a true madreporite, which is, however, ven- 
 trally situated, but otherwise the class is more like the ophiurids, since 
 the body cavity does not extend into the rays as in true starfishes. 
 However, the water-vascular canal in the Auluroidea does not lie 
 outside of the ambulacrals as in the Asteroidea, but within these 
 ossicles along the mid-line of the ambulacrum in a canal that is cut 
 out of the sides of adjoining ambulacral columns. On the other 
 hand, the Ophiu- 
 
 roidea have the am- AA A A i* A4 A A Ad 
 
 bulacralia coossified 
 and modified into 
 vertebral ossicles; 
 there are no open 
 ambulacral furrows, 
 and the entire rays 
 are covered by four 
 columns of shields or by an integument more or less studded with 
 calcareous plates and granules. 
 
 It appears that the Auluroidea all have dorsally four columns of 
 plates, of which the two medial ones are the most prominent. These 
 are undoubtedly the dorsal aspect of the thickened ambulacrals. 
 Outside of the disk they are usually convex and more or less orna- 
 mented with granules, but within the disk are less prominent and take 
 on other expressions, commonly with concave surfaces. The plates 
 outside of these margin the rays and are the adambulacrals; while 
 in some forms they are prominent and tuberculate, usually they are 
 made up of narrow vertical pieces that bear spines along the ventral 
 or only the distal ventral edge. 
 
 FIGS. 15 AND 16. VENTEAL AND DOESAL AEM STBUCTUEE OF AULUBOIDEA, 
 WITH THE AMBULACEA ALTEENATING. SCHEMATIC, AFTEE SCHSNDOEF. 
 A, AMBULACEALIA; A 1 , VENTEAL EXTENSIONS OF AMBULACEALIA; A 3, 
 AD AMBULACEALIA; FS, PODIAL CAVITIES. 
 
KEVISION OF PALEOZOIC STELLEKOIDEA. 215 
 
 The Auluroidea can be divided into two orders on the basis of 
 whether the ambulacrals on each side of the median line are arranged 
 alternately (the Lysophiurae), or are opposite to one another (the 
 Streptophiurae). The following classification is a modification of 
 the one offered by Gregory in 1897, and kis work was in turn a 
 modification of that of Bell in 1892. 
 
 After the present work was written, its author first became aware 
 of the works of Sollas and Sollas, and Spencer. The reader should 
 consult those papers for important studies on the Auluroidea. 
 
 Order LYSOPHIUR^E: Gregory. 
 
 Encrinasterise BRONN (part), Klassen u. Ordnungen d. Tierreichs, vol. 1, 1859, 
 
 p. 287. SCHONDORF, Palaeontographica, vol. 57, 1910, p. 61. 
 Ophio-Encrinasterise STURTZ, Verb, naturh. Ver. preuss. Rheinl., etc., vol. 56, 
 
 1900, p. 198. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, 
 
 vol. 63, 1910, pp. 234, 237. 
 Lysophiurse GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1030 (contains 
 
 Protasteridse and Palaeophiuridae) ; Treat. Zool., vol. 3, Echinoderma, 1900, 
 
 p. 274. SOLLAS and SOLLAS, Philos. Trans. Roy. Soc. London, ser. B, vol. 
 
 202, 1912, p. 223. 
 Ophiurasterix SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 
 1910, p. 251. 
 
 Auluroidea in which the ambulacral ossicles of adjoining columns 
 are alternate to one another. The individual plates are separate and 
 not coossified into vertebrae. 
 
 Remarks. The Lysophiurae are Paleozoic or primitive Auluroidea, 
 that is, ophiurid-like animals, with wide and open ambulacral furrows 
 in which the ambulacralia are free and alternately arranged. The 
 ambulacralia are common to the actinal and abactinal sides. 
 This order contains the following families: 
 
 Protasteridse. Have boot-shaped ambulacralia ventrally. 
 Palseophiuridae. Have subquadrate ambulacralia ventrally. 
 Encrinasteridae. Have boot-shaped ambulacralia ventrally 
 and large disks that are bordered by marginalia. 
 
 Family PROTASTERIDSE Miller. 
 
 Protasteridse MILLER, N. Amer. Geol. Pal., 1889, p. 216. GREGORY, Proc. Zool. 
 Soc. London for 1896, 1897, p. 1031; Treat. Zool., vol. 3, Echinoderma, 1900, 
 p. 274. PARKS, Trans. Canadian Inst., vol. 8, 1908, p. 366. 
 
 Paldeophiomyxidse STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 p. 202. 
 
 "Lysophiurae with boot-shaped ambulacral ossicles, each composed 
 of a 'body ' in the median line of the arm, and a lateral 'wing' at right 
 angles to it" (Gregory). There is either a well-marked scale-covered 
 or granular disk, and five flexible arms. The adambulacral plates are 
 rather stout, with many lateral spines. 
 
216 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Schondorf states that Gregory's family Palseopliiuridae has no 
 value and is to be merged into the one under discussion. The reasons 
 for this are given beyond under the former family heading. 
 The family contains: 
 
 Tseniaster Billings. Alepidaster Meek. 
 
 EopTiiura Jaekel. Gregoriura Chapman. 
 
 Bohemura Jaekel. Bundenbachia Stiirtz. 
 
 Palseura Jaekel. PalseopJiiomyxa Stiirtz. 
 
 Protaster Forbes. 
 
 Genus T^ENIASTER Billings. 
 Plate 36, figs. 1-3. 
 
 Tseniaster BILLINGS, Geol. Surv. Canada, Can. Org. Rem., dec. 3, 1858, p. 80. 
 CHAPMAN, Canadian Journ., n. ser., vol. 6, 1861, p. 517. WRIGHT, Mon. 
 British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Paleeontogr. Soc. for 1861), 1862, 
 pp. 24, 34. HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 300; 
 rev. ed., 1868=1870, p. 338. ZITTEL, Handb. Pal., vol. 1, 1879, p. 445. 
 STURTZ, N. Jahrb. fur Min., etc., 1886, vol. 2, p. 150; Palseontographica, vol. 
 32, 1886, pp. 78, 83. MILLER, N. Amer. Geol. Pal., 1889, p. 285. GREGORY, 
 Geol. Mag., dec. 3, vol. 6, 1889, p. 26. STURTZ, Verh. naturh. Ver. preuss. 
 Rheinl., etc., vol. 50, 1893, p. 20. J. F. JAMES, Journ. Cincinnati Soc. Nat. 
 Hist., vol. 18, 1896, p. 138. GREGORY, Proc. Zool. Soc. London for 1896, 1897, 
 p. 1035; Treat. Zool., vol. 3, Echinoderma, 1900, p. 250. SPENCER, Mon. 
 Brit. Pal. Asterozoa, pt. 1 (Paleeontogr. Soc. for 1913), 1914, pp. 8, 19. 
 
 Taeniura GREGORY, (not Tseniura Miiller and Heule 1837, sting-ray), Proc. Zool. 
 Soc. London for 1896, 1897, p. 1035. 
 
 Original description of Tseniaster. " Generic Characters. Body 
 deeply stellate; no disk [there is a disk] or marginal plates; rays 
 long, slender, flexible, and covered with small spines; two rows of 
 large ambulacral pores; adambulacral plates elongated and sloping 
 outward so that they partly overlap each other; ambulacral ossicles 
 contracted in the middle, dilated at each end. Generic name from 
 tainia, a riband." 
 
 Genolectotype (the first species of Billings is here selected as the 
 genolectotype) . Palxocoma spinosa Billings. 
 
 Remarks. Hall restudied the type-material of T&niaster and 
 records his observations as follows : 
 
 "In reviewing the characters of Protaster and Eugaster, I became 
 satisfied that there was an intimate relation between these and 
 Tseniaster of Billings, and in order to satisfy myself on this point, 
 I have * * * received from Sir William E. Logan, permission to 
 examine specimens of T&niaster spinosus and T. cylindricus. 
 
 "An examination of the specimen illustrated in fig. 3 (ut sup.) 
 reveals what I conceive to be a disk not at all unlike the disk of Prot- 
 aster, but less extended than in the Lower Helderberg species. The 
 structure of the ray is precisely of the same character as the ray of 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 217 
 
 that species which I have named Protaster forbesi, the proportions of 
 plates and relations of parts showing specific differences/' 
 
 "Mr. Billings remarks, under the description of T. spinosus, that 
 ' the ambulacral ossicles appear in some places to alternate with each 
 other, but this is owing to a distortion; those on one side of the furrow 
 are opposite to those upon the other. 7 
 
 "Now the specimen of this species which I have examined, and 
 which I suppose to be the one figured upon Plate X, figures 3d, Z>, 
 has the ambulacral plates alternating * * *. 
 
 "In the specimen of T. cylindricus examined the ambulacral 
 plates are less distinctly alternate, but the relation of the adam- 
 bulacral plates and the pores are the same as in the other form. 
 Not having seen the specimen showing the dorsal view, figure 4o- of 
 plate X, I can only remark that the structure of the rays is very 
 similar to that of Protaster." 
 
 Without restudying the type-material of Tseniaster, or paying 
 attention to Hall's statements that T. spinosus has what he con- 
 ceived "to be a disk not at all unlike the disk of Protaster," Gregory 
 (1897) regarded Tseniaster as a Cryptozonia starfish and made of 
 Billings's second species, T. cyliiidricus, a new genus, Tseniura. The 
 latter he correctly refers to the primitive ophiurids. Under these 
 circumstances it is desirable to repeat here what Gregory wrote 
 about Tseniaster. 
 
 Tseniaster "was described as diskless, which in respect to the type 
 species T. spinosus is correct. In that species the oral skeleton 
 consists of five pah's of large adambulacrals, as in ordinary Asterids. 
 The affinities of the true Tseniaster appear to me to be with such forms 
 as Palssaster ruthveni [= Urasterella ruthveni]. It is asteroid in the 
 oral armature, in its alternately arranged ambulacral ossicles, and in 
 the absence of a disk. I therefore consider Tseniaster a genus of 
 Asteroidea. The second species placed by Billings in this genus 
 has, however, a well-marked disk, and has the oral armature com- 
 posed of five pairs of Ophiuroid syngnaths. It must, therefore be 
 included among the Ophiuroidea." 
 
 To adjust this matter, the writer restudied the genotype of Tseniaster 
 at Ottawa (two specimens, No. 1404, the originals of figures 3a-3d 
 of Billings's Plate X). There can be no doubt that we have here a 
 genuine lysophiurid. There is a small disk present in the individual 
 figured as 3a and 3Z>, but it is not one with a round outline, as in 
 typical ophiurids, but is concave along the margin between the rays. 
 Actinally this disk is abundantly covered with prominent but slender 
 spines. 
 
 The ambulacrals are distinctly alternate throughout the rays and ap- 
 pear as in the sketch presented on page 218; this condition is not due 
 to distortion or other causes. The side plates are narrow, and each 
 
218 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 bears three spines (see fig. 17B); toward the mouth the two columns 
 diverge far more than one would assume from the original figure, and 
 in consequence there are long and slender syngnaths and not the 
 asterid-like mouthpieces figured in the illustration. (See fig. 17C.) 
 
 3 
 
 FIG. 17. DIAGRAMS OF T^NIASTEB SPINOSUS (BILLINGS). A, To SHOW THE SPINOSE DISK WITH CONCAVE 
 
 SIDES. B, ACTINAL PLATE ARRANGEMENT: C, AMBULACRALS; ad, ADAMBULACRALS OR SIDE PLATES, 
 WITH THEIR SPINES. C, MOUTH PLATES: a, AMBULACRALS; S, SYNGNATH. 
 
 The specimen of figures 3c and 3d is too poorly preserved to add 
 anything further. Associated with these types there is another and 
 much larger specimen with a well-marked disk, of which Billings 
 said nothing in his original description. This form is clearly of 
 another species (probably T. cylindricus) , and is mentioned here so 
 that other workers will not confound it with the original material 
 of T. spinosus. 
 
 In 1900 Gregory referred Tseniaster to the asterid family Tsenias 
 teridse, and placed here as well the unrelated genera Stenaster, S alter- 
 aster, and Urasterella. From what has been stated above it is plain 
 that T&niaster can not be closely related to the cryptozonian genus 
 Urasterella , since the latter has an abundance of narrow ambulacralia, 
 asterid in type, while these ossicles in the former are far fewer in 
 number and of the form seen in other and related Lysophiurse. It 
 is very probable that Tseniaster -arose in the same stock that gave 
 rise to Urasterella and Stenaster, but the former genus is clearly one 
 of the aulurids. 
 
 In 1896 Gregory took out of T&niaster the second species of 
 Billings (T. cylindricus) and based on it the new genus Tseniura. 
 As will be seen, this name can have no standing, as the generic char- 
 acters are those of Tseniaster, and, further, the name is preoccupied 
 since 1837. 
 
 Thinking T. cylindricus most closely related to the primitive 
 ophiurids PalseopTiiura and St&rteura, Gregory defined T&niura as 
 follows : 
 
 "Diagnosis: Palseophiuridse with a small pentagonal disk, not 
 bounded by marginal ossicles. The ambulacral furrow is broad. 
 The oral skeleton is conspicuous and the syngnaths each composed 
 of two separate pieces. The two jaws of each oral angle are closely 
 attached; the mouth frames are separated, and each of them is a 
 short, thick, slightly bent bar." 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 219 
 
 Genotype and only species. Palxocoma cylindrica Billings. 
 11 Remarks: This genus differs from PalseopTiiura by the absence 
 of marginal ossicles from the disk, and from Sturtzura by the smaller 
 size of the disk and the form of the syngnaths. In Sturtzura the 
 jaws end bluntly against a jaw plate, whereas in Tseniura they appear 
 to taper to a point and have no jaw plate." 
 
 The two cotypes of T. cylindricus (1405a) were lost for many years, 
 but have recently been rediscovered in the collections at Ottawa. 
 In addition, there is another specimen in that Museum under this name, 
 and it is probable that it was so identified by Billings (No. 1405). 
 This was the only specimen studied, and its generic characters agree 
 very well with the originals of the cotypes (figs. 4b and 4c of pi. X), 
 and appear to be in harmony with the genotype of Tseniaster. The 
 only important difference is that here the ambulacralia are directly 
 opposite one another, and not slightly alternating, as in T. spinosus 
 (see fig. 18), a difference, it seems to the writer, not in itself alone 
 worthy of being the base of a new genus distinct from Tseniaster. 
 Tseniaster has the following species: 
 
 T. spinosu^s (Billings). Lower Trenton. 
 
 T. cylindricus (Billings). Trenton. 
 
 T. schofiarize Ruedemann. Upp^r Trenton. 
 
 T. elegans Miller. Richmondian (Waynesville). 
 
 T. meafoadensis Foerste. Richmondian. 
 
 TXENIASTER SPINOSUS (Billings). 
 
 Plate 36, fig. 1; text fig. 17. 
 
 Palseocoma spinosa BILLINGS, Geol. Surv. Canada, Rep. Progress for 1853-1856, 
 
 1857, p. 292. 
 Tseniaster spinosus BILLINGS, Geol. Surv. Canada, Can. Org. Hem., dec. 3, 1858, 
 
 p. 81, pi. 10, figs. 3a-3d. MILLER, N. Amer. Geol. Pal., 1889, p. 285, fig. 439. 
 
 Revised description ly BiUings. "The specimens collected are 
 about seven lines in diameter; the rays linear-lanceolate, one line 
 in width at the base, and covered at the sides with numerous small 
 spines. 
 
 "In the view of the enlarged specimen (pi. X, 3s), the ambulacral 
 ossicles appear in some places to alternate with each, other, but this 
 is owing to a distortion. Those on one side of the furrow are oppo- 
 site those upon the other. The adambulacral plates are elongated, 
 and so placed that the outer extremity of the one lies upon the inner 
 extremity to the next. The rays are flexible." 
 
 For remarks on this species, see the discussion under Tseniaster. 
 
 Formation and locality. Two specimens from the Lower Trenton, 
 Falls of Montmorency, east of Quebec, Canada. The original of 
 figures 3a to 3d is in the Victoria Memorial Museum, Ottawa 
 (No. 1404). 
 
220 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 T^NIASTER CYLINDRICUS (Billings). 
 
 Plate 36, figs. 2, 3; text fig. 18. 
 
 Palseocoma cylindrica BILLINGS, Geol. Surv. Canada, Rep. Progress for 1853- 
 1856, 1857, p. 292. 
 
 Txniaster cylindricus BILLINGS, Geol. Surv. Canada, Can. Org. Rem., dec. 3, 
 1858, p. 81, pi. 10, figs. 4a-4c. WRIGHT. Mon. British Foss. Echinod., Oolitic, 
 vol. 2, pt. 1 (Palseontogr. Soc. for 1861), 1862, p. 34. PARKS, Trans. Cana- 
 dian Inst., vol. 8, 1908, p. 371. 
 
 Txniura cylindrica GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1035. 
 
 Lapworthura cylindrica PARKS, Trans. Canadian Inst., vol. 8, 1908, p. 371. 
 
 Original description. "One inch and a half in diameter; rays 
 five [very flexible], covered with spines, subcylindrical, regularly 
 
 rounded on the upper side, flattened 
 on the lower, about one line in width 
 at base, and regularly tapering to an 
 acute point." 
 
 Formation and locality. In the Tren- 
 ton limestone at Ottawa, Canada. The 
 
 . i8.-DiAGRAMOp7cTmAL BAY-PLATES cotypes (14050), along with a third 
 OF TJSKIASTKR CYLINDKICUS BILLINGS, specimen (1405), are in the Victoria 
 
 a, AMBTJLACKAL; ad, SIDE PLATES. _* . , v , 
 
 Memorial Museum at Ottawa. 
 
 T^ENIASTER SCHOHARL Ruedemann. 
 
 Tseniaster schoharise RUEDEMANN, Bull. N. Y. State Mus., No. 162, 1912, p. 88, 
 pl. 3, fig. 1. 
 
 Original description. The holotype "is small, the arms about 15 
 mm. long, and it is without a disk. The arms are slender and flexible, 
 about 1.3 mm. wide at the base, and almost as high in lateral view, 
 originally probably cylindrical. The ventral view shows a straight or 
 slightly zigzagged ambulacral canal, and on both sides of this squarish 
 depressions surrounded by the ambulacral and adambulacral ossicles, 
 the covering lower arm plates not being retained if they existed. 
 The inner (ambulacral or vertebral) ossicles appear as narrow and 
 outwardly curved ridges, the outer or adambulacral ossicles as ridges 
 bent in the opposite direction with a projection in the middle of the 
 outer arch. The ambulacral ossicles are not directly opposite nor 
 regularly alternating, but those of the right side on the ventral view 
 advanced about one-third the length of the ossicles beyond those of 
 the other side. 
 
 "The lateral view of one other arm exhibits the ossicles as ver- 
 tical bars, that are thickened at both ends resembling vertebrae 
 and terminating at the dorsal side with a flat surface and forming 
 there an apparently continuous layer. They appear almost twice 
 as wide as the intervening spaces. The dorsal surface bears bundles of 
 obliquely forward directed spines, one bundle corresponding to each 
 ossicle. These spines appear in the right arm to proceed from 
 
REVISION OF PALEOZOIC STELLEROIDEA. 221 
 
 small spine-bearing plates attached to the adambulacrals, as in the 
 closely related Bundenbachia. On one arm two bundles are seen 
 to proceed from each segment, one oblique, the other vertical to 
 the arm. The oral skeleton consists of stout, bifid pieces, much 
 resembling the oral pairs of adambulacrals of the genotype." 
 
 Formation and locality. Upper Schenectady formation, the 
 eastern shale phase of the Upper Trenton limestones. From near 
 Schoharie Junction, New York. The holotype is in the New York 
 State collection at Albany. 
 
 T^ENIASTER ELEGANS Miller. 
 
 Tseniaster elegans MILLER, Journ. Cincinnati Soc. Nat. Hist., vol. 5, 1882, p. 41, 
 pi. 1, figs. 6-6c. J. F. JAMES, Journ. Cincinnati Soc. Nat. Hist., vol. 18, 
 1896, p. 139. PARKS, Trans. Canadian Inst., vol. 8, 1908, pp. 365, 371. 
 
 Protaster elegans PARKS, Trans. Canadian Inst., vol. 8, 1908, p. 368. 
 
 Original description. "This species is founded upon more than 30 
 specimens occurring on a single slab, but showing only the ventral 
 side, with the exception of the ends of some of the rays. 
 
 "The body is deeply stellate, and the rays long, slender, and 
 flexible, and margined on either side with a row of spines. 
 
 "From the length of some of the rays, a complete specimen, 
 properly spread, would probably have a diameter of an inch and a 
 quarter, or more. The rays taper to a sharp point, are rounded on 
 the dorsal side, and margined on the ventral side by a row of spines, 
 one spine arising from each plate. Only two rows of plates seem to 
 form the dorsal side of a ray. The ventral side of each ray is marked 
 by a furrow in the middle, separating two series of plates or ossicles. 
 These plates are a little longer in the direction of the ray than wide, 
 and alternately break joints at the middle, where they are slightly 
 contracted." 
 
 Formation and locality. This extraordinary slab is in the Harris 
 collection of the United States National Museum. It was found near 
 Waynesville, Ohio, in the Richmond formation of the Ordovicic 
 period. 
 
 Cat. No. 40878, U.S.N.M. 
 
 TffiNIASTER MEAFORDENSIS Foerste. 
 
 Txniaster meafordensis FOERSTE, Bull. Sci. Lab. Denison Univ., vol. 17, 1914, p. 
 326, pi. 4, figs. 5-7. 
 
 The reference to this species is inserted as this book is going through 
 the press. The form appears to be common in the lowest Richmon- 
 dian on Workman Creek, three miles southeast of Meaford, Ontario, 
 Canada. The types are probably in the Victoria Memorial Museum, 
 Ottawa, Canada. 
 
222 
 
 BULLETIN 88, UNITED STATES NATIONAL MUSEUM, 
 
 Genus EOPHIURA Jaekel. 
 
 Text figs. 19, 20. 
 
 EopUura JAEKEL, Zeits. geol. Gesell., vol. 55, 1903, Protokol, p. 14 (107), figs. 1, 4. 
 
 GenoJwlotype. EopMura, species not named. To give this genus 
 
 proper standing according to the rules of nomenclature, the form is 
 
 here named E. bohemica, new species. It is the only species of the 
 
 genus, and occurs in the Ordovicic (Dj) at Osek, Bohemia. 
 
 The genus is not defined in the regular manner, but from the general 
 discussion and the illustrations the following has been made out: 
 
 Kays outside of the disk, 
 apparently petaloid i n 
 form, with wide-open am- 
 bulacral furrows, having 
 narrow alternating ambu- 
 lacralia that are \ shaped, 
 with the podial openings 
 excavated on each side of 
 the lateral extensions. 
 The adambulacrals are 
 very large, drawn out lat- 
 erally, rectangular, lie hori- 
 zontally, and in no way 
 resemble the side plates of 
 typical ophiurids, or, for 
 that matter, even the Lys- 
 ophiurse. The lateral 
 edges of these ossicles are 
 slightly elevated, tubercu- 
 lated, and each bears about 
 four long and very slender 
 spines. Inside of the disk 
 the adambulacrals are nar- 
 row and stand vertically 
 as in Paleozoic ophiurids ; 
 the columns first diverge 
 The two proximal pieces of 
 mouth extensions, with the 
 
 FIG. 19. END OF A KAY OF EOPHIUKA BOHEMICA, MUCH EN- 
 LARGED, AFTER JAEKEL. a, AMBULACRALIA; ad, ADAMBULA- 
 CRALIA; Afg, PIT OF PODIA; ads, LATERAL EXTENSION OF 
 AD AMBULACRALIA; Rr, RADIAL FURROW; St, SPINE BASES. 
 
 and then converge in the mouth area. 
 
 each column make the adambulacral 
 
 terminal ossicles of adjacent columns side by side but not coalesced, 
 
 forming the syngnaths. The two most proximal ambulacrals rapidly 
 
 decrease in size, enlarging the mouth area, with none of these ossicles 
 
 on each side of the two final adambulacrals. 
 
 The disk seems to be small, with concave interbrachial sides. 
 Actinally these areas are covered with scale ossicles. Madreporite 
 ventral, in the outer and lateral part of an interradius. Immediately 
 outside of the syngnaths occur interradially two small ossicles, 
 reminding one of vestigial inframarginalia. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 
 
 Genus BOHEMURA Jaekel. 
 Text fig* 21. 
 
 223 
 
 Bohemura JAEKEL, Zeits. geol. Gesell., vol. 55, 1903, Protokol, p. 18 (111), fig. 6. 
 This genus, like the foregoing, is not defined in the regulation way. 
 Jaekel's fine drawing shows that it is closely related to Eophiura, 
 differing mainly in that the rays do not end bluntly, but have slowly 
 tapering whip-like terminations. These ends are of course ontoge- 
 netically young and reveal the progressive ray development. Here 
 
 FIG. 20. ORAL SKELETON OB- EOPHIUEA BOHEMICA, AFTER JAEKEL. a, AMBULACRALIA; ad, ADAMBU- 
 LACRALIA; Ma, MADREPORITE AMONG THE SCALE PLATES. 
 
 the rays are made up of overlapping and alternating adambulacrals 
 that distally have no ambulacral grooves. Gradually an ambulacral 
 groove is developed and it becomes rapidly wider as one examines 
 the rays more and more proximally, and the adambulacrals turn 
 over and flatten out, finally making the great open ambulacral 
 furrows. The illustration here reproduced, figure 21 on page 224, 
 will show the generic characters as drawn by Jaekel. 
 
 Oenoholotype and only species. B. jahni Jaekel. Ordovicic (DJ 
 at Zahorzan, Bohemia. 
 
 Genus PALvEURA Jaekel. 
 
 Text fig. 22. 
 Palseura JAEKEL, Zeits. geol. Gesell., vol. 55, 1903,Protokol,p.l6(109)-17(110),fig. 5. 
 
 Oenoholotype. Palseura, species not named. No species is again 
 mentioned, nor is it stated that the generic name is new. To give 
 the name standing, the form figured is here named P. neglecta, new 
 genus, new species. It occurs in the Ordovicic (D t ) of Bohemia; 
 the exact locality is not given, but may be Osek. 
 
 50601 Bull. 88 15 15 
 
224 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Jaekel here again fails to diagnose his genus, but some of the 
 characters can be clearly made out from his excellent drawing. 
 The disk is small and tends to have convex interbrachial areas. So 
 far as the oral disk area is concerned, the general structure is that 
 of Eophiura, with this marked difference the opposite and asterid- 
 like ambulacralia of the rays do not vanish proximally as in that 
 
 genus but crowd over and finally 
 rest wholly upon the adambulacrals, 
 and end against the distal edges of 
 the syngnaths . These are made up 
 of the coossified terminal adambu- 
 lacral ossicles. 
 
 Genus PROTASTER Forbes. 
 Text fig. 23. 
 
 Protester FORBES, Mem. Geol. Surv. 
 United Kingdom, dec. 1, 1849, pi. 
 4, pp. 1-2; in McCor, British Pal. 
 Foss., 1851, p. 60. MURCHISON, 
 Siluria, 1854, p. 221, fig. 39-4. 
 SALTER, Rep. Twenty-sixth Meet., 
 Brit. Assoc. Adv. Sci., Notices and 
 abstracts, 1857, p. 76; Ann. Mag. 
 Nat. Hist., ser. 2, vol. 20, 1857, pp. 
 325, 330 HALL, Nat. Hist. N. Y., 
 Pal., vol. 3, 1859, p. 134. SALTER, 
 Ann. Mag. Nat. Hist., ser. 3, vol. 8, 
 
 1861, p. 484. WRIGHT, Mon. Brit- 
 ish Foss. Echinod., Oolitic, vol. 2, 
 pt. 1 (Palseontogr. Soc. for 1861), 
 
 1862, pp. 23, 31. HALL, Twentieth 
 Rep. N. Y. State Cab. Nat. Hist., 
 1868, p. 293; rev. ed., 1868=1870, 
 p. 335. QUENSTEDT, Petrefacten- 
 kunde Deutschlands, vol. 4, 1876, 
 p. 133, pi. 95, fig. 11. STURTZ, N. 
 Jahrb. fiir Min., etc., 1886, vol. 2, 
 pp. 148, 150. GREGORY, Geol. 
 Mag., dec. 3, vol. 6, 1889, p. 26. 
 ST^RTZ, Verh. naturh. Ver. preuss. 
 Rheinl., etc., vol. 50, 1893, p. 18. 
 J. F. JAMES, Journ. Cincinnati Soc. 
 
 Nat. Hist., vol. 18, 1896, p. 137. GREGORY, Proc. Zool. Soc. London for 1896, 
 1897, p. 1031, fig. 1. WHIDBORNE, Palseontogr. Soc., 1898, p. 206. PARKS, 
 Trans. Canadian Inst., vol. 8, 1908, pp. 363, 366. SCHONDORF, Jahrb. nas- 
 sauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 238. SOLLAS and SOLLAS, 
 PMlos. Trans. Roy. Soc. London, ser. B, vol. 202, 1912, p. 223. SPENCER, 
 Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. for 1913), 1914, p. 35. 
 
 Encrinaster (part) HAECKEL, Gen. Morphologie, vol. 2, 1866, p. Ixvii (no definition). 
 
 Also Bee Sturtzura. 
 
 FiG.21. VENTRAL VIEW OF A RAY OF BOHEMURA 
 
 JAHNI, ENLARGED ABOUT X 2, AFTER JAEKEL. 
 
 a, AMBULACRALIA; ad, AD AMBULACRALIA WITH 
 
 THEIR LATERAL EXTENSIONS; ddm, SYNGNATHS. 
 
REVISION OF PALEOZOIC STELLEBOIDEA. 
 
 225 
 
 Original description. " (Order Ophiuridse. Family Euryales.) 
 Body circular, covered with squamiform plates; genital openings 
 in the angles of junction of the arms beneath; arms (simple) formed 
 of alternating ossicula." 
 
 Genoholotype. " Species Unica. Protaster sedgwickii. Forbes." 
 
 Original description of P. sedgwickii. "The disk is circular, and 
 shaped like that of an OpTiiura. The arms are five in number, very 
 narrow, equidistant, and similar. 
 
 "The upper and under surfaces of the disk were covered by small, 
 similar, more or less regular, polygonal or crescentic plates, imbri- 
 cated in scale-fashion, and having punctated surfaces. Those of 
 the under side of the 
 body are smaller and 
 more regular than 
 those of the upper. 
 The mouth is cen- 
 tral, and rather small 
 in proportion to the 
 disk. The buccal ap- 
 paratus is composed 
 of ten parts or proc- 
 esses, arranged in 
 pairs; half of each 
 springs from the 
 origin of each arm in 
 a diverging manner, 
 and meets the corre- 
 sponding half to form 
 a lanceolate tooth- 
 
 1 i lr <* rkrrn'antirkn FlG> 22. ORAL SKELETON OF PAI^EUBA NEGLECTA, MUCH ENLARGED, 
 
 u j t? i o II, AFTER JAEKEL> at AMB ULACBALIA; ad, ADAMBULACEALIA. 
 
 deeply indenting the 
 
 cavity of the mouth. Of how many separate ossicles each of the 
 buccal processes was composed the specimen affords but very indis- 
 tinct indication. They seem to affect a slightly falcate form at their 
 extremities. The arms were composed of alternating, somewhat 
 quadrate ossicula, the sides of which were deeply indented supe- 
 riorly, in order to form spiniferous crests. The spines were appar- 
 ently short, and not equal in length to the length of an ossicle, obtuse, 
 and few in a row. The under surfaces of the brachial ossicula were 
 not indented laterally. The central portions of the upper surfaces 
 of the brachial ossicles were hollowed out slightly, and the sutures 
 between them deeply impressed. About 12 of the brachial ossicles 
 were imbedded in the disk, and the parts of the dorsal surface of 
 the latter, corresponding to the arms and central skeleton, do not 
 present traces of scales, a feature seen in existing Euryales. 
 
226 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 "The dimensions of Prof. Sedgwick's specimens are as follows: 
 "Breadth of disk, 8/12ths inch. 
 "Average breadth between arms, 5/12ths inch. Breadth of 
 
 an arm, at its junction with the body, 1/1 2th inch. 
 "Locality and, geological horizon. Silurian, from Ludlow rocks 
 at Docker Park, near Kendal, Westmoreland (specimen figured), 
 associated with Encrinites, and at Benson Knot, also near Kendal, 
 hi hard sandstones, full of characteristic Ludlow fossils." 
 
 Gregory restudied this genus and in 1897 defined it as follows: 
 
 "Protasteridse with a well-marked disk; long, tapering, very flexible 
 
 arms. Some of the adambulacral ossicles are Y-shaped. Scales of 
 
 the disk fairly large. Type species. Protaster sedgwickii, Forbes." 
 
 Gregory remarks that "Forbes's figures of the arm-structures are 
 
 not satisfactory," 
 
 figure 23 as drawn 
 by the former. 
 This illustration 
 a b shows each set of 
 
 FIG. 23. AMBULACHALIA AND ADAMBULACRALIA OF PROTASTEB SEDGWICKII, 
 AFTER GREGORY, a, NEAR THE DISTAL END; 6, IN THE MIDDLE; c, AT ambulacralia dif- 
 
 THE PROXIMAL END. THESE DIFFERENCES ARE DUE TO PRESERVATION. 
 
 tion thought to be due to preservation and adhering rock rather than 
 to structure (see fig. 28, on p. 242). 
 
 Madreporite probably abactinal in position. 
 
 In regard to the term Encrinaster, see Encrinaster (Aspidosoma) , 
 page 242. 
 Protaster has the following species : 
 
 P. sedgwickii Forbes. Ludlow of England. 
 P. biforis Gregory. Wenlock of Wales. 
 P. groomi Sollas and Sollas. Ordovicic of England. 
 ' P. (?) whiteavesianus Parks. Black River. 
 
 P. (t) salteri (Salter). Ordovicic of Wales. 
 . P. (?) stellifer Ringueberg. Rochester. 
 
 PROTASTER BIFORIS Gregory. 
 
 Text figs. 24, 25. 
 
 Protaster biforis GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1032, figs. 
 2, 3 on p. 1033. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, 
 vol. 63, 1910, p. 238. 
 
 Original description. "Disk fairly large; interbrachial outlines 
 concave. The syngnaths are simple, prominent, and stout. The 
 ambulacral ossicles consist of a thick body and a stout curved wing. 
 The distal margin of the ossicles is notched by a depression for a 
 ventral muscle-field, which also cuts into the proximal margin of the 
 adjoining ossicle. Owing to these muscular depressions the arm has 
 apparently two series of pores. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 227 
 
 "The adambulacral ossicles are massive and taper slightly to their 
 distal ends; they are closely attached and form a regular series of 
 marginal plates. 
 
 "Arms very flexible. 
 
 "Dimensions: 
 
 Length of longest arm 18 mm.+a; 
 
 Diameter of arm at the base 2.5 mm. 
 
 Diameter of arm near the distal end 1 mm. 
 
 Diameter of mouth 1.5 mm. 
 
 Length of syngnath 1 mm. 
 
 Width of ambulacral furrow at edge of disk 1.25 mm. 
 
 "Distribution. Wenlock Shale, Castell Dinas, Bran, near Llan- 
 gollen," Wales. Museum Practical Geology, London. 
 
 if 
 
 24 25 
 
 FIGS. 24 AND 25. PROTASTER BIFOEIS. AFTEE GEEGOEY. 24, AMBULACRALIA AND ADAMBULACEAUA. 
 25, O, OUTLINE OF THE DISK AND AEMS; 6, A PAIE OF SYNGNATHS. 
 
 PROTASTER GROOMI Sollas and Sollas. 
 
 Protaster groomi SOLLAS and SOLLAS, Philos. Trans. Roy. Soc. London, ser. B 
 
 vol. 202, 1912, pp. 223, 224. 
 Occurs in the Middle Ordovicic of Shropshire, England. 
 
 PROTASTER (?) WHITEAVESIANUS Parks. 
 
 Protaster whiteavesianus PARKS, Trans. Canadian Inst., vol. 8, 1908, p. 368, 
 
 figs. 1-6. 
 
 This is a large form with a, disk 15 mm. across and with rays 60 mm. 
 long. It is described in too much detail to quote here. The ambula- 
 cralia are distinctly alternate and boot-shaped. 
 
 Formation and locality. In the Lower Trenton (Kirkfield), at 
 Kirkfield, Ontario, Canada. The cotypes (five) are in the University 
 of Toronto (No. 638 T.). 
 
 PROTASTER (?) SALTERI (Salter). 
 
 Ophiura salteri SALTER and SOWERBY, Quart. Journ. Geol. Soc. London, vol. 1. 
 
 1845, pp. 9, 20 (table) (nomen nudum). 
 Protaster salteri WRIGHT, Mon. British foss. Echinod., Oolitic, vol. 2, pt. 1 (Pala>on- 
 
 togr. Soc. for 1861), 1862, p. 33 (nomen nudum). SALTER, Mem. Geol. Surv. 
 
 Great Britain, vol. 3, 1866, p. 289, pi. 23, fig. 3 (is inclined to refer it to 
 
 Tseniaster}. PARKS, Trans. Canadian Inst., vol. 8, 1908, pp. 364, 367. 
 
 Formation and locality. The holotype is from the Ordovicic, near 
 Cerrig-y-Druidion on the Holyhead road, Wales. 
 
228 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 PROTASTER (?) STELLIFER Ringueberg. 
 
 Protaster stellifer RINGUEBERG, Bull. Buffalo Soc. Nat. Sci., vol. 5, 1886, p. 7, pi. 1, 
 fig. 2. 
 
 Generic relations not established. 
 
 Original description. "Disk of medium size, flat, circular, slightly 
 flexible, distinct from the rays on the dorsal side, and has on that 
 side a quinque-dentate, stellate, central elevation, which again has 
 a central, stellate depression of about one-half the lateral extension 
 of the stellate elevation upon which it is impressed. The points of 
 the star-like figure are opposite the several rays and extend about 
 two-thirds across the disk. 
 
 "Surface finely granulose. Rays slender, almost imperceptibly 
 tapering in the upper half of their known length; rounding on the 
 dorsal side, with two rows of regular, quadrilateral, alternating 
 [ambulacral] plates which can with difficulty be made out, and which 
 have a fine granulose [integumentary] surface resembling the surface 
 of the disk; opposite each transverse suture there is a corresponding 
 linear depression across the surface of the opposite plate on the other 
 side of the median suture, which at first sight gives the impression 
 that the ray is composed of opposite plates of only one-half the real 
 length. 
 
 "Ventral side with ten short, oral plates which are slightly sepa- 
 rated below, and meet at the discal surface, where they are rounded. 
 
 "Ambulacral series long, regularly quadrilateral; alternately 
 arranged. 
 
 "Adambulacrals indistinct in the only specimens found showing 
 the ventral surface. 
 
 "Marginal series slightly imbricating; spiniferous; spines rather 
 short." 
 
 Formation and locality. Three specimens were collected in the 
 Rochester shale of the Siluric at Lockport, New York. They are in 
 the author's collection. Two other fine specimens were found by C. 
 J. Sarle at Lockport and are now at Yale University. Another good 
 specimen is in the Walker collection of the University of Toronto 
 (No. 1007) ; it was found at Grimsby, Ontario. 
 
 Genus ALEPIDASTER Meek. 
 Plate 36, fig. 4; text fig. 26. 
 
 AlepidasterM-EEK, Amer. Journ. Sci., ser. 3, vol. 4, 1872, p. 275; Geol. Surv. Ohio, 
 
 Pal., vol. 1, 1873, p. 68, at end of specific description. 
 Protasterina ULRICH, Journ. Cincinnati Soc. Nat. Hist., vol. 1, 1878, p. 95. J. F. 
 
 JAMES, Journ. Cincinnati Soc. Nat. Hist., vol. 18, 1896, p. 139 (genoholotype, 
 
 P. fimbriata Ulrich). 
 
 Original description. "The only specimen I have seen that is 
 certainly known to belong to this species [P. ? granuliferus] is very 
 
REVISION OF PALEOZOIC STELLEROIDEA. 
 
 imperfect, being merely an incomplete disk, and the inner ends of the 
 rays. It does not conform to the characters of Protaster given in 
 Prof. Forbes' s diagnosis, in all respects, since its disk, especially on 
 the upper side, is covered by an integument composed of a vast 
 number of very minute grains of calcareous matter, instead of dis- 
 tinct imbricating scales. It is therefore not improbable that perfect 
 specimens would show other characters that would warrant the 
 establishment of a new genus or subgenus for such forms, in which 
 case the name Alepidaster might be applied to the group." 
 
 Genoholotype. Protaster (?) granuliferus Meek. 
 
 Original description of 
 Protasterina. "Rays five, 
 slender, flexible, and ex- 
 tending much beyond a cir- 
 cular and minutely granu- 
 lar disk, which is provided 
 with short, slender, and 
 outwardly directed spines; 
 inner ray pieces [ambu- 
 lacra] regularly alternating, 
 of an hour-glass shape, and 
 interlocking along the me- 
 dian line, which is there- 
 fore not straight but zig- 
 zag ; outer ray pieces elon- 
 gated [adambulacrals or 
 side plates], directed ob- 
 liquely outwards, so as to 
 partly overlap each other; 
 two rows of large pores between the inner [ambulacral] and outer 
 [side plates] ray pieces; in the type-species these pores appear to have 
 been occupied by loosely-fitting subpyramidal plates, some of which 
 have a deep depression in the top, as though they were perforated; 
 their 1 true nature, however, is very uncertain. Oral pieces ten, each 
 pair being formed by two of the outer ray pieces. Type, P. fimbriata." 
 
 When the original material of Alepidaster and Protasterina is re- 
 studied, it may be shown that the latter is not a synonym of the 
 former, but at present the writer does not see any generic differences. 
 
 Alepidaster is easily distinguished from Protaster, not only by its 
 greater geologic age, but also in that its disk is minutely granular 
 and spiniferous while that of the latter is scale-bearing. Further, 
 when the exact shape of the ambulacrals is determined, it is probable 
 that other differences 'will be found there. Particular attention 
 should be paid to Ulrich's statement that in Protasterina the podial 
 openings " appear to have been occupied by loosely fitting, sub- 
 
 FIG. 26. DIAGRAMS OF ALEPIDASTER GRANULIFERTJS (MEEK). 
 DRAWN BY E. O. ULRICH FROM A SPECIMEN IN THE UNITED 
 STATES NATIONAL MUSEUM. A, ACTINAL VIEW OF RAY 
 PLATES. B, SAME FROM ABACTINAL SIDE. C, SECTION 
 
 THROUGH RAY. D, SlDE-PLATE FROM THE INSIDE AND IN 
 
 SECTION. 
 
230 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 pyramidal plates/' If these extra plates existed, Protasterina will 
 be a good genus, differing not only from Protaster, but also from 
 Alepidaster. 
 
 Apparently no one has actually seen the abactinal side of the rays. 
 The writer also fails to see it in the few specimens studied. It would, 
 therefore, seem that there are no dorsal plates and that the dorsal 
 covering is integumentary or finely granular. 
 This genus contains the folio whig species : 
 
 A. (?), new species. Trenton. 
 
 A. granuliferus (Meek). Bichmondian. 
 
 A.flexuosus (Miller and Dyer). Eden and Maysville. 
 
 A. miamiensis (Miller). Bichmondian (Waynesville) . 
 
 ALEPIDASTER (?), new species. 
 
 In the Walcott collection at Harvard University there are three 
 specimens (Nos. 28, 29, 30) of a "Protaster" that probably will prove 
 to be new. They are from the Trenton limestone at Trenton Falls, 
 New York. 
 
 ALEPIDASTER GRANULIFERUS (Meek). 
 Text fig. 26. 
 
 Protaster ? granuliferus (Alepidaster at end of description) MEEK, Amer. Journ. 
 Sci., ser. 3, vol. 4, 1872, p. 274; Geol. Surv. Ohio, Pal., vol. 1, 1873, p. 68, 
 pi. 3 bis, figs. 8a, 86. J. F. JAMES, Journ. Cincinnati Soc. Nat. Hist., vol. 18, 
 1896, p. 138. PARKS, Trans. Canadian Inst., vol. 8, 1908, p. 368. 
 
 Original description. "Disk small, apparently circular; rays rather 
 slender, and of unknown length. Dorsal surface of disk and rays 
 covered by an integument composed of innumerable minute grains 
 of calcareous matter. Ventral side of disk not well exposed in the 
 specimen but apparently provided, in the interradial spaces, with 
 minute spines directed outward. Oral pieces not well exposed in 
 the specimen. Arm pieces [ambulacrals] regularly alternating, but 
 apparently rectangular at their inner ends, and not interlocking along 
 the minute mesial impressed line, longer transversely than in the 
 direction of the length of the rays; each largely excavated at its 
 anterior outer end so as to form a large pore, or porelike depression, 
 and divided transversely by a furrow into two parts, the anterior of 
 which is very short, and the posterior longer, and marked by a minute 
 [muscle] pit at its inner end; about eight or nine of these pieces in 
 each range of each ray included within the margin of the disk. Outer 
 arm [or ray] pieces (adambulacral of some) smaller than those of the 
 the inner ranges, and placed edge upward, with an oblique outward 
 direction so as to imbricate outward or toward the extremities of 
 the rays, each bearing one or more minute articulating spines. 
 
 " Breadth of disk, about 0.43 inch; breadth of arms at their inner 
 ends, 0.10 inch." 
 
REVISION OF PALEOZOIC STELLEROIDEA. 231 
 
 Formation and locality. In the lower part of the Richmondian at 
 Moore's Hill, Indiana. It was found by C. B. Dyer, and is now in 
 the Museum of Comparative Zoology, Harvard University (No. 21). 
 
 ALEPIDASTER FLEXUOSUS (Miller and Dyer). 
 Plate 36, fig. 4. 
 
 Protaster flexuosus MILLER and DYER, Journ. Cincinnati Soc. Nat. Hist., vol. 1, 
 1878, p. 31, pi. 2, figs. 1, la. MILLER, N. Amer. Geol. Pal., 1889, p. 276, 
 fig. 409. PARKS, Trans. Canadian Inst., vol. 8, 1908, p. 368. 
 
 Protasterina ("Protaster" lapsus) fimbriata ULRICH, Journ. Cincinnati Soc. Nat. 
 Hist., vol. 1, 1878, p. 95, pi. 4, figs. 9-9c. 
 
 Protasterina flexuosa and P. fimbriata J. F. JAMES, Journ. Cincinnati Soc. Nat. 
 Hist., vol. 18, 1896, pp. 139, 140. 
 
 Original description of P. flexuosus. " The disk is composed of very 
 thin, small plates, the order of arrangement of which is not deter- 
 mined. The specimens examined differ in size, and show the disk 
 varying in diameter from one-quarter to one-half an inch. The rays 
 were very flexuous when living, and are found winding and turning 
 and thrown in different directions in different specimens. 
 
 "Four series of plates are seen upon the dorsal side of each ray 
 near the disk. The two inner series [the ambulacrals seen from the 
 dorsal side] form an angular ridge, each plate is concave at the uniting 
 surface, the arrangement is alternate, and the appearance, therefore, 
 of the top of the ray, is something like the alternate arrangement of 
 two series of hourglasses. The outer series, or marginal [side] plates, 
 are spinous, the spines directed toward the point of the ray. A 
 weathered ray shows three series of pores one row between the inner 
 series of plates, and one between the marginal plates and inner series, 
 upon each side of the ray [probably the plates are worn through by 
 weathering; there should be but two rows of podial openings, the 
 others being either muscle pits or weathering holes]. The plates are 
 a little the longest in the direction of the length of the ray, and in 
 this direction there are about four to the line. The rays cross the 
 disk on the dorsal side and unite near the center of it, but the speci- 
 men figured, Plate II, figure 1, has this part of the rays removed. 
 Plate II, figure la, illustrates the ventral side of a specimen, which 
 is too indistinct to show the arrangement of the plates. Small 
 pieces, showing the ventral side of the rays, from other specimens, 
 have two rows of spines springing from the marginal plates on each 
 side of the rays." 
 
 Original description of P. fimbriata. 1 "Disk of medium size, circu- 
 lar. Dorsal side of disk, and rays to margin of disk, covered with a 
 granular integument. Ventral surface of disk provided with a large 
 number of outwardly directed, short and slender spines. Oral 
 
 i Ulrich still maintains that this species is a good one and distinct from P. flexuosus. 
 
232 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 pieces 10, subrhomboidal in outline, arranged in pairs, each pair 
 being formed of two of the marginal series of ray plates ; on the lower 
 inner edge there are five spines, and extending from each pair, 
 over the mouth, is a bundle of rather long ones. 
 
 "Rays apparently very flexible, contracted toward the mouth; 
 six series of plates are exposed on the ventral side of each ray. The 
 two middle series [ambulacrals] alternate regularly, and interlock 
 along the mesial line; they are about twice as long in the direction 
 of the ray, than measuring transversely; each piece is contracted 
 in the middle on the inner side to admit the wide ends of the two 
 pieces immediately opposite, and on the outer side to form a pore- 
 like impression, between them and the outer series of plates; four 
 [five or possibly six] of these plates in each range of each ray are 
 included within the disk, and the series terminate abruptly at a 
 distance of one and a half lines from the inner end of the oral plates; 
 from the margin of the disk to the extremity of the ray there are 
 about 16 pieces in each range. The pores mentioned above, are 
 occupied by a series of loosely fitting, obtusely conical or pyramidal 
 plates, some of which distinctly show a deep depression in the top, 
 and may have been perforated. Outer or marginal pieces [side 
 plates] flat, placed on edge, and directed obliquely outward so as 
 to overlap each other; the two free edges, that is, the one toward 
 the point of the rays and the one seen on the ventral surface, are 
 lined with from 10 to 12 short club-shaped spines, varying somewhat 
 in length. The marginal [side plates] and middle [ambulacral] series 
 of plates articulate by means of corresponding prolongations from 
 the sides of the plates. These prolongations arise from near that 
 end of the plate which is directed toward the mouth. 
 
 " Dorsal side of rays composed of two rows of alternating and 
 interlocking plates, which near the disk are very deeply sculptured 
 and about as wide as long, becoming gradually less excavated, and 
 longer in proportion to the width, toward the point of the rays; on 
 each side they articulate with the upper edge of the oblique mar- 
 ginal series of plates [these are the ambulacral plates seen from the 
 dorsal side, either because there were no dorsal plates or because 
 there was an integument]. 
 
 " Breadth of disk, 0.60 inch; breadth of arm at margin of disk, 
 0.16 inch; length of same from oral plates, 0.88 inch. This species 
 is related to Protaster flexuosus" 
 
 Formation and locality. "This species has been found at differ- 
 ent elevations from near low-water mark in the Ohio River [that 
 is, in basal Eden] to the top of the hills at Cincinnati," in the upper 
 Maysville beds. The type-specimens of P. flexuosus were found 
 by Mr. C. B. Dyer and are now in the collection of Harvard Uni- 
 versity (Nos. 17, 18). Those of P. fimbriata were obtained by 
 
REVISIOH OF PALEOZOIC STELLEEOIDEA. 233 
 
 Ulrich in the lower Eden at about 100 feet above low-water mark 
 in the Ohio River at Covlngton, Kentucky. This material is now 
 in the Ulrich collection of the United States National Museum. 
 Other poor specimens from a still lower level in the Eden and asso- 
 ciated with Triarihrus are from the first ward, eastern Cincinnati. 
 Two specimens are at Yale University. 
 Cat. No. 60615, U.S.N.M. 
 
 ALEPIDASTER MIAMIENSIS (Miller). 
 
 Protaster miamiensis MILLER, Journ. Cincinnati Soc. Nat. Hist., vol. 5, 1882, 
 p. 116, pi. 5, figs. 6-66. J. F. JAMES, Journ. Cincinnati Soc. Nat. Hist., 
 vol. 18, 1896, p. 138. PARKS, Trans. Canadian Inst., vol. 8, 1908, p. 368. 
 
 Original description. "This species is large, with a proportion- 
 ally small disk. A specimen having a disk four-tenths of an inch 
 in diameter, has rays an inch in length. Five specimens have 
 been examined, all showing the ventral side. The dorsal side is 
 unknown. Only that part of the disk between the rays is visible 
 in any of the specimens, and the plates are so anchylosed together 
 that no special definition of them can be given. The rays are long 
 and coarser and stronger than usual in this genus, though they were 
 quite as pliable and flexuous when living as others. Two series of 
 subquadrangular plates, or ambulacral ossicles, alternating with 
 each other, constitute the bottom of each ambulacral furrow; these 
 are bordered by spinous adambulacral plates, which terminate at 
 the angles of the mouth in only five oral plates." 
 
 Formation and locality. In the Richmond formation, about 
 Waynesville, Ohio. The specimens are in the Harris collection 
 of the United States National Museum. 
 
 Cat. No. 40886, U.S.N.M. 
 
 Genus GREGORIURA Chapman. 
 
 Gregoriura CHAPMAN, Proc. Royal Soc. Victoria, n. ser., vol. 19, 1907, p. 24, pi. 6, 
 fig. 1; pi. 8, figs. 1, 3. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wies- 
 baden, vol. 63, 1910, p. 238. 
 
 Original definition. "A Protasterid in which the usual boot- 
 shaped ambulacrals are laterally developed, and modified into a 
 subtriangular form. Ossicles on each side of the ambulacral canal 
 subalternate, excepting at the junction with the mouth frames, 
 where they are parallel. Adambulacral ossicles narrow, slender, 
 extending laterally in a line with the proximal border of the ambu- 
 lacral ossicle. Spine-bearing plates, slender, at right angles to the 
 adambulacrals, carrying (in the genotype) two conspicuous spines. 
 Oral skeleton having jaw plates three-fourths the length of the 
 mouth frames; teeth thick and prominent. No traces of a disk 
 preserved in the specimen on which the genus is founded. Arms 
 very slender and very flexible." 
 
234 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Genoholotype and only species. G. spryi Chapman (same references 
 as above). 
 
 Found in the Siluric (Melbournian) shale at South Yarra, Vic- 
 toria, Australia. 
 
 Genus BUNDENBACHIA Sturtz. 
 
 Text fig. 27. 
 
 Bundenbachia STURTZ, Palaeontographica, vol. 32, 1886, p. 83; vol. 36, 1890, 
 p. 216. GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1033, fig. 4 
 on p. 1034. PARKS, Trans. Canadian Inst., vol. 8, 1908, p. 367. SCHON- 
 DORF, Palseontographica, vol. 57, 1910, p. 57. 
 
 Rays five, short, basally wide, terminally pointed or blunt. Disk 
 large, soft and delicate, with concave interradial margins. 
 
 Abactinally the disk is covered with symmetrical scales, and 
 medially there is a pentamerous rosette (the oral armature squeezed 
 through), from the points of which the rays originate. Rays covered 
 
 with a granular integument. 
 
 Gregory states : "Ambulacral ossicles with 
 a dumbbell-shaped body and thin tapering 
 wing. The body of the ossicle is apparently 
 divided into two pieces by a transverse de- 
 pression. The adambulacral plates are small 
 an( * narrow > an d support a triangular spine- 
 bearing plate. [There is only one plate here, 
 
 FIG. 27.- VENTRAL ABM STRTTC- L J > 
 
 TURK OF BUJNDENBACHIA. EN- the adambulacral. I here are no lateral 
 
 LARGED. AFTER GREGORY. pieces as in Ophiuroidea.] 
 
 "The syngnaths are curved, narrow bars." 
 Genoholotype and only species. B. beneckei Sturtz. 
 Remarks. " Bundenbachia differs from Protaster by the irregular 
 
 nature and soft plating of the disk, by the presence of spine-bearing 
 
 plates attached to the adambulacral ossicles, and by the different 
 
 form of the ambulacral ossicles." (Gregory.) 
 
 BUNDENBACHIA BENECKEI Sturtz. 
 
 Bundenbachia beneckei STURTZ, Palseontographica, vol. 32, 1886, p. 83, pi. 8, figs. 7, 
 7a; pi. 9, figs. 1, la. GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 
 1034, figs. 4. 
 
 Formation and locality. Occurs in the Lower Devonic roofing 
 slates of Bundenbach, Germany. 
 
 Genus PAL^EOPHIOMYXA Sturtz. 
 
 Palseophiomyxa STURTZ, Verb, naturh. Ver. preuss. Kheinl., etc., vol. 56, 1900, 
 
 p. 202. 
 Palxophwmyxidx STURTZ, Verh. naturh. Ver. preuss. Kheinl., etc., vol. 56, 1900, 
 
 p. 202. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 
 1910, p. 235. 
 
 Genoholotype and only species. P. grandis (Sturtz). 
 
REVISION OF PALEOZOIC STELLEROIDEA. 235 
 
 PAL^OPHIOMYXA GRANDIS (Sttirtz). 
 
 Bundenbachia grandis STURTZ, Palaeontographica, vol. 32, 1886, p. 84, pi. 9, figs. 
 
 2, 2a, 3, 3a. 
 Palseophiomyxa grandis STURTZ, Verh. naturh. Ver. preuss. Rhei.nl., etc., vol. 56, 
 
 1900, pp. 196, 202. 
 
 Formation and locality. Lower Devonic roofing slates of Bun- 
 denbach, Germany. 
 
 Cat. No. 59388, U.S.N.M. 
 
 Family PAL^OPHIURID^E Gregory. 
 
 Palseophiuridx GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1034; Treat. 
 Zool., vol. 3, Echinoderma, 1900, p. 274. SCHONDORF, Jahrb. nassauisch. 
 Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 237. 
 
 "Lysophiuras in which the [alternate] ambulacral ossicles consist 
 of a bar-shaped or subquadrate 'body' without wings. " (Gregory, 
 1900.) 
 
 Remarks. This family differs from the Protasteridse in "having 
 the ambulacral ossicles longer than wide, and never divided trans- 
 versely by muscular depressions. The ambulacral ossicles are either 
 bar-shaped or thickened to a subquadrate form. They are never 
 boot-shaped." (Gregory, 1897.) 
 
 Schondorf states that Gregory established the families Protas- 
 terida6 and Palaeophiuridae on the form of the ambulacralia. He 
 says: "The first family has boot-shaped, and the second family 
 bar-shaped or subquadrate ambulacrals. The form of the latter is 
 nothing more than a poor development of the boot-shaped type of 
 ambulacrals. Accordingly the second family has no value and is 
 to be withdrawn." In addition the forms of Sturtzura have boot- 
 shaped ambulacrals, and these "are so little alternate in arrangement 
 that their alternation appears to me more than questionable." 
 (Schondorf, 1910.) 
 Contains the following genera: 
 Pal&ophiura Stiirtz. 
 Sturtzura Gregory. 
 Eugasterella, new name. 
 Ptilonaster Hall. 
 
 Genus PAL^EOPHIURA Stlirtz. 
 
 Palxophiura STURTZ, Palseontographica, vol. 36, 1890, p. 233. GREGORY, Proc. 
 Zool. Soc. London for 1896, 1897, p. 1034. 
 
 " Palaeophiuridse with the disk surrounded by rod-shaped marginal 
 ossicles. The ambulacral ossicles are rods lying parallel to the arm. " 
 (Gregory.) 
 
 Genoholotype and only species. P. simplex Sturtz (citations as 
 above). Lower Devonic, Bundenbach, Germany. 
 
236 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Genus STURTZURA Gregory. 
 
 Sturtzura GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1034. SCHON- 
 DORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, pp. 215, 237. 
 
 fRhodostoma SOLLAS and SOLLAS, Philos. Trans. Roy. Soc. London, ser. B, vol. 
 202, 1912, p. 225 (genoholotype, Protaster leptosoma Salter.) 
 
 " Palseophiuridse having thick, subquadrate, ambulacral ossicles 
 and narrow adambulacral plates. The disk is fragile, and its plates 
 are small and thin: it has no marginal plates. The mouth-frames 
 are narrow and separate. 
 
 "Distribution. Silurian, England and Australia." 
 
 Genoholotype. Protaster brisingoides Gregory. 
 
 "Remarks. This genus differs from PalseopTiiura, as the ambu- 
 lacral ossicles are thick and subquadrate, instead of being in the 
 form of narrow bars; also by the absence of the strong marginal 
 plates round the disk." (Gregory.) 
 
 Chapman in 1907 refers the genotype back to Protaster, adding: 
 "In consequence of this determination Sturtzura leptosoma may now 
 be considered as the type of the genus." This is in violation of the 
 rules of nomenclature and the generic name will stand or fall on the 
 basis of Protaster brisingoides. 
 
 Schondorf states: "The ambulacra of S. brisingoides are not 
 at all bar-shaped or subquadrate, if the figures of Chapman ( 1907, 
 pi. 8, fig. 2) are correct, but are also essentially boot-shaped and 
 alternate in arrangement. S. leptosoma also has alternating ambu- 
 lacra. Their identity with LapwortTiura miltoni ranges them with 
 the Auluroidea, where S. brisingoides undoubtedly also belongs. 
 That this form and with it also the genus Sturtzura is to be retained 
 as valid is very questionable, but the final answer may as well wait 
 until the originals are restudied. In any event it is plain that 
 both forms can not belong to the Lysophiurse." 
 
 Contains the following species: 
 S. brisingoides (Gregory). Siluric of Australia. 
 S. leptosoma (Salter). Ludlow of England. 
 S. leptosomoides Chapman. Siluric of Australia. 
 
 STtJRTZURA BRISINGOIDES (Gregory). 
 
 Tseniaster australis McCoY, see CHAPMAN 1907, p. 23 (nomen nudum). 
 
 Protaster brisingoides GREGORY, Geol. Mag., dec. 3, vol. 6, 1889, pp. 24-27, fig. 1. 
 
 CHAPMAN, Proc. Roy. Soc. Victoria, n. ser., vol. 19, 1907, p. 22, pi. 6, 
 
 fig. 2; pi. g; fig. 2. 
 Sturtzura brisingoides GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1034. 
 
 Formation and locality. From Siluric sandstones at Moonee Ponds 
 Creek, Flemington, near Melbourne, Australia. The type-material 
 is in the British Museum (Natural History), London. Other speci- 
 mens from the same locality and from the parish of Yering, Upper 
 Yarra district. Victoria, are in the National Museum at Melbourne. 
 
REVISION" OF PALEOZOIC STELLEEOIDEA. 237 
 
 STtfRTZURA LEPTOSOMA (Salter). 
 
 Protaster leptosoma SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 331, 
 pi. 9, fig. 5. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 
 (Palaeontogr. Soc. for 1861), 1862, p. 33. QUENSTEDT, Petrefactenktmde 
 Deutschlands, vol. 4, 1876, p. 133, pi. 95, fig. 12. STURTZ, Palseonto- 
 graphica, vol. 32, 1886, p. 79; N. Jahrb. fiirMin., etc., 1886, vol. 2, p. 148. 
 
 Sturtzura leptosoma GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1035. 
 CHAPMAN, Proc. Roy. Soc. Victoria, n. ser., vol. 19, 1907, p. 26, pi. 8, fig. 5 . 
 SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, 
 p. 215. 
 
 Rhodostoma leptosoma SOLLAS and SOLLAS, Philos. Trans. Roy. Soc. London, 
 ser. B, vol. 202, 1912, p. 223, text fig. 40, pi. 9, figs. 3, 4. 
 
 Formation and locality. Common in the Siluric, Ludlow forma- 
 tion, at Leintwardine, Shropshire, England. 
 
 Remarks. Schondorf says S. leptosoma is but a miniature edition 
 of Lapworthura miltoni, both forms being completely identical. The 
 disk margin is not convex but concave between the radii. 
 
 STURTZURA LEPTOSOMOIDES Chapman. 
 
 Sturtzura leptosomoides CHAPMAN, Proc. Roy. Soc. Victoria, n. ser., vol. 19, 
 1907, p. 26, pi. 7, figs. 1, 2; pi. 8, fig. 4. 
 
 Formation and locality. In the Siluric (Melbournian), Moonee 
 Ponds Creek, Flemington, near Melbourne, Australia. 
 
 Genus ETJGASTERELLA, new name. 
 
 Eugaster HALL (not Eugaster Seville 1839, Orthoptera), Twentieth Rep. N. Y. 
 State Cab. Nat. Hist., 1868, p. 290; rev. ed., 1868=1870, p. 332. ZITTEL, 
 Handb. Pal., vol. 1, 1879, p. 444. STURTZ, N. Jahrb. fur. Min., etc., 1886, 
 vol. 2, p. 151. MILLER, N. Amer. Geol. Pal., 1889, p. 244. STURTZ, Verh. 
 naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, p. 20. GREGORY, Proc. 
 Zool. Soc. London for 1896, 1897, p. 1035. 
 
 Eugasterella SCHUCHERT, Fossilium Catalogus, Animalia, pt. 3, April, 1914, 
 p. 19. 
 
 Original description. "Body stellate, consisting of a central alated 
 disk, and five long, slender, somewhat flexuous rays. Disk composed 
 of small, polygonal tuberculose or subspinose plates on the ventral 
 side. Rays consisting of a double series of alternating subquadrate 
 ambulacral ossicles, and a series of curved adambulacral plates 
 bordering the grooves, and forming the margin of the ray; the outer 
 ends overlap the edge of the next plate in advance. Oral plates ten, 
 arranged in pairs, forming the terminal plates of the adambulacral 
 ranges. Pores large, arranged in two rows in each ray; penetrating 
 the ray at the junction of the ambulacral and adambulacral plates 
 hi such a manner that four different plates border each perforation. 
 Adambulacral and disk-plates bearing spines. Dorsal surface 
 unknown." 
 
 Genoholotype. E. logani (Hall). 
 
238 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Gregory comments on this genus as follows : 
 
 "Palseophiuridae in which the ambulacral ossicles are subhep- 
 tagonal in form, the central suture along the arm being zigzag, while 
 the outer angles of the ossicles are cut away for the reception of the 
 podia. The adambulacral ossicles have a flat base, and thence bend 
 forward crescentically. The mouth frames are massive, and those 
 of each pair meet along the middle line of the oral angle. 
 
 "This genus I only know from Prof. James Hall's figures, and, in 
 spite of their clearness, I feel much doubt as to the wisdom of diag- 
 nosing it from these alone. Its affinities are clearly with the Palse- 
 ophiuridae, but it approaches the Protasteridse in one respect, for, 
 owing to the deep depressions in the outer angles of the ambulacral 
 ossicles, the outer side forms a short rudimentary wing. The genus 
 differs from all the Protasteridae by the absence of a muscular groove 
 across the ambulacral ossicles. 
 
 " Among the Palseophiuridse it differs from Palseophiura by the 
 absence of marginal ossicles, and from Sturtzura and T&niura by 
 the massive nature of the mouth frames." 
 
 Contains : 
 
 E. logani (Hall). Hamilton. 
 
 E. (?) concinna (Ringueberg) . Rochester. 
 
 EUGASTERELLA LOGANI (Hall). 
 
 Eugaster logani HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 290; 
 rev. ed., 1868=1870, p. 333, pi. 9, figs. 7, 8. 
 
 Original description. "Body stellate, with a small disk and long 
 attenuate fiexuose rays. Disk composed of numerous small poly- 
 gonal plates with radiated surfaces; the diameter, measured from the 
 sinus to its extension on the opposite ray, is about half as great as the 
 length of the ray measured from the center of the disk. Rays, as seen 
 from the ventral side, narrow, attenuate, with the ambulacral plates 
 curving, and near the base of the rays a little wider than long, and 
 toward the extremities longer than wide, with a strong elevated 
 transverse ridge. There are about eight pairs of plates inclosed 
 within the limits of the disk. Pores penetrating the interstices 
 near the outer extremities of the plates, while near the inner end there 
 is a depression or pit resembling a partially excavated pore. The 
 adambulacral plates as seen from below are extremely narrow and 
 very convex on their outer surfaces, forming the margins of the ray. 
 Oral plates in pairs, narrow and elongate. 
 
 "This specimen measures, from the center of the disk to the extrem- 
 ities of the rays, about one inch and a half; the widest part of the ray, 
 which is near the margin of the disk, is about an eighth of an inch 
 in diameter. The rays toward their extremities have the ambula- 
 cral field covered by the curving of the marginal plates over the 
 
REVISION OF PALEOZOIC STELLEROIDEA. 239 
 
 groove, and which, closely uniting by their margins, give a tereti- 
 form termination of nearly one-third the entire length, each one 
 having the aspect of a slender crinoidean proboscis. 
 
 " Geological formation and locality. In the Hamilton group, near 
 Fenner, in Madison County, New York. The specimen was collected 
 during the geological survey, and is now in the State Museum." 
 
 EUGASTERELLA (?) CONCINNA (Ringueberg). 
 
 Eugaster condnnus RINGUEBERG, Bull. Buffalo Soc. Nat. Sci., vol. 5, 1886, p. 8, 
 pi. 1, fig. 3. 
 
 This species does not belong to EugastereUa, but until the holo- 
 type is restudied it can remain in this genus. It is from the Kochester 
 shale at Lockport, New York, and is in Dr. Bingueberg's collection. 
 
 Original description. "Disk flat, thin, alated, composed of very 
 fine granulose plates. Rays broad at their base; flattened, rapidly 
 tapering for two-thirds of their length; terminal third attenuate, 
 rounded; plates, if any, undefinable. 
 
 " Dorsal side with four series of plates; two median and two lateral; 
 the transverse sutures dividing the outer series are continuous with 
 every other transverse suture dividing the central series. Medial 
 series with twice the number of plates of the outer, and are raised 
 above them. 
 
 " Sutures depressed. Surface of the plates rounded and finely 
 granular. 
 
 "The lateral series of plates decrease regularly in size after reach- 
 ing the disk until they end in a pronounced elevation formed by the 
 last pair of the medial series at a point about halfway from the 
 border toward the center of the disk measuring at the narrowest 
 part where both series end. Between these elevations the disk 
 has a shallow, stellate depression with the points opposite the several 
 rays. The two outer rows of plates apparently disappear toward 
 the attenuate tip before the median does so. The imperfect cast 
 of the upper part of one of the rays is all that is known of the ventral 
 side; this shows traces of an alternating series of ambulacral plates. 
 
 "Marginal plates spiniferous. 
 
 "Length of ray, one-half inch." 
 
 Genus PTILONASTER Hall. 
 
 Ptilonaster HALL, Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, pp. 291-292; 
 
 rev. ed., 1868=1870, p. 334. LUTKEN, Dansk. Vid. Selsk. Skrift., ser. 5, 
 
 vol. 8, pt. 3, 1869, p. 82. STURTZ, Palseontographica, vol. 32, 1886, p. 83; 
 
 N. Jahrb. fur Min., etc., 1886, vol. 2, p. 152. GREGORY, Proc. Zool. Soc. 
 
 London for 1896, 1897, p. 1036. STURTZ, Verb, naturb. Ver. preuss. Rbeinl., 
 
 etc., vol. 56, 1900, p. 188. 
 Palseocoma MILLER (part), N. Amer. Geol. Pal., 1889, p. 266. 
 
 Original description. "Form and general features as in Eugaster, 
 but differing in the plates of the rays. Rays composed of an ambu- 
 
 Bull. 88 15 16 
 
240 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 lacral, adambulacral and marginal series, which are united by their 
 edges, and apparently not imbricating, the projecting or oblique 
 anterior face of the marginal plates bearing spines which are inclined 
 toward the extremity of the ray. Margins of the rays alated by the 
 extension of the disk. 
 
 "I had originally united this form with Eugaster, but further ex- 
 amination has shown the ray to have a range of marginal plates 
 outside of the adambulacral plates, and I am unable to discover any 
 such feature in Eugaster logani. 
 
 "This and the preceding genus [EugastereTla] belong to the Ophiu- 
 ridae, to which may also be referred the genus Protaster." 
 
 " Note. It is only as these pages are going to press that my atten- 
 tion has been directed to the similarity of structure in the ray of 
 Palseocoma of Salter with that of the proposed genus Ptilonaster. 
 In this illustrated species of the former genus (Palseocoma marstoni) 
 the disk is proportionately larger, and the rays much shorter, while 
 the outer range of plates is represented as imbricating; but being 
 characterized by a double row of plates bordering the ambulacral 
 area, it must be regarded as very nearly related if not generically 
 identical with Ptilonaster. 11 
 
 Gregory comments on Ptilonaster as follows: "This genus is an ally 
 of Eugaster; * * * it is, however, generically distinct. I only 
 know it from Hall's figures, and therefore prefer to leave the prep- 
 aration of a formal diagnosis to an American palaeontologist." 
 
 GenoJwlotype and only species. P. princeps Hall. 
 
 PTILONASTER PRINCEPS Hall. 
 
 Ptilonaster princeps HAT.?., Twentieth Hep. N. Y. State Cab. Nat. Hist., 1868, 
 
 p. 292; rev. ed., 1868=1870, p. 334, pi. 9, fig. 9. 
 Palseocoma princeps MILLER, N. Amer. Geol. Pal., 1889, p. 267. 
 
 Original description. "The specimen consists of the impression of 
 the greater part of one ray, with parts of two others, and intervening 
 portions of the disk. The disk has extended along the ray nearly an 
 inch from the center of the body; the plates are small, and have been 
 furnished with slender spinules. The ray is strong and extremely 
 elongate, having been at least 4 inches in length; its greatest width 
 is outside of the disk, where it measures seven-sixteenths of an inch. 
 The ventral side of the ray shows three series of plates ambulacral, 
 adambulacral, and marginal on each side of the center; of these at 
 least seven ranges have been included within the disk. The ambula- 
 cral plates are a little wider than long, arranged in alternating order. 
 The pores penetrate the interstices near the outer extremity of the 
 plates, while the partial or obsolete pores are obscure, becoming 
 deeper and more conspicuous toward the extremity of the ray. Near 
 the base of the ray there are 12 plates in the length of an inch, 
 
REVISION OF PALEOZOIC STELLEROIDEA. 241 
 
 and 14 plates in the same distance in the central portion, while 
 toward the extremities there are 20 or more in the same space. 
 The marginal plates are subhexagonal, a little longer than wide, and 
 ornamented by long slender spines on their outer margins. 
 
 "This is a much larger and more robust species than the Eugaster 
 logani, and in its entire condition it is the largest star-fish known in 
 our palaeozoic rocks. 
 
 " Geological formation and locality. In the Chemung group. The 
 specimen is in a brownish-gray sandstone, which weathers to a very 
 light ashen color. It was received from Henry S. Randall, Esq., of 
 Cortlandville [New York], in the vicinity of which place it was ob- 
 tained." 
 
 The holotype, an imprint, is in the American Museum of Natural 
 History, No. 4472. 
 
 Family ENCRINASTERID^E, new name. 
 
 Aspidosomatidse GREGORY, Geol. Mag., dec. 4, vol. 6, 1899, p. 351; Treat. Zool., 
 vol. 3, Echinoderma, 1900, p. 250. SCHONDORF, Palseontographica, vol. 57, 
 1910, pp. 55-61. 
 
 Palxgoniasteridce STURTZ (part), Palseontographica, vol. 36, 1890, p. 246 (contains 
 Aspidosomella and Palxaster). 
 
 Lysophiurae with boot-shaped ambulacralia ventrally, and large 
 disks that are bordered with simple marginalia. Apparently only 
 the inframarginals are present. 
 
 As Aspidosoma Goldfuss is preoccupied, this name can no longer 
 be used for the family name. Encrinaster Haeckel replaces it and 
 therefore becomes the base of the family designation. 
 
 The family has the single genus Encrinaster. 
 
 Genus ENCRINASTER Haeckel. 
 Plate 35, text fig. 28, 29. 
 
 Aspidosoma GOLDFUSS (not Aspidosoma Fitzinger 1843, Keptilia), Verh. naturh. 
 Ver. preuss. Rheinl., etc., vol. 5, 1848, pp. 145-146. SIMONOVITSCH, Sitzb. 
 d. mat.-naturw. Classe Akad. Wiss., Wien., vol. 64, Abt. 1, 1871, p. 103. 
 ZITTEL, Handb. Pal., vol. 1, 1879, p. 451, fig. 322. STURTZ, Palseonto- 
 graphica, vol. 32, 1886, p. 92; N. Jahrb. fiir Min., etc., 1886, vol. 2, p. 151; 
 Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 38, 55. SCHON- 
 DORP, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 62, 1909, p. 35; 
 Palseontographica, vol. 57, 1910, pp. 1-63. SPENCER, Mon. Brit. Pal. Aste- 
 rozoa, pt. 1 (Palseontogr. Soc. for 1913), 1914, pp. 23, 24, 49. 
 
 Encrinaster HAECKEL, Gen. Morphologie, vol. 2, 1866, p. Ixvii (genolectotype 
 Aspidosoma arnoldi Goldfuss). 
 
 Diagnosis. Animals attaining large size, with a comparatively 
 large disk. Rays five, more or less petaloid, slender and long, with 
 wide and open ambulacral furrows. 
 
242 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 "Ambulacrals alternating in adjoining columns, while the neigh- 
 boring ambulacrals and adambulacrals are directly opposite each 
 other. The margin of the disk is concave and limited by a row 
 of more or less conspicuous simple [not two rows of superposed] 
 marginalia restricted to the disk. The sides of the free rays are 
 bounded by adambulacrals. These and the ambulacrals are [common 
 to the two sides of the animals, and abactinally are] roughly sculp- 
 
 tured, usually naked, and only 
 in rare cases were adambulacral 
 spines observed. Madreporite 
 actinal, situated near the peri- 
 stome in one of the interradial 
 ~ I " c ' areas nearest to the left adam- 
 
 FIG. 28. AMBULACKALIA AND ADAMBULACRALIA OF bulacrals of a radius. 7 ' (Sch6n- 
 ENCRINASTER ROEMERI, AFTER SCHONDORF. a, AP- A^^t lain "\ 
 
 - ' ' 
 
 PEARANCE OF THE PLATES WHEN CRUSHED OR OB- 
 SCTTRED BY CLAY. EACH AMBULACRAL HERE APPEARS 
 
 AS IF OF TWO PIECES; b, SAME BETTER PRESERVED -,-j- (^ O l r lf 11 ^ G. prm q 
 OR MORE CLEANED; c, THE ACTUAL FORM OF THE ossi- noLai ^ ss - ^ e 
 
 CLES WHEN WELL PRESERVED AND COMPLETELY to the Lower Devonic of Rhenish 
 
 
 Germany. 
 
 Remarks. This well-known genus has been referred to the asterids 
 and to the ophiurids, and though it has most often been placed 
 among the true starfishes, it now appears to belong to neither of 
 these orders. Schondorf has restudied the material with great 
 care and has made out the detail of the ambulacralia, with the 
 result that he erects for Aspidosoma the order Auluroidea. In 
 the work of 1910 cited above the matter is set forth in great detail, 
 and all that can be done here is to direct atten- 
 tion to the more important of his illustrations, 
 with their descriptions, reproduced in part here 
 and on pages 213 and 214. 
 
 As Aspidosoma was first used for a genus of 
 reptiles, it can not, under the rules of nomen- 
 clature, be used again for another group of 
 animals. It is possible, however, under the FIG. 29. ORAL SKELETON OF 
 rules to make use of Enerinaster, but in doing ^7*^"! 
 
 SO the proceeding should first be explained. MUCH ENLARGED. AFTER 
 
 Encrinaster was proposed by Haeckel as fol- SCHONDOEF - 
 lows : In defining his sixth order of asterids, the Crinastra or lily stars, 
 forms that he said already had crinoid characters, he cited as exam- 
 ples of it Protaster sedgwickii and P. = Aspidosoma arnoldi. These 
 forms, he added, are so different from Protaster miltoni ( i that we here 
 separate the former as Encrinaster (E. sedgwickii, E. arnoldi, etc.)." 
 Under ordinary circumstances it would be best to disregard the 
 name because of the inadequate definition, but as Aspidosoma is 
 preoccupied, we are obliged to propose another name to take its 
 
EEVISION OF PALEOZOIC STELLEKOIDEA. 243 
 
 place. The first mentioned genotype of Encrinaster is Protaster 
 sedgwickii, but as this is also the type-species of Protaster, a genus 
 in good standing, we may accept the second named species, Aspido- 
 soma arnoldi. Therefore it is here proposed to replace Aspidosoma 
 Goldfuss (not Fitzinger) by Encrinaster Haeckel, with Aspidosoma 
 arnoldi Goldfuss as the genolectotype. 
 
 ENCRINASTER ARNOLDI (Goldfuss). 
 
 Aspidosoma arnoldi GOLDFUSS, Verb, naturh. Ver. preuss. Rheinl., etc., vol. 5, 
 1848, pp. 145-146, pi. 5. MULLER, Verh. naturh. Ver. preuss. Rheinl., 
 etc., vol. 12, 1855, p. 4, pi. 1, figs. 1-3. STURTZ, Palaeontographica, vol. 32, 
 1886, p. 93. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, 
 vol. 62, 1909, p. 38; Palseontographica, vol. 57, 1910, pp. 4, 62, pi. 1, fig. 2; 
 pi. 2, figs. 6, 7; pi. 3, figs. 7-9; Jahrb. preuss. geol. Landesanst., Berlin, vol. 
 29, 1908, p. 706. SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. 
 Soc. for 1913), 1914, p. 40. 
 
 Encrinaster arnoldi HAECKEL, Gen. Morphologie, vol. 2, 1866, p. Ixvii. 
 
 Formation and locality. This species is common in the grauwacke 
 of the Lower Coblenzian at Winningen, on the Mosel, Germany. 
 
 ENCRINASTER GOLDFUSSI (Schbndori). 
 
 Text fig. 29. 
 
 Aspidosoma goldfussi SCHONDORF, Palseontographica, vol. 57, 1910, pp. 11, 62, 
 pi. 3, figs. 1, 6. 
 
 Formation and locality. A common form found associated with 
 E. arnoldi about Winningen, Germany. 
 
 ENCRINASTER PETALOIDES (Simonovitsch). 
 
 Plate 35, figs. 5, 6. 
 
 Aspidosoma petaloides SIMONOVITSCH, Sitzb. mat.-naturw. Classe Akad. Wiss., 
 Wien., vol. 64, Abt. 1, 1871, p. 106, pi. 4, figs. 1-3. ZITTEL, Handb. Pal., 
 vol. 1, 1879, p. 453, text fig. 322. STURTZ, Palseontographica, vol. 32, 1886, 
 p. 92. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 62, 
 1909, p. -37, pi. 4, figs. 4, 5; Palaeontographica, vol. 57, 1910, pp. 14, 63, pi. 1, 
 figs. 3, 4; pi. 2, fig. 4; pi. 3, figs. 10-16 (complete synonymy given here). 
 
 This species is described in great detail by its author and by 
 Schondorf, and is well illustrated. Here as elsewhere the abactinal 
 skeleton is that of the actinal area seen from the dorsal side. 
 
 Four specimens of this species were found in grauwacke of Upper 
 Coblenzian age, in the old quarry back of the Hohenrheiner furnace 
 at Niederlahnstein, Rhenish Germany. 
 
 ENCRINASTER PETALOIDES GOSLARIENSIS (Halfar). 
 
 Aspidosoma petaloides, var. goslariensis HALFAR, Jahrb. preuss. geol. Lande- 
 sanst., Berlin, vol. 13, 1893, p. 186, pi. 10, figs. 1, la. SCHONDORF, 
 Palaeontographica, vol. 57, 1910, pp. 21, 63, pi. 2, fig. 5; Jahrb. preuss. geol. 
 Landesanst., Berlin, vol. 29, 1908, p. 707. 
 
 Formation and locality. The holotype is from the Lower Devonic 
 of the Harz. Germany. 
 
244 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 ENCRINASTER TISCHBEINIANUS (Roemer) emend. Sttirtz. 
 
 Aspidosoma tischbeinianum ROEMER, Palaeontographica, vol. 9, 1863, pp. 144-146, 
 pi. 23. QUENSTEDT, Petrefactenkunde Deutschlands, vol. 4, 1876, p. 76, 
 pi. 92, fig. 39. STURTZ, Palaeontographica, vol. 32, 1886, p. 92, pi. 12, figs. 
 1, 2. SCHONDORF, Palaeontographica, vol. 57, 1910, pp. 23, 62, pi. 1, fig. 1; 
 pi. 3, figs. 4, 5 (complete synonymy given here). 
 
 Formation and locality. Common in the roofing slates of the 
 Rhenish Lower Devonic at Bundenbach, near Birkenfeld, Germany. 
 As many as 60 individuals have been found on a slab. 
 
 Cat. No. 35117, U.S.N.M. 
 
 ENCRINASTER ROEMERI (SchSndorf). 
 
 Text fig. 28. 
 
 Aspidosoma tischbeinianum ROEMER (part), Palaeontographica, vol. 9, 1863, pi. 25, 
 
 fig. 11. 
 
 Aspidosoma roemeri SCHONDORF, Palaeontographica, vol. 57, 1910, pp. 28, 62, 
 pi. 2, fig. 3; pi. 3, figs. 2, 3. 
 
 Formation and locality. Found associated with E. tiscTibeinianus 
 at Bundenbach, Germany. 
 
 ENCRINASTER SCHMIDTI (SchSndorf). 
 
 Aspidosoma schmidti SCHONDORF, Palaeontographica, vol. 57, 1910, pp. 31, 63, 
 pi. 1, fig. 6; pi. 3, figs. 17, 18 (complete synonymy given here). 
 
 Formation and locality. A slab with six specimens from the Lower 
 Devonic (Herdorfer zone of the Siegen) at Oberdielfen ; Germany. 
 
 ENCRINASTER EIFELENSIS (SchOndorf). 
 
 Aspidosoma eifelense SCHONDORF, Palaeontographica, vol. 57, 1910, pp. 34, 63, 
 
 pi. 1, fig. 5. 
 
 
 
 Formation and locality. Known by several examples from the 
 Lower Coblenzian at Oberstadtfeld, Eifel, Germany. 
 
 ENCRINASTER PONTIS (Clarke). 
 
 Aspidosoma ? pontis CLARKE, Monog., I, Serv. Geol. Min. Brasil, 1913, p. 312, 
 pi. 27, figs. 1-8; Bull. N. Y. State Mus., No. 164, 1913, pi. 35, figs. 1-4. 
 
 Original description. "This very graceful starfish occurs in abund- 
 ance in the soft gray shales of Ponta Grossa, sometimes in clustered 
 groups with its long and slender arms curled and intertwined, more 
 often as single individuals lying in beds with shells of Orbiculoidea 
 and various lamellibranchs. I have counted 20 individuals among 
 the specimens at my command and, singularly, every one of these is 
 preserved with its ambulacra! face up. The removal of all calcareous 
 matter has left only internal casts of this surface from which it has 
 been possible to gain an idea of external structures from carefully 
 
REVISION OF PALEOZOIC STELLEEOI0EA. 245 
 
 made impressions. Na specimen gives any clue to the dorsal exterior 
 save one arm which has been turned sidewise showing a part of that 
 surface. 
 
 "The striking character of this starfish is the unusual delicacy of 
 its arms, which are very slender and long for a true asteroid and 
 present an appearance very suggestive of an ophiuran. These slender 
 arms are usually so exposed as to show only the alternating am- 
 bulacral plates which increases the effect of slenderness; but the 
 adambulacrals are occasionally present and give the arms increased 
 width. These arms are all clearly sulcate, the median groove being 
 sharply marked in all casts by a thin elevated ridge running the 
 entire length of the arm. The soft shale holding these specimens is 
 not a very satisfactory matrix from which to take the special struc- 
 tures of the animal but in good part these can be made out. The 
 ambulacral plates are quadrate in outline, alternate in position along 
 the arm groove, and together are arched so that normally the am- 
 bulacral surface is an arched ridge rising above the rest of the surface. 
 These plates, in their arched position, are slightly spaced or dis- 
 placed along adjoining edges leaving passages from the ambulacra. 
 They are usually broken down or slipped over each other in com- 
 pression so that the arm seldom* shows them in the true position. 
 The surface of these plates is finely granular. The adambulacrals 
 constitute one (or more ?) lateral rows and are so seldom well defined 
 that I am not able to represent them with precision but each of them 
 seems to carry one short spine and all to be granulated on the surface. 
 The body of the animal is deeply incut by the arms, which radiate 
 from a narrow center, sharply quinquepartite by the buccal cavity. 
 The oral apparatus is pretty well made out. The oral frames, one 
 for each arm, are very conspicuous, though varying in size in different 
 individuals. Each is broadly saddle-shaped, split medially, the distal 
 parts joined by a suture, the proximal ends spreading apart at a 
 sharp angle which opens into the oral cavity. Their surface is 
 rounded and granulate, the distal ends elevated, and often each half 
 is inclined downward toward the other along the median suture. 
 At each proximal angle lies a sharp jaw or tooth. The whole of the 
 body surface is occupied by the oral rosette composed of the five 
 Jbuccal divisions." 
 
 Formation and locality. From the Devonic of Ponta Grossa and 
 Jaguariahyva, Brazil. 
 
 ENCRINASTER (?) GRAY^E (Spencer). 
 
 Aspidosoma grayse. SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. 
 for 1913), 1914, pp. 23, 24, 33, 38, text figs. 22, 24, pi. 1, fig. 8. 
 
 Occurs in the Caradoc of Great Britain. 
 
246 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Order STREPTOPHIUR^ Bell. 
 
 Streptophiurse BELL, Proc. Zool. Soc. London for 1891, 1892, p. 179. GREGORY, 
 
 Proc. Zool. Soc. London for 1896, 1897, p. 1036; Treat. Zool., vol. 3, Echino- 
 
 derma, 1900, p. 274. 
 Protophiurex STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 
 p. 200. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 
 1910, pp. 234, 239, 251. 
 Ophiurasterise SCHONDORF, Palseontographica, vol. 57, 1910, p. 61. 
 
 Diagnosis by Gregory (1897). Auluroidea "in which the ambu- 
 lacral ossicles are opposite and are generally fus.ed into vertebral 
 ossicles. In such cases the vertebral ossicles articulate by a more 
 or less simple ball-and-socket joint." 
 
 "Remarks. The main character of this order is that the ambu- 
 lacral ossicles are paired, but primitive. The order differs from the 
 preceding [Lysophiurse] by having the vertebral ossicles always 
 opposite instead of alternate. In some of the simplest members of 
 the order, as Ophiurina, the ossicles are not fused, there are no 
 ventral arm shields, and an ambulacral furrow runs along the ven- 
 tral side of the arm. In the next higher family, as in the genus 
 Lapworihura, the ambulacral ossicles are fused, but have plain 
 articulating surfaces, and there is* an ambulacral furrow." 
 Contains the f amilies : 
 
 Ophiurinidae. 
 
 Lapworthuridas. 
 
 Eoluidiidae. 
 
 Aganasteridae. 
 
 Cholasteridae. 
 
 Family OPHIUKINIIXE Gregory. 
 
 Ophiurinidse GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1037; Treat. 
 Zool., vol. 3, Echinoderma, 1900, p. 275. STURTZ, Verh. naturh. Ver. preuss. 
 Bheinl., etc., vol. 56, 1900, p. 201. SCHONDORF, Jahrb. nassauisch. Ver. 
 Naturk., Wiesbaden, vol. 63, 1910, p. 234. 
 
 Original diagnosis. " Strep tophiurae with ambulacral ossicles, 
 only slightly united, and without ventral arm plates." 
 Contains the genera: 
 Ophiurina Sttirtz. 
 Tremataster Worthen and Miller. 
 
 Genus OPHIURINA Sturtz. 
 
 Ophiurina STURTZ, Palaeontographica, vol. 36, 1890, p. 232. GREGORY, Proc. 
 Zool. Soc. London for 1896, 1897, p. 1037. 
 
 Gregory's diagnosis reads as follows: "Disk circular, with mar- 
 ginal plates. Ambulacral ossicles long, narrow bars. Syngnaths 
 rod-shaped. Adambulacral plates absent or altogether lost from 
 the fossil." 
 
KEVISION OF PALEOZOIC STELLEEOIDEA. 247 
 
 Genoliolotype and only species. 0. lymani Stiirtz (citations as 
 above). Lower Devonic, Bundenbach, Germany. 
 
 Genus TREMATASTER Worthen and Miller. 
 
 Tremataster WORTHEN and MILLER, Geol. Surv. Illinois, vol. 7, 1883, p. 330. 
 MILLER, N. Amer. Geol. Pal., 1889, p. 286. GREGORY, Proc. Zool. Soc. 
 London for 1896, 1897, p. 1037. 
 
 Original description. "Body stellate, central part discoid, rays 
 long, flexuous, and gradually tapering. Rays consisting of a double 
 series of ambulacral plates, forming, together, a subcuneiform se- 
 ries, with the tapering ends directed toward the apices of the rays 
 and uniting with the larger ends of the succeeding double plates, 
 upon each side of which there is a series of curved adambulacral 
 plates, which form the margins of the rays. The pores are large 
 and situated between the contracting sides of the ambulacral plates 
 and the concave sides of the curving adambulacrals. Four plates 
 border upon each pore though nearly surrounded by two of them. 
 Plates 10. Dorsal surface unknown. 
 
 "This genus is distinguished by the parallel arrangement of the 
 ambulacrals and adambulacrals, instead of the alternate order, and 
 by the large pores." 
 
 Gregory's diagnosis is as follows: "Disk with concave inter- 
 brachial outlines. No marginal plates. Ambulacral ossicles short. 
 Adambulacrals present." 
 
 Genoholotype. T. difficilis Worthen and Miller. T. (?) decheni 
 (Dewalque) may also belong here. 
 
 TREMATASTER DIFFICILIS Worthen and Miller. 
 
 Tremataster diffidlis WORTHEN and MILLER, Geol. Surv. Illinois, vol. 7, 1883, 
 p. 330, pi. 31, figs. 3fl, 36. 
 
 Original description. "Body stellate, disk small, rays long, 
 flexuous, and gradually tapering. Ambulacral plates subtrigonal, 
 elongated, and united upon their straight faces in parallel order, 
 so as to form a series of subcuneiform sections at the bottom of 
 the ambulacral groove, with the tapering end of each directed toward 
 the apex of the ray, and uniting with the larger end of the next 
 succeeding double plate. 
 
 "Adambulacral plates parallel with the ambulacrals, and each 
 forms a curve from the larger end of an ambulacral toward the 
 apex of the ray, to unite with the next succeeding adambulacral as 
 it curves away from its attachment to the ambulacral. By this 
 order of construction the adambulacrals are fixed, at one end, to 
 the ambulacrals, while the other end moves upon the curved surface 
 of an adambulacral so as to allow the same lateral flexibility of 
 the rays, secured in other genera by the alternate arrangement of 
 
248 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 the plates. The pores are large and situated between the contract- 
 ing sides of the ambulacral plates, the concave sides of the adam- 
 bulacrals, and the attaching ends of the succeeding plates, so that 
 they are bounded by four plates while nearly surrounded by two. 
 
 "The oral plates form, in pairs, elongated triangles, with the 
 acute angle directed toward the center of the visceral cavity. The 
 apices are joined by a suture with the basal portions, which are 
 partly separated by a dividing furrow. A single genital pore per- 
 forates each basal section of the oral plates. Dorsal side unknown. 
 
 "Locality and position: Prairie du Long Creek, Monroe County 
 [Illinois], Chester limestone. 
 
 "No. 2479, Illinois State collection of 1878." 
 
 .' TREMATASTER (?) DECHENI (Dewalque). 
 
 Protaster decheni DEWALQUE, Ann. Soc. ge"ol. Belgique, vol. 8, 1880, pp. 52-54, 
 
 pi. 3, figs. 1, 2. 
 Tremataster (?) decheni GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1037, 
 
 footnote. 
 
 Formation and locality. Upper Devonic at Walcourt (Namur) 
 and Tohogne (Luxemburg), Belgium. 
 
 Family LAPWORTHUKID^E Gregory. 
 
 Lapworthuridse GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1037. 
 STURTZ, Verb, naturh. Ver. preuss. RheinL, etc., vol. 56, 1900, p. 203. 
 GREGORY, Treat. Zool., vol. 3, Echinoderma, 1900, p. 275. SCHONDORF, 
 Palseontographica, vol. 57, 1910, p. 58; Jahrb. nassauisch. Ver. Naturk., 
 Wiesbaden, vol. 63, 1910, pp. 235, 239. 
 
 Furcasteridx STURTZ, Verb, naturh. Ver. preuss. RheinL, etc., vol. 56, 1900, p. 
 203. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, 
 p. 235. 
 
 Palxospondylidsd STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 p. 201. SCHONDORP, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 1910, p. 235. 
 
 Original diagnosis. "Streptophiuroida without ventral armplates 
 or buccal shields; ambulacral ossicles fused, but their articulating 
 surfaces are plain. Madreporite dorsal." Schondorf states that this 
 plate is on the ventral side, and that the ambulacrals are not fused 
 (p. 239). 
 Contains the genera: 
 
 Squamaster Ringueberg. 
 
 Lapworihura Gregory. 
 
 Sturtzaster Etherrdge. 
 
 Bdellacoma Salter. 
 
 RTiopalocoma Salter. 
 
 Hallaster Stiirtz. 
 
 Sympterura Bather. 
 
 Fur caster Stiirtz. 
 
 Palastropecten Sttirtz. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 249 
 
 Sturtz proposes that the family Lapworthuridse be divided into 
 three families. In the original family will remain Squamaster, Lap- 
 worthura, HaTLaster, and Sympterura. The family Furcasteridse has 
 Furcaster, while the Palaeospondylidae embraces Palseospondylus, the 
 latter name being later changed to Palastropecten by Sturtz, as it 
 was preoccupied; the family name will, therefore, have to be 
 changed to Palastropectinidse, as was done by Bather in 1905 (p. 168). 
 
 % Genus SQUAMASTER Ringueberg. 
 
 Squamaster RINGUEBERG, Bull. Buffalo Soc. Nat. Sci., vol. 5, 1886, p. 5. 
 
 Original description. "Body small. Rays long, slender, tapering, 
 flexible, and divided into annular segments. 
 
 "Ventral side of ray with two series of paired, opposite ambulacral 
 plates, divided by a straight median line; they are irregularly sub- 
 quadrilateral, with one short side, and are arranged in pairs in each 
 series, so that two long and two short sides are joined alternately; 
 consequently there is a long transverse suture regularly alternating 
 with a short one. This disposition gives dentate lateral margins to 
 the ambulacral series. The lateral ends of the long transverse 
 sutures curve away from each other, leaving a small notch between 
 the inferior plates of each pair and the superior plates of the adjoining 
 pairs. This notch receives the inner lateral corners of the squamose 
 dorsal plates. Between the dentate elevations of the ambulacral 
 plates and the lateral margins of the dorsal plates there are large 
 triangular openings, which constituted, or in which were placed, the 
 pores. 
 
 "Dorsal side composed of large, quadrangular, squamose plates, 
 that encircle the arm as far as the ambulacral groove of which they 
 form the margin. They are divided in the upper portion of the 
 ray by a median suture. 
 
 "Dorsal, ray plates fimbriated on the free margins. 
 
 "All plates are perforated by minute, closely arranged pores." 
 
 Genoholotype and only species. 8. echinatus Ringueberg. 
 
 SQUAMASTER ECHINATUS Ringueberg. 
 
 Squamaster echinatus RINGUEBERG, Bull. Buffalo Soc. Nat. Sci., vol. 5, 1886, 
 p. 6, pi. 1, fig. 1. 
 
 Original description. ' ' Body small. Rays long, slender, not widen- 
 ing at the base ; regularly tapering to a subobtuse point. Dorsal side 
 covered by thin imbricating plates, with free external margins which 
 are edged on the outer and lateral sides with closely arranged, long, 
 slender, filiform spinules, that articulate into minute rounded sockets, 
 which are scalloped out of the margin of the plate; they are slightly 
 longer than the exposed portion of the plate, and are placed about 
 their own diameter apart. 
 
250 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 ''Ray divided into about 40 segments or articulations by the 
 encircling, dorsal plates; these grow rapidly narrower near the body, 
 and are divided by a dorsal suture running along a raised median 
 ridge which extends about two-fifths of the length of the ray from 
 the body out, where it gradually disappears with the last divided 
 plate; the rest are entire. These plates are quadrangular, and have 
 then- inner corners articulated into the socket formed in the dentate 
 lateral -extensions of the ambulacral series. They are ornamented 
 on each side by two or three closely arranged, subparallel, very fine 
 ridges, that commence near the dorsal line at the free margins and 
 extend diagonally backward across the plate toward the inner lateral 
 articulated corner. Ambulacral groove furnished with opposite, 
 irregularly quadrilateral, ambulacral plates, divided by a median 
 suture which is crossed alternately by one long and one short suture. 
 
 "The superior plate of each pair has the greatest extension later- 
 ally, while in the inferior it is the direction of the median line, it 
 being about twice as long as the superior, which, however, is but 
 slightly broader. 
 
 "Between the lateral margins of the dorsal plates and the dentate 
 elevations of the ambulacral plates are large sub trigonal open spaces. 
 
 "The plates are punctured by very closely arranged minute 
 perforations." 
 
 Formation and locality. In the Rochester shale, at Lockport, New 
 York. The holotype is in the collection of Dr. Ringueberg. At 
 least one (No. 1110) and probably two other specimens (No. 465) 
 are in the Walker collection of the University of Toronto. They are 
 from the Rochester shale, at Grimsby, Ontario. 
 
 Genus LAPWORTHURA Gregory. 
 
 Text fig. 30. 
 
 Lapworthura GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1037, fig. 5. 
 SCHONDORF, Palseontographica, vol. 57, 1910, p. 58; Jahrb. nassauisch. Ver. 
 Naturk., Wiesbaden, vol. 63, 1910, p. 208. SOLLAS and 
 SOLLAS, Philos. Trans. Roy. Soc. London, ser. B, vol. 
 202, 1912, p. 213. SPENCER, Mon. Brit. Pal. Asterozoa, 
 pt> l (Pa 186011 * ^- Soc. for 1913), 1914, pp. 25, 32, 40, 49. 
 
 Original diagnosis. "Disk circular, well 
 marked. Arms very flexible, broad; at first 
 FIG. SO.-VENTRAL STRUCTURE uniform in width and then tapering slowly. 
 OP ARM OF LAPWORTHURA, Ambulacral ossicles with the distal and prox- 
 
 AFTER GREGORY. . . . 
 
 imal margins parallel; with lateral wings curv- 
 ing round the podial pores. Madreporite large," dorsal. 
 
 Genoholotype. Protaster miltoni Salter. 
 
 Schondorf remarks as follows (1910&:58): 
 
 The ossicles of Lapworthura have been described several times, 
 but never correctly. The ambulacrals are undoubtedly opposite, 
 
REVISION OF PALEOZOIC STELLEROIDEA. 251 
 
 and both dorsally and ventrally have the structure of Encrinaster. 
 The adambulacrals are also opposite to the ambulacrals, and have 
 long forward directed spines. In regard to the dorsal position of 
 the madreporite, he states that the abactinal area has been mistaken 
 for the actinal, and that therefore the madreporite lies upon the 
 ventral side. 
 
 The disk is not circular in outline, but concave between the inter- 
 radii. 
 
 LAPWORTHURA MILTONI (Salter). 
 
 Protaster miltoni SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 330, pi. 9, 
 fig. 4. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palse- 
 ontogr. Soc. for 1861), 1862, p. 32, fig. 18. QUENSTEDT, Petrefactenkunde 
 Deutschlands, vol. 4, 1876, p. 75, pi. 92, fig. 36. STURTZ, N. Jahrb. fur Min., 
 etc., 1886, vol. 2, p. 148; Palseontographica, vol. 32, 1886, pp. 79, 94, pi. 8, 
 fig. 6. 
 
 Lapworthura miltoni GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1037, 
 fig. 5. SCHONDORF, Palseontographica, vol. 57, 1910, p. 58; Jahrb. nassau- 
 isch. Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 208. SOLLAS and SOLLAS, 
 Philos. Trans. Roy. Soc. London, ser. B, vol. 202, 1912, p. 214, text figs. 1, 
 2, 4 D, pi. 9, figs. 1, 2; pi. 10, figs. 1-4. SPENCER, Mon. Brit. Pal. Aster- 
 ozoa, pt. 1 (Palseontogr. Soc. for 1913), 1914, pp. 25, 32, 35, 36, pi. 1, fig. 9. 
 
 Formation and locality.- Abundant in the Lower Ludlow of the 
 Siluric at Leintwardine, England. See elsewhere in this work 
 (p. 237) under Sturtzura leptosoma, which Schondorf states is but 
 the young of L. miltoni. The same author states further that the 
 latter species either embraces several species or the form has a long 
 geologic range, for a number of species and genera appear to be 
 identical with L. miltoni. . 
 
 Cat. No. 59394, U.S.N.M. 
 
 LAPWORTHURA SOLLASI Spencer. 
 
 Lapworthura sollasi SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. 
 for 1913), 1914, pi. 1, fig. 10. 
 
 Occurs in the Siluric of Great Britain. 
 
 LAPWORTHURA (? "probably n. gen.") species (Miller and Gurley). 
 
 Aganaster (?) sp., MILLER and GURLEY, Sixteenth Rep. Geol. Surv. Indiana, 
 1891, p. 372, pi. 9, figs. 12, 13; authors' extracts, 1890, p. 58. GREGORY, 
 Proc. Zool. Soc. London for 1896, 1897, p. 1038. ' 
 
 Original description. "We have figured this fragment to show the 
 anchylosis of the oral plates, and the pores passing through the 
 ambulacral plates, and also those passing between them. It will 
 be observed that one pore passes through each plate near the marginal 
 end, while a double row of pores passes between the plates in the 
 central part of the arm furrow. We believe this is an Aganaster, 
 from the <Jepth of the central part of the disk, and the arrangement 
 of the plates in the arm furrows; but the specimen is larger than any 
 
252 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Aganaster gregarius we have seen and the rays are wider, and as we 
 do not know the position of the pores in the rays of Aganaster, it 
 may be our specimen does not belong to this genus." 
 
 Remarks. " Seems to me to be allied to Lapworfhura, and at least 
 a member of the same family. It apparently has no ventral arm- 
 plates, but an open furrow, and thus differs widely from Aganaster. 
 It is probably a new genus." (Gregory.) 
 
 Formation and locality. Not given. The specimen may be in 
 the Gurley collection of the University of Chicago. 
 
 Genus STURTZASTER Etheridge. 
 
 Palaeocoma SALTER (not D'Orbigny 1850), Rep. Brit. Assoc., 1857, Trans, of sec- 
 tions, p. 76; Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, pp. 324, 327. WRIGHT, 
 Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palseontogr. Soc. for 1861), 
 1862, pp. 23, 29. QUENSTEDT, Petrefactenkunde Deutschlands, vol. 4, 1876, 
 p. 81, pi. 92, fig. 43. ZITTEL, Handb. Pal., vol. 1, 1879, p. 453. STURTZ, 
 N. Jahrb. fur Min., etc., 1886, vol. 2, p. 152; Verb, naturh. Ver. preuss. Rbeinl., 
 etc., vol. 50, 1893, pp. 45, 62. 
 
 Sturtzaster ETHERIDGE, Rec. Australian Mus., vol. 3, 1899, p. 129. SCHONDORF, 
 Jabrb. nassauiscb. Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 217. 
 
 Genoholotype. Palseocoma marstoni Salter. 
 
 Remarks. Palseocoma = Sturtzaster, Bdellacoma, and Rhopalocoma, 
 all of Salter, are ver}^ poorly known, due to the fact that the specimens, 
 though not rare, occur in a calcareous shale and are pressed flat till 
 they have become a thin film of plates greatly obscured by an abun- 
 dance of spines. Of P. marstoni, the genotype, the writer has seen 
 five examples, presented to the United States National Museum by 
 W. R. Billings. On the basis of the characters revealed by these 
 specimens, he was inclined to leave the genus among the Asteroidea 
 and in close association either with the Mesopalaeasterinse (nearest 
 Mesopalseaster, a phanerozonian) , or the Schuchertiidse (near Schuch- 
 ertia, a cryptozonian) . 
 
 The long, slender and serrated spines of Sturtzaster are peculiar to 
 the genus. In. their abundance and character they remind one more 
 of ophiurids than of asterids. 
 
 The figures of Salter and Wright, if correct, recall the large-disked 
 cryptozonian genus Schuchertia, and it was this character that prob- 
 ably also led Sttirtz to refer Sturtzaster to the same group in asso- 
 ciation with the genera Palasteriscus, Loriolaster, and OTieiropteraster. 
 
 Etheridge in 1899 called attention to the fact that D ' Orbigny pro- 
 posed in 1850 * the new generic name Palseocoma for OpJiiura mulleri 
 Phillips of the Lias. A name once proposed can not be used again 
 in another sense, and therefore Mr. Etheridge is within the rules of 
 nomenclature in substituting for Salter 's second usage of Palseocoma 
 
 1 Prodome, vol. 1, p. 240. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 253 
 
 the name of Sturtzaster , with Palseocoma marstoni SaJter as the 
 genotype. 
 
 In 1910 Schondorf was able to study "several right good examples" 
 of S. marstoni, and strangely the form turns out not to be an asterid 
 but an aulurid, with the essential ambulacra! characters of Lap- 
 wortJiura miltoni. He states that the ambulacrals are not alternate, 
 as stated by Salter, but opposite one another. Therefore the 
 ambulacrals and the ad ambulacrals are also opposite. The ad am- 
 bulacrals bear two or three spines on then" outer edges, and Salter's 
 statement and figures showing two columns of ossicles outside of the 
 ambulacrals appear to be very wrong. Schondorf states that the 
 peculiar preservation of the arm skeleton has given rise to this state- 
 ment of Salter, and that there are only ambulacrals and adambula- 
 crals present. The oral skeleton is distinctly adambulacral. A 
 madreporite is not determinable. 
 
 On the dorsal side, all that can be clearly made out is the presence 
 of ambulacrals and adambulacrals, all of which are arranged in trans- 
 verse rows. 
 
 STURTZASTER MARSTONI (Salter). 
 
 Palseocoma marstoni SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 328, 
 pi. 9, figs. 3a-3c. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, 
 pt. 1 (Palseontogr. Soc. for 1861), 1862, p. 30, fig. 17. QUENSTEDT, Petrefacten- 
 kunde Deutschlands, vol. 4, 1876, p. 81, pi. 92, fig. 43. 
 
 Sturtzaster marstoni SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, 
 vol. 63, 1910, p. 217. 
 
 Formation and locality. Common in the Lower Ludlow of Church 
 Hill, Leintwardine, England. Specimens are in many museums, the 
 United States National Museum and the Yale Museum both having 
 individuals. See S. colvini and S. cygnipes. 
 
 Cat. Nos. 60624, 60625, U.S.N.M. 
 
 STtfRTZASTER COLVINI (Salter). 
 
 Palseocoma colvini SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 328. 
 WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palseontogr. Soc. 
 for 1861), 1862, p. 30. 
 
 Sturtzaster colvini SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 
 63, 1910, p. 219. 
 
 Formation and locality. In the Lower Ludlow, Leintwardine, Eng- 
 land. "Probably completely identical with 8. marstoni." (Schondorf.) 
 
 STtJRTZASTER CYGNIPES (Salter). 
 
 Palseocoma cygnipes SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 329. 
 WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palaeontogr. Soc. 
 for 1861)', 1862, p. 30. 
 
 Sturtzaster cygniceps (QIC) SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wies- 
 baden, vol. 63, 1910, p. 219. 
 
 Formation and locality. Lower Ludlow, Leintwardine, England. 
 " Probably completely identical with S. marstoni." (Schondorf.) 
 
254 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 STtJRTZASTER (?) MITCHELLI Etheridge, jr. 
 Sturtzaster (?) mitchelli ETHERIDGE, jr., Rec. Australian Mus., vol. 3, 1899, p. 128. 
 
 Formation and locality. A single specimen from the Upper Trilo- 
 bite bed of the Siluric (Wenlock series) at Bowning, New South 
 
 Wales. 
 
 Genus BDELLACOMA Salter. 
 
 Palseocoma (Bdellacoma) SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 
 
 324. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palee- 
 
 ontogr. Soc. for 1861), 1862, p. 31. ZITTEL, Handb. Pal., vol. 1, 1879, p. 
 
 453. STURTZ, Palseontographica, vol. 32, 1886, p. 96. 
 Bdellacoma STURTZ, Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, pp. 46, 
 
 63. 
 
 Genoholotype and only species. P. (B.) vermiformis Salter. Lower 
 Ludlow, Leintwardine, England. 
 
 Remarks. Until this form is restudied and brought up to date the 
 supposed subgenus of Paldeocoma has no value. 
 
 Genus RHOPALOCOMA Salter. 
 
 Palseocoma (Rhopalocoma} SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, 
 p. 329. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palae- 
 ontogr. Soc. for 1861), 1862, p. 31. ZITTEL, Handb. Pal., vol. 1, 1879, p. 453. 
 STURTZ, Palaeontographica, vol. 32, 1886, p. 96. 
 
 Rhopalocoma STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, 
 pp. 46, 63. 
 
 GenoJiolotype and only species. P. (R.) pyrotechnica Salter. Lower 
 Ludlow, Leintwardine, England. 
 
 Remarks. This form also requires modernization, and until then 
 the supposed subgenus has no value. 
 
 Genus HALLASTER Sturtz. 
 
 Protaster HALL (not Forbes), Nat. Hist. N. Y., Pal., vol. 3, 1861, p. 134; 
 
 Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 293; rev. ed., 1868= 
 
 1870, p. 336. 
 Hallaster STURTZ, N. Jahrb. fur Min., etc., 1886, vol. 2, p. 150. 
 
 Original description (Sturtz). "Ambulacral plates alternating 
 [they are opposite]; the podial pores lie between these and the side 
 plates. The dorsal skeleton consists of two columns of dorsal plates 
 and two of lateral plates, of which the former adjoin medially along 
 the rays. For P. forbesi Hall of the Silurian of North America I 
 propose the generic name Hallaster, because on the one hand Forbes 
 did not sufficiently characterize his Protaster, and on the other the 
 above species in the sense of Salter's Protaster is not congeneric 
 with it." 
 
 GenoJiolotype and only species. Protaster forbesi Hall. 
 
 Remarks. This genus appears to be most closely related to Lap- 
 worihura, with the most obvious difference in the shape of the am- 
 
REVISION OF PALEOZOIC STELLEROIDEA. 
 
 255 
 
 bulacral ossicles. In Hallaster the lateral wings of the plates curve 
 round the podial openings proximally, while in Lapworthura they do 
 so distally. Further, the side plates of the latter genus bear spines 
 along their sides, while in the former genus they are restricted to the 
 distal ends of the plates. 
 
 HALLASTER FORBESI (Hall). 
 
 Text fig. 31. 
 
 Protaster forbesi HALL, Nat. Hist. N. Y., Pal., vol. 3, 1861, p. 134, pi. 7 A, figs. 
 8-10; Twentieth Rep. N. Y. State Cab. Nat. Hist., 1868, p. 293, pi. 9, figs. 5, 
 6; rev. ed., 1868=1870, p. 336, pi. 9, figs. 5, 6. QUENSTEDT, Petrefacten- 
 kunde Deutschlands, vol. 4, 1876, p. 134, pi. 95, fig. 13. STUKTZ, Palaeonto- 
 graphica, vol. 32, 1886, pp. 78, 83. 
 
 Hallaster forbesi STURTZ, N. Jahrb. fur Min., etc., 1886, vol. 2, p. 150. 
 
 The original description will not be repeated here because it is 
 faulty and was later corrected by Hall. 
 
 Hall's description of 1868. P. forbesi "has a circu- 
 lar disk, composed of squamif orm spiniferous plates 
 and five long flexuous rays. These rays I have 
 [originally] represented as composed, on the lower 
 side, of a double range of [adambulacral] plates, as 
 described and represented by Professor Forbes, but 
 finding outside of these a range of small ossicles 
 [side plates] to which are attached the spine bases, 
 these have been shown as a part of an articulating 
 spine (in the illustration, plate 7 A 1 ), an unnatural representation, 
 which I am now able to correct. 
 
 "In the species from the Lower Helderberg group, Protaster forbesi , 
 the ventral surfaces of the rays are composed of an ambulacral and 
 adambulacral series of plates on each side [there are no ventral ray 
 plates]. The ambulacral plates are obliquely quadrangular and alter- 
 nating in a slight degree [in the type they are opposite] ; the adambu- 
 lacral plates as seen from the lower side are narrow, elongate, oblique, 
 and laterally imbricating, presenting the appearance of an oblique 
 ridge with the anterior extremity projecting, and forming the point 
 of attachment for the spines, with which each one is furnished. [These 
 spines are striated longitudinally.] When the ray is abruptly curved, 
 these plates project outward, sometimes almost rectangularly; and 
 when at the same time the ambulacral area is obscured by aclhering 
 matrix, these plates might readily be mistaken for appendages of 
 the inner ranges. The pores are comparatively large, truncating 
 the outer adjacent angles of the ambulacral plates, while the base 
 of one adambulacral plate and the side of another form the exterior 
 margin. The centers of the upper sides of the rays are composed of 
 
 FIG. 31. ACTINAI, BAT 
 PLATES OP HALLASTER 
 FORBESI (HALL). OP- 
 POSITE AMBULACRALS, 
 AND THE SIDE PLATES. 
 
 * Nat. Hist. New York, Pal., vol. 3, 1861. 
 50601 Bull. 8816 17 
 
256 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 two ranges of subimbricating [dorsal] plates, which are closely joined 
 along the median line; the marginal plates are the upper edges of the 
 adambulacral plates, which bear on their anterior ends one, two, or 
 three short spines." 
 
 Formation and locality. From the Coeymans member of the Hel- 
 derbergian series of the Lower Devonic, at Jerusalem Hill, near 
 Litchfield, New York. The holotype is in the American Museum of 
 Natural History, No. 2302. There are two good specimens and a 
 single arm in the Beecher collection at Yale University. 
 
 Genus SYMPTERURA Bather. 
 Text fig. 32. 
 
 Sympterura BATHER, Geol. Mag., dec. 5, vol. 2, 1905, pp. 161-169, pi. 6, figs. 1, 
 2, 3, 6. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 1910, p. 216. 
 
 Original diagnosis. "A Lapworthurid with spinulose disk ex- 
 tending to second arm segment, with oral skeleton of teeth, long 
 
 A 3 
 
 rame 
 
 t&etk 
 
 FIG. 32. SYMPTERURA MINVERI, AFTER BATHER. A. SEMIDIAGRAMMATIC RECONSTRUCTION OF SYN- 
 GNATHS, X 10. B. RECONSTRUCTION OF SEVENTH AND EIGHTH ARM SEGMENTS, x 18: a, DISTAL, AND ft, 
 
 PROXIMAL PORTION OF VERTEBRA; C, 'ADAMBULACRALIAJ p, PODIAL DEPRESSION; q, INTERSPACE, OCCU- 
 PIED, AT LEAST IN PART, BY INTERVERTEBRAL MUSCLES. 
 
 jaws, and short mouth frames (torus not seen), with free arm seg- 
 ments containing a vertebral ossicle, possibly compound, grooved 
 ventrally and provided on each side with two wings, to the distal of 
 which is attached an adambulacral spiniferous element." 
 
 GenoJiolotype and only species. S. minveri Bather (same references 
 as above). The holotype was found in the Devonic (?Lower) at 
 Epphaven, near Padstow, North Cornwall, England. 
 
 As this specimen presents in the ambulacralia characters of great 
 value in the morphology of the Ophiurid vertebrse, it is advisable 
 to quote here somewhat extensively from Bather's statements. 
 
 "The median body of each segment is undoubtedly the equivalent 
 of the normal Ophiurid vertebra. On the accepted theory that 
 this -vertebra was evolved by the fusion of a pair of ossicles originally 
 alternating, then opposite, and finally joined along the middle or 
 
REVISION OF PALEOZOIC STELLEROIDEA. 257 
 
 radial line, the present specimen may be described as in a stage of 
 development later than the fusion, but possibly retaining hi the 
 median groove a trace of the primitive distinctness of the ossicles. 
 Those ossicles are usually described as ambulacra!, and that term 
 may be accepted so far as it denotes homology with the ossicles 
 so named in an Asterid. * * * 
 
 "As a rule among Ophiurids in this stage of evolution, each ver- 
 tebra has on each side a single side process on which abuts an outer 
 ossicle, the so-called adambulacral, and these adambulacrals, which 
 bear the lateral spines, alternate with the ambulacral ossicles or 
 vertebrae. It is a little difficult to interpret the appearances of the 
 present specimen in harmony with such an arrangement. On the 
 assumption that each segment should contain one ambulacral pair 
 (here fused) and one adambulacral pair bearing spines, ray i has been 
 assigned nine segments. But each such segment is seen to have two 
 processes on each side, and the distal one of these bears the spines. 
 For this reason, and because of the appearances in segment 8, it may 
 be supposed that the outer spiniferous portion of the distal process 
 (c in fig. 1) is an adambulacral element. What, then, is the proxi- 
 mal side process? To this question two possible answers present 
 themselves. 
 
 "The appearance of a transverse division in the vertebra, between 
 the proximal and distal processes, suggests that each segment really 
 consists of two ambulacral pairs, of which only the distal one is 
 associated with adambulacrals, the proximal pair of adambulacrals 
 being suppressed. Each of these supposed ambulacral pairs pos- 
 sesses a single pair of lateral processes, but those of the distal pair 
 are partly overlaid by the adambulacral elements. In the distal 
 region of the ray the proximal and distal halves of the vertebra are 
 distinguishable; but nearer the disk and within it they have come 
 closer together, the transverse division has disappeared, and the 
 side processes are reduced to structures which appear as bars, but 
 are probably flattened laminae. Thus the vertebrae seen in ray v are, 
 on this explanation, of compound origin. * * * 
 
 "Now, comparison of the vertebrae of recent Ophiurids with the arm 
 segments, especially the proximal ones, of our fossil leaves no room for 
 doubt that the depression marked p is for the reception of a podium, 
 while that marked q is for the insertion of the ventral intervertebral 
 muscles. A single arm segment of a recent Ophiurid, such as OpTii- 
 amchno, or Amphium, is therefore homologous with any one of the 
 whole segments here numbered 1-8. If one of these is really com- 
 posed of a distal and a proximal hah 7 (lettered a and & respectively 
 in figs. 1 and 2) the same statement would apply to the recent Ophi- 
 urid, and some trace of this origin might be seen in the development. 
 
258 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 The observations of Prof. Ludwig 1 and Mr. J. W. Fewkes 2 on 
 Amphiura squamata have shown that the two lateral halves of each 
 vertebra unite first at the proximal and distal ends, leaving a space 
 between. This is suggestive of an origin from proximal and distal 
 elements. On the other hand each lateral half springs from a 
 single center of calcification, from which it stretches out in a distal 
 direction, so that the incipient ambulacral element is thicker at its 
 proximal end. This last-mentioned feature is paralleled by the 
 boot-shaped proximal portions of the ambulacral ossicles in the Prot- 
 asteridas. At a slightly later stage the ambulacral of Amphiura 
 broadens at the distal end, which thus comes to resemble the distal 
 portion of the Protasterid ambulacral. If this distal portion in 
 Amphiura were, as indicated by Prof. Ludwig's observations, merely 
 an extension of the proximal portion, then it might be inferred 
 that the whole structure, both here and in the various Paleozoic 
 forms alluded to, represented a single ambulacral pair and not two 
 successive pairs. In such case one would accept Dr. Gregory's 
 suggested explanation 3 'that the smaller pieces are only triangular, 
 distal portions of the ambulacral ossicles, apparently separated from 
 the proximal portion[s] by a groove.' Dr. Gregory further sug- 
 gests that these grooves or depressions 'were for the lodgment of 
 the ventral muscles which moved the arms. 7 A far more probable 
 explanation surely is that they were for the reception of the branches 
 from the radial water- vessel to the podia. This explanation, how- 
 ever, consonant as it is with the facts of development of Amphiura, 
 reminds one of another difficulty. Prof. Ludwig 4 has pointed out 
 that, whereas the so-called ambulacrals of Asterids He at right angles 
 to the perradius and between the successive branches and podia, 
 those of Ophiurids lie parallel to the perradius and across the branches 
 to the podia. Now, if, as we have every reason to believe, the Ophi- 
 urids were derived from Asterids, it is hard to see why this change 
 should have taken place. That is the difficulty, but it is a difficulty 
 that disappears if we suppose that the vertebra is really compounded 
 of two successive ambulacral pairs in the manner outlined above. 
 The remaining objection to this latter ' hypothesis is that, as Dr. 
 Gregory has pointed out, it postulates the suppression of alternate 
 podia. Nevertheless, similar fusion and concomitant suppression 
 are not so unknown among Echinoderms as to render this objection 
 a fatal one. 
 
 "The suggestion that the vertebrae of Ophiurids are composed of 
 two successive ambulacral pairs certainly can not be proved with 
 
 1 Zeits. wiss. Zool., vol. 36, 1881, p. 181. 
 
 2 Bull. Mus. Comp. ZooL, vol. 13, No. 4, 1887. 
 
 Proc. Zool. Soc. London for 1896, 1897, p. 1032. 
 * Op. cit., p. 185. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 259 
 
 the evidence at our disposal. But it is doubtful whether it can 
 be disproved, and I therefore make it to promote a search for 
 further evidence pro or con. 
 
 "Two other features in the present specimen need discussion, 
 and may perhaps throw light on the problem just posed. The 
 first of these is the fact that the broadest and stoutest portion of 
 each arm segment appears to be the distal half (marked a in fig. 1), 
 whereas in the developing Ampliiura, and in the adult Protasteridse 
 the reverse is the case. This character is also found in Furcaster 
 palseozoicus as figured by Mr. Sttirtz, in Ptilonaster princeps of 
 J. Hall, and in Lapworthura Miltoni, as interpreted by Dr. Gregory. 
 (See our fig. 4 [30].) In the Epphaven fossil the feature is to some 
 extent accounted for by the supposed fusion of a spiniferous adam- 
 bulacral element with the distal wing of the ambulacral; but in 
 Lapworthura and Furcaster this whig, while unconnected with the 
 adambulacral, is still more preponderant. In some other early 
 Palaeozoic genera, e. g. Eugaster, J. Hall, and EopJdura, Jaekel, 
 the wing is neither distal nor proximal, but arises half way up the 
 ambulacral, so that one can not say to which of two successive seg- 
 ments the podium belongs; in fact, the structure is in this respect 
 absolutely that of an Asterid. 1 These differences call for some 
 explanation. Starting from the indifferent Ordovician type of 
 EopMura, we may suppose that in one series of genera (e. g. Protas- 
 teridse) the whig moved toward the mouth, while in another series 
 (e. g. Lapworthuridse) it moved away from the mouth. In both 
 series the podium ultimately became inclosed within the substance 
 of (apparently) a single ossicle; but, if this took place by a sub- 
 sequent lateral outgrowth of stereom, then in the former case the 
 vertebra must have inclosed a podium distal to itself, and in the 
 latter case a podium proximal to itself. Thus the relations of the 
 vertebras to the podia would be fundamentally different in the 
 two lines of descent. On the other hand, alternate podia may, 
 as suggested on a previous page, have been inclosed by the union 
 of successive pairs of vertebrae, and this type of structure may 
 be the one seen in process of development in the arm segments of 
 our fossil, and the one that persisted to the present day. 
 
 "The second feature worthy of attention is the considerable 
 space that seems to intervene between the distal wing of one seg- 
 ment and the proximal wing of the next. This is conspicuous in the 
 distal region of ray i, where, further, the depression (g in fig. 1 [32 B]) 
 markedly resembles the podial depression (p in fig. 1), and differs 
 from it mainly in being rather nearer the axis of the arm. The 
 theory that the Ophiurids are descended from Asterids does not 
 
 i See Jaekel, Zeits. geol. Ges., vol. 55, Protok., 1904, pp. 106-113. 
 
260 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 explain the evolution of such an interspace, and the general tendency 
 to shortening and approximation of the vertebrae, shown in the 
 history of the Ophiurids, leads one to inquire why there should 
 ever have been introduced a stage in which, as in the Devonian 
 OpJiiurina, the recent deep-sea Ophwhelus, and the young AmpTiiura, 
 the vertebrae have so far departed from the primitive type as to 
 become axially elongate. This stage has been regarded as primi- 
 tive by Lyman, Ludwig, and other zoologists, but in theory and 
 fact it is ' primitive' only so far as the later forms are concerned, 
 while with reference to the complete series it is 'intercalated.' 
 
 "Recurring to the hypothesis that the vertebrae are compounded 
 of successive pairs of ambulacrals, we find in it an explanation 
 not merely of this curious elongation of the arm segments in general, 
 but of the interspaces between them in this genus (lettered q). An 
 objection to the hypothesis was the necessity for assuming the sup- 
 pression of alternate podia. Here, it may be, is evidence of a 
 stage in which those podia were not yet suppressed, though perhaps 
 somewhat atrophied. If both depressions (p and q) were for the 
 reception of podia, then their alternate approximation to and re- 
 moval from the perradius may be compared with the similar phe- 
 nomenon in Asterids. 
 
 " Whether the features just discussed be or be not accepted as 
 evidence in favor of the compound origin of the Ophiurid vertebra, 
 they demand some explanation; and it may be added that the same 
 hypothesis will perhaps furnish an equally needed explanation for 
 the hitherto unexplained differences that obtain between Palaeo- 
 zoic genera of Ophiurids in the relations of the adambulacrals to the 
 ambulacrals. 
 
 "The origin of the Ophiurid mouth-skeleton also may be illu- 
 minated by the preceding hypothesis, which is in full harmony with 
 the opinion that many more arm segments enter into the composition 
 of that structure than is the case in Asterids, an opinion based on 
 embryological research by Dr. O. zur Strassen, 1 and on palaeonto- 
 logical investigation by Dr. O. Jaekel in the paper quoted above. 
 In this region of the ray, at any rate, adambulacrals and podia must 
 have been suppressed in all Ophiurids. We may here note the 
 apparent absence from our specimen of the adambulacral elements 
 known as side mouth-shields, as well as of the peristomial plates. 
 The latter are wanting in most early Ophiurids, a fact confirmatory 
 of Dr. zur Strassen's conclusion that they are not ambulacral elements, 
 but ' secondary calcifications confined to the interradial region.' ' 
 
 Schondorf states that the structure of the arms is like that in 
 LapwortJiura miltoni and the oral armature as in Encrinaster. 
 
 i Zool. Anzeiger, vol. 24, 1901, p. 609. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 261 
 
 Genus FURCASTER Stlirtz. 
 
 Furcaster STURTZ, Palaeontographica, vol. 32, 1886, p. 79; N. Jahrb. fiir Min., 
 etc., 1886, vol. 2, p. 148; Verh. naturh. Ver. preuss. Eheinl., etc., vol. 50, 
 1893, p. 25. GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1038; 
 Treat. Zool., vol. 3, Echinoderma, 1900, p. 275, fig. 31. 
 
 Disk small, circular. Rays five, short, narrow, tapering gradually, 
 and slightly flexible. Actinally flat and abactinally rounded. There 
 is a dorsal median column of slightly projecting plates and two lateral 
 ranges of side plates. The dorsal plates are medially depressed, with 
 their outer sides extended into ears, into which fit the spine-bearing 
 side plates. 
 
 "Ambulacral ossicles [opposite] of a long central body and two 
 short wings, which are attached only to the anterior corner of the 
 ossicle." (Gregory.) Buccal scutes small. 
 
 GenoJiolotype. F. palseozoicus Stlirtz. F. (?) daoulasensis (Davy) 
 may also belong here. 
 
 Remarks. "In Stiirtz's description he refers to the existence in 
 this genus of ventral arm plates, and even figures them. His type- 
 specimens are now in the British Museum, but I can not verify the 
 existence of any ventral arm plates." (Gregory.) 
 
 FURCASTER PALvEOZOICUS Stiirtz. 
 
 Furcaster palseozoicus STURTZ, Palaeontographica, vol. 32, 1886, p. 79, pi. 8, 
 figs. 4, 5; N. Jahrb. fiir Min., etc., 1886, vol. 2, p. 148; Palaeontographica, 
 vol. 36, 1890, p. 214. GREGORY, Proc. Zool. Soc. London for 1896, 1897, 
 p. 1038. 
 
 Formation and locality. In the Lower Devonic roofing slates, 
 Bundenbach, Germany. There are three specimens of this species 
 at Yale University. 
 
 Cat. No. 59383, U.S.N.M. 
 
 FURCASTER (?) DAOULASENSIS (Davy). 
 
 Protaster daoulasensis DAVY, Bull. Soc. geol. France, ser. 3, vol. 14, 1887, pp. 182- 
 187, text figs. GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1038, 
 footnote ("is an ally of Furcaster"). 
 
 Formation and locality. From the Lower Devonic, Rumguen, near 
 
 Brest, France. 
 
 
 
 Genus PALASTROPECTEN Sturtz. 
 
 Palastropecten STURTZ, Palseontographica, vol. 32, 1886, p. 88, pi. 10, figs. 3, 4; 
 vol. 36, 1890, p. 213, pi. 26, figs. 12, 13. GREGORY, Proc. Zool. Soc. London 
 for 1896, 1897, p. 1038. 
 Palsespondylus STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 
 p. 190. 
 Palxospondylus STURTZ, Verh. naturh. Ver. preuss. Kheinl., etc., vol. 56, 1900, 
 
 pp. 191, 202. 
 
 Diagnosis ly Gregory. "Disk circular, large (badly preserved in 
 the specimens; probably originally soft and irregular). Arms thick, 
 
262 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 broad, and somewhat lanceolate in shape. Ambulacral ossicles 
 narrow, the lateral wings resting on the whole body of the ossicle.' 7 
 Genoholotype and only species. P. zitteli (Stiirtz) (citations as above) . 
 In the Lower Devonic, Bundenbach, Germany. 
 
 Family EOLUIDIIME Gregory. 
 
 Eoluidiidx GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1038. 
 Eophiuridss STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 
 p. 203. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 
 1910, p. 235. 
 
 Original diagnosis. " Strep tophiuras with the ambulacra! ossicles 
 united to form vertebral ossicles. Ventral arm plates present, but 
 there are 310 buccal shields. (Dorsal arm plates present only in 
 the highest genus.) 
 
 "Remarks. This family includes three Devonian genera, which 
 differ from the previous families of this order by the presence of 
 ventral arm plates and by having vertebral ossicles, which articulate 
 ( ? always) by simple rounded pits and processes. The family differs 
 from living Streptophiurse by the absence of buccal shields and 
 the simplicity of the oral armature." 
 Contains the genera: 
 Eoluidia Stiirtz. 
 Eospondylus Gregory. 
 Miospondylus Gregory. 
 
 Genus EOLUIDIA Sturtz. 
 
 Asterias asperula ROEMER (part), Palaeontographica, vol. 9, 1863, p. 146, pi. 24, 
 
 figs. 1-5; pi. 26, -fig. 6; pi. 27. 
 Eoluidia STURTZ, Palseontographica, vol. 32, 1886, p. 89, pi. 11, figs. 1, 2; vol. 36, 
 
 1890, p. 211, pi. 26, figs. 10, 11. GREGORY, Proc. Zool. Soc. London for 
 
 1896, 1897, p. 1038. SOLLAS and SOLLAS, Philos. Trans. Roy. Soc. London, 
 
 ser. B, vol. 202, 1912, p. 226, fig. 4E. 
 EopMurites STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, p. 190. 
 
 Diagnosis. "Disk rather large; the interbrachial outlines are 
 deeply concave. [Kays very long, slender, and fragile.] Each 
 syngnath consists of pairs of mouth frames and jaws; a jaw plate 
 is present. The vertebral ossicles are small and the union of the 
 two lateral elements incomplete; the lateral wings are thin. The 
 adambulacral plates are triangular and each of them bears several 
 spines. The pores for the podia occur at the middle of the lateral 
 margin of the ventral arm shields. " (Gregory.) 
 
 Genoholotype and only species. E. decheni Sturtz (citations as 
 above). Lower Devonic, Bundenbach, Germany. 
 
 Cat. No. 35116, U.S.N.M. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 263 
 
 Genus EOSPONDYLUS Gregory. 
 
 Ophiurella STURTZ (not Agassiz, 1834), Palseontographica, vol. 32, 1886, p. 77. 
 Eospondylus GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1039. 
 
 Original diagnosis. "Disk circular. Ambulacral ossicles com- 
 pletely fused into vertebral ossicles, each of which, however, is trav- 
 ersed by a pore. The adambulacral ossicles are somewhat pear- 
 shaped. The podial pores are at the posterior angles of the ventral 
 arm plates." 
 
 Genoholotype and only species. Ophiurella primigenia Stiirtz. 
 
 EOSPONDYLUS PRIMIGENIUS (Stiirtz). 
 
 Ophiurella primigenia STURTZ, Palseontographica, vol. 32, 1886, p. 77, pi. 8, 
 
 figs. 1, 2; vol. 36, 1890, p. 210, pi. 26, figs. 6, 7. 
 Eospondylus pnmigenia GREGORY, Proc. Zool. Soc. London for 1896, 1897, 
 
 p. 1039. 
 
 Formation and locality. Lower Devonic, Bundenbach, Germany. 
 
 Genus MIOSPONDYLUS Gregory. 
 
 Ophiura rJienana STURTZ, Verb, naturh. Ver. preuss. Rheinl., etc., vol. 50, 1893, 
 
 p. 29, pi. 1, figs. 1-3. 
 Miospondylus rhenanus GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 
 
 1039. SOLLAS and SOLLAS, Philos. Trans. Koy. Soc. London, ser. B, vol. 
 
 202, 1912, p. 226. 
 
 Onginal diagnosis (Gregory). "Disk circular. Ambulacral ossi- 
 cles completely united; each half of the vertebral ossicle is boot- 
 shaped. The oral angles each consist of a pair of syngnaths without 
 jaw plate. The ventral arm plates are small and are not notched 
 by podial pores." 
 
 Genoholotype and only species. Opliiura rhenana Stiirtz (citations 
 as above). Lower Devonic, Bundenbach, Germany. 
 
 Remarks. Eospondylus and Miospondylus " agree in family char- 
 acters with Eoluidia, but differ from it in the structure of both the 
 ambulacral and adambulacral plates." (Gregory.) 
 
 Family AGANASTERID.^ Stiirtz. 
 
 Aganasteridse STURTZ, Verb, naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, 
 p. 203. SCHONDORP, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 
 1910, p. 235. 
 
 Genus AGANASTER Miller and Gurley. 
 
 Aganaster MILLER and GURLEY, Sixteenth Rep. Geol. Surv. Indiana, 1891, p. 
 372; authors' extracts, 1890, p. 57. GREGORY, Proc. Zool. Soc. London for 
 1896, 1897, p. 1039. 
 
 ^ Ophiopege BOHM, Zeit. geol. Gesell., vol. 45, 1893, p. 159 (same genoholotype as 
 for Aganaster). 
 
 Original description. "In 1869 Meek and Worthen described an 
 Ophiuroidea, in the Proceedings of the Academy of Science of 
 
264 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 Philadelphia, page 169, under the name of Protaster gregarius, which 
 they redefined and illustrated in the Geological Survey of Illinois, 
 volume 5, page 509, under the name of Protaster ( ?) gregarius. They 
 had numerous specimens 'in the condition of casts and molds, in 
 a very fine, somewhat granular matrix, that did not show the details 
 of its structure very clearly/ but they said, 'It will probably be 
 found to be generically distinct from the Silurian typical forms of 
 Protaster, but we prefer to place it provisionally in that genus for the 
 present.' In the collection of Mr. Gurley there are several specimens 
 belonging to this species, and they show a few characters not ob- 
 served by Meek and Worthen, and demonstrate very clearly this 
 species does not belong to the genus Protaster; we therefore propose 
 to include this species in a new genus, Aganaster, and describe the 
 characters, so far as known, as follows: 
 
 " General outline, a central circular disk with five long, narrow 
 rays ; the circular disk on the dorsal side is covered with small polygo- 
 nal plates which are not interrupted by the presence of the rays, 
 thus showing the disk had a depth greater than the depth of the 
 rays; rays very narrow and convex or half cylindrical, spine bearing, 
 gradually tapering, and from the dorsal side appear as if composed 
 of plates arranged exactly opposite each other; the ventral side shows 
 a rather deep central disk with marginal plates. There are 10 oral 
 plates in the central part of the disk." 
 
 Genoholotype and only species. Protaster gregarius Meek and 
 Worthen. 
 
 Remarks. Aganaster "has nothing to do with Protaster and is 
 clearly a member of the Streptophiurse. As far as its characters are 
 known to me it must be included among the Eoluidiidae. It differs 
 from the rest of this family by the presence of dorsal arm plates. 
 * * * Bohm has founded the genus OpJiiopege on the type species 
 of Aganaster." (Gregory.) 
 
 AGANASTER GREGARIUS (Meek and Worthen). 
 
 Protaster f gregarius MEEK and WORTHEN, Proc. Acad. Nat. Sci. Philadelphia, 
 vol. 21, 1869, p. 169; Geol. Surv. Illinois, vol. 5, 1873, p. 509, pi. 16, fig. 5. 
 
 Alepidaster gregarius MEEK, Amer. Journ. Sci., ser. 3, vol. 4, 1872, p. 275 (gen. 
 ref. only). 
 
 Aganaster gregarius MILLER and GURLEY, Sixteenth Rep. Geol. Surv. Indiana, 
 1891, p. 372, pi. 9, figs. 10, 11; authors' extracts, 1890, p. 57, pi. 9, figs. 10, 
 11. MILLER, N. Amer. Geol. Pal., 1st. App., 1892, p. 673, fig. 1208. 
 
 Description of 1873. "The disk of this species is circular in out- 
 line, slightly convex above, and measures from 0.20 to 0.30 inch in 
 diameter. In most cases it looks as if merely covered by a smooth, 
 membranaceous integument. Some casts of its external surface, 
 however, seem to show traces of flat, nearly smooth, imbricating 
 scales above. The five arms are slender, flexible, and rather long 
 
KEVISION OF PALEOZOIC STELLEROIDEA. 265 
 
 in proportion to breadth. In a specimen with a disk measuring 
 0.25 inch in breadth, the diameter of the arms near the disk is only 
 0.05 inch. None of the specimens show the entire length of the arms, 
 though some fragments of them were seen lying detached in the 
 matrix, about 0.55 inch in length, without being complete at either 
 end. From the breadth and gradual taper of these, it would seem 
 probable that when entire they may have been 0.75 to 1 inch in length. 
 Their impressions in the matrix give no indications of a longitudinal 
 furrow along the under side, but show that there were about six 
 pairs of arm pieces in a length of 0.16 inch. These pieces appear 
 to be nearly though not exactly opposite, and each one provided 
 below with a comparatively large, round, deep pit, or pore, near 
 the middle of its anterior side. Along their lateral margins there 
 appear to be impressions in the matrix of very small spines (one to 
 each arm piece), though if such, they must have been extremely 
 short. Impressions of the upper side of the slender arms show 
 them to have been somewhat rounded above, with the nearly square 
 arm pieces slightly alternating. Some of the impressions seem to 
 show traces of central pores or pits, one at the middle of each pair 
 of pieces, though in others no traces of these are visible/ 7 
 
 Formation and locality. Common as molds in a fine impure 
 sandstone and in the famous crinid bed at Crawfordsville, Indiana, 
 in the Keokuk formation of the Mississippic. 
 
 There are two specimens (No. 6) of this species in the Wachsmuth 
 collection at Harvard University. At Yale University there are 
 four specimens. 
 
 Family CHOLASTERID^ Worthen and Miller. 
 
 Cholasteridse WORTHEN and MILLER, Geol. Surv. Illinois, vol. 7, 1883, p. 328. 
 Original deHnition. Cholaster "is so widely different from those 
 heretofore discovered that we think it belongs to a distinct family, 
 which might very appropriately be designated the Cholasteridse, 
 but until other specimens have been found showing other parts 
 of the body, we prefer to let the family remain undefined." 
 Contains the genus : 
 
 Cholaster Worthen and Miller. 
 
 Genus CHOLASTER Worthen and Miller. 
 
 Cholaster WORTHEN and MILLER, Geol. Surv. Illinois, vol. 7, 1883, p. 328. 
 GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1040. 
 
 Original description. Dorsal side alone known. "Body trun- 
 cated pentagonal, central area circular, deep and large in propor- 
 tion to the rays; rays distant, smaU, short and abruptly truncated. 
 
266 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 " Dorsal side possessing a rather large centro-dorsal plate, which 
 is surrounded by five plates occupying the position of radials, while 
 the other part is covered with numerous small disk plates. " 
 
 Gfenoholotype and only species.- C. peculiaris Worthen and Miller. 
 
 Gregory states that CJiolaster "appears to be allied to Aganaster, 
 but the structure of the ambulacral ossicles is unknown." 
 
 CHOLASTER PECULIARIS Worthen and Miller. 
 
 Cholaster peculiaris WORTHEN and MILLER, Geol. Surv. Illinois, vol. 7, 1883, 
 p. 329, pi. 31, figs. 4a, 4b. 
 
 Original description. "The general form of the body is that of a 
 truncated pentagonal star, with a large circular disk. A centro- 
 dorsal plate is surrounded by five others, all of which are much larger 
 than other plates of the body, and occupy a centro-dorsal depres- 
 sion. The position of these five plates is that of radials, resting 
 upon a basal, and therefore all other plates of the body might be 
 regarded as radials and interradials, the latter being very numer- 
 ous, because of the wide separation of the rays at their junction 
 with the body. The interradials are polygonal, convex, or sub- 
 spinous plates, without much variation in size whether filling the 
 larger or smaller interradial spaces. The plates following the larger 
 radial plates, as above defined, in the direction of the rays, are not, 
 however, by their form or arrangement to be distinguished from 
 the interradials, though differing from those forming the rays. 
 The plates covering the dorsal side are thus divided into three 
 kinds, viz.: First, the larger plates filling the centro-dorsal depres- 
 sion; second, the disk plates which cover all other parts of the body 
 except the rays, and, third, the plates which cover the rays proper, 
 which in this species are easily distinguished from the central disk 
 plates. 
 
 "The rays are short, abruptly truncated, and slightly expanded 
 at the apices by reason of an enlargement of the terminal plates. 
 They are widely separated from each other, though not at uniform 
 distances, and present the appearance of having been stuck on the 
 central disk, instead of having grown from it, an appearance more 
 marked, by reason of the change in the form of the plates, from the 
 disk to the rays. 
 
 "One of the interradial spaces is much greater than the others, 
 so that a line may be drawn across the disk, leaving three entire 
 rays upon the smaller half. The back of each ray is covered by a 
 series of transversely elongated plates separated from the side 
 series by a longitudinally impressed line. A single series of plates 
 covers either side of a ray, interlocking with the transverse dorsal 
 series and directed backward toward the disk. 
 
 "The oral plates are unknown, and no madreporiform tubercle 
 has been detected." 
 
REVISION OF PALEOZOIC STELLEBOIDEA, 
 
 267 
 
 Formation and locality. Okaw Bluffs, between Chester and 
 Kaskaskia, Illinois, in the Chester formation of the Upper Missis- 
 sippic. The holotype is in the Illinois State collection, No. 2480. 
 
 Subclass OPHIUROIDEA. 
 
 These animals are not present in the older Paleozoic, may have 
 appeared in the late Devonic, and <Jo not seem to have been abundant 
 
 FIG. 33. OPHIOTERESIS. AFTER BELL FROM GREGORY. 
 ABORAL SURFACE OF AN ARM OSSICLE: a, ARTICULAR 
 CAVITIES; d, THE DOUBLE DORSAL SHIELDS; I, LATERAL 
 
 ARM PLATES. 
 
 FIG. 34. SYNGNATHS OF OPHIURA CIUARIS. 
 AFTER MULLER FROM GREGORY. ;, JAW; 
 m.f., MOUTHFRAME; n, g., GROOVE FOR CIR- 
 
 CUMCESOPHAGEAL NERVE-RING; p. d., PORE 
 AND DEPRESSION FOR ORAL TENTACLE. 
 
 before the Triassic, since which time they occur more and more com- 
 monly. In the present oceanic waters they are popularly known as 
 sand-stars, brittle-stars, branching-stars, or basket starfish. They 
 range from shallow and estuarine waters to abyssal depths. Typical 
 Ophiuroidea differ from typical Asteroidea in having the arms sharply 
 marked off from the disk as appendages, and in the absence of 
 grooves along the actinal side of the arms. This means that the body 
 cavity which in the Asteroidea extends out into the rays is restricted 
 in the Ophiuroidea to the disk. 
 
 The subclass Ophiuroidea is defined by Schondorf as follows: 
 "Ainbulacral water-vascular system situated in a small groove 
 at the base of the ray ossicles, and ventrally covered by a single 
 column of ventral shields. From the radial canal outside of the 
 ambulacrals arise simple lateral branches that never have ampullae, 
 as a rule curve upward, pass into and through the substance of the 
 ossicles, and finally open out laterally between the ventral and side 
 shields as the ambulacral podia. Ambulacrals opposite, each right 
 and left piece coossified into a vertebra with complicated articular 
 surfaces [see figs. 34-36]. Adambulacrals transformed into lateral 
 shields. Vertebrae dorsally covered by a single column of dorsal 
 shields." Disk circular in outline, lt without marginal plates, and 
 sharply separated from the rays, that as a rule are rounded. There 
 is no typical madreporic plate. One of the ventrally situated mouth 
 shields serves as madreporite" (1910a: 246). 
 
268 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 In ophiurids the oral skeleton, or syngnaths, is composed of three 
 pairs of adambulacrals and ambulacrals. Of these the two first 
 pairs alone are prominent and preserved. The third pair remains 
 internal, small, and rudimentary. 
 
 Family ONYCHASTERID^ Miller. 
 
 Onychasteridae MILLER, N. Amer. Geol. Pal., 1889, p. 216. GREGORY, Proc. Zool. 
 Soc. London for 1896, 1897, p. 1040. STURTZ, Verh. iiaturh. Ver. preuss. 
 Kheinl., etc., vol. 56, 1900, p. 202. SCHONDORF, Jahrb. nassauisch. Ver. 
 Naturk., Wiesbaden, vol. 63, 1910, p. 235. 
 
 Original diagnosis. " Strep tophiurse with well-developed vertebral 
 ossicles, and with very flexible, contorted, unbranched arms; there 
 
 U.S. " 
 
 u. ^ 
 
 FIGS. 35 AND 36. VERTEBRAL OSSICLE OF OPHIURA CILIARIS. AFTER MULLER FROM GREGORY. 35; 
 ABORAL SURFACE; 36, ADORAL SURFACE, c, CANAL FOR THE PODION (SHOWN BY REMOVAL OF A PART OF 
 
 MUSCLE FIELD ON RIGHT SIDE); J.W., LOWER MUSCLE FIELD; l.f., LOWER AND ./., UPPER CANAL FURROWS, 
 ., UMBO; U. *., UMBONAL SOCKET. 
 
 are no external arm plates, the integument containing granules 
 only.' 7 
 
 Contains the genus : 
 
 Ony chaster Meek and Worthen. 
 
 Genus ONYCHASTER Meek and Worthen. 
 
 Onychaster MEEK and WORTHEN, Geol. Surv. Illinois, vol. 3, 1868, p. 526; Proc. 
 Acad. Nat. Sci. Philadelphia, vol. 21, 1869, p. 82; Geol. Surv. Illinois, vol. 5, 
 1873, p. 474. ZITTEL, Handb. Pal., vol. 1, 1879, p. 443. MILLER, N. Amer. 
 Geol. Pal., 1889, p. 264. STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., 
 vol. 50, 1893, p. 30. GREGORY, Proc. Zool. Soc. London for 1896, 1897, p. 
 1040. STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, p. 183. 
 SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 62, 1909, 
 pp. 47-61, vol. 63, 1910, p. 240; Palaeontographica, vol. 57, 1910, p. 59. 
 SPENCER, Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. for 1913), 1914, 
 pp. 26, 50. I. B. J. SOLLAS, Philos. Trans. Hoy. Soc. London, ser. B, vol. 
 204, 1913, p. 51. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, 
 vol. 66, 1913, pp. 97-114. 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 
 
 269 
 
 Genoholotype. 0. flexilis Meek and Worthen. 
 
 For generic description, see under 0. flexilis. 
 
 Remarks ly Gregory.- "This interesting genus has hitherto been 
 placed among the Euryalidse, of which it has been regarded as the best 
 known fossil representative. As Prof. Bell, however, has remarked, 
 Meek and Worthen's clear figures of the vertebral ossicles show that 
 the articular surfaces are Strep tospondy line and not Cladophiuroid." 
 
 Schondorf in 1909 restudied Ony chaster hi detail, and came to the 
 following conclusions : 
 
 u Ony chaster flexilis shows plainly in the structure of its arm ossicles 
 that it belongs to the Ophiuroidea. As in this subclass, so also in 
 Onychaster the arm ossicles originated from two halves (ambulacrals) 
 that grew tightly together. When compared with living Ophiurids, this 
 
 40 
 
 41 
 
 FIGS. 37-41 .ONYCHASTER FLEXILIS. AFTER SCHONDORF. 37 AND 38, PROXIMAL VERTEBRA SEEN FROM 
 
 THE ABORAL AND ADORAL SURFACES. 39, VENTRAL VIEW OF TWO PROXIMAL VERTEBRA, ORIENTED 
 WITH THE ABORAL SIDE UP AND THE ADORAL DOWN. 40, SIDE VIEW OF SAME. ADORAL SIDE ON LEFT, 
 ABORAL ON RIGHT. 41, VENTRAL VIEW OF SEVERAL SUCCESSIVE VERTEBRA WITH THE ABORAL SIDE 
 AT THE TOP. O, UPPER LATERAL ARTICULAR KNOB; O', SOCKET FOR KNOB OF ADORAL SIDE; C, INSERTION 
 FIELD FOR THE UPPER, AND 0, FOR THE LOWER INTERMEDIARY VERTEBRAL MUSCLES; gr, MEDIAN UN- 
 PAIRED DEPRESSION; gr\, SMALL DEPRESSION FOR THE KNOB, fci, OF THE ADORAL SIDE; gr, LARGE DE- 
 PRESSION OF THE CENTRAL AREA OF VERTEBRA; TO, BARRIER SEPARATING THE UPPER AND LOWER 
 INTERMEDIARY VERTEBRAL MUSCLES; T, LATERAL GROOVE (? FOR LATERAL BRANCHES OF WATER- 
 VASCULAR SYSTEM); S, VENTRAL PROJECTION OF THE LATERAL KNOBS OF ADORAL SIDE; t AND t' , UNPAIRED 
 MEDIAN ARTICULAR KNOB AND SOCKET. 
 
 amalgamation of the two arm ossicles in Onychaster is still plainly to be 
 seen. The equivalent skeleton of the adambulacrals in the asterids is 
 not yet completely separated from the arm ossicles nor developed into 
 independent side or lateral shields ; on the contrary, they still remain 
 attached and in articulation with the arm ossicles on their ventral outer 
 margin. On their somewhat fluted outer margin they bear a few spines. 
 The arm ossicles are not externally naked but are covered by smaller 
 additional plates that bear flat calcareous particles. Individual large 
 dorsal shields do not appear to be present, for on the large Berlin speci- 
 men the arm ossicles lie directly beneath the small flat dorsal plates. 
 Only in the distal part of the rays does one observe some rows of 
 
270 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 apparently independent dorsal plates, that overlie one another in 
 a scalelike manner, but this determination needs to be substantiated 
 on better preserved material. Along the median line of the arm 
 ossicles there lies ventrally a single column of ventral plates, that 
 bear spines and externally cover the radial canal of the water vas- 
 cular system. The lateral branches from the radial canal to the 
 ambulacral podia do not penetrate the substance of the arm ossicles 
 as in living ophiurids, but lie between each pair of vertebrae. The 
 oral skeleton consists of five interradially placed mouth-corner 
 pieces. Each one of these is made up of three elements, the two 
 outer of which are united into pairs" (pp. 60-61). 
 Contains the following species : 
 
 0. flexilis Meek and Worthen. Keokuk. 
 
 0. asper Miller. Keokuk. 
 
 0. barrisi (Hall). Burlington. 
 
 0. confragosus Miller. Keokuk. 
 
 0. demissus Miller. Keokuk. 
 
 ONYCHASTER FLEXTLIS Meek and Worthen. 
 Text figs. 37 to 42. 
 
 Onychastei* flexilis MEEK and WORTHEN, Geol. Surv. Illinois, vol. 3, 1868, p. 526, 
 figs. A-D; Proc. Acad. Nat. Sci. Philadelphia, vol. 21, 1869, p. 83; Geol. Surv. 
 Illinois, vol. 5, 1873, p. 510, pi. 16, figs. 3a-3Z. ZITTEL, Handb. Pal., vol. 1, 
 1879, p. 444, fig. 314. MILLER, N. Amer. Geol. Pal., 1889, p. 264, fig. 374. 
 SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 62, 1909, 
 pp. 47-61; vol. 63, 1910, p. 240. I. B. J. SOLLAS, Philos. Trans. Roy. Soc. 
 London, ser. B, vol. 204, 1913, pp. 51-62, text figs. 1-4, pi. 8, figs. 1-6. 
 SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wiesbaden, vol. 66, 1913, pp. 
 97-114, text figs. 1, 2, pi. 3, figs. 3-9. SPENCER, Mon. Brit. Pal. Asterozoa, 
 pt. 1 (Palseontogr. Soc. for 1913), 1914, pp. 26, 50. 
 
 Original description. "The interesting fossil on which we propose 
 to found this genus and species seems to differ so widely, in some of 
 its characters, from the true starfishes, as well as from the Ophi- 
 urians, as to leave doubts whether it can be properly placed in either 
 of these groups as now understood. * * * In habit and general 
 appearance it most nearly resembles the Ophiurians, from which, 
 however, it differs widely in structure. It is composed of a rather 
 small subdiscoid body, and five long, slender, rounded, flexible arms 
 or rays. In nearly all of the specimens yet found the arms are folded 
 together like the claws of a bird when grasping some small object. 
 A few of them, however, have the arms opened out more or less, so 
 as to show that they were very flexible, or capable of being moved 
 about in all directions. They usually increase slightly in thickness 
 for a short distance from the body, then taper very gradually to their 
 extremities, being about 2.50 inches in length, and 0.22 inch in 
 breadth, at the widest part. 
 
KE VISION OF PALEOZOIC STELLEKOIDEA. 271 
 
 "On the dorsal side of the body * * * there is seen a compar- 
 atively large circular area or disk, composed of an outer circle of ten 
 rather prominent pieces, united together in five pairs by close-fitting 
 sutures, each piece being pierced by a round ovarian ? pore. Imme- 
 diately within this circle there is, apparently, another circle of ten 
 smaller pieces, also united in five pairs, but without pores; and within 
 this latter circle there is a third range of five still smaller, nonporif- 
 erous pieces, surrounding a central anal? opening; the whole re- 
 minding one of the apical disk of an Echinoid, though differing in 
 structure from this part of the known types of that group. It is 
 also worthy of note that there is some analogy between this disk and 
 the body of a crinoid, excepting that there is a central opening, and 
 thnt the first division of the radial series takes place immediately on 
 the inner range of pieces corresponding to the basal pieces of a crinoid, 
 while all of the third range of pieces are pierced by pores. * * * 
 
 "Immediately outside of the circle of ten pore pieces, mentioned 
 above, each pair of these pieces is succeeded by two or three pairs of 
 differently formed, interlocking, transverse pieces, in direct range, con- 
 necting them with the dorsal side of each of the five rays. A little far- 
 ther out the dorsal side of the rays, these transverse pieces are seen 
 to become disconnected by more or less wide spaces, and gradually 
 pass into pairs of lanceolate pieces, deeply furrowed longitudinally, 
 while between the inner ends of the two pieces of each pair there 
 appears to be a porelike opening. These latter disconnected pieces 
 continue all the way out to the extremities of the rays, and, with 
 numerous smaller intervening ossicles, form together, as it were, the 
 skeleton or framework of the long flexible rays. It is only, however, 
 when an outer granular integument has been removed that this 
 skeleton structure can be seen. In some parts of some of our specimens 
 this outer granular covering remains, and is seen to be composed of 
 numerous small, rounded, rather prominent ossicles, regularly 
 arranged in qui[n]cunx, so as to give the surface a chagreenlike rough- 
 ness. These ossicles were doubtless attached to, and secreted by, a 
 soft dermal envelope, covering the whole surface, while the larger 
 pieces within formed the frame, as it were, of the whole structure, 
 and probably furnished points of attachment for the muscles that 
 moved the rays. 
 
 "None of our specimens show clearly the inner side or ambulacral 
 furrows of the rays, nor the under side of the body consequently 
 we know nothing of the nature or position of the mouth or of the 
 ambulacra. In several instances, however, we have seen the remains 
 of one or more rows of small, short, longitudinally striated spines 
 along the inner side of the arms. 
 
 50601 Bull. 8815 18 
 
272 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 "The entire breadth of a mature individual, across between the 
 extremities of the rays on opposite sides, if these rays were straight- 
 ened out, would be about 5 to 6 inches." 
 
 Formation and locality. This species occurs quite commonly in 
 the famous crinid bed at Crawfordsville, Indiana, in the Keokuk 
 formation of the Mississippic. Specimens are in several American 
 museums; two are at Yale University, others in the United States 
 National Museum. 
 
 Cat. No. 59392, U.S.N.M. 
 
 ONYCHASTER ASPER Miller. 
 
 Onychaster asper MILLER,. Seventeenth Rep. Geol. Surv. Indiana, 1892, p. 684, 
 pi. 12, figs. 3-5; advance extras, 1891, p. 74, pi. 12, figs. 3-5. MILLER, N. 
 Amer. Geol. Pal., App. 1, 1892, p. 680, fig. 1240; App. 2, 1897, p. 749, fig*. 
 1366. KEYES, Missouri Geol. Surv., vol. 4, 1894, p. 131. 
 
 Original description. " Dorsal side covered with an integument of 
 small plates and numerous short spines. Central disk rather large, 
 circular, convex, inflated from the point of contact with the arms. 
 The outer integument covers the whole surface of the central disk, 
 leaving no orifice exposed. Where the outer integument is worn off 
 the disk is composed of rather large, polygonal spine bearing plates. 
 The spines do not arise from the center of the plates, but laterally 
 from little pits or sockets at the sutures. These sockets give the 
 plates a somewhat sculptured appearance. The spines have a bulb 
 at the base and taper to an obtuse point above. 
 
 "The arms are long, rounded on the dorsal side, and very flexible. 
 Figure 4 shows the arms abruptly folded from the middle over the 
 ventral part, while figures 3 and 5 have the arms folded like the claws 
 of a bird grasping some small object. There is a row of spines on each 
 side of the arm furrows. 
 
 "This species is so different from the type that the generic reference 
 is very doubtful." 
 
 Formation and locality. In the Keokuk formation of the Missis- 
 sippic, at Boonville, Missouri. The specimens are said to be in the 
 Miller and F. A. Sampson collections. 
 
 ONYCHASTER BARRISI (Hall). 
 
 Protester f barrisi HALL, Desc. N. Sp. Crinoidea, 1861, p. 18. 
 Onychaster ? barrisi MEEK and WORTHEN, Proc. Acad. Nat. Sci. Philadelphia, 
 vol. 21, 1869, p. 83; Geol. Surv. Illinois, vol. 5, 1873, p. 476, pi. 10, figs. la-Id 
 
 Hall's original description. " A fragment of an Asterias } among the 
 Burlington fossils, presents, in the rays and in the oral plates, some 
 characters in common with Protaster; but I can discover no evidence 
 of a central disk. The fragment preserves the center of the lower 
 side and parts of four rays. All that remain of the rays are two 
 distinct ranges of plates, which, near the base, are separated by a 
 
REVISION OF PALEOZOIC STELLEROIDEA. 273 
 
 wide groove, but farther on appear to come in contact on their inner 
 margins. These plates consist of joints closely articulated together, 
 with a longitudinal foramen: their lower sides are marked lengthwise 
 by a comparatively wide but not deep groove. The body of the plate 
 has, on each side, a lateral arching process which is jointed at the 
 two extremities, and separated in the center by a pore-like perfo- 
 ration. There are ten oral plates, two from each division of the ray: 
 these plates are expanded vertically; their extreme points have the 
 inner edges slightly curving; the lower external faces are slightly 
 indented, or crenulate ; the surface of attachment is wide and strong, 
 and constricted at the base by a distinct groove, beyond which it 
 again expands. 
 
 "This form, if really without a disk, differs essentially from Prot- 
 aster; and there are also other differences, which may make it 
 necessary to constitute a distinct genus when better specimens shall 
 be obtained." 
 
 Formation and locality. In the Burlington limestone at Burlington, 
 Iowa. There are three specimens of this species in the Wachsmuth 
 collection (Nos. 10, 11, and 12) at Harvard University. 
 
 ONYCHASTER CONFRAGOSUS Miller. 
 
 Onychaster confragosus MILLER, Seventeenth Rep. Geol. Surv. Indiana, 1892, 
 p. 684, pi. 12, figs. 6, 7; advance extras, 1891, p. 74, pi. 12, figs. 6, 7. 
 
 Original description. "This species is so different from the one ^ast 
 described [0. asper], and also from the type of this genus, that it may 
 not be congeneric with either of them. I have no doubt that it 
 belongs to the same family. I have seen only the dorsal side of the 
 disk and the dorsal and lateral sides of the rays. There is no such 
 integument of small plates covering the dorsal side as belongs to 
 0. asper, but the surface is covered with short spines. 
 
 "The central part of the disk is somewhat injured in our specimens, 
 and its character can not be definitely determined. It is surrounded 
 by large, centrally convex, six-rayed plates. These rays seem to be 
 the elevated ridges that separate the sockets for the insertion of the 
 spines. Outside of this circle of ten six-rayed plates, there is a circle 
 of quadrilateral plates more or less sculptured by the sockets for the 
 spines, and here the radials may be said to commence. The dorsal 
 side of each ray consists of three series of plates, and there is one 
 series upon each side, or five series in an arm. The first plates are 
 connected laterally by smaller ones, in the angular depressions, 
 between the commencement of the rays, which form part of the disk* 
 All of the radial plates are more or less sculptured by the depressions 
 for the insertion of the spines. The spines are longer than the diam- 
 eter of a plate, bulbous at the lower end, and taper to an obtuse point. 
 The arms are long, round on the dorsal side, flexible and capable of 
 being rolled up on the ventral side or being twisted laterally. No 
 
274 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 such ovarian pores piercing the plates of the disk, as described and 
 illustrated in O.flexilis, have been discovered." 
 
 Formation and locality. In the Keokuk formation, at Boonville, 
 Missouri. The cotypes are said to be in the Miller collection. 
 
 ONYCHASTER DEMISSUS Miller. 
 
 Ony chaster demissus MILLER, Seventeenth Rep. Geol. Surv. Indiana, 1892, p. 685, 
 pi. 12, figs. 8-10; advance extras, 1891, p. 75, pi. 12, figs. 8-10; N. Amer. 
 Geol. Pal., App. 1, 1892, p. 680, fig. 1241. 
 
 Original description. "This species hangs its arms down and folds 
 them like the claws of a bird grasping some small object, and in these 
 respects is more like 0. flexilis than either of the preceding species. 
 The central disk is slightly concave, subpentagonal in outline, and 
 the rays drop down at right angles to the circumference of the disk. 
 
 "In the center of the disk there is a low, subcircular elevation, in 
 which I have been unable to find any sutures, or to determine whether 
 or not there is an opening of any kind ; it appears to consist of a single 
 plate. It is surrounded by a series of ten plates that form the sub- 
 pentagonal rim of the central disk. These plates are large, very 
 convex, radiately sculptured, and bent down in the direction of the 
 radial series as well as curving in to unite with the central plate. The 
 sculpturing is due to the sockets for the insertion of the rays. The 
 radial series commence from this circle of plates. The rays are 
 angular on the dorsal side or obtusely rounded. The dorsal side of 
 each ray consists of three series of plates, and there is one series on 
 each side, or five series in an arm. The first two plates in each ray 
 are connected laterally by smaller ones, which form part of the disk, 
 in the angular depressions, between the commencement of the rays. 
 All of the radial plates are more or less sculptured or pitted by the 
 depressions for the insertion of the spines. 
 
 "The arms are longer, more angular, and have rather smaller spines 
 than either of the preceding species. I have been unable to detect 
 any ovarian pores, but spine sockets very much resembling pores are 
 indicated in figure 8, but they occur in the sutures and are readily 
 distinguished from pores that pierce the plates." 
 
 Formation and locality. In the Keokuk formation, at Boonville, 
 Missouri. The three cotypes are said to be in the Miller collection. 
 There are two good specimens (No. 10994) in the Gurley collection at 
 the University of Chicago, and another specimen, from Crawfords- 
 ville, Indiana, in Yale University. 
 
 FORMS WHOSE RELATIONSHIPS ARE UNKNOWN. 
 
 CRIBELLITES CARBONARIUS Tate. 
 
 Cribellites carbonarius TATE, Rept. Brit. Assoc. Adv. Sci., for 1863, 1864, Notices 
 and abstracts, p. 88. 
 
 Original description. "This Asteroid, the first recorded from the 
 Mountain Limestone, is an impression of the upper surface, in a 
 
REVISION OF PALEOZOIC STELLEROIDEA. 275 
 
 fine-grained micaceous sandstone. It is named CribeUites carbo- 
 narius; and the following characters are observable: Rays five, 
 rounded, lanceolate, five times as long as the disk, ridged in the center, 
 covered with longitudinal rows of reticulating tubercles; disk small 
 and tuberculated. The disk is only 0.3 of an inch in diameter, 
 while the rays are 1.5 inches in length. A circular impression in the 
 disk may be the impression of the Madreporiform nucleus. In the 
 form of this Asteroid, and in the characters observable, it is similar 
 to Oribella rosea, Muller; but the rays are proportionally longer, the 
 disk smaller, and the tubercles much nearer to each other than in 
 the recent analogue. The sandstone from which the fossil Sea-star 
 was obtained lies 20 feet above the Shilbottle coal, and about 600 
 feet below the base of the millstone grit, being in the upper part of 
 the Mountain Limestone formation, which, in Northumberland, is 
 about 3,000 feet in thickness. In this sandstone there also occur 
 Strophomena crenistria and the remains of carboniferous plants." 
 
 Order OPHIOCISTIA Sollas. 
 
 Ophiocistia SOLLAS, Quart. Journ. Geol. Soe. London, vol. 55, 1899, pp. 692, 700. 
 SOLLAS and SOLLAS, Philos. Trans. Roy. Soc. London, ser. B, vol. 202, 
 1912, pp. 214, 222. 
 
 An anomalous order of free Echinoderma. 
 
 "The Ophiocistia are Ophiuroidea with five paired series of append- 
 ages, proceeding from the ventral surface of a plated test; and in 
 which vertebral ossicles are absent or insignificant" (p. 700). 
 
 Contains but one family, the Eucladiidse. 
 
 Remarks. That Eudadia and Euthemon, the genera belonging to 
 this order, are ophiurids is said to be apparent from the following: 
 "The absence of any openings on the dorsal surface, and of any indi- 
 cation of an anus, the ventral position of the madreporite, and the 
 sharp distinction of the arms from the test." On the other hand, 
 they differ from all known ophiurids in several important particu- 
 lars: 
 
 "The structure and disposition of the arms is unlike anything 
 known among either the Ophiurse or the Euryalse, and finds no 
 parallel among any group of fossil Ophiuroidea. If we consider the 
 disposition of the arms first, we find as a constant character among the 
 rest of the Ophiuroidea the extension of five of these appendages over 
 the ventral surface of the disk as far as the buccal aperture; the 
 vertebral ossicles of the arms are also serially represented in the 
 buccal armature. In the Euciadiidae also the arms are given off 
 from the- ventral surface of the test, and the first pair have their 
 origin in the outer distal angle of the jaws; if, however, we are to 
 regard the serial arms of Eucladiidse as the free extremities of lateral 
 
276 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 branches given off in pairs from a median hypothetical arm, then we 
 must admit that the branching takes place within the test to an extent 
 otherwise unknown within the class. If we turn next to the structure 
 of the arms, we find no less striking peculiarities. No decisive 
 evidence exists to prove that vertebral ossicles are present, but if 
 they are they must be out of all proportion small compared with the 
 lumen of the arm. Since the cavity of the arm is almost entirely 
 unoccupied by skeletal structures, the question naturally arises as 
 to the nature of the soft parts which it contained. The distal arms 
 are so large that they might well have afforded room for extensions 
 of the digestive viscera from the test. The absence of visible aper- 
 tures in the arms is another very puzzling feature, and one is almost 
 tempted to inquire whether the paired appendages are to be compared 
 with arms at all. 
 
 "The nature of the buccal armature is very different from that 
 of any other Ophiuroid, though there is a certain amount of corre- 
 spondence in the paired structure of its five pieces. The absence of 
 any opening that could be taken for bursal apertures is noteworthy." 
 
 Family EUCLADIID^E Gregory. 
 
 Eudadiidse GEEGORY, Proc. Zool. Soc. London for 1896, 1897, p. 1040. SOLLAS, 
 Quart. Journ. Geol. Soc. London, vol. 55, 1899, p. 692. STURTZ, Verh. 
 naturh. Ver. preuss. Rheinl., etc., vol. 56, 1900, p. 204. SCHONDORF, Jahrb. 
 nassauisch. Ver. Naturk., Wiesbaden, vol. 63, 1910, p. 236. 
 
 Contains the genera: 
 Eudadia Woodward. 
 Euthemon Sollas. 
 
 Genus EUCLADIA Woodward. 
 Plates 37, 38. 
 
 Eudadia johnsoniH. WOODWARD, Geol. Mag., vol. 6, 1869, p. 241, pi. 8. ZITTEL, 
 Handb. Pal., vol. 1, 1879, p. 443. STURTZ, Verh. naturh. Ver. preuss. 
 Rheinl., etc., vol. 50, 1893, p. 30. GREGORY, Proc. Zool. Soc. London for 
 1896, 1897, p. 1040, fig. 6 on p. 1041. SOLLAS, Quart. Journ. Geol. Soc. Lon- 
 don, vol. 55, 1899, p. 692. STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., 
 vol. 56, 1900, p. 183. SCHONDORF, Jahrb. nassauisch. Ver. Naturk., Wies- 
 baden, vol. 62, 1909, p. 47; vol. 63, 1910, p. 240. SOLLAS and SOLLAS, Philos. 
 Trans. Roy. Soc. London, ser. B, vol. 202, 1912, pp. 214, 222. SPENCER, 
 Mon. Brit. Pal. Asterozoa, pt. 1 (Palseontogr. Soc. for 1913), 1914, p. 50. 
 
 This genus has seven pairs of arms in each radius, or 35 in all. 
 These are covered with finely scaly integument. 
 
 Genoholotype. E. johnsoni Woodward (citations as above), Lower 
 Ludlow formation, at Sedgley, near Dudley, England. Other species 
 are E. woodwardi Sollas, also from the Lower Ludlow, at Leintwar- 
 dine, England, and E. f leecheri, new species, from the Lower Devonic 
 Coeymans limestone, New York. 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 277 
 
 EUCLADIA WOODWARDI Sollas. 
 
 Plate 37, figs. 1, 2. 
 
 Eucladia woodwardi SOLLAS, Quart. Journ. Geol. Soc. London, vol. 55, 1899, p. 
 695, figs. 1 and 2 on p. 694. 
 
 Original description. Ten specimens " agree in presenting five 
 paired series of appendages, proceeding from the ventral surface 
 of the body, which now possesses a more or less oval outline. The 
 specimens are all of nearly the same size, the central body measur- 
 ing about 2 by 3 cm., the longest arms 2.5 cm. in length, and about 
 3 mm. in breadth where broadest. Not more than four, possibly 
 only three, pairs of arms can be traced in connection with each 
 radius, but an additional pair may have existed close to the buccal 
 armature, and have since become crushed out of recognition. 
 
 " TTie dorsal surface [fig. 1]. This is completely covered by nu- 
 merous rounded polygonal or irregular scales, about 0.2 mm. thick 
 and not exceeding 5 mm. in diameter; their surface is richly granu- 
 lated. They are not arranged according to any discoverable law, 
 though there may be a tendency to run parallel with the ambitus. 
 In their present state they overlap each other to such an extent 
 that one plate may be half concealed by another; no doubt they 
 were imbricated during life, but the excessive overlap now presented 
 is probably due in part to crushing. The direction of the imbrica- 
 tion is upward, that is, in the direction opposite to that of tiles on 
 a roof, and thus resembles the imbrication of the dorsal surface of a 
 recent Ophiuroid. The plates are all of the same nature, and there 
 are no openings on the dorsal surface. 
 
 " The ventral surface [fig. 2]. In the center the powerful buccal 
 armature is a very conspicuous object. It consists of five pairs 
 of strong plates or ossicles, precisely similar in their form and 
 arrangement to those of Eiicladia johnsoni. Around the armature 
 are numerous small plates, irregularly disposed; from their form 
 and size these may be regarded as elements of the test, though they 
 may possibly include remains of crushed arms. If, as judging 
 from analogy we might suppose, minute arms proceeded from the 
 outer angles of the jaws, they have since disappeared. 
 
 " Outside the irregularly scattered small plates larger ones are 
 seen arranged; along the five radii these are escutcheon-shaped, 
 imbricated, and form a single series of three. Distally, each plate 
 is produced into three processes, a single median and two lateral; 
 the angle formed by the side of the plate and each lateral process 
 is rounded and thickened to form one side of a circular aperture 
 for the passage or insertion of the arm, and the other half of the 
 aperture is completed by the thickened margin of a similarly exca- 
 
278 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 vated adjacent or adradial plate. The adradial plates form a pair, 
 which, meet in the interradius. The arrangement is similar to that 
 which occurs in the genus EutTiemon, to be next described; in the 
 latter, however, the plates are not overlapping, but tesselated. 
 The overlapping of the plates is less on the ventral than on the 
 dorsal side, a difference which is probably due to the less amount 
 of displacement suffered by the ventral plates; and this, again, is 
 explicable on the assumption that the ventral surface was flatter 
 than the dorsal. 
 
 " The arms. The arms of this species do not exhibit that marked 
 increase in size, as their position in the series becomes more distal, 
 which is characteristic of Eucladia johnsoni. Their average length 
 is 25 mm. Near their tapering extremities the arms present on both 
 dorsal and ventral surface three plates, two of which are lateral 
 and one median, recalling the characteristic plating of an Ophiuroid 
 arm; but nearer the origin the number of conspicuous plates on 
 either surface is increased to four or even more, and smaller supple- 
 mental plates are inserted between them in a manner precisely 
 similar to that already described hi the case of Eucladia johnsoni. 
 The larger plates, swollen at first and becoming mucronate finally, 
 are produced into a short awn-like termination. 
 
 "A search, which proved unsuccessful, was made for some trace 
 of vertebral ossicles; had these structures been present originally, 
 they must either have been very small or some traces would still 
 be discernible. In Lapworihura, which occurs in the same rocks, 
 the vertebral ossicles are the most obvious elements in the brachial 
 skeleton. 
 
 "The distinction of Eucladia woodwardi from E. johnsoni rests 
 on the smaller number of arms possessed by the former and the 
 closer approach of these to equality in dimensions. The speci- 
 men selected as the 'type' is exhibited in the Oxford University 
 Museum, and bears a label stating where its description may be 
 found." 
 
 Formation and locality. In the Lower Ludlow, Leintwardine, 
 England. 
 
 EUCLADIA (?) BEECHERI, new species. 
 Plate 38, fig. 1. 
 
 As this problematic fossil is of considerable interest, it is thought 
 best to make it known in this work, even though the preservation 
 is not good. The general characters are easily seen in the specimen, 
 however, and much better than can be shown by photography, but 
 in detail very little can be made out. The fossil lies in a dense 
 dark limestone beneath the surface of a parting between two beds 
 
EEVISION OF PALEOZOIC STELLEEOIDEA. 279 
 
 of stone. Originally but a few of the arms showed, and it was at 
 once seen by the late Professor Beecher that he had found some- 
 thing very different from a crinid. He bestowed a great deal of 
 skill and labor on the fossil later on, bringing it out to its present 
 relief, and in this condition it has remained since 1901, the year 
 of its collection. It seemed to both Professor Beecher and the writer 
 that it was an early form of branching or basket star, recalling the 
 living AstropJiyton. Recently, since reading the work of Sollas on 
 Eudadia, it became clear that this view could not be maintained. 
 
 The specimen seemingly shows the ventral side. 
 
 The disk is large and distinctly pentagonal, and from its five cor- 
 ners radiate the more or less coiled rays. Disk composed of de- 
 cidedly thick plates, apparently closely adjoining, but then- arrange- 
 ment is too much disturbed and crystalline to make out. R = ? about 
 13 mm., r ) =10.5 mm., B, to edge of rays averaging 22 mm. 
 
 Bays apparently completely circular in outline and covered by 
 an abundance of imbricating scales, of which there are about five 
 across the diameter of a ray. The average diameter of the rays 
 is between 1.5 and 2 mm. As the rays are crystalline the nature 
 of the internal skeleton can not be made out further than that 
 there are vertebrae present. Each radius appears to have 4 pairs 
 of arms, there being therefore 40 in all, but then* situation in the 
 disk and how they appear during growth cannot be made out. Three 
 pairs are of the same size throughout, while the fourth pair, which 
 lies upon the others, seems to be about half grown, and if there is no 
 decided distortion of the disk plates, these appeared alternately, 
 first on one side and then on the other. In Eudadia the 30 rays 
 are practically all alike, but in EutJiemon the 20 arms are equally 
 divided between full and half grown ones. 
 
 Formation and locality. From about the middle of the Coeymans 
 limestone of the Helderbergian (Lower Devonic), at Jerusalem Hill, 
 Litchfield, Herkimer County, New York. The holotype is hi the 
 Peabody Museum of Yale University. 
 
 Genus EUTHEMON Sollas. 
 
 Euthemon igerna SOLLAS, Quart. Journ. Geol. Soc. London, vol. 55, 1899, p. 696, 
 figs. 3 and 4 on p. 698. SOLLAS and SOLLAS, Philos. Trans. Roy. Soc. Lon- 
 don, ser. B, vol. 202, 1912, p. 222. 
 
 This genus is very similar to Eudadia , but differs at once in having 
 but 4 arms in each radius, or 20 in all; 10 of these are more than 
 twice as long (12 to 13 mm.) as the others (5 mm.). 
 
 GenoJiolotype and only species. E. igerna Sollas, from the Wenlock 
 limestone, Croft farm, Malvern, England. 
 
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 HAECKEL, E. H. 
 
 1866. Generelle Morphologie der Organismen. (Encrinaster.) 
 HALFAR, A. 
 
 1893. Die erste Asteride aus den palaozoischen Schichten des Harzes. Jahrb. 
 
 k. preuss. geol. Landesanst. u. Bergakad., Berlin, 1892, vol. 13, pp. 186- 
 199, pi. 10. (Aspidosoma petaloides goslariensis.) 
 HALL, J. 
 
 1847. Natural history of New York. Palaeontology, vol. 1. (Asterias matutina.) 
 
 1852. Natural history of New York. Palaeontology, vol. 2. (Palseaster, P. 
 
 niagarensis.) 
 
 1859. Natural history of New York. Palaeontology, vol. 3. (Protaster forbesi.) 
 1861. Descriptions of new species of Crinoidea. Preliminary notice. (Protaster ? 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 283 
 
 HALL, J. Continued. 
 
 1868. Contributions to palaeontology. 12. Note on the genus Palseaster and other 
 
 fossil starfishes. Twentieth Kept. New York State Cab. Nat. Hist., 
 
 pp. 282-303, pi. 9; also revised edition, 1868-1870, pp. 324-345, pi. 9. 
 
 (Palseaster shafferi, P. granulosus, P. eucharis, Ptilonaster, P. princeps, 
 
 Eugaster, E. logani.) 
 HICKS, H. 
 
 1873. On the Tremadoc rocks in the neighborhood of St. David's, South Wales, 
 
 and their fossil contents. Quart. Journ. Geol. Soc., London, vol. 29, 
 
 pp. 39-52, pis. 3, 4. (Palasterina ramseyensis.) 
 HUDSON, G. H. 
 
 1912. A fossil starfish with ambulacral covering plates. Ottawa Naturalist, vol. 
 
 26, pp. 21-26, 45-52, pis. 1-3. (Protopalxaster, P. narrawayi.) 
 1913a. The use of the stereogram in paleobiology. Bull. New York State Mus., 
 
 No. 164, pp. 103-130, pis. 1-13. (Stereograms of Mesopalseaster parvius- 
 
 culus, Hudsonaster narrawayi, and Palseaster niagarensis.) 
 19136. Does the type of Protopalaeaster narrawayi present the oral or aboral aspect? 
 
 Ottawa Naturalist, vol. 27, pp. 77-84, pis. 8, 9. 
 JAEKEL, O. 
 
 1903. Asteriden und Ophiuriden aus dem Silur Bohmens. Zeits. d. d. geol. 
 
 Gesell., vol. 55, Protok., pp. 13-20 (106-113), text figs. (Ataxaster, A. 
 
 pygmseus, Siluraster, S. perfectus, Bohemura, B. jahni, Eophiura, Palseura.") 
 JAMES, J. F. 
 
 1896. Manual of the paleontology of the Cincinnati group, pt. 7. Journ. Cincinnati 
 
 Soc. Nat. Hist., vol. 18, pp : 115-140. 
 
 DE KONINCK, L. 
 
 1878. Recherches sur les fossiles pa!6ozoiques de la Nouvelle-Galles du Sud 
 (Australie), pt. 3. Mem. Soc. Roy. Sci., Liege, ser. 2, vol. 7, pp. 1-255, 
 pis. 5-24. (Palssaster darkei.) 
 1898. Descriptions of the Palaeozoic fossils of New South Wales (Australia). 
 
 Mem. Geol. Surv. New South Wales, Pal., No. 6. 
 LOCKE, J. 
 
 1848. [Notice of an Asterias from the Blue Limestone of Cincinnati]. Proc. Acad. 
 Nat. Sci., Philadelphia, for 1846-1847, vol. 3, pp. 32-34, text fig. (Asterias 
 antiquata.) 
 McCoY, F. 
 
 1874. Prodromus of the palaeontology of Victoria. Geol. Surv. Victoria, dec. 1. 
 
 (Petraster smythi, Vrasterella selwyni.) 
 MEEK, F. B. 
 
 1872a. Description of two new ' star-fishes, and a crinoid, from the Cincinnati 
 
 group of Ohio and Indiana. Amer. Journ. Sci., ser. 3, vol. 3, pp. 257-262. 
 
 (Palseaster f dyeri, Stenaster grandis.) 
 18726. Descriptions of a few new species and one new genus of Silurian fossils 
 
 from Ohio. Amer. Journ. Sci., ser. 3, vol. 4, pp. 274-281. (Protaster ? 
 
 granuliferus, Palseaster incomptus, P. granulosus, P. spetiosus, Alepidaster.) 
 1873. Descriptions of the invertebrate fossils of the Silurian and Devonian systems. 
 
 Geol. Surv. Ohio, Pal., vol. 1, pp. 1-243, pis. 1-23, text figs. 
 MEEK, F. B., and WORTHEN, A. W. 
 
 1861. Descriptions of new Carboniferous fossils from Illinois and other Western 
 
 States. Proc. Acad. Nat. Sci., Philadelphia, for 1860, vol. 12, pp. 447-472. 
 (Schcenaster, S.fimbriatus.) 
 
 1862. Descriptions of new Palaeozoic fossils from Illinois and Iowa. Proc. Acad. 
 
 Nat. Sci., Philadelphia, for 1861, vol. 13, pp. 128-148. (Petraster wilber- 
 anus.) 
 
284 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 MEEK, F. B., and WORTHEN, A. W. Continued. 
 
 1866a. Descriptions of invertebrates from the Carboniferous system. Geol. Surv. 
 
 Illinois, vol. 2, pp. 145-411, pis. 14-32. 
 18666. Contributions to the palaeontology of Illinois and other Western States. 
 
 Proc. Acad. Nat. Sci., Philadelphia, for 1866, vol. 18, pp. 251-275. 
 
 (Schcenaster wachsmuthi.) 
 1868. Palaeontology. Geol. Surv. Illinois, vol. 3, pp. 291-565, pis. 1-20, text figs. 
 
 ( Onychas ter, 0. flexilis . ) 
 1869a. Descriptions of new Crinoidea and Echinoidea from the Carboniferous 
 
 rocks of the Western States, with a note on the genus Onychaster. Proc. 
 
 Acad. Nat. Sci., Philadelphia, for 1869, vol. 21, pp. 67-83. 
 18696. Descriptions of new Carboniferous fossils from the Western States. Proc. 
 
 Acad. Nat. Sci., Philadelphia, for 1869, vol. 21, pp. 137-172. (Protaster ? 
 
 gregarius.) 
 
 1873. Palaeontology of Illinois. Geol. Surv. Illinois, vol. 5, pp. 323-619, pis. 1-32. 
 MILLER, S. A. 
 
 1878. Description of a new genus and eleven new species of fossils. Journ. Cin- 
 
 cinnati Soc. Nat. Hist., vol. 1, pp. 100-108, pi. 3. (Palseaster longibrachi- 
 atus, P. clarkei.) 
 
 1879. Description of twelve new fossil species, and remarks upon others. Journ. 
 
 Cincinnati Soc. Nat. Hist., vol. 2, pp. 104-118, pis. 9, 10. (Palseaster 
 harrisi.} 
 
 1880a. Description of two new species from the Niagara group, and five from the 
 Keokuk group. Journ. Cincinnati Soc. Nat. Hist., vol. 2, pp. 254-259, 
 pi. 15. (Palseaster crawfordsvillensis.) 
 18806. Description of four new species of Silurian fossils. Journ. Cincinnati Soc. 
 
 Nat. Hist., vol. 3, pp. 140-144, pi. 4. (Palseaster miamiensis.) 
 1880c. Description of four new species and a new variety of Silurian fossils, and 
 remarks upon others. Journ. Cincinnati Soc. Nat. Hist., vol. 3, pp. 
 232-236, pi. 7. (Palseaster clarkana.) 
 
 1881. Description of some new and remarkable crinoids and other fossils of the 
 Hudson River group. Journ. Cincinnati Soc. Nat. Hist., vol. 4, pp. 69-77, 
 pi. 1. (Palseaster exculptus.) 
 
 1882a. Description of two new genera and eight new species of fossils from the 
 Hudson River group, with remarks upon others. Journ. Cincinnati Soc. 
 Nat. Hist., vol. 5, pp. 34-44, pis. 1, 2. (Tseniaster elegans.) 
 
 18826. Description of three new species, and remarks upon others. Journ. Cin- 
 cinnati Soc. Nat. Hist., vol. 5, pp. 116-117, pi. 5. (Protaster miamiensis.) 
 1884. Description of a beautiful star fish and other fossils. Journ. Cincinnati Soc. 
 
 Nat. Hist., vol. 7, pp. 16-20, pi. 4. (Palseaster magnificus.) 
 1889. North American geology and palaeontology. First appendix, 1892; Second 
 
 appendix, 1897. 
 
 1892. Palaeontology. Seventeenth Rept. Geol. Surv. Indiana, pp. 611-705, pis. 
 1-20; Advance extras, 1891. (Onychaster asper, 0. confragosiis, and 0. 
 demissus.} 
 MILLER, S. A., and DYER, C. B. 
 
 1878a. Contributions to palaeontology. Journ. Cincinnati Soc. Nat. Hist., vol. 1, 
 pp. 24-39, pis. 1-2. (Palseaster simplex, P. spinulosus, Palseasterina 
 approximata, P. speciosa, Protaster flexuosus.) 
 18786. Contributions to palaeontology, No. 2. Privately printed. (Palseaster 
 
 dubius.) 
 MILLER, S. A., and GURLEY, W. F. E. 
 
 1891. Description of some new genera and species of Echinodermata from the 
 Coal Measures and Subcarboniferous rocks of Indiana, Missouri, and 
 Iowa. Sixteenth Rept. Geol. Surv. Indiana, pp. 327-373, pis. 1-10; 
 Advance extras, 1890. (Schcenaster legrandensis, Aganaster.) 
 
REVISION" OF PALEOZOIC STELLEROIDEA. 285 
 
 MILLER, S. A., and GURLEY, W. F. E. Continued. 
 
 1897. New species of crinoids, cephalopods, and other Palaeozoic fossils. Bull. 
 Illinois State Mus. Nat. Hist., No. 12. (Palseaster wykoffi.) 
 
 MtJLLER, J. 
 
 1855. In ZEILER and WIRTGEN, Bemerkungen uber die Petrefacten der altern 
 devonischen Gebirge am Rheine, etc.; Verh. d. naturh. Ver. preuss. 
 Rheinl., etc., vol. 12, pp. 1-28, pis. l-9a. (Asterias rhenana.) 
 MURCHISON, R. I. 
 1854. Siluria. 
 NICHOLSON, H. A., and ETHERIDGE, R., JR. 
 
 1880. A monograph of the Silurian fossils of the Girvan District in Ayrshire, 
 fasc. 3. (Tetraster, T. wyville-thomsoni.} 
 
 D'ORBIGNY, A. D. 
 
 1849. Prodrome de Pal6ontologie, vol. 1. (Ccelaster americanus.} 
 PARKS, W. A. 
 
 1908. Notes on the ophiuran genus, Protaster, with description of a new species. 
 
 Trans. Canadian Inst., vol. 8, pp. 363-372, 1 pi. (Gives summary of 
 
 history of genus. P. whiteavesianus.) 
 
 QUENSTEDT, F. A. 
 
 1876. Petrefactenkunde Deutschlands, vol. 4, Asteriden und Encriniden. 
 RAYMOND, P. E. 
 
 1912a. On two new Paleozoic starfish (one of them found near Ottawa), and a new 
 crinoid. Ottawa Naturalist, vol. 26, pp. 77-81, pi. 5, 2 text figs. 
 (Palxaster f wilsoni, Schcenaster f montanus.) 
 
 19126. On the nature of the so-called "covering plates" in Protopalseaster narra- 
 wayi. Ottawa Naturalist, vol. 26, pp. 105-108, pi. 6. 
 
 RlNGUEBERG, E. N. S. 
 
 1886. New genera and species of fossils from the Niagara shales. Bull. Buffalo 
 Soc. Nat. Sci., vol. 5, pp. 5-22, pis. 1,2. (Squamaster, S. echinatus, 
 Protaster stellifer, Eugaster condnnus.) 
 ROEMER, F. 
 
 1863. Neue Asteriden und Crinoiden aus devonischem Dachschiefer von Bunden- 
 bach bei Birkenfeld. Palaeontographica, vol. 9, pp. 143-152, pis. 23- 
 29. (Aspidosoma tischbeinianum, Asterias asperula, A. spinosissima, 
 Helianthaster, H. rhenanus.) 
 
 RUEDEMANN, R. 
 
 1912. The Lower Siluric shales of the Mohawk valley. Bull. N. Y. State Mus., 
 
 No. 162. (Txniaster schoharix.) 
 SALTER, J. W. 
 
 1857. On some new Palaeozoic star-fishes. Ann. Mag. Nat. Hist., ser. 2, vol. 20, 
 pp. 321-334, pi. 9. (Palseocoma, P. marstoni, P. colvini, P. cygnipes, 
 Bdellacoma. B. vermiformis, Rhopalocoma, R. pyrotechnica, Palseaster 
 asperrimus, P. coronella, Palasterina, Protaster miltoni, P. leptosoma.) 
 
 1861. Additional notes on some new Palaeozoic star-fishes. Ann. Mag. Nat. 
 Hist., ser. 3, vol. 8, pp. 484-486, pi. 18, figs. 9-11. 
 
 1866. On the fossils of North Wales. Mem. Geol. Surv. Great Britain, vol. 3, 
 
 App., pp. 240-381, pis. 1-28. (Palseaster imbricatus.) 
 SALTER, J. W., and SOWERBY, J. de C. 
 
 1845. In SEDGWICK, On the Older Palaeozoic (Protozoic) rocks of North Wales. 
 Quart. Journ. Geol. Soc., London, vol. 1, pp. 5-22. (Ophmra salteri 
 and Asterias primseva listed in table, without description.) 
 SANDBERGER, G., and SANDBERGER, F. 
 
 1850-1856. Die Versteinerungen des rheinischen Schichtensystems in Nassau. 
 (Ccelaster, C. latiscutatus.) 
 
286 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 SCHONDORF, F. 
 
 1907a. Ueber einen fossilen Seestern Spanister latiscutatus Sandb. spec, aus 
 dem Naturhistorischen Museum zu Wiesbaden. Jahrb. nassauisch. 
 Ver. f . Naturk. , Wiesbaden, vol. 60, pp. 17XM76, 3 text figs. (Spaniaster. ) 
 
 19076. Ueber Archseasterias rhenana Joh. Muller und die Porenstellung palao- 
 zoischer Seesterne. Centralb. f. Mineral., etc., pp. 741-750, 6 text 
 figs. 
 
 1909a, Palaozoische Seesterne Deutschlands. I. Die echten Asteriden der 
 rheinischen Grauwacke. Palseontographica, vol. 56, pp. 37-112, text 
 figs., pis. 7-11. (Agalmaster, A. grandis, A. intermedius, A. miellensis, 
 Rhenaster, R. schwerdi, Trimeraster, T. parvulus, Eifelaster, E. foll- 
 manni, Xenaster dispar, X. elegans.) 
 
 19096. Die Asteriden des russischen Karbon. Palseontographica, vol. 56, pp. 
 323-338, text fig., pis. 23, 24. 
 
 1909c. Die fossilen Seesterne Nassaus. Jahrb. nassauisch. Ver. f. Naturk., 
 Wiesbaden, vol. 62, pp. 7-46, text figs., pis. 2-5. (Discusses skeletal 
 structure of asterids; Miomaster, M. drevermanni.) 
 
 1909rf. Organization und Aufbau der Armwirbel von Ony chaster. Jahrb. nassau- 
 isch. Ver. f. Naturk., Wiesbaden, vol. 62, pp. 47-63, pi. 6. 
 
 1910a. Ueber einige "Ophiuriden und Asteriden" des englischen Silur und ihre 
 Bedeutung fiir die Systematik palaozoischer Seesterne. Jahrb. nassau- 
 isch. Ver. f. Naturk., Wiesbaden, vol. 63, pp. 206-256, text figs. (Im- 
 portant for classification.) 
 
 19106. Palaozoische Seesterne Deutschlands. II. Die Aspidosomatiden des 
 deutschen Unterdevon. Palseontographica, vol. 5 7 , pp. 1-63, pis. 1-3. 
 (Discusses structure and systematics of group in much detail. Erects 
 a new order, Auluroidea. Aspidosoma goldfussi. A. roemeri. A. eifelense.) 
 
 1910c. Aspidosoma schmidti nov. spec. Der erste Seestern aus den Siegener 
 Schichten. Jahrb. k. preuss. geol. Landesanst. und Bergakad., Berlin, 
 vol. 29, 1908, pt. 1, pp. 698-708, 1 pi. 
 
 1913a. Palaeaster eucharis Hall aus dem nordamerikanischen Devon. Jahrb. 
 nassauisch. Ver. f. Naturk., Wiesbaden, vol. 66, pp. 87-96, text figs. 
 1, 2, pi. 3, figs. 1, 2. 
 
 19136. Ueber Onychaster, einen Schlangenstern aus dem Karbon. Jahrb. nas- 
 sauisch. Ver. f. Naturk., Wiesbaden, vol. 66, pp. 97-116, text figs. 
 1, 2, pi. 3, figs. 3-12. 
 
 SCHUCHERT, C. 
 
 1914. Fossilium Catalogus, I : Animalia, pars 3, Stelleroidea palaeozoica. 
 SIMONOVITSCH, S. 
 
 1871. Ueber einige Asterioiden der rheinischen Grauwacke. Sitzb. d. mat.- 
 naturw. Classe d. k. Akad. d. Wiss.. Wien, vol. 64, Abt. 1., pp. 77-122, 
 pis. 1-4. (Xenaster, X. margaritatus, X. simplex, Asterias acuminatus, 
 Aspidosoma petaloides.} 
 
 SOLLAS, I. B. J. 
 
 1913. On Onychaster, a Carboniferous brittle-star. Philos. Trans. Roy. Soc. 
 
 London, ser. B, vol. 204, pp. 51-62, text figs. 1-5, pis. 8, 9. 
 SOLLAS, W. J. 
 
 1899. Fossils in the University Museum, Oxford: I. On Silurian Echinoidea and 
 
 Ophiuroidea. Quart. Journ. Geol. Soc., London, vol. 55, pp. 692-715, 
 
 text figs. (Erects new order, Ophiocistia. Eudadia woodwardi, Euthe- 
 
 mon, E. igerna.) 
 SOLLAS, W. J., and SOLLAS, I. B. J. 
 
 1912. Lapworthura: a typical brittle-star of the Silurian age. Philos. Trans. 
 
 Roy. Soc. London, ser. B, vol. 202, pp. 213-232, text figs. 1-5, pis. 9, 10. 
 
 (Rhodostoma, Protaster groomi.) 
 
KEVISIOK OF PALEOZOIC STELLEROIDEA. 287 
 
 SPENCER, J. W. 
 
 1884. Niagara fossils, Pt. 3. Bull. Mus. Univ. State Missouri, No. 1, pp. 52-61, 
 
 pis. 7, 8. (Palseaster granti.} 
 SPENCER, W. K. 
 
 1914. A monograph of the British Palaeozoic Asterozoa. Pt. 1. Palaeontogr. Soc. 
 for 1913 ; pp. 1-56, text figs. 1-31, pi. 1. (Eoactis, E. simplex, Uranaster 
 elizx, Aspidosoma grayse, Lapworthura sollasi.) 
 STSCHUROWSKY. 
 
 1874. Nachr. d. Moskauer Gesell. d. Liebhaber d. Naturges. (Asterias montanus.) 
 
 Not seen. 
 STURTZ, B. 
 
 1886a. Ueber palaozoische Seesterne. N. Jahrb. f. Mineral., etc., vol. 2, pp. 
 
 142-154. (Hallaster.) 
 
 18866. Beitrag zur Kenntniss palaozoischer Seesterne. Palseontographica, vol. 32, 
 pp. 75-98, pis. 8-14. (Ophiurella, 0. primigenia, Roemeraster, R. asperula, 
 Astropecten schluteri, Eoluidia, E. decheni, Protester acanthion, P. pri- 
 mus, Fur caster, F. palseozoicus, Bundenbachia, B. beneckei, B. grandis, 
 Palastropecten, P. zitteli, Loriolaster, L. mirabilis, Palasteriscus, P. 
 devonicus.) 
 
 1890. Neuer Beitrag zur Kenntniss palaozoischer Seesterne. Palseontographica, 
 vol. 36, pp. 203-247, pis. 26-31. (Echinasterella, E. sladeni, Cheiropter- 
 aster, C. giganteus, Medusaster, M. rhenanus, Palseostella, P. solida, 
 Ophiurina, 0. lymani, Palseophiura, P. simplex, Palasterina follmanni. 
 Describes additional material of forms dealt with in 1886, revises 
 other species, discusses structure, systematics, habits, etc., of Paleozoic 
 ophiurids and asterids.) 
 
 1893. Ueber versteinerte und lebende Seesterne. Verh. naturh. Ver. preuss. 
 Rheinl., etc., vol. 50, pp. 1-92, pi. 1. (Salteraster, Ophiura rhenana, 
 Palxnectria, P. devonica.) 
 
 1900. Ein weiterer Beitrag zur Kenntniss palaozoigcher Asteroiden. Verh. naturh. 
 Ver. preuss. Rheinl., etc.,- vol. 56, pp. 176-240, pis. 2-4. (Reviews 
 Gregory's work of 1896 and gives classification of Ophiuroidea with 
 definition of families. Hisingeraster, Trentonaster, Hudsonaster, Pseudo- 
 palasterina, Eophiurites, Palseophiomyxa, Palseospondylus, Palxosolaster, 
 P. gregoryi, Echinasterias, E. spinosus, Echinodiscus, E. multidactylus, 
 Echinostella, E. traquairi, Jaekelaster, J. petaliformis.) 
 THORENT. 
 
 1838. M^moire sur la constitution ge*ologique de la partie nord du Departe*ment 
 de 1'Aisne. Mem. Soc. ge"ol. de France, vol. 3, pp. 239-260, pi. 22. 
 (Asterias constellata.) 
 TRAUTSCHOLD, H. 
 
 1879. Die Kalkbriiche von Mjatschkowa, Theil 3. M^m. Soc. imp. Nat. Moscou, 
 vol. 14, pp. 101-180, 7 pis. (Calliaster, C. mirus, Stenaster confluens.) 
 TROOST, G. 
 
 1835. Description of a new species of fossil Asterias (Asterias antiqua). Trans. 
 
 Geol. Soc. Pennsylvania, vol. 1, pp. 232-235. 
 ULRICH, E. 0. 
 
 1878. Descriptions of some new species of fossils from the Cincinnati group; 
 
 Journ. Cincinnati Soc. Nat. Hist., vol. 1, pp. 92-100, pi. 4. (Protasterina, 
 P.fimbriata.) 
 
 1879. Descriptions of new genera and species of fossils from the Lower Silurian 
 
 about Cincinnati. Journ. Cincinnati Soc. Nat. Hist., vol. 2, pp. 8-30, 
 pi. 7. (Palseaster finei.) 
 50601 Bull. 88 15 19 
 
288 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 VERRILL, A. E. 
 
 1914. Monograph of the shallow-water starfishes of the North Pacific coast from 
 the Arctic Ocean to California. Smithsonian Institution, Harriman 
 Alaska ser., vol. 14. 
 WOODWARD, H. 
 
 1869. On Eucladia, a new genus of Ophiuridae, from the Upper Silurian, Dudley. 
 
 Geol. Mag., vol. 6, pp. 241-245, pi. 8. (Eucladia, E. johnsoni.) 
 1874. Description of a new species of starfish from the Devonian of Great Ingle- 
 bourne, Harberton, South Devon. Geol. Mag., dec. 2, vol. 1, pp. 6-10, 
 96, 238, 432. (Helianthaster filitiformis.} 
 WORTHEN, A. W., and MILLER, S. A. 
 
 1883. Descriptions of new Carboniferous Echinoderms. Geol. Surv. Illinois, 
 vol. 7, pp. 327-331, pi. 31. (Compsaster, C. formosus, Cholaster, C. pe- 
 culiaris, Tremataster, T. dijficilis.) 
 WRIGHT, T. 
 
 1862. A monograph on the British fossil Echinodermata from the Oolitic forma- 
 tions, vol. 2, pt. 1. Palseontogr. Soc. for 1861. (Contains a diagnosis of 
 nine Paleozoic genera with species.) 
 1873. On a new genus of Silurian Asteriadse. Quart. Journ. Geol. Soc., London, 
 
 vol. 29, p. 421. (Trichotaster, T. plumiformis.) 
 ZITTEL, K. von. 
 
 1879. Handbuch der Palaontologie, vol. 1. 
 
EXPLANATION OF PLATES. 
 PLATE 1. 
 
 FIG. 1. Rudsonaster narrawayi (Hudson) (also see plates 2 and 4). 
 
 A greatly enlarged photograph of the genoholotype of Protopalssaster 
 narrawayi Hudson. The inner ventral side of the specimen is here seen 
 with all of the dorsal skeleton weathered away except one of the basal 
 supramarginalia. Note the well-preserved oral armature and in places 
 the ambulacralia. The latter are the "covering plates" of Hudson. 
 
 Photograph by Prof. George H. Hudson. 
 
 Middle Ordovicic (Black River). Ottawa, Canada. 
 
 Collection of Mr. J. E. Narraway. 
 
 PLATE 2. 
 
 FIG. 1. Hudsonaster narrawayi (Hudson) (also see plates 1 and 4). 
 
 A photograph X 6 of the actinal side. Note the five long spines (tori) 
 of the oral armature. 
 
 Middle Ordovicic (Black River). Kirkfield, Ontario, Canada. 
 
 Collection of Peabody Museum, Yale University. 
 FIG. 2. Hudsonaster matutinus (Hall) (also see plates 3 and 5). 
 
 A photograph X 3 of three specimens showing the actinal area as preserved 
 on a piece of black limestone. 
 
 Middle Ordovicic (Trenton). Rathbone Brook, near Newport, Her- 
 kimer County, New York. 
 
 Collection of Museum of Comparative Zoology, Harvard University 
 (No. 26). 
 
 PLATE 3. 
 
 FIG. 1. Hudsonaster rugosus (Billings). 
 
 A photograph X 2 of the abactinal area of a cotype. 
 Upper Ordovicic (Richmondian). Charleton Point, Anticosti Island, 
 Gulf of St. Lawrence, Canada. 
 
 Collection of the Geological Survey of Canada (No. 1999). 
 FIG. 2. Hudsonaster matutinus (Hall) (also see plates 2 and 5). 
 
 A retouched photograph X 2 showing the abactinal side. 
 Middle Ordovicic (Trenton). Trenton Falls, New York. 
 Collection of the Museum of Comparative Zoology, Harvard University 
 (No. 3). 
 FIG. 3. Hudsonaster batheri, new species. 
 
 A diagram X 3 of the actinal side made from a wax squeeze by Bather, 
 now in the United States National Museum (Cat. No. 60601). 
 Upper Ordovicic. Thraive, Girvan, Scotland. 
 
 289 
 
290 ' BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 PLATE 4. 
 
 FIG. 1. Hudsonaster narrawayi (Hudson) (also see plates 1 and 2). 
 
 A camera lucida drawing X 8 of the actinal side. The granules are 
 drawn somewhat too strongly. 
 
 Middle Ordovicic (Black River). St. Paul, Minnesota. 
 
 Ulrich collection of the United States National Museum (Cat. No. 
 60602). 
 FIG. 2. Hudsonaster milleri, new species. 
 
 A diagram, considerably enlarged, of an axillary area from the actinal 
 side. 
 
 Middle Ordovicic (Trenton). Fayette County, Kentucky. 
 
 Collection of the State University of Kentucky. 
 FIG. 3. Mesopalxaster (?) lanceolatus, new species. 
 
 Camera lucida drawing of one ra> from the actinal area, X 2. The 
 central furrow in the ambulacrum is decidedly V-shaped. 
 
 Upper Ordovicic (Utica). Near Rome, New York. 
 
 Collection of Peabody Museum, Yale University. 
 FIG. 4. Australaster giganteus (Etheridge). 
 
 An axillary area and part of two rays somewhat reconstructed from the 
 original figure. Natural size. Note the single very large axillary plate, 
 the enlarging adambulacrals, and the diminishing inframarginals. 
 
 "Permo-Carboniferous" (Lower Marine). Parley, Northumberland 
 County, New South Wales. 
 
 Collection of the Mining and Geological Museum, Sydney. 
 
 PLATE 5. 
 
 FIGS. 1 and 2. Hudsonaster matutinus (Hall) (also see plates 2 and 3). 
 
 1. Camera lucida drawing X 3.5 of the actinal side of one of the speci- 
 mens photographed on plate 2, fig. 2. 
 
 Middle Ordovicic (Trenton). Near Newport, New York. 
 Collection of Museum of Comparative Zoology, Harvard University 
 (No. 26). 
 
 2. Camera lucida drawing X 4.5 of the abactinal area of a specimen in 
 which the ossicles are somewhat displaced. 
 
 Middle Ordovicic (Trenton). Lachine, near Montreal, Canada. 
 Collection of the United States National Museum (Cat. No. 60603). 
 Collected by W. R. Billings. 
 
 PLATE 6. 
 
 FIGS. 1 and 2. Hudsonaster incomptus (Meek). 
 
 1. Camera lucida drawing X 4 of the actinal side. 
 
 Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 40882). 
 
 2. Camera lucida drawing X 4 of the abactinal area in a well preserved 
 specimen. The anal opening may have been in the first circle of small 
 plates adjacent to the centro-dorsal piece and in the same interradius as 
 the madreporite. 
 
 Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 40882). 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 291 
 
 PLATE 7. 
 
 FIGS. 1-4. Palseaster niagarensis Hall. 
 
 1. Camera lucida drawing X 4 of the abactinal side in its present 
 preservation. Holotype. 
 
 2. Abactinal side of theholotype restored, X 4. The drawing probably 
 has too many accessory disk pieces. 
 
 3. Camera lucida drawing X 4 of the a'ctinal side of one of the rays of 
 the holotype. Since this drawing was made the rock in the ambulacral 
 furrow has been dug away down to the ambulacral plates, which are 
 small and deep-seated. 
 
 4. A few of the inframarginals and supramarginals from the abactinal 
 side to show the smooth central areas surrounded by granular borders, X 4. 
 Siluric (Rochester shale). Lockport, New York. 
 Collection of Cornell University (No. 7331). 
 FIG. 5. Mesopalseaster find (Ulrich) (also see plate 9). 
 
 Camera lucida drawing X 16 of one of the rays. The ossicles are always 
 more or less displaced in this species. 
 
 Upper Ordovicic (Eden shales). Cincinnati, Ohio. 
 
 Ulrich collection of the United States National Museum (Cat. No. 60604). 
 
 PLATE 8. 
 
 FIGS. 1 and 2. Mesopalseaster shafferi (Hall). 
 
 1. Camera lucida drawing X 8 of the abactinal side of a one-third 
 adult-sized specimen. As the medial disk pieces are displaced in the 
 individual, they are here drawn in in their probable natural arrangement 
 all should be pointed like the central disk plate. 
 
 Upper Ordovicic (Maysvillian, Corryville member). Cincinnati, Ohio. 
 Vaupel collection of the United States National Museum (Cat. No. 
 60605). 
 
 2. Camera lucida drawing X 3 of the actinal area of a mature indi- 
 vidual. 
 
 Upper Ordovicic (Kichmondian). Waynesville, Ohio. 
 Harris collection of the United States National Museum (Cat. No. 
 59391). 
 FIG. 3. Miomaster drevermanni Schondorf. 
 
 Actinal side as reconstructed by Schondorf. Natural size. 
 Lower Devonic (Upper Coblenzian). Miellen, Germany. 
 
 PLATE 9. 
 
 FIG. I. Mesopalseaster (?) parviusculus (Billings). 
 
 Camera lucida drawing X 5 of a gutta-percha squeeze of the holotype, 
 actinal side. 
 
 Siluric (Lower Arisaig). Arisaig, Nova Scotia. 
 
 Original at McGill University; gutta-percha squeeze in United States 
 National Museum (Cat. No. 60620). 
 FIG. 2. Mesopalseaster (?) cataractensis, new species. 
 
 Photograph X 3 of the well-preserved holotype. 
 
 Siluric (Cataract formation). Hamilton, Ontario. 
 
 Collection of the Hamilton Natural History Society. 
 FIG. 3. Mesopalseaster (?) granti (Spencer). 
 
 Photograph X 2 of a specimen showing the dorsal side. 
 
 Siluric (Cataract formation). Hamilton, Ontario. 
 
 Collection of Peabody Museum, Yale University. 
 
292 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 FIG. 4. Mesopalseaster intermedius, new species. 
 
 Photograph X 3 of the holotype. Between the two rays lies an arm of 
 a crinid, giving the impression that this form has a large disk. 
 Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 
 Collection of the University of Chicago (No. 9575). 
 FIG. 5. Mesopalseaster finei (Ulrich) (also see plate 7). 
 
 Ulrich's original figures. Fig. 5, one of the cotypes from the abactinal 
 side X 2; fig. 5a, the madreporite X 6; fig. 56, a ray from the actinal side X 3. 
 Upper Ordovicic (Eden). Cincinnati, Ohio. 
 
 Ulrich collection of the United States National Museum (Cat. No. 60604). 
 FIG. 6. Mesopalseaster caractad (Gregory) (also see plate 11). 
 
 Retouched photograph X 3 of a wax squeeze by Bather, now in the 
 United States National Museum (Cat. No. 60606). Actinal area. 
 Ordovicic (Caradoc). Church Stretton, England. 
 
 PLATE 10. 
 
 FIGS. 1 and 2. Mesopalseaster clarki (Clarke and Swartz). 
 
 1. Drawing of the actinal side of the holotype X 1.5. 
 
 2. Abactinal area X 1.5. Note the few accessory pieces in the angles 
 between the radials. 
 
 Upper Devonic (Chemung). Near Oakland, Maryland. 
 Collection of the Maryland Geological Survey. 
 
 PLATE 11. 
 
 FIG. 1. Mesopalxaster caractad (Gregory) (also see plate 9). 
 
 Retouched photograph X 3 of a wax squeeze by Bather, now in the 
 United States National Museum (Cat. No. 60606). Abactinal area. 
 
 Ordovicic (Caradoc). Church Stretton, England. 
 FIG. 2. Devonaster chemungensis, new species. 
 
 Photograph of the natural mold of the actinal side of the holotype, 
 natural size. 
 
 Upper Devonic (Chemung). "Central Pennsylvania." 
 CoUection of Columbia University (No. 6228G). 
 
 PLATE 12. 
 
 FIGS. 1 and 2. Spaniaster latiscutatus (Sandberger). 
 
 1. Abactinal side. 
 
 2. Actinal side. 
 After Schondorf . 
 
 Lower Devonic. Germany. 
 FIGS. 3-5. Devonaster eucharis (Hall). 
 
 3. Abactinal side, natural size, a, the madreporite. After Hall. 
 
 4. Actinal side, natural size. After Hall. The tiny ambulacral plates 
 should have been drawn as opposite one another and not alternate. 
 
 5. Hall's diagram (3a) of the actinal plate arrangement. The ambu- 
 lacrals are incorrectly drawn, as their arrangement is opposite and not 
 alternate, a, ambulacralia; aa, adambulacralia; m, inframarginalia; o, 
 pairs of oral armature ossicles; p, podial openings, but drawn a little too 
 large; tm, the single interbrachial axillaries. 
 
 Middle Devonic (Hamilton). Near Hamilton, New York. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 293 
 
 PLATE 13. 
 
 FIGS. 1 and 2. Promopalseaster wilsoni (Raymond). 
 
 1. Photograph X 1.5 of the holotype, showing the abactinal side. 
 
 2. One of the rays of the holotype X 3. 
 
 Middle Ordovicic (Lowville). City View, Ottawa, Canada. 
 
 Collection of Miss A. E. Wilson. 
 FIG. 3. Promopalseaster prenuntius, new species (also see plate 15). 
 
 Photograph, natural size, of the actinal side of the holotype. 
 
 Middle Ordovicic (Lower Trenton). Frankfort, Kentucky. 
 
 Collection of the State University of Kentucky. 
 FIG. 4. Anorthaster miamiensis (Miller) (see also plate 20). 
 
 Retouched photograph, natural size, of the actinal side of the holotype. 
 
 Upper Ordovicic (Richmondian). Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 40880). 
 FIG. 5. Neopalseaster crawfordsvillensis (Miller) (see also plate 23). 
 
 Retouched photograph, natural size, of the holotype, showing the abac- 
 tinal area. 
 
 Mississippic (Keokuk). Crawfordsville, Indiana. 
 
 Harris collection of the United States National Museum (Cat. No. 60607). 
 
 PLATE 14. 
 
 FIGS. 1 and 2. Promopalseaster speciosus (Meek)? 
 
 Reproduction, natural size, of the original lithograph of "Asterias prir 
 mordialis." Probably the young of P. speciosus. 
 
 Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 
 
 The specimen is now lost. 
 FIGS. 3 and 4. Promopalseaster speciosus (Meek) (also see plate 15). 
 
 Photographs, natural size, of the abactinal and actinal sides of the 
 holotype. 
 
 Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 
 
 Dyer collection of the Museum of Comparative Zoology, Harvard 
 University (No. 22). 
 
 PLATE 15. 
 
 FIGS. 1-4. Promopal&easter speciosus (Meek) (also see plate 14). 
 
 1. Camera lucida drawing X 4 of an interbrachial area. 
 
 2. Camera lucida drawing X 4 across a ray at about its mid-length. 
 From the actinal side, showing the ambulacrals, podial openings, 
 
 adambulacrals, inframarginals, and supramarginals. 
 
 3. Two adambulacral spines near oral region, X 7. 
 
 4. A part of the abactinal area of a ray near its mid-length, X 2.5. 
 All drawn from the holotype. 
 
 Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 
 Dyer collection of the Museum of Comparative Zoology, Harvard Uni- 
 versity (No. 22). 
 FIG. 5. Promopalseaster prenuntius, new species (also see plate 13). 
 
 Diagram of the actinal interbrachial plate arrangement. 
 
294 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 FIGS. 6-8. Promopalseaster bellulus, new species (also see plates 16 and 18). 
 
 6. Camera lucida drawing X 4 of an interbrachial area. The adambu- 
 lacrals are in natural position, but the interbrachial axillaries and the 
 inframarginals are somewhat displaced. Taken from the specimen on 
 plate 16, fig. 1. 
 
 7. Camera lucida drawing X 7 of the abactinal area of a ray. The 
 ossicles are all displaced, but originally they were united in a spicular 
 and partially overlapping mesh. 
 
 8. Madreporite X 7. 
 
 Upper Ordovicic (Richmondian). Waynesville, Ohio. 
 Harris collection of the United States National .Museum (Cat. No. 
 40879). 
 
 PLATE 16. 
 
 FIG. 1. Promopalseaster bellulus, new species (also see plates 15 and 18). 
 
 Retouched photograph, natural size, of the actinal side. The specimen 
 is in limestone. 
 
 Upper Ordovicic (Richmondian). Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 40879). 
 FIG. 2. Promopalseaster spinulosus (Miller and Dyer) (also see plates 17 and 18). 
 
 Retouched photograph, natural size, of the actinal side of the holotype 
 of Palseaster longibrachiatus Miller. The well-preserved columns are the 
 inframarginals, but in places some of the adambulacrals are also shown. 
 
 Upper Ordovicic (Richmondian). Near Clarksville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 40881). 
 
 PLATE 17. 
 
 FIGS. 1 and 2. Promopalseaster spinulosus (Miller and Dyer) (also see plates 16 and 
 
 18). 
 
 Retouched photographs X 3 of the actinal and abactinal sides of the 
 holotype. 
 
 Upper Ordovicic (Richmondian). Probably near Waynesville, Ohio. 
 Dyer collection of the Museum of Comparative Zoology, Harvard 
 University (No. 16). 
 
 PLATE 18. 
 
 FIGS. 1-3. Promopalseaster spinulosus (Miller and Dyer) (also see plates 16 and 17). 
 
 1. Camera lucida drawing X 2, somewhat restored, of the holotype 
 of Palseaster longibrachiatus Miller. 
 
 2. Camera lucida drawing X 7 of the abactinal area of a ray near its 
 base. Shows the large infra- and supramarginals and ambital pieces. 
 Center of ray has spicular ossicles. 
 
 3. Madreporite X 7. 
 
 Upper Ordovicic (Richmondian). Near Clarksville, Ohio. 
 Harris collection of the United States National Museum (Cat. No. 
 40881). 
 
REVISION OF PALEOZOIC STELLEEOIDEA. 295 
 
 FIGS. 4 and 5~Promopalseaster bellulus, new species (also see plates 15 and 16). 
 
 4. Adambulacralia and their spines, X 7. The ambulacrum lies to 
 the left. 
 
 5. A few abactinal spines, X 7. 
 
 Upper Ordovicic (Richmondian). Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 40879). 
 FIG. G.Promopalseaster wyloffi, (Miller and Gurley) (also see plate 19). 
 
 Diagram X 3.5 of one of the interbrachial areas. 
 
 From the holotype. 
 
 Upper Ordovicic (Richmondian). Near Madison, Indiana. 
 
 Collection of the University of Chicago (No. 6066). 
 FIG. 7. Promo palaeaster exculptus (Miller) (also see plate 20). 
 
 Adambulacral and ambulacral plates at about mid-length of a ray, X 4. 
 
 From the holotype. 
 
 Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 60608). 
 FIG. S.Promopalssaster dyeri (Meek) (also see plates 20 and 25). 
 
 Five inframarginal plates X 4. To show the articulations for the stout 
 spines that lie on the right. Also note the smaller spines. The plate 
 extensions to the left connect with the vertical ridges on the ambulacral 
 plates. 
 
 From the holotype. 
 
 Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 
 
 Dyer collection of the Museum of Comparative Zoology, Harvard Univer- 
 sity (No. 13). 
 
 PLATE 19. 
 
 FIG. 1. Trimeraster parvulus Schondorf. 
 
 Reconstruction X 1.75 of the actinal side. After Schondorf. 
 
 Lower Devonic (Coblenzian). Near Rhens, Germany. 
 FIG. 2. Promo palseaster wykoffi (Miller and Gurley) (also see plate 18). 
 
 Photograph X 2 of the holotype, showing the actinal side. One of 
 the finest of Paleozoic specimens. 
 
 Upper Ordovicic (Richmondian). Near Madison, Indiana. 
 
 Collection of the University of Chicago (No. 6066). 
 
 PLATE 20. 
 
 FIG. 1. Anorthaster miamiensis (Miller) (also see plate 13). 
 
 Camera lucida drawing X 5.5 of one of the interbrachial areas of the 
 holotype. The only Paleozoic form known with the area wholly made 
 up of adambulacrals. 
 
 Upper Ordovicic (Richmondian). Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 40880). 
 FIG. 2.Promopalseaster exculptus (Miller) (also see plate 18). 
 
 Camera lucida drawing X 4 of an interbracbial area. Note the modified 
 ambulacral plates in connection with the oral armature. Holotype. 
 
 Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 
296 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 FIGS. 3-6. Promopalseaster dyeri (Meek) (also see plates 18 and 25). 
 
 3. One of the interbrachial areas with the ossicles displaced and the 
 adjoining adambulacral plates with their spines, X 4. 
 
 4. Madreporite X 4. The rest of the plate is covered. 
 
 5. Two abactinal spines, X 7. 
 
 6. Five different abactinal ossicles, X 7. 
 All drawn from the holotype. 
 
 Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 
 Dyer collection of the Museum of Comparative Zoology, Harvard Uni- 
 versity (No. 13). 
 
 PLATE 21. 
 
 FIG. 1. Promopalseaster magnificus (Miller) (also see plates 22 and 23). 
 
 Photograph, natural size, of the actinal side of one of the cotypes. This 
 speci nen is probably the best preserved of Paleozoic starfishes and is one 
 of the largest species. 
 
 Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 40883). 
 
 PLATE 22. 
 
 FIG. 1. Promopalseaster magnificus (Miller) (also see plates 21 and 23). 
 
 Abactinal side of the same specimen illustrated on plate 21. 
 
 PLATE 23. 
 
 FIGS. 1-3. Promopalseaster magnificus (Miller) (also see plates 21 and 22). 
 
 1. Camera lucida drawing X 3.5 of an interbrachial area. Additional 
 tube-feet probably also came out at the junction of the forked crests. 
 
 2. Camera lucida drawing X 4 of the actinal area of one of the rays 
 toward the distal ends. Large adambulacrals bound the rays distally, 
 while the smaller pieces outside are the inframarginals. 
 
 3. A distal portion of the abactinal area, X 3.5. 
 All drawn from the cotypes. 
 
 Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 40883). 
 FIG. 4. Neopalseaster crawfordsvillensis (Miller) (also see plate 13). 
 
 Camera lucida drawing X 4 of the abactinal area of the holotype. Ac- 
 cessory disk pieces are drawn in; in the specimen they are all displaced. 
 The madreporite should be more finely striate. In places the dorsal 
 skeleton is lost, exposing the ambulacrals. 
 
 Mississippic (Keokuk). Crawfordsville, Indiana. 
 
 Harris collection of the United States National Museum (Cat. No. 
 60607). 
 FIGS. 5-7. Petraster spedosus (Miller and Dyer) (also see plates 26 and 27). 
 
 5. The ambulacral, adambulacral and inframarginals of a ray at its 
 mid-length, X 4. Seen from the actinal side. 
 
 6. Inframarginal, accessory interbrachial, and adambulacral pieces, X 4. 
 Seen from the dorsal side. 
 
 7. Ambulacral and adambulacrale, X 4. Seen from the dorsal area. 
 
REVISION OF PALEOZOIC STELLEROIDEA. 297 
 
 PLATE 24. 
 
 FIGS. 1-2. Xenaster margaritatus Simonovitsch. 
 
 1. Reconstruction, somewhat enlarged, of the abactinal side. The 
 structure of the medial portion of the disk is based upon Agalmaster 
 miellensis. 
 
 2. Reconstruction, somewhat enlarged, of the actinal area. 
 After Schondorf. 
 
 * Lower Devonic (Upper Coblenzian). Niederlahnstein, Germany. 
 
 PLATE 25. 
 
 FIG. 1. Promopalssaster dyeri (Meek) (also see plates 18 and 20). 
 
 Retouched photograph, natural size, of the actinal side of the holotype. 
 
 Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 
 
 Dyer collection, Museum of Comparative Zoology, Harvard University 
 (No. 13). 
 FIG. 2. Lepidasterella babcocki, new species. 
 
 Photograph X 1.5 of the holotype. A natural mold of the abactinal 
 area in sandstone. 
 
 Upper Devonic (Lower Chemung). Near Ithaca, New York. 
 
 Collection of Mrs. G. W. Babcock. 
 
 PLATE 26. 
 
 FIG. 1. Petraster spedosus (Miller and Dyer) (also see plates 23 and 27). 
 
 Retouched photograph, natural size, of the abactinal area of the holotype. 
 
 Upper Ordovicic (Richmondian). Near Winchester, Ohio. 
 
 Dyer collection of the Museum of Comparative Zoology, Harvard Uni- 
 versity (No. 14). 
 FIG. 2. Petraster (?) americanus (D'Orbigny). 
 
 Reproduction, natural size, of Meek's original figure. The specimen is 
 seen from the abactinal side, exposing, however, the inner surface of the 
 actinal skeleton, which is deeply embedded in limestone. 
 
 Upper Ordovicic (Maysvillian). Cincinnati, Ohio. 
 
 Collection of the University of Chicago. 
 
 PLATE 27. 
 
 FIGS. 1-4. Petraster spedosus (Miller and Dyer) (also see plates 23 and 26). 
 
 1. Camera lucida drawing X 4 of the abactinal side of a ray. Holotype 
 The inframarginals border the animal, with the supramarginals imme- 
 diately inside of them. The radial column is readily distinguished 
 along the center of the rays. 
 
 2. Camera lucida drawing X 6 of an interbrachial area in a young 
 individual (Harris collection, Cat. No. 60609, U.S.N.M.). The inframar- 
 marginals are above and the adambulacrals below to the right. The rest 
 rest of the plates are accessory interbrachials. 
 
 3-4. Madreporite from the side and from the lower or under surface, X 8. 
 FIG. 5. Petraster rigidus (Billings). 
 
 Outline tracing of the actinal skeleton from a photograph X 2 of the 
 holotype. 
 
 Middle Ordovicic (Trenton). Ottawa, Canada. 
 Collection of the Geological Survey of Canada (No. 1401a). 
 
298 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 FIGS. 6-8. Urasterella grandis (Meek) (also see plates 28 and 30). 
 
 6. Camera lucida drawing X 8 of part of the abactinal area of a ray proxi. 
 mally. Note how the ossicles are drawn out into nonarticulating blunt 
 spines. 
 
 7. Camera lucida drawing X 4 of the actinal side about the mouth. The 
 complete oral armature is preserved. 
 
 8. Madreporite in outline, X 7. 
 
 From specimens in the Harris collection of the United States National 
 Museum (Cat. No. 40885). 
 
 PLATE 28. 
 
 FIGS. 1 and 2. Urasterella grandis (Meek) (also see plates 27 and 30). 
 
 1. Retouched photograph, natural size, of a large and folded specimen. 
 Both ventral and dorsal areas are shown. 
 
 2. Retouched photograph, natural size, of an average individual seen 
 from .the actinal side. 
 
 Upper Ordovicic (Richmondian). Near Waynesville, Ohio. 
 Harris collection of the United States National Museum (Cat. No. 40885). 
 FIGS. 3 and 4. Urasterella pulchella (Billings) (also see plate 30). 
 
 3. Photograph, natural size, of an electrotype, seen from the actinal side. 
 Middle Ordovicic (Trenton). Hull, Ottawa, Canada. 
 
 Original in collection of the Geological Survey of Canada; electrotype in 
 United States National Museum (Cat. No. 60610). 
 
 4. Retouched photograph, natural size, of the abactinal area. 
 Middle Ordovicic (Trenton). Trenton Falls, New York. 
 
 Collection of the Museum of Comparative Zoology, Harvard University 
 (No. 31). 
 FIG. 5.' Urasterella girvanensis, new species. 
 
 Reproduction X 2 of the original figure by Nicholson and Etheridge, 
 somewhat altered. 
 
 From a wax squeeze made by Bather, now in the United States National 
 Museum (Cat. No. 60611). 
 
 Upper Ordovicic. Thraive, Girvan, Scotland. 
 
 PLATE 29. 
 
 FIG. 1. Urasterella ulrichi, new species (also see plate 30). 
 
 Retouched photograph, natural size, of the abactinal side of a cotype. 
 The three short blunt rays are interpreted as healed stumps. 
 
 Middle Ordovicic (Black River). Minneapolis, Minnesota. 
 
 Ulrich collection of the United States National Museum (Cat. No. 60612). 
 FIG. 2. Urasterella huxleyi (Billings). 
 
 Photograph X 2 of the holotype. Abactinal view. 
 
 Middle Ordovicic (about Chazy). Point Rich, Newfoundland. . 
 
 Collection of the Geological Survey of Canada (No. 554.) 
 
 PLATE 30. 
 
 FIGS. 1-4. Urasterella grandis (Meek) (also see plates 27 and 28.) 
 
 1-2. Camera lucida drawing X 16 of the adambulacrals with their articu- 
 lar spines and probable paxillse. 
 
 3. Camera lucida drawing X 8 of the two columns of ambulacra! 
 plates a little displaced. The podial openings are situated laterally 
 between the thinner ends of the ossicles. 
 
 4. Camera lucida drawing X 7 of the adambulacrals with their spines. 
 From specimens in the Harris collection of the United States National 
 
REVISION OF PALEOZOIC STELLEROIDEA. 299 
 
 FIG. 5. Urasterella pulchella (Billings) (also see plate 28). 
 
 Camera lucida drawing X 8. The large plates to the left are the coin- 
 shaped adambulacrals (some have tipped over and show their articular 
 faces), next are the small elongate inframarginals, and outside of these 
 are the spinose ambitals. 
 
 FIGS. 6 and 7. Urasterella ulrichi, new species (also see plate 29). 
 
 6. Camera lucida drawing X 4 of the abactinal side of a young 
 individual. The medial ray plates should be more tumid than here 
 represented. Note the primitive structure of the disk. 
 
 7. Camera lucida drawing X 6 of the actinal side of a young indi- 
 vidual. The outer dark margin is adhering rock, through which some 
 of the abactinal ambital nonarticulating spines project. Note the 
 phanerozonian interbrachial characters. 
 
 Middle Ordovicic (Black River). Minneapolis, Minnesota. 
 Ulrich collection of the United States National Museum (Cat 
 No. 60612). 
 
 PLATE 31. 
 
 FIGS. 1 and 2. Compsaster formosus Worthen and Miller. 
 
 1. Actinal view, natural size, of the holotype. Reproduction of the 
 original illustration. 
 
 2. Part of a ray, X 2. After Worthen and Miller. 
 Upper Mississippic (Chester). Okaw Bluffs, Illinois. 
 " Illinois State collection of 1880, No. 2476." 
 
 FIG. S.Calliasterella mira (Trautschold). 
 
 Reproduction, natural size, of Schondorf's reconstruction. 
 
 Upper Carboniferous (Moscovian). Mjatschkowa, near Moscow, Russia. 
 
 PLATE 32. 
 FIG. 1. Stenaster salteri Billings. 
 
 Retouched photograph X 3 of a cotype. Actinal view. 
 
 Middle Ordovicic (Trenton). Belleville, Ontario, Canada. 
 
 Collection of the Geological Survey of Canada. 
 FIG. 2. Schuchertia stellata (Billings) (also see plate 33). 
 
 Photograph X 4 of the actinal side of the holotype. 
 
 Middle Ordovicic (Trenton). Ottawa, Canada. 
 
 Collection of the Geological Survey of Canada (No. 1399). 
 FIG. 3. Schuchertia laxata, new species (also see plate 33). 
 
 Retouched photograph X 2 of the holotype from the abactinal side. 
 
 Upper Ordovicic (Richmondian). Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 60613). 
 FIGS. 4 and 6. Schcenaster (?) legrandensis Miller and Gurley. 
 
 4-5. Actinal and abactinal views, natural size. 
 
 6. Part of actinal side X 6.5. After Miller and Gurley. 
 
 Lower Mississippic (Kinderhookian). Le Grand, Iowa. 
 
 ?Gurley collection of the University of Chicago. 
 
 PLATE 33. 
 
 FIG. 1. Schuchertia stellata (Billings) (also see plate 32). 
 
 Camera lucida drawing X 8 of the abactinal surface. Somewhat 
 restored. 
 
 Middle Ordovicic (Trenton). Near New Edinburgh, Canada. 
 
 Collection of the Geological Survey of Canada. 
 FIGS. 2 and 3. Schuchertia laxata, new species (also see plate 32). 
 
 2. Some of the outer ambital plates, all disjointed, X 8. 
 
 3. An interbrachial area and ambulacrum, X 4. 
 Upper Ordovicic (Richmondian). Waynesville, Ohio. 
 
 Harris collection of the United States National Museum (Cat. No. 
 
300 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 
 
 FIG. 4. Tetraster wyville-thoTtisoni Nicholson and Etheridge. 
 
 Diagram X 4 of the actinal skeleton. From a wax squeeze by Bather, 
 in the United States National Museum (Cat. No. 60614). 
 
 Upper Ordovicic. Thraive, Girvan, Scotland. 
 FIG. 5. Schcenaster (?) montanus Raymond. 
 
 Reproduction X 2 of the original figure. Actinal side. 
 Mississippi (Madison). Spring Canyon, near Alder, Montana. 
 Collection of the Carnegie Museum. 
 FIG. 6. SJicenaster (?) wachsmuihi Meek and Worthen. 
 
 Reproduction, natural size, of the original figure. Actinal view. 
 Lower Mississippi (Burlington). Burlington, Iowa. 
 Collection of the Museum of Comparative Zoology, Harvard University 
 (No. 7). 
 
 PLATE 34. 
 
 FIG. 1. Palseosolaster (?) gyalum (Clarke). 
 
 Actinal view of one of the cotypes, natural size. 
 Upper Devonic (Portage). Ithaca, New York. 
 Collection of Cornell University. 
 
 PLATE 35. 
 
 FIGS. 1-4. Schcenaster fimbriatus Meek and Worthen. 
 
 1. View of the abactinal side, natural size, of one of the cotypes. 
 
 2. Enlarged view of one of the rays, showing the arrangement of the 
 ossicles and the pores, as seen when the surface is ground down. 
 
 3. Actinal side of a ray, enlarged, showing only the adambulacrals. 
 
 4. Actinal side of another cotype, natural size. 
 The original figures of plate 19, figs. 7 a to 7d. 
 
 Upper Mississippi (St. Louis). St. Clair County, Illinois. 
 FIGS. 5 and 6 Encrinaster petaloides (Simonovitsch). 
 
 5. Abactinal view, about X 2. 
 
 6. An arm from the actinal side, about X 2. 
 After Schondorf. 
 
 Lower Devonic (Upper Coblenzian). Niederlahnstein, Germany. 
 
 PLATE 36. 
 
 FIG. 1. Tseniaster spinosus (Billings). 
 
 Photograph X 2 showing the actinal side of one of the cotypes. 
 Middle Ordovicic (Lower Trenton). Montmorency Falls, Quebec, 
 Canada. 
 
 Collection of the Geological Survey of Canada (No. 1404). 
 FIGS. 2 and 3.Taeniaster cylindricus (Billings). 
 
 2. Abactinal view X 2 of one of the cotypes. 
 
 3. Actinal view X 2 of another cotype. Both specimens are on the 
 same slab. 
 
 Middle Ordovicic (Trenton). Ottawa, Canada. 
 Collection of the Geological Survey of Canada (No. 1405a). 
 FIG. 4. Alepidaster flexuosus (Miller and Dyer). 
 
 An unpublished photograph X 3.5, made many years ago, of the holo- 
 type of Protasterina fimbriata Ulrich. 
 
 Upper Ordovicic (Lower Edenian). Covington, Kentucky. 
 Ulrich collection of the United States National Museum (Cat. No. 60615). 
 
REVISION OF PALEOZOIC STELLEKOIDEA. 301 
 
 PLATE 37. 
 
 FIGS. 1 and 2. Eucladia woodwardi Sollas. 
 
 Dorsal and ventral reconstructions X 5/3 of this remarkable fossil. On it 
 is based the order Ophiocistia Sollas. "One arm, the most proximal of 
 the radius on the lower right-hand corner, is omitted, so as to show the 
 aperture from which it proceeds." After Sollas. 
 Siluric (Lower Ludlow). Leintwardine, England. 
 
 PLATE 38. 
 
 FIG. l.Eucladm (?) beecheri, new species. 
 
 Photograph X 2 of the holotype from the actinal side. The specimen 
 itself is difficult to make out, hence the indistinctness of the photograph. 
 
 Lower Devonic (Coeymans). Jerusalem Hill, Litchfield, Herkimer 
 County, New York. 
 
 Collection of Peabody Museum, Yale University. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 1 
 
 HUDSON ASTER NARRAWAYI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 289. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 2 
 
 1, HUDSONASTER NARRAWAYI; 2, H. MATUTINUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 289. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 3 
 
 1, HUDSONASTER RUGOSUS; 2, H. MATUTINUS; 3, H. BATHERI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 289. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 4 
 
 1, HUDSONASTER NARRAWAYI; 2, H. MILLERI; 3, MESOPAL/EASTER (?) LANCEOLATUS; 
 4, AUSTRALASTER GIQANTEUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 290. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 5 
 
 HUDSONASTER MATUTINUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 290. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 6 
 
 HUDSONASTER INCOMPTUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 290. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 7 
 
 1-4, PAL/EASTER NIAGARENSIS; 5, MESOPAL/EASTER FINEI 
 
 FOR EXPLANATION OF PLATE SEE PAGE 291. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 8 
 
 1, 2, MESOPAL/EASTER SHAFFERI; 3, MIOMASTER DREVERMANNI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 291. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 9 
 
 Six SPECIES OF MESOPALXE ASTER. 
 
 FOR EXPLANATION OF PLATE SEE PAGES 291 AND 292. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 10 
 
 MESOPAL/E ASTER CLARKI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 292. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 11 
 
 , MESOPAL/EASTER CARACTACI; 2, DEVONASTER CHEMUNGENSIS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 292. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 12 
 
 1 , 2, SPANIASTER LATISCUTATUS; 3-5, DEVONASTER EUCHARIS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 292. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 13 
 
 1-3, PROMOPAMEASTER; 4, ANORTHASTER; 5, NEOPAL/EASTER. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 293. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 14 
 
 Asterlas prtmorci tails 
 
 PROMOPALXEASTER SPECIOSUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 293. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 15 
 
 1-4, PROMOPAL/EASTER SPECIOSUS; 5, P. PRENUNTIUS; 6-8, P. BELLULUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGES 293 AND 294. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 16 
 
 1, PROMOPAL/EASTER BELLULUS; 2, P. SPINULOSUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 294. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 17 
 
 PROMOPAL/CASTER SPINULOSUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 294. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 18 
 
 4 
 
 DETAIL OF FIVE SPECIES OF PROMOPAL/EASTER. 
 
 FOR EXPLANATION OF PLATE SEE PAGES 294 AND 295. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 19 
 
 1 , TRIMERASTER PARVULUS; 2, PROMOPAL/EASTER WYKOFFI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 295. 
 
S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 20 
 
 1, DETAIL OF ANORTHASTER; 2-6, PROMOPAL/EASTER. 
 
 FOR EXPLANATION OF PLATE SEE PAGES 295 AND 296. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 21 
 
 PROMOPALXEASTER MAGNIFICUS. 
 FOR EXPLANATION OF PLATE SEE PAGE 296. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 22 
 
 PROMOPAL/EASTER MAQNIFICUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 296. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 23 
 
 1-3, DETAIL OF PROMOPALXEASTER; 4, NEOPAL/EASTER; 5-7, PETRASTER. 
 
 
 
 FOR EXPLANATION OF PLATE SEE PAGE 296. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 24 
 
 XENASTER MARQARITATUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 297. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 25 
 
 1, PROMOPAL/EASTER DYERI; 2, LEPIDASTERELLA BABCOCKI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 297. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 26 
 
 i 
 
 j:| | 
 .$ - t: 
 
 r1-% 
 
 M/7-? 4- > y . ' - l -4- >r r^T > - 
 -^f^^f 1 : fc# V : '>'" 
 
 wtt. 
 
 m?' ^%| 
 
 
 "'" 
 
 1, PETRASTER SPECIOSUS; 2, P. (?) AMERICANUS. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 27 
 
 1-5, DETAIL OF PETRASTER; 6-8, URASTERELLA. 
 
 FOR EXPLANATION OF PLATE SEE PAGES 297 AND 298. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 28 
 
 1, 2, URASTERELLA GRANDIS; 3, 4, U. PULCHELLA; 5, U. QIRVANENSIS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 298. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 29 
 
 1, URASTERELLA ULRICHI; 2, U. HUXLEYI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 298. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 30 
 
 DETAIL OF URASTERELLA. 
 
 FOR EXPLANATION OF PLATE SEE PAGES 298 AND 299. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 31 
 
 1, COMPSASTER FORMOSUS; 2, CALLIASTERELLA MIRA. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 299. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 32 
 
 1, STENASTER; 2, 3, SCHUCHERTIA; 4-6, SCHCENASTER (?). 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 33 
 
 ^K^fflK^ 
 
 1-3, DETAIL OF SCHUCHERTIA; 4, TETRASTER; 5, 6, SCHCENASTER (?). 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 34 
 
 .~~ 
 
 Kg^K, ji ^ .^ 
 
 "^l^te'^ 
 
 PAL/EOSOLASTER (?) GYALUM. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 300. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 35 
 
 1-4, SCHCENASTER FIMBRIATUS; 5, 6, ENCRINASTER PETALOIDES. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 300. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 36 
 
 1, T>ENIASTER SPINOSUS; 2, 3, T. CYLINDRICUS; 4, ALEPIDASTER FLEXUOSUS. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 300. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 37 
 
 EUCLADIA WOODWARDI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 301. 
 
U. S. NATIONAL MUSEUM 
 
 BULLETIN 88 PL. 
 
 EUCLADIA (?) BEECHERI. 
 
 FOR EXPLANATION OF PLATE SEE PAGE 301. 
 
INDEX. 
 
 [The important references In each case are in heavy-faced type. Synonyms are in italics.] 
 
 Page. 
 
 abactinal 13 
 
 abnormal development 101 
 
 aboral, see abactinal. 
 
 accessory actinals 13 
 
 accessory interbrachials 13, 15,45,46 
 
 accessory plates 13, 47, 51 
 
 Acroura ( Ophiura) schlotheimii 18 
 
 actinal 13 
 
 acuminatus, Asterias. ., 93 
 
 acuminatus, Mesopalseaster (?) 75, 93 
 
 acuminatus, Roemeraster (?) 93 
 
 adambulacralia, see adambnlacrals. 
 
 adambulacral oral skeleton 16 
 
 adambulacral spines 13, 43 
 
 adambulacrals (see also lateral shields) 13, 
 
 34,43,162,213,214,222 
 
 Agalmaster 40, 49, 128, 13 1 , 133 
 
 A.grandis 132 
 
 A. intermedium 133 
 
 A.miellensis 132 
 
 Aganaster 263 
 
 A . gregarius 264 
 
 A. (?) sp. Miller and Gurley 251 
 
 Aganasteridse 246, 263 
 
 Alepidaster 216,228 
 
 A. flexuosus 230, 231 
 
 A. granuliferus 229, 230 
 
 A. gregarius 264 
 
 A. miamiensis '. 230, 238 
 
 A. n. sp 230 
 
 ambital and ambital plates 13, 46, 174 
 
 ambulacralia, see ambulacrals. 
 
 ambulacral oral skeleton 16 
 
 ambulacrals 13,33,34,41,213,235,258 
 
 alternate arrangement 13, 
 
 33, 41 , 152, 172, 174, 213, 214, 215, 222, 226 
 
 opposite arrangement 13, 
 
 41,163,213,214,224,246 
 
 americanus, Cadaster 146 
 
 americanus, Petraster (?) 139, 146 
 
 ampullae 213 
 
 anal opening 13,89,54,61 
 
 Anorthaster 41,42,43,50, 125 
 
 A. miamiensis 127 
 
 Anorthasterinse 52, 74, 126 
 
 anthonii, A sterlas 146 
 
 antiqua, Argaster 86 
 
 antiqua, Asterias, Hisinger 149 
 
 antiqua, Asterias, Troost 86 
 
 antiqua, Hisingeraster 149 
 
 antiqua, Palseaster (Argaster) 80 
 
 antiqua, Palxasterina 149 
 
 50601 Bull. 8815 20 
 
 Page. 
 
 antiqua, Palmipes 149 
 
 antiqua, Petraster (?) 86 
 
 antiquata, Asterias 109 
 
 antiquata, Palxaster 109 
 
 antiquus, Asteriscus 149 
 
 antiquus, Lindstromaster 149, 153 
 
 antiquus, Mesopalseaster (?) 75, 86 
 
 antiquus, Palxaster 86 
 
 anus, see anal opening. 
 
 approximata, Palxasterina 142 
 
 A rchxasterias 129, 130 
 
 arcs, see axil. 
 
 ? Argaster 74, 77, 87 
 
 A . antiqua 86 
 
 arnoldi, Aspidosoma 243 
 
 arnoldi, Encrinaster 241, 248 
 
 asper, Onychaster 270, 2 72 
 
 asperrima, Palxaster. 187 
 
 asperrima, Urasterella (?) 175, 18 7 
 
 asperrimus, Salteraster 187 
 
 asperrimus, Tetraster 187 
 
 asperula, A sterias 188, 262 
 
 asperula, Roemeraster 188 
 
 asperula, Urasterella 175, 188 
 
 Aspidosoma 241 
 
 A . arnoldi 243 
 
 A.eifelense 244 
 
 A. goldfussi 243 
 
 A . gray se 245 
 
 A. petaloides 243 
 
 A. petaloides goslariensis 243 
 
 A . ? pontis 244 
 
 A . roemeri 244 
 
 A. sehmidti 244 
 
 A. tischbeinianum 244 
 
 Aspidosomatidx 241 
 
 Asterias 33 
 
 A sterias Graham, Anthony and James 146 
 
 A . acuminatus 93 
 
 A . anthonii 146 
 
 A . antiqua Hisinger. 149 
 
 A . antiqua Troost 86 
 
 A . antiquata 109 
 
 A, asperula 188,262 
 
 A.constellata 187 
 
 A. matutina 57 
 
 A. montanus 189 
 
 A . primxva 167 
 
 A . primordialis 108 
 
 A. (Archxasterias) rhenana 131 
 
 A. spinosissima 19 
 
 asterid radicle 34 
 
 ysterina 33 
 
 303 
 
304 
 
 INDEX. 
 
 Page. 
 
 Asteriscus antiquut 149 
 
 Asteroidea 41, 42, 43, 51 
 
 evolution of 11, 30, 48, 52, 106 
 
 number of, in Paleozoic 2 7, 28 
 
 terminology 13 
 
 Astropecten 161 
 
 A. (?) schliiteri 161 
 
 Ataxaster 161 
 
 A. pygmseus 161 
 
 Auluroidea 80,38,40,41,42,43,163,212,213 
 
 geological distribution of 28 
 
 number of, in Paleozoic 27,28 
 
 Australaster 44,45,49,66,72, 171 
 
 A.giganteus 73, 171 
 
 A. (?) stutchburii 73 
 
 australis, Txniaster 236 
 
 axil 14 
 
 axillary inframarginal 14 
 
 axillary interbrachial 14 
 
 axillary marginal 15 
 
 axillary ossicles 34, 49 
 
 babcocki, Lepidasterella 160 
 
 barrisi, Onychaster 270, 272 
 
 barrisi, Protester (?) 272 
 
 bathed, Hudsonaster J 55, 65, 167 
 
 Bdellacoma 248,252,254 
 
 B. vermiformis 254 
 
 beecheri, Eucladia (?) 278 
 
 bellulus, Mesopalseaster 75, 91 
 
 bellulus, Petraster 91 
 
 bellulus, Promopalseaster 104, 105, 1 13 
 
 beneckei, Bundenbachia 234 
 
 bibliography 281-288 
 
 biforis, Protaster 226, 227 
 
 bivium 14 
 
 body-wall 14 
 
 bohemica, Eophiura 222 
 
 Bohemura 216, 22 8 
 
 B.jahni 223 
 
 bonneyi, Palxasterina 153 
 
 bonneyi, Palasterina 151, 152, 168 
 
 brisingoides, Protaster 236 
 
 brisingoides, Stiirtzura 236 
 
 buccal processes 225 
 
 Bundenbach 29 
 
 Bundenbachia 216, 284 
 
 B . beneckei 234 
 
 B. grandis 235 
 
 caecal pores 14 
 
 Calliaster 190 
 
 C. mirus 190 
 
 Calliasterella 39, 47, 49,50, 190 
 
 C. mira 191 
 
 Calliasterellidse 162, 163, 190 
 
 Calliasteridx 190 
 
 caractaci, Mesopalseaster 75, 92 
 
 caractaci, Palseaster 92 
 
 caractaci, Protopalxaster 92 
 
 carbonarius, Cribellites 274 
 
 carinals, see radials. 
 
 catalogue of Paleozoic Stelleroidea 51 
 
 cataractensis, Mesopalaeaster (?) 75, 89 
 
 central disk, see disk. 
 
 central disk plate, see centrodorsal plate. 
 
 central plate, see centrodorsal plate. 
 
 centrodorsal plate 14, 34,35,48 
 
 Page. 
 
 Cheiropteraster 40, 199, 202, 252 
 
 C. giganteus 202 
 
 chemungensis, Devonaster 101 
 
 Cholaster 265 
 
 C. peculiaris 266 
 
 Cholasteridse 246, 265 
 
 ciliaris, Ophiura 268 
 
 clarkana, Palseaster 61,63 
 
 clarkei, Etheridgaster 172 
 
 clarkei, Monaster 171, 1 7 2 
 
 clarkei, Palseaster, De Koninck 172 
 
 clarkei, Palseaster, Miller 61 
 
 clarki, Mesopalaeaster (?) 75, 94 
 
 clarki, Palxaster 94 
 
 Classification 51 
 
 Cadaster 95 
 
 C. americanus 146 
 
 C. latiscutatus 96 
 
 C. tenuiradiatus 19 
 
 colvini, Palzocoma 253 
 
 colvini, Stiirtzaster 253 
 
 Compsaster 192 
 
 C. formosus 193 
 
 C. n.sp 194 
 
 Compsasteridse 162, 163, 191 
 
 concinna, Eugasterella (?) 238, 289 
 
 concinnus, Eugaster 239 
 
 confluens, Stenaster (?) 165,167 
 
 confragosus, Onychaster 270, 273 
 
 constellata, Asterias 187 
 
 constellata, Urasterella (?) 175, 187 
 
 coronella, Palxaster 167 
 
 coronella, Stenaster (?) 165, 167 
 
 crawfordsvillensis, Neopalseaster 135, 186 
 
 crawfordsvillensis, Palaeaster 136 
 
 Cribellites carbonarius 274 
 
 Crossaster 38 
 
 Cryptozonia.... 80,33,38,40,41,43,44,45,46,47,162 
 
 cygnipes, Palseocoma 253 
 
 cygnipes, Sturtzaster. 253 
 
 cylindrica, Lapworthura 220 
 
 cylindrica, Palseocoma 220 
 
 cylindrica, Txniura. 220 
 
 cylindricus, Tseniaster 216,217,218,219,220 
 
 daoulasensis, Furcaster (?) 261 
 
 daoulasensis , Protaster 261 
 
 darwini, Echinasterella (?) 200 
 
 decheni, Eoluidia 262 
 
 decheni, Eophiurites 262 
 
 decheni, Protaster 248 
 
 decheni, Tremataster (?) 247, 248 
 
 demissus, Onychaster 270,274 
 
 development, abnormal 101 
 
 geological, of Stelleroidea 27, 28 
 
 Devonaster 40, 44, 
 
 46, 47, 49, 50, 74 , 76, 77, 9 7 , 129, 130, 133 
 
 D. chemungensis 101 
 
 D.eucharis 29,37,98 
 
 devonica, Palxnectria 155 
 
 devonicus, Palasteriscus 200 
 
 difflcilis, Tremataster 247 
 
 disk 14,213,225 
 
 how enlarged 32 
 
 disk accessory plates 34, 46 
 
 disk ambitals 13 
 
 disk inframarginals 15 
 
INDEX. 
 
 305 
 
 disk marginals 14 
 
 disk plates 14 
 
 primary 49,179,184,190,191 
 
 disk supramarginals 15 
 
 dispar, Xenaster 130, 131 
 
 dorsal, see abactinal. 
 dorsals, see radials. 
 
 dorsal shield 213 
 
 dorso-laterals, see accessory plates. 
 
 drevermanni, Miomaster 96 
 
 dubius, Mesopalseaster (?) 75, 85 
 
 dubius, Palxaster 85 
 
 dyeri, Palxaster 120 
 
 dyeri, Petraster 121 
 
 dyeri, Promopalaeaster 104, 105, 120 
 
 Echinaster 45 
 
 Echinasterella 199, 200 
 
 E. (?) darwini 200 
 
 E . sladeni 200 
 
 EcMnasterias 38,207,209, 211 
 
 E. spinosus 211 
 
 echinatus, Squamaster 249 
 
 Echini, radii of 35 
 
 Echinodiscaster 38,40,207,209,211 
 
 E. multidactylus 211 
 
 Echinodiscites 211 
 
 Echinodiscus 211 
 
 E. multidactylus 211 
 
 Echinostella 38,207,209,212 
 
 E. traquairi 212 
 
 Eifelaster 128, 133 
 
 E. follmanni 134 
 
 eifelense, Aspidosoma 244 
 
 eifelensis, Encrinaster 244 
 
 elegans, Protaster 221 
 
 elegans, Tseniaster 219,221 
 
 elegans, Xenaster 130, 131 
 
 elizae, Uranaster 155 
 
 Encrinaster (part) 224 
 
 Encrinaster 43, 45, 226, 241 
 
 E. arnoldi....; 241,243 
 
 E. eifelensis 244 
 
 E.goldfussi 243 
 
 E. (?)grayae 245 
 
 E.petaloides 243 
 
 E. petaloides goslariensis 243 
 
 E.pontis 244 
 
 E. roemeri 242, 244 
 
 E. schmidti 244 
 
 E. tischbeinianus 244 
 
 Encrinasterix (part) 215 
 
 Encrinasteridse 215, 241 
 
 Eoactis 173,178 
 
 E. simplex 186 
 
 Eoluidia 262 
 
 E. decheni 262 
 
 Eoluidiidse 246,262 
 
 Eophiura 216,222,223,259 
 
 E . bohemica 222 
 
 Eophiuridx 262 
 
 Eophiurites 262 
 
 E. decheni 262 
 
 Eospondylus 262, 2 63 
 
 E . primigenius 263 
 
 Etheridgaster 170 
 
 Page. 
 E. clarkei 172 
 
 eucharis, Devonaster 29,37, 98 
 
 eucharis, Palxaster 93 
 
 eucharis, Xenaster 93 
 
 Eucladia 275, 276 
 
 E. (?)beecheri 278 
 
 E. johnsoni 276 
 
 E. woodwardi 276, 277 
 
 Eucladiidge 276 
 
 Eugaster 237 
 
 E. concinnus 239 
 
 E. logani 238 
 
 Eugasterella 235, 237, 259 
 
 E. (?) concinna 238, 239 
 
 E . logani 237, 2 3 8 
 
 Euophiuroidea 213 
 
 EuryalQ annulatum 20 
 
 Euthemon.....' 275,276, 279 
 
 E. igerna 279 
 
 evolution of Asteroidea .% 30 
 
 exculptus, Palxaster 117 
 
 exculptus, Promopalseaster 104, 105, 117 
 
 eye-plate, see ocular plate. 
 
 ferox, Palaeodiscus 23 
 
 filiciformis, Helianthaster 159, 1 60 
 
 fimbriata, Palxasterina 204 
 
 fimbriaid, Protaster 231 
 
 fimbriata, Protasterina 231 
 
 fimbriatus, Schoenaster 204 
 
 flnei, Mesopalseaster 75, 81 
 
 fine i Palxaster 81 
 
 flexilis, Onychaster 269, 270 
 
 flexuosus, Alepidaster 230, 231 
 
 flexuosus, Protaster 231 
 
 flexuosa, Protasterina 231 
 
 follmanni, Eifelaster 134 
 
 follmanni, Palasterina 157 
 
 follmanni, Pseudopalasterina 156, 157 
 
 forbesi, Hallaster 254, 2 66 
 
 forbesi, Protaster 255 
 
 formosus, Compsaster 193 
 
 Furcaster 248,259, 261 
 
 F. (?) daoulasensis 261 
 
 F. palseozoicus 259, 261 
 
 Furcasteridx 248 
 
 genitals, see interradial plates. 
 
 genitals in Echini 35 
 
 geological development of Stelleroidea 27, 28 
 
 geological distribution of Stelleroidea 28 
 
 giganteus, Australaster 73, 171 
 
 giganteus, Cheiropteraster 202 
 
 giganteus, Monaster 73 
 
 giganteus, Palxaster ( Monaster) 73 
 
 girvanensis, Urasterella 167, 175, 186 
 
 goldfussi, Aspidosoma 243 
 
 goldfussi, Encrinaster 243 
 
 Goniaster 61 
 
 grandis, Agalmaster 132 
 
 grandis, Sundenbachia 235 
 
 grandis, Palseophiomyxa 234, 286 
 
 grandis, Stenaster 180 
 
 grandis, Urasterella 174, 175, 180 
 
 granti, Mesopalaeaster 75, 89 
 
 granti, Palxaster 89 
 
 granuliferus, Alepidaster 229, 280 
 
306 
 
 INDEX. 
 
 Page. 
 
 granuliferus, Protester (f) 230 
 
 granulosus, Palxaster, Hall 112 
 
 granulosus, Palxaster, Meek 109 
 
 granulosus, Promopalaeaster 104, 1 1 2, 113 
 
 graspers 33 
 
 grayx, Aspidosoma 245 
 
 grayse, Encrinaster (?) 245 
 
 grayi, Lepidast*r 158 
 
 gregarius, Aganaster 264 
 
 gregarius, Alepidaster 264 
 
 gregarius, Protester (/) 264 
 
 Gregoriura 216,233 
 
 G. spryi 234 
 
 gregoryi, Palseosolaster 209 
 
 groomi, Protaster 226, 227 
 
 gyalum, Helianthaster 160,210 
 
 gyalum, Palseosolaster (?) 210 
 
 Hallaster 248, 254 
 
 H. forbesi 254, 255 
 
 Harris, I. H., gift oietarflshes by 9 
 
 Jiarrisi, Palxaster 180 
 
 Helianthaster Clarke (part) 209 
 
 Helianthaster Roemer 38, 
 
 40,45,157,158,159,209,211 
 
 H. flliciformis 159,160 
 
 H. gyalum (part) 160, 210 
 
 H. rhenanus 159 
 
 H.roemeri 209,211 
 
 H. n. sp . Clarke 160 
 
 Helianthasteridx 157 
 
 Helianthasterinse 157 
 
 Heliaster 38,208 
 
 hirudo, Palxaster 188 
 
 Urudo, Uraster 188 
 
 hirudo, Urasterella 175,188 
 
 Hisingeraster 148 
 
 H, antiqua 149 
 
 Hudsonaster 31,32,34,36, 
 
 38, 39, 40, 41, 42, 44,45, 47, 48, 49, 52, 68, 
 69, 75, 105, 135, 140, 158, 165, 179, 194, 196 
 
 H.batheri 55,65,167 
 
 H. incomptus. 34,36,40,55,61 
 
 H. matutinus 34,55, 57, 139, 141, 166 
 
 H. milleri ..... 55,60 
 
 H.narrawayi 43,50,55,59 
 
 H. rugosus 36, 55, 64 
 
 Hudsonasteridse] 52, 53,162 
 
 huxleyi, Stenaster 182 
 
 huxleyi, Urasterella 175, 182 
 
 igerna, Euthemon 279 
 
 imbricatus, Palxaster 169 
 
 imbricatus, Tetraster (?) 168, 169 
 
 incomptus, Hudsonaster 34,36,40,55, 61 
 
 incomptus, Palxaster. 61 
 
 inframarginalia 16, 34, 48, 152, 194 
 
 inframarginal plates 16, 33, 174, 179, 185 
 
 Interact] nals 13 
 
 interbrachial adambulacrals 1 5, 126 
 
 interbrachial areas and arcs.. . . 14, 60, 138, 185, 194 
 
 interbrachial marginals 15 
 
 intennarginal plates, see ambital plates, 
 intermarginals, see ambital. 
 
 intermedius, Agalmaster 133 
 
 intermedius, Mesopalseaster 75, 79 
 
 interadial plates 15, 32 
 
 Jaekelaster 40, 192 
 
 Page. 
 
 J. petaliformis 192 
 
 jahni, Bohemura 223 
 
 jamesi, Palxaster 146 
 
 jamesi, Palasterina (t) 146 
 
 johnsoni, Eucladia 276 
 
 kinahani, Palasterina 155 
 
 kinahani, Uranaster 154, 155 
 
 Labidaster 208 
 
 lanceolatus, Mesopalaeaster (?) 75, 82 
 
 Lapworhtura 248, 250, 254 
 
 L. cylindrica 220 
 
 L. miltonl 250,261,253 
 
 L. sollasi. 251 
 
 L. (?)sp 251 
 
 Lapworthuridae 246, 248 
 
 lateral shields 214 
 
 latiscutetus, Coelaster 96 
 
 latiscutatus, Spaniaster 96 
 
 laxata, Schuchertia 196, 198 
 
 legrandensis, Schoenaster (?) 206 
 
 Lepidaster 38,40,158,160 
 
 L . grayi 158 
 
 Lepidasteracea 53 
 
 Lepidasterella 38, 40, 1 60 
 
 L.babcocki 160 
 
 Lepidasteridae 52,53,157 
 
 leptosoma, Protaster 237 
 
 leptosoma, Rhodostoma 237 
 
 leptosoma, Sturtzura 236, 237 
 
 leptosomoides, Sturtzura 236, 237 
 
 Lindstromaster 138, 140, 148, 154, 156 
 
 L. antiquus 1 4 9 , 153 
 
 Lindstromasterinx 138 
 
 logani, Eugaster 238 
 
 logani, Eugasterella 237, 288 
 
 longibrachiatus, Palxaster 115 
 
 Loriolaster 199,200, 201, 202,252 
 
 L. mirabilis 201 
 
 lymani, Ophiurina 247 
 
 Lysophiurae 215 
 
 madreporite 15,39,40,209,211,214,222,223,226 
 
 magniflcus, Promopalaeaster 42, 
 
 104,105,106,113,122 
 
 margaritetus, Xenaster 131,132 
 
 margaritatus, Xenaster 129, 130, 181 
 
 marginalia, see marginal plates. 
 
 marginal plates 1 6,33, 43, 135, 152, 213 
 
 marstoni, Palxocoma 253 
 
 marstoni, Sturtzaster 253 
 
 matutina, Asterias 57 
 
 matutinus, Hudsonaster 34, 55, 6 7,139, 141, 166 
 
 matutinus, Palxaster 67 
 
 meafordensis, Tseniaster 221 
 
 measurements 15 
 
 median dorsals, see radials. 
 
 Medusaster 38,207,212 
 
 M. rhenanus 212 
 
 Mesopaleeaster 28, 39, 41, 44, 45, 46, 47, 49, 
 
 50, 56, 74,95,98, 105, 126, 130, 135, 158 
 
 M.(?) acuminatus 75, 93 
 
 M. (? ) antiquus 75, 8 6 
 
 M.beUulus 75,91 
 
 M. caractaci 75, 92 
 
 M.(?) cataractensis 75,89 
 
 M.(?)clarki 75,94 
 
 M.(?)dubius 75,85 
 
INDEX. 
 
 307 
 
 Page. 
 
 M.finei 75,81 
 
 M. grant! 75,89 
 
 M. intermedius 75, 79 
 
 M.(?) lanceolatus 75, 82 
 
 M.(?) parviusculus 75, 87 
 
 M. proavitus 75, 83,85 
 
 M.shafferi 44,75,77 
 
 M.(?) wilberanus 75, 84 
 
 Mesopalseasterinae 52, 74,162 
 
 miamiensis, Alepidaster 230, 238 
 
 miamiensis, Anorthaster 127 
 
 miamiensis, Palseaster 127 
 
 miamiensis, Protaster 233 
 
 miellensis, Agalmaster 132 
 
 milleri, Hudsonaster 55, 60 
 
 miltoni, Lapworthura 250, 251, 253 
 
 mittoni, Protaster 251 
 
 minveri, Sympterura. . : 256 
 
 Miomaster 43,50, 74, 96 
 
 M. drevermanni 96 
 
 Miospondylus 262, 263 
 
 M. rhenanus 263 
 
 mira, Calliasterella 191 
 
 mirabilis, Loriolaster 201 
 
 mirus, Calliaster 190 
 
 mitchelli, Sturtzaster (?) 254 
 
 Monaster Gregory 49, 72 
 
 Monaster Etheridge 40, 1 70 
 
 M. Clarkei 171, 172 
 
 M. giganteus 73 
 
 M . stutchburii 73 
 
 Monasteridae 162, 163, 1 70 
 
 montana, Urasterella 175, 189 
 
 montanus, Asterias 189 
 
 montanus, Palseaster 189 
 
 montanus, Schoenaster (?) 43, 207 
 
 mouth angle plate, see oral armature. 
 
 multidactylus, Echlnodiscaster 211 
 
 multidactylus, Echinodiscus 211 
 
 multlrayed starfishes 38, 40, 157, 207 
 
 narrawayl, Hudsonaster 43, 50, 55, 69 
 
 narrawayi, Protopalseaster 59 
 
 neglecta, Palseura 223 
 
 Neopalseaster 40, 43, 48, 49, 57, 69, 98, 134 
 
 N. crawfordsvillensis 135, 136 
 
 Neopalseasteridse 52,53, 184 
 
 niagarensis, Palaeaster 68, 69 
 
 obtusus, Ophiura 25 
 
 obtusus, Palssaster 167 
 
 obtusus, Protaster (Ophiura) 25 
 
 obtusus, Stenaster (?) 165, 167 
 
 obtusus, Uraster 167 
 
 occurrence of starfishes 28 
 
 ocularplate 16,34,48,134,135 
 
 oculars in Echini 35 
 
 ontogeny of Stelleroidea 36 
 
 Onychaster 268 
 
 O.asper 270,272 
 
 O. barrisi 270, 272 
 
 O. confragosus 270, 273 
 
 O. demissus 270, 274 
 
 O.flexllis 269,270 
 
 Onychasteridse 268 
 
 Ophiocistia 275 
 
 Ophio-Encrinasterix .' 215 
 
 OpJiiopege 263 
 
 Page. 
 
 Ophiura ciliaris 268 
 
 O. obtusus 25 
 
 O. (?)ramosa 22 
 
 O . rhenana 263 
 
 O . salteri 227 
 
 O. schlotheimii 13 
 
 Ophiurasterix 215,246 
 
 Ophiurella 263 
 
 0- primigenia 263 
 
 Ophiurina 246, 260 
 
 O. lymani 247 
 
 Ophiurinidse 246 
 
 Ophiuroidea 41, 42, 43, 2 1 2 , 258, 267 
 
 geological distribution of 28 
 
 number of, in Paleozoic 27, 28 
 
 oral, see actinal. 
 
 oral angles 16 
 
 oral armature 16, 43, 162, 172, 210, 242 
 
 oral skeleton, see oral armature. 
 
 ordinaria, Schuchertia 196, 199 
 
 ossicles, see plates. 
 
 Palseaster 10, 
 
 40, 41, 44, 49, 56, 66, 67 , 75, 98, 104, 135, 158 
 
 Palseaster (Monaster) Etheridge (part) 72,170 
 
 P. (Argaster) antiqua 86 
 
 P. antiquata 109 
 
 P. aniiquus 86 
 
 P. asperrima 187 
 
 P. caractad 92 
 
 P. clarkana 61,63 
 
 P. clarke i De Koninck .- 172 
 
 P. clarkei Miller 61 
 
 P.darki : 94 
 
 P. coronella 167 
 
 P. crawfordsvillensis 136 
 
 P.dubius 85 
 
 P.dyeri 120 
 
 P. eucharis 98 
 
 P.exculptus 117 
 
 P. fin* 81 
 
 P. (Monaster) giganteus 73 
 
 P. grant i 89 
 
 P. granulosus Hall 112 
 
 P. granulosus Meek 109 
 
 P.Mrrisi 180 
 
 P.Mrudo 188 
 
 P. imbricatus 169 
 
 P. incomptus 61 
 
 P.jamesi 146 
 
 P. longibrachiatus 115 
 
 P. matutinus 57 
 
 P. miamiensis 127 
 
 P. montanus 189 
 
 P. niagarensis 68, 69 
 
 P . obtusus 167 
 
 P. parviusculus 87 
 
 P.pukJiellus 178 
 
 P. pygmaea. 23 
 
 P.ruthveni 187 
 
 P.sJiafferi - 77 
 
 P. simplex. 61, 62 
 
 P.speciosus 109 
 
 P. spinulosus - ^ 
 
 P. squamatus 2 s 
 
 P. (Monaster) stutchburii 73 
 
 P. wilberanus 84 
 
308 
 
 INDEX. 
 
 P. ? wilsoni 106 
 
 P.wykoffi 119 
 
 Palaeasteridse 52, 53, 66 
 
 Palxasterina 138, 150 
 
 P. antiqua 149 
 
 P. approximata 142 
 
 P. bonneyi. 153 
 
 P. fimbriata 204 
 
 P. primxva 153 
 
 P. speciosa 142 
 
 Palxasterinx 66 
 
 Palxasterinidx 138 
 
 Palxbrisingidx 199 
 
 Palxchinasteridx 199 
 
 Palxgoniasteridx (part) 66,241 
 
 Palxgoniasteridx 128 
 
 Palxnectria 155 
 
 P. devonica 155 
 
 Palxocoma Miller (part) 239 
 
 Palxocoma Salter 252 
 
 Palxocoma (Bdellacoma) 254 
 
 Palxocoma (Rhopalocoma) 254 
 
 P. colvin i 253 
 
 P. cygnipes 253 
 
 P. cylindrica 220 
 
 P. marstoni , 253 
 
 P. princeps 240 
 
 P. pyrotechnica 254 
 
 P. spinosa 219 
 
 P. vermiformis 254 
 
 Palaeodiscus ferox. . 23 
 
 Palseophiomyxa. 216, 234 
 
 P. grandis. 234, 235 
 
 Palxophiomyxidx 215, 234 
 
 Paiseophiura 235 
 
 P. simplex 235 
 
 Palxophiuridx 215,216, 235 
 
 Palaeosolaster 38, 40,207, 209, 211 
 
 P. gregoryi 209 
 
 P. (.)gyalum 210 
 
 P.rcemeri 211 
 
 Palseosolasteracea 163 
 
 Palseosolasteridse 162, 163, 20 7 
 
 Palxospondylidx 248 
 
 Palxospondylus 261 
 
 Palaeostella 51,138,155 
 
 P.solida 156 
 
 palaeozoicus, Furcaster 259, 261 
 
 Palxspondylus 261 
 
 P.zitteli 262 
 
 Palaeura 216,223 
 
 P.neglecta 223 
 
 Palasteracanthion 173 
 
 Palasterina Billings (part) 195 
 
 Palasterina Salter 40, 
 
 49, 130, 138, 140, 1 50, 154, 156, 196 
 
 P. bonneyi 151,152,153 
 
 P.follmanni. , 157 
 
 P.(f)jamesi. 146 
 
 P. kinahani. 155 
 
 P. primaeva 149, 151, 152, 153 
 
 P. (?) ramseyensis 152, 154 
 
 P. rigidus 141 
 
 P. rugosa 64 
 
 P. stellata 196 
 
 Palasterinacea. . . 53 
 
 Page. 
 
 Palasterinidae 52,53, 138, 196 
 
 Palasteriscidae 162, 163, 199 
 
 Palasteriscus 40, 199, 200, 252 
 
 P. devonicus 200 
 
 Palastropecten 248, 261 
 
 P. zitteli 262 
 
 Palmipes antiqua 149 
 
 papulae 16 
 
 parviusculus, Mesopalseaster (?) 75, 87 
 
 parviusculus , Palxaster 87 
 
 parvulus, Trimeraster 134 
 
 paxillae 116,156 
 
 peculiaris, Cholaster 266 
 
 pedicellariae 16 
 
 perfectus, Siluraster 66 
 
 perradial 17 
 
 petaliformis, Jaekelaster 192 
 
 petaloides, A spidosoma 243 
 
 petaloides, Encrinaster 243 
 
 petaloides goslariensis, A spidosoma 243 
 
 petaloides goslariensis, Encrinaster 243 
 
 Petraster 39, 
 
 44,45,46,47,51,138,149,154,156,196 
 
 P. (?) americanus 139,146 
 
 P. (?) antiqua 86 
 
 P. bellulus 91 
 
 P.dyeri 121 
 
 P. rigidus (part) 57 
 
 P.rigidus 139,141 
 
 P. smythi 139,147 
 
 P. speciosus 47, 139, 142 
 
 P. wilberianus 84 
 
 petri, Protaster 25 
 
 Phanerozonia 80, 
 
 38,39, 40, 41, 43, 44, 45, 46, 48, 51 
 
 phylembryo of Stelleroidea 34 
 
 Pisaster 38 
 
 plates 17 
 
 plumiformis, Trichotaster 26, 38 
 
 podia and podial openings 18, 
 
 17,33,38,39,209,213 
 
 pontis, Aspidosoma? 244 
 
 pontis, Encrinaster 244 
 
 prenuntius, Promopalseaster 104, 1 7 
 
 preservation of starfishes 28 
 
 primxva, Asterias 167 
 
 primxva, Palxasterina 153 
 
 primaeva, Palasterina 149, 151, 152, 153 
 
 primxvus, Uraster 153 
 
 primary inframarginal 15 
 
 primary radials 1 7, 32 
 
 primary skeleton 13, 15, 1 7 , 31, 32, 34, 56, 191 
 
 primary supramarginal 15 
 
 primigenia, Ophiurella 263 
 
 primigenius, Eospondylus 263 
 
 primitive starfish, most 31, 33 
 
 primordialis , Asterias 108 
 
 primus, Protasteracanthion 188 
 
 princeps, Palxocoma 240 
 
 princeps, Ptilonaster 240, 259 
 
 proavitus, Mesopalaeaster 75, 83, 85 
 
 Promopalaeaster 28, 
 
 39,41,42,44,45,46,47,50,56,76,98, 102, 126 
 
 P. bellulus 104,105,118 
 
 P.dyeri 104,105,120 
 
 P.exculptus 104,105,117 
 
INDEX. 
 
 309 
 
 Page. 
 
 P. granulosus 104, 112,113 
 
 P. magnificus 42, 104, 105, 106, 113, 122 
 
 P. prenuntius 104, 107 
 
 P. speciosus 104, 105, 109, 113 
 
 P. sp. undet 104, 108, 109 
 
 P, spinulosus 44, 104, 105, 116 
 
 P. wilsoni 104, 106 
 
 P. wykoffi 42, 104, 119 
 
 Promopalaeasteracea 53 
 
 Promopalsesteridse 52, 53, 73 
 
 Promopalaeasterinse 52, 74, 102 
 
 Protaster Hall (part) 254 
 
 Protaster Forbes 216,217, 224, 229 
 
 P. (?) barrisi 272 
 
 P. biforis 226, 722 
 
 P. brisingoides 236 
 
 P. daoulasensis 261 
 
 P.decheni 248 
 
 P.elegans * 221 
 
 P. fimbriata 231 
 
 P. flexuosus 231 
 
 P.forbesi 255 
 
 P. (?) granuliferus 230 
 
 P. (?) gregarius '264 
 
 P.groomi 226,227 
 
 P. leptosoma 237 
 
 P. miamiensis 233 
 
 P. miltoni 251 
 
 P. (Ophiura) obtusus 25 
 
 P.petri 25 
 
 P. (?) salted 226,227 
 
 P.sedgwicki 225,226,243 
 
 P. (?) steUifer 226, 228 
 
 P. (?) whiteavesianus 226, 227 
 
 Protasteracanfhion 173, 178 
 
 P. primus 188 
 
 Protasteridae 215 
 
 Protasterina 228 
 
 P. fimbriata 231 
 
 P.flexuosa 231 
 
 Protoeuryale 25 
 
 Protopalxaster 53, 56 
 
 P. caractad 92 
 
 P. narrawayi 59 
 
 Protophiurex 246 
 
 Protophiuroidea 213 
 
 proximal inframarginals 14, 16 
 
 proximal radials 17 
 
 proximal supramarginal 15 
 
 Pseudopalasterina 138, 156 
 
 P.foUmanni 156,157 
 
 Ptilonaster 235,289 
 
 P. princeps 240, 259 
 
 pulchella, Urasterella. 175, 178 
 
 pulchellus, Palxaster 178 
 
 pulchellus, Stenaster 178 
 
 Pycnopodia 38, 42, 207, 208 
 
 pygmaea, Palaeaster 23 
 
 pygmaeus, Ataxaster 161 
 
 pyrotechnica, Palxocoma 257 
 
 pyrotechnica, Rhopalocoma 254 
 
 radial accessory plates 13 
 
 radialia 17,34,35,46 
 
 radicle of asterids 34 
 
 ramosa, Ophiura (?) 22 
 
 s, Palasterina (?) 152,154 
 
 Page. 
 
 ray ambitals 13 
 
 rays 17,38,44,48,207,213,223 
 
 regeneration of. 185 
 
 regeneration 87, 185 
 
 respiration, see papulae and csecal pores. 
 
 rhenana, Asterias (Archxasterias) 131 
 
 rhenana, Ophiura 263 
 
 rhenanus, Helianthaster 159 
 
 rhenanus, Medusaster 212 
 
 rhenanus, Miospondylus 263 
 
 rhenanus, Xenaster (?) 130, 1 8 1 
 
 Rhenaster 43, 128, 188 
 
 R. schwerdi 133 
 
 Rhodostoma 236 
 
 R. leptosoma 237 
 
 Rhopalocoma 248,252, 254 
 
 R. pyrotechnica 254 
 
 rigidus, Palasterina 141 
 
 rigidus, Petraster 57 
 
 rigidus, Petraster 139, 141 
 
 Roemeraster 173, 177 
 
 R. (?) acuminatus 93 
 
 R. asperula 188 
 
 Roemerasterinx 172 
 
 roemeri, Aspidosoma 244 
 
 roemeri, Encrinaster 242,244 
 
 roer eri, Helianthaster 209, 211 
 
 roemeri, Palseosolaster 211 
 
 rugosa, Palasterina 64 
 
 rugosus, Hudsonaster 36,55, 64 
 
 ruthveni, Palxaster 187 
 
 ruthveni, Uraster. 187 
 
 ruthveni, Urasterella 174, 175, 18 7 
 
 SaUeraster 173,178 
 
 S. asperrimus 187 
 
 salted, Ophiura 227 
 
 salted, Protaster (?) 226,227 
 
 salted, Stenaster 164, 166 
 
 schlotheimii, Acroura (Ophiura) 18 
 
 schlotheimii, Ophiura 18 
 
 schluteri, Astropecten (?.) 161 
 
 schmidti, A spidosoma 244 
 
 schmidti, Encrinaster 244 
 
 Schcenaster 202 
 
 S.fimbriatus 204 
 
 S. (?) legrandensis 206 
 
 S. (?) montanus 43,207 
 
 S. (?)n.sp 206 
 
 S. ( ?) wachsmuthi 205 
 
 Schcenasteridse 162,163,202 
 
 schohariae, Taeniaster 219,220 
 
 Schondorf, on revision of German starfishes. . 11 
 
 Schuchertia. 51, 140, 152, 194, 195, 252 
 
 S. laxata 196, 198 
 
 S.ordinaria 196,199 
 
 S.stellata 195,196 
 
 Schuchertiacea 163 
 
 Schuchertiidae 162,163,194 
 
 schwerdi, Rhenaster 133 
 
 secondary skeleton, see secondary plates. 
 
 sedgwicki, Protaster 225, 226, 243 
 
 selwyni, Urasterella 175,188 
 
 shafferi, Mesopalajaster 44, 75, 77 
 
 shafferi, Palxaster 77 
 
 Siluraster 49,53 65 
 
 S.perfectus 66 
 
310 
 
 INDEX. 
 
 simplex, Eoactis . -. 186 
 
 simplex, Palxaster 61, 62 
 
 simplex, Palaeophiura 235 
 
 simplex, Xenaster 69 
 
 skeleton, secondary, see accessory plates. 
 
 sladenl, Echinasterella 200 
 
 smythi, Petraster 139, 147 
 
 Solaster 38 
 
 solida , Palseostella 156 
 
 sollasi, Lapworthura 251 
 
 Spanlaster 39,43,47,49,50,74,95 
 
 S. latiscutatus 96 
 
 speciosa, Palxasterina 142 
 
 speciosus Palxaster 109 
 
 speciosus, Petraster 47, 139, 142 
 
 speciosus, Promopalaeaster 104, 105, 109,113 
 
 spines, see paxillae and pedicellarise. 
 
 spinosa, Palxocoma 219 
 
 spinosissima, Asterias 19 
 
 spinosity 37,41 
 
 spinosus, Echinasterias 211 
 
 spinosus, Tgeniaster 216, 217,218, 219 
 
 spinulosus, Palxaster 115 
 
 spinulosus, Promopalaeaster 44, 104, 105, 115 
 
 spryi, Gregoriura 234 
 
 Squamaster 248,249 
 
 S. echinatus 249 
 
 squamatus, Palaeaster 23 
 
 stalk of primitive starfishes 83, 34 
 
 starfish, most primitive 31 , 33 
 
 origin of graspers 33 
 
 origin of wriggling type 32 
 
 radicle 34 
 
 stellata, Palasterina 196 
 
 stellata, Schuchertia 195, 1 96 
 
 stellata, Trentonaster 196 
 
 SteUeroidea 
 
 geological development 27,28 
 
 geological distribution 28 
 
 ontogeny 36 
 
 phylembryo 34 
 
 typembryo 8 5, 36 
 
 stellifer, Protaster (?) 226, 228 
 
 Stenaster (part) 173 
 
 Stenaster 31,41,42,43,50,68,163,168,212 
 
 S. (?) confluens 165,167 
 
 S. (?) coronella 165,167 
 
 S.grandis 180 
 
 S.huxleyi 182 
 
 S. (?) obtusus 165, 167 
 
 S.pulcJiellus 178 
 
 S.salteri 164,165 
 
 Stenasteracea 163 
 
 Stenasteridae 162, 168 
 
 stone-canal, see madreporite. 
 
 Strep tophiurse 215, 249 
 
 Stiirtzaster 248,252 
 
 S.colvini 253 
 
 S.cygnipes 253 
 
 S. marstoni 253 
 
 S. (?) mitchelli 254 
 
 Stiirtzura 235,286 
 
 S. brisingoides 236 
 
 S.leptosoma 236,237 
 
 S. leptosomoides 236,237 
 
 Page. 
 
 stutchburii, Australaster (?) 73 
 
 stutchburii, Monaster 73 
 
 stutcJiburi i, Palaeaster ( Monaster} 73 
 
 supramarginalia 15, 34,35, 46 
 
 Sympterura ; 248, 256 
 
 S. minveri 256 
 
 syngnaths 218,222,224,242,256,267 
 
 Tseniaster 216,218 
 
 T. australis 236 
 
 T. cylindricus 216,217,218,219,220 
 
 T.elegans 219,221 
 
 T. meafordensis 221 
 
 T. schohariae 219, 220 
 
 T. spinosus 216,217,218, 219 
 
 Txniasteridx 172 
 
 Txniura 216 
 
 T.cylindrica 220 
 
 tenuiradiatus, Coelaster 19 
 
 terminals, see ocular plates. 
 
 terminology of Asteroidea 13 
 
 Tetraster 31,41,42,43,50,164,165,167,212 
 
 T. asperrimus 187 
 
 T. (?) imbricatus 168,169 
 
 T . sp . ind . Nicholson and E theridge 186 
 
 T. wyville-thomsoni (part) 65 
 
 T. wyville-thomsoni 168 
 
 t ischbeinianum, Aspidosoma 244 
 
 tischbeinianus, Encrinaster 244 
 
 torus 1 6, 43, 54, 174 
 
 traquairi, Echinostella 212 
 
 Tremataster 246, 247 
 
 T. (?) decheni 247, 248 
 
 T. difficilis 247 
 
 Trentonaster 195 
 
 T. stellata 196 
 
 Trichotaster plumiformis 26, 38 
 
 Trimeraster 44,45,50, 128, 184 
 
 T. parvulus 134 
 
 trivium 14 
 
 Trochitaster, see Trichotaster. 
 
 typembryo of Stelleroidea 85, 36 
 
 ulrichi, Urasterella 37, 43, 45, 49, 175, 183 
 
 Uranaster 61,138,154 
 
 U. elizse 155 
 
 U. kinahani 154, 155 
 
 Uraster hirudo 188 
 
 U. obtusus 167 
 
 U. primxvus 153 
 
 U.ruthveni 187 
 
 Urasterella Sturtz 163 
 
 Urasterella McCoy 40, 
 
 41,42,45,47,49,50,69,164,178,194,212 
 
 U. (?)asperrima 175,187 
 
 U. asperula 175, 188 
 
 U. (?) constellata 175, 187 
 
 U. girvanensis 167, 175, 186 
 
 U. grandis 174,175,180 
 
 U. hirudo 175,188 
 
 U.huxleyi 175,182 
 
 U. montana 175,189 
 
 U. n. sp 189 
 
 U.pulchella 175,178 
 
 U . ruthveni 174, 175, 1 8 7 
 
 U.selwynl 175,188 
 
 U. ulrichi 37,43,45,49,175,188 
 
INDEX. 
 
 811 
 
 Page. 
 
 Urasterellacea 163 
 
 Urasterellidse 162,163,172 
 
 ventral, see actinal. 
 
 ventral shield 213 
 
 vermiformis, Bdellacoma 254 
 
 vermiformis, Palxocoma 254 
 
 vertebral ossicles 18,213,257,267,269 
 
 wachsmuthi, Schoenaster (?) 205 
 
 whiteavesianus, Protaster (?) 226, 22 7 
 
 wilberanus, Mesopalseaster (?) 75, 84 
 
 wilberanus, Palseaster 84 
 
 Wilberianus, Petraster 84 
 
 wilsoni, Palseaster (?) 106 
 
 wilsoni, Promopalseaster 104, 106 
 
 woodward!, Eucladla 276, 27 7 
 
 wrigglers 32,33,38 
 
 Page. 
 
 wykoffi, Palseaster 119 
 
 wykoffi, Promopalseaster 42, 104, 1 1 9 
 
 wyville-thomsoni, Tetraster 65 
 
 wyville-thomsoni, Tetraster 168 
 
 Xenaster 40,44,45,46,47,49,50,98,128,129 
 
 X. dispar 130,181 
 
 X.elegans 130,181 
 
 X. eucharis 98 
 
 X. margaritatus Follmann 131 
 
 X. margaritatus Simonovitsch (part) 131, 132 
 
 X. margaritatus Simonovitsch 129,130, 181 
 
 X. (?)rhenanus 130,181 
 
 X. simplex 96 
 
 Xenasteridse 52,53, 128 
 
 zitteli, Palseos'pondylus 262 
 
 zitteli, Palastropecten 262 
 
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