IMAGE EVALUATION TEST TARGET (MT-3) 1.0 M JO 1^ 20 1.8 1.25 u 16 : = ^ 6" ► V] <^ /J A ^c:- e^ >, y '/ # Photographic Sciences Corporation m tios. Those too large to be entirely induce in one exposure are filmed beginning in the uppak left hand corner, left to right and top to bottom, as many frames as required. The following diegrams illustrate the method: Les cartes, planches, tableaux, etc., peuvent Atre filmAs A des taux de reduction diffArents. Lorsque le document est trop grand pour Atre reproduit en un seul clichA. il est filmA A partir de I'angle supArieur gauche, de gauche A droite. et de haut en bas. en prenant le nombre d'images nAcessaire. Les diagrammes suivants illustrent la mAthode. rata telure. I A J 32X 1 2 3 1 2 3 4 5 6 y< ■ ' W A <■ \ r' ] [From the American Journal or SciESCf; Voi.. XX, Xovemhku. I88(i.] KKVISION OF TIIK LAND SNAILS OF TIIF PAI.KOZOIO KHA, Wrril DFSCRII'- TIONS OF XKW SI'FAiKS. Hv .1. W. Dawson. 'm [From REVI .a f [From tub Aubrioan Journal of Science, Yol. XX, Novbubgu, 1880.] I ' REVISION OF THE LAND SNAILS OF THE PALEOZOIC ERA, WITH DESCRIP- TIONS OF NEW SPECIES. Hy J. W. Dawson. [Fbox REVI The brian, tion of instead any for bonifer - r. I : A', I li ■' [Fbou thk Axerioan Journal of Science, Vol. XX, November, 1880,] REVISION OF THE LAND SNAILS OF THE PALEOZOIC ERA, WITH DESCRIP- TIONS OF NEW SPECIES. By J. W. Dawson. The Gasteropods as a class occur as early as the Upper Cam- brian, but all the earlier known types are marine. That por- tion of the group distinguished by the possession of air sacs instead of gills (Pulmonif'era) has not hitherto been found in any formation older than the Carboniferous, and only four Car- boniferous species have been described. In the present paper 404 ./. W. Dawson — Paleozoic Lund Snails. I propose to state some ndditionnl facts respectinp the species alreauy known, to discuss their nflinities, and to describe two additional species, making six in all from the Paleozoic rocks, including one from the Erian or Devonian. For reasons to be mentioned in the sequel, I do not admit the genus Pakvorhis founded, by some German naturalists, on fossils which 1 believe to be tubes of Annelids. It may be useful to premise that of the two leading sub- divisions of th« group of Pulmonifera, the Operculate and Inoperculate, the first lias been traced no farther back than the Eocene. The second, or Inoperculate division, includes some genera that are iiquatic and .some that are terrestrial. Of the aquatic genera no representatives are known in formations older than the Wealden and Purbeek, and these only in Europe. The terrestrial group or the family of the Hdicidoe, which, singularly enough, is that which diverges farthest from the ordinary gill-bearing (ja.steropods, is the one which has been traced fartliest back, and includes the Paleozoic species. It is further remarkal)le that a very great gap exists in the geolog- ical history of this family. No species are known between the Carboniferous and the early Tertiary, though in the inter- vening formations there are many fresh-water and er>tuarine deposits in which such remains might be expected to occur. There is perhaps no reason to doubt the continuance of the Ilelicidiu through this long portion of geological time, though it is prolmble that during the interval the family did not increase much in tiie number of its species, more especially as it seems certain that it has its culmination in the modern period, when it is represented by very many and large species, which are dispersed over nearly all parts of our continents. The mode of occurrence of the Paleozoic Pulmonifera in the few localities where they have been found is characteristic. The earliest known species. Pupa velusta^ was found by Sir Charles Lyell and the writer, in the material filling the once hollow stem of a Sigillaria at the South Jt)ggins in Nova Scotia, and many additional specimens have subse(piently been ob- tained from similar repositories in the.«ame locality, where they are associated with bones of Batrachians and remains of Milli- f)edes. Other specimens, and also the species Zonites priscus, lave been found in a thin, slialy layer, containing debris of plants and crusts of Cyj)rids, and which was probably depo.sited at the outlet of a small stream flowing through the coal-forma- tion forest The two species found in Illinois occur, according to Bradley, in an underclay or fo.ssil soil which may have been the bed of a pond or estuary, and subsequently became a forest sub-soil. The Erian species occurs in shales charged with remains of land plants, and which must consequently have rcccivefl in suchi •pected Pulmoil sliouldl niinousi (JypJ'iJf fossil \\ Witll J. \Y. Dawson — Paleozoic Land Snails. 405 : the species JfHcribe two jozoic rocks, casons to he us Pahvorhis (^h 1 hoJiove oading sub- i«!ulatu and icjk thfti) the eludes some «I. Of the formations ' in Europe. id(f., which, It from the li lias been 'tiies. It is he gcolog- t'tween the the inter- 1 ei!tuarii)e 1 to occur, lice of the 'le, though y cut with tli> ■y to (li mi nisi ie mioroscopii those of tli( to regnn] a. i'lai transitior to .iccompan\ cies. ^ entire, ^^ui ed in the pro ith the entire or bleached having been, ^pressions of having been fis in such a 'ct specimens f, like that of Coal-forma ^ophloios am] , ggins, Nova . ined in con- » can be dis They have shale. The 3pa rated bv no less than 3rting erect locality for »cal vicissi- 1 Paleozoic le writer in ee holding ree having tted to the recognized shell. It Fig. 1, Pupa retusta, magniflod 8 times linenlly ; 2, same, sliowing the aperture, , X 8 ; 3, same, nuclear whorl, x 26 ; 4, same, mature egg and embryo shell, x 25. 5, 6, Pupa Bigsbii, x 8. 7, Pupa Vermilionensis, x 8 ; 8, pamo, showing aper- ture X 8, the small tooth on the columella somewhat exaggerated ; 9, same, (flection of aperture, showing tooth x IG. 10, Zonitea priscua, x8; 11, same, crushed speamen, showing aperture x 20. 408 J. ir. Dawson — Paleozoic Land Snails. was subsequently examined by M. Deshayes and Mr. Gw\Tid is JeftVies, 'vho concurred in this determination ; and its micnbput scopic structure was described by the late Prof. Quekett, ?^ich London, as similar to that of modern land shells. The sing' specimen obtained on this occasion was somewhat crushed an did not show the aperture. Hence the hesitation as to i nature, and the delay in naming it, though it was figure and described in the paper above cited in 1852. Better spec mens showing the aperture were afterward obtained by tli writer, and it was named and described by him in his " Ainf alreJi breatliers of the Coal Period," in 1863. Prof. Owen, in higay co| 'Paiffiontology,' subsequently proposed the generic name Bounties dropnpa. This I have hesitated to accept, as expressing ii^few vl generic distinction not warranted by the facts ; but shoulca^eous the shell be considered to require a generic or sub-generic disa^e moi tinction, Owen's name should be adopted for it There seemsan frag however, nothing to prevent it from being placed in one of tiumud d modern sub-genera of simple-lipped Pupa?. With regard to thfstream. form of its aperture, I may explain that some currency ha. occur i been given to an incorrect representation of it, through an uii only g fortunate accident In the case of delicate shells like this, though imbedded in a hard matrix, it is of course difficult to work out Would the aperture perfectly; and in my published figure in the "Air- in the breathers," I had to restore somewhat the broken specimens a sand in my possession. This restoration, specimens subsequently 6rina( found have shown to be very exact Nevertheless it was Except criticised by some English conchologists, and when Sir Charles lies are Lyell was about to publish his Student's Manual, he asked me tliat m to give him one of my best specimens to be figured. This I tfcey cc sent with micro-phc.ographs of others. It seems, however, ^le thfi that the artist or engraver mistook the form of the aperture liabit ( and gave it an entirely unnatural appearance in the Student's dence Manual. That now given is taken from a photograph of the most perfect and least compressd specimen in my possession. As already stated, this shell seems closely allied to some modern Pupae. Perhaps the modern species which approaches most nearly to it in form, markings and size, is Macrocheilus Gossei from the West Indies, specimens of which were sent to me some years ago by Mr. Bland, of New York, with the re- mark that they must be very near to mj^ Carboniferous species. Such edentulous species as Pupa {Leucochila) fallax or East- ern America very closely resemble it ; and it was regarded by the late Dr. Carpenter as probably a near ally of those species which are placed by some European conchologists in the genus Pupilla. The lowest bed in which Pupa vetusla occurs belongs to group VIII of Division 4 of my section of the South Joggins, blogy They linimfi i bav tinbrc mode the si been fou\n suffic trun hori: othe iwitV tails. J. W. Dawson — Paleozoic Laud Stiails. 409 ' '^"o Mr. Gw\iid is between Coal 37 and Coal 38 of Logan's section, being ' ^^'^ >ts micivbout 42 feet below Conl 87. Tiie next horizon, and that in *''of. Quekett, (jTich the shell was first discovered, is 1217 feet of vertical sJIa Thosing'"' '• ' ' "'^^ ^ -.1 ■ ■ . . • hat crushed an£ itation as to ckness higher, in group XV of Division 4 of my section. e shells occur here in erect SiyillaricH, standing on Coal 15 Logan's section. The third horizon is in group XXVI of >t was figureSvision 4, about 800 feet higher than the last. Here also the iietter spec^ells occurred in an erect Sirjillaria. otained by tli In the lowest of these three horizons, the shells are found, ni m his "Ainnp already stated, in a thin bed of concretionary clay of dark • Uwen, in higiay color, though associated with reddish beds. It contains 6ric name Deii^pnites priscus as well, though this is very rare, and there are 8 expressing i^few valves of Cythere and shells of Naiadiles as well as carbon- ' ; but shoulcg^eous fragments, fronds of ferns, Tngonocarpa, etc. The Pupce '^^^^^leric disuse mostly adult, but many very young shells also occur, as well -Ihere seemsai fragments of broken shells. The bed is evidently a layer of t m one of tlifotfud deposited in a pond or creek, or at the mouth of a small 1 regard to thfstream. In modern swamps, multitudes of fresh-water shells currency haj occur in such places, and it is remarkable that in this case the fP^? an unofnly gasteropods are land shells, and these very plentiful, ells like this, though only in one bed about an inch in thickness. This It to work out Would seem to imply an absence of fresh-water Pulmonifera. e m the "Air- In the erect Sigillarice of group XV, the shells occur either in en specimens a sandy matrix, more or less darkened with vegetable matter, subsequently 6r in a carbonaceous mass composed mainly of vegetable debris. leless it was Except when crushed or flattened, the shells in these rejiosito- n Sir Charles lies are usually filled with brownish calcite. From this I infer he asked me that most of them were alive when imbedded, or at least that "*ed. This I tliey contained the bodies of the animals ; and it is not improba- ns, however, ble that they sheltered themselves in the hollow trees, as is the tne^aperturc habit of many similar animals in modern forests. Their resi- he btudent's dence in these trees as well as the characters of their ernbry- ?i'aph of the i>logy are illustrated by the occurrence of their mature ova. They may also have formed part of the food of the rejtilian linimals whose remains occur with them. In illustration of this J have elsewhere stated that I have found as many as eleven Unbroken shells of Physa heleroslropha in the stomach of a modern AJenobranchvs. I think it certain, however, that both the shells and the reptiles occurring in these trees must have ous species, been strictly terrestrial in their habits, as they could not have ix of East- found admission to the erect trees unless the ground had been sufficiently dry to allow several feet of the imbedded hollow trunks to be free from water. In the highest of the three horizons the shells occurred in an erect tree, but without any other fossils, and they had apparently been washed in along 'with a grayish mud.* * The discovery of the shells in this tree was made by Albert I. Hill, C.E. )ossession. ied to some approaches ifacroc/ieilus vere sent to 'ith the re- Bgarded by ose species ' the genus belongs to h «Ioggins, 410 J. W. Duivson — Paleozoic Land S7iails. 2. l*npa liif/sbii 8. n. (Figs. 6 and 6.) ourse all Description. — Shell half the size of Pupa i>etnsta, or betwe^W"^ '^^ three and four millimeters in length and one and five-ten tlQBp'""^^^ millimeters in breadth. Form, long conieal. Body whorl abolf^F'^*^ *'^, one-third of the entire length, giving the shell a somewhi«"^ ^*^'| bulimoid form. Whorls five in the largest specimens founiJlf^^^M tumid, suture much impressed. Surface smooth. Apertuiift-^^. ^ apparently oval in form, but not perfectly known, as the bod***'* '^ whorl is crushed in all the specimens. bbc apen A few specimens, none of them quite j)erfect, were found i'^^* ^1 the erect trees of group XV at the Joggins, along with Ptqf^' : '"'*j vehisla. They difi'er from that species in smaller si/.e, differeTi*fl*^^'S^ form and absence of .sculpture. The specimens do not sho' iThis whether the aperture was toothed or simple, but it was prob.ilw^^> "\ bly the latter, as the lip is evidently very thin and delicate^ ^on\ From its form it is })rol)ablc that it belongs to a different sulion Riv( genus from P. veiiiala. It is very much more rare than thal^V^''^* species in the erect trees, and has not been found elsewhere. Pi'P<^ ^'' I dedicate it to my venerable and dear friend Dr. Bigsbyio the ^ F.R.S., of London, a pioneer in American geology, and still ai 'ig with Pnif4t ''• Tupicola. It has also some reseml)lance to the western ' size, difFeren^^ecies P. hordeacea Gabb, from Ari;^ona. do not sbo' -This shell was discovered by the late Mr. F. II. Bradley in it was prob,'!l869, in concretionary limestone accompanying the underclay «'id delicat(Of C'>«il No. 6, Wabash Valley Section, at Felly's Fort, Vermil- different sulion River, Illinois. In the first notice, which apjieared in the are than thaR6|'0''t of the Geological Survey of Illinois, it was referred to elsewhere. Pi'2)a vetttsfa, but was subsequently described by Mr. Bradley fl Dr. Bigsbyifl the American Journal of Science, under the name above y, and still ai rated. I am indebted for specimens of this shell to Mr. John Collett, of the Geological Survey of Indiana, and also to Mr. W. Gurley, of Danville, Illinois. \ !>, and 14c.) 254. Id. iuAtt to an obtusf n a millime 'blique, oval 4. Zonites ( Conulus) 2)riscns Carpenter. (Figs. 1 and 1 1, and 14f7.) [Quarterly Journal of Geological Society of London, Nov. 1867. Acadian Geol- ogy, 2d edition, 1868, p. 385.] Description.* — Shell small, helicoid. Length two and five- Sexed, thick tenths millimeters, width two and eight-tenths millimeters, h, projecting Spire little elevated. Nucleus small. Whorls four, somewhat >f columella flattened, with the suture little impressed. Base somewhat In old indi- 6xcavated with large umbilicu.s. Aperture oblique, suboval, through an Bomewhat regularly rounded. Lip simple. Surface marked ng IcvSs than ^'th uneven striae and somewhat more conspicuous ridges of ingth of the growth. Angle of divergence about 130". Shell thin and face glossy. prol)ably horny. millimeters. This little shell was discovered in 1866, in the bed already )th or desti- referred to as the lowest of those at the South Joggins in which is a natural Pupa vetusta has been found. Shortly after I had discovered this bed, being impressed with the probability that it might hold other remains of land animals beside the Pupa, I had 8ome excsjvations made in it, and a considerable quantity of material taken out. I found, however, that the thin layer •Containing the land shells was not continuous but in limited .patches, and was rewarded only by the discovery of a few * Slightly nioditled from Carpenter. , IS not cer- ' than half e rounded, 3 sculpture fture is of 412 J. W. Dawson — Paleozoic Land Snails. 12. 16. specimens of Zonites priscua and a small and not determinafc|^a^i"<* fragment of bone, in addition to specimens of Pupa wiws^o. i^thougi The specimens found at this time were submitted to the I'the gel I)r. P. P. Carpenter, b}' whom the species was named jfl^*'^ ^\ described. One or two crushed specimens have been sub^^^g^j quently found in the erect trees holding Pupa vetusta in gn^ TrocR XV, but the species is extremely rare in comparison. This rw^T ; an<^ however have depended on some difference in habitat or nv i subg of life, rendering it less likely to be imbedded in the depoilO ^^ in process of formation. It is also to be observed that -fl^ desi^ shell is much more delicate than that of Pupa vetu.sla, ;» • Heli3 therefore less likely to be preserved. > tnore Ukils wit] ^t 5. [Beporl o >l.lv, p. 8f l)escrip ase, con.^ I^ree and [iCe smo( ]f^en in raoted b; ag, more )ater lip mperforu egion. Qicrosco] nferred 1 .hdi of ; This s) liacovert •efer it t< ifith goc [n. size I expand ii DH^e dis are of t\ aperture Fig. 12, Dawsonelhi Meeki, x8; 1,3, same, section of aperture, x 16 ; \7!^n.ntre outer edge of the lamella ia imperfect. 14. Markings of surface x 100 : (a) A^ v5|« vetusta; (ti) Pupa vetusta var. tenuistrlata; (c) Fripa Vermilionensk ; {d) Zonii m^^ ^ priscus ; 15, Sirophites grandceva, natural size and magnified 8 dianieters. fc^v-WP^® ^ With regard to its affinities, it was compared by Dr. Carpe:*"^''*""' ter with the African species Panjphanla Caffra Fer., "on a ^ extremely small; scale." Dr. Carpenter also compared it wit Wescr Hygromia, and stated that it might well be ranked under' Aff#r or 14. X ?oc laifs. J. W. Dawson — Paleozoic Land Snails. 413 not determinaSra?i«c[ of Morse, with the living species minuscitla and exigua. Pupa vetuafa. ^t\io\xg\it it best, however, to place it in the subgenus Conulus nitted to the 1 ithe genus Zoniles, as defined by Messrs. Adams. With was named siiii'd to the subgeneric name, Dr. Carpenter explained that ave been suHieubgenus Conulus of Fitz, 1883, appears to be synonymous vetusta in »rc«A Trochiscns Held, 1837 (non Sby.) ; also with Petasia Beck, ison. This nfi^ '■> and with Perforatella Schliitt. ; and according to Adams liabitat or nif i subgenus of Zonites Montf. (non Leach, Gray). Those I in the depo.iw? do not care to enter into these subgeneric distinctions, served that '1^ designate the species as a Zonites, or even, speaking loosely, ipa vetusta, ^ Helix. There seems nothing in its characters to separate ,'4nore than specifically, from many of our smaller helicoid Udls with thin shells and simple aperture. 5. Dawsonella Meeki Bradley. (Figs. 12 and 13.) rSeport of Geological Survey of Illinois, vol. iv, p. 254. Am. Joura. of Sci., Ill, >tlv, p. 88. Ibid, vol. vii, p. 157.] pescription.* — Shell broad, depressed, helicoid. Spire ob- J8<^, consisting of three to three and one-half turns. Length aree and two-tenths millimeters, width four millimeters. Sur- ao^ smooth, but with fine micro.scopic lines of growth, about ]ft^n in a millimeter. Aperture oblique, oval, greatly con- r^ted by a broad lamellar expansion of the columella, extend- Oft; more than half way across, even in small individuals. )\l%er lip thickened, slightly reflexed. Suture little impressed, mperforate, but last turn slightly excavated in the umbilical egion. The shell is usually black in color, and under the Qicroscope shows no distinct structure, from which it may be nf^rred that it was corneous in texture. It is thicker than the ,hell of Zonites pi-iscus. This species is found along with Pupa Vermilionensis, and was liscovered by Bradley, who was, however, at first disposed to •efer it to genus Anomphalus of Meek ; but subsequently, and i^ith good reason, regarded it as distinct and as a land shell, [n. size and general form it resembles Zonites priscus, though expanding less rapidly and with rounder whorls; but it is at jnce distinguished by its want of the somewhat coarse sculpt- ure of that species, and by the plate which partially covers its aperture. Its nearest modern allies in eastern America would seem to be such shells as Helix {Triodopsis) palUata, and H. ri'Too •''(if >,|<'%^o/rema) monodon. lensis; (d) Zonv F*^'' specimens of this shell I am indebted to the persons tlian^etora. fc^,,jJh!y Dr. Carpe ««>«"***• Fer. "oil ' i>i ^' >^^^^P^*^^^^^ (franda^va, s. n. (Fig. 15.) ipared it wit l^escription. — Shell cylindrical, with obtuse apex. Whorls d under_[/^vf faip* or more. Surface covered with sharp vertical ridges, :| * Modified from Bradley. 414 J. W. Dawson — Paleozoic Land Snails. separated by spaces three times as wide. The body whorl about 4 millimeters in diameter, witli about thirteen vertical ridges visible on one side. Length of a specimen probably not quite perfect, about 8 millimeters. The shell, which has dis- appeared, must have been very tliin, and the surface remaining is smooth and shining. In general form, so far as can be asoer- tained from a very imperfect specimen, this shell must have closely resembled the modern Pupae of the genus Strophia of Albers. The only specimen known is from the Erian (Devonian) plant-beds of St. John, New Brunswick, which, besides aflford- ing great numbers of remains of land plants, have produced the only Erian insects as yet known. It was sent to me by Mr. G. F. Matthew, of St. Jolin, along with specimens of fossil plants, several years ago, but I hesitated to describe it, waiting in hope of additional specimens. As these have not occurred, and I have now carefully examined the whole of the material from these beds to which I have been able to obtain access, I venture to name it as probably the oldest known land shell, the beds in which it is found being either middle or upper Erian. If a land snail, it is larger in size and probably of higher type than any of those known from the Coal-formation, This would not be wonderful, when we consider the greater variety of sur- face and the high character of the vegetation, which, as I have elsewhere endeavored to show, distinguished the later Erian age in Northeastern America. Goncluding Hetuarks. It may be proper to mention here the alleged Pulmonifera of the genus Palceorbis described by some German naturalists. These T believe to be worm-tubes of the genus Spirorbis, and in fact to be nothing else than the common S. carhonariua or S. pusilhis of the Coal-formation. The history of this error rnay be stated thus. The eminent paleobotanists Germar, Goeppert and Geinitz have referred tne Spirorhis, so common in the Coal- measures to the fungi, under the name Gyromyces, and in this they have been followed by other naturalists, though as long ago as 1868 I had shown that this little organism is not only a calcareous shell, attached by one side to vegetable matters and shells of mollusks, but that it has the microscopic structure characteristic of modern shells of this ty])e,^ More recently Van Beneden, Casnius and Goldenberg, perceiving that the fossil is really a calcareous shell, but apparently unaware of the observations made in this country by myself and Mr. Lesque- reux, have held the Spirorhis to be a pulmonate mollusk allied to Planorhis, and have supi)osed that its presence on fossil * Acadian Goolnj^y, -«1 Oflition, p. 205. ; I 1 plants attache found I R. Eth has rec these si of artic Urn Paleozc howeve Insects likely announ are in John, a of the other G; holding of the in so fa: rated n successc It is J erous w faunae consider have be( contain any lart occurred Paleozoi in those most coi that we Carbonif country revelatio Coal-forri snails an of reptih perfect t of this k speculate with anir or later f of form ( time whii w J. W. Datvson — Paleozoic Land &iails. 415 whorl .rertical bly not [as dis- lainiDg B asoer- }t have tphia of vonian) I aflford- iced the Mr. G. plants, in hope ed, and lal from venture beds in ler type IS would r of sur- 3 I have !r Brian nifera of uralists. and in us or S. -or rnay joeppert he Coal- in this as long lot only matters ructure ecently lat the e of the jesque- allied fossil n plants is confirmatory of this view, though the shells are attached by a flattened side to these plants, and are also found attached to shells of bivalves of the genus Naiaditea. Mr. R. Etheridge, Jr., of the Geological Survey of Great Britain, has recently summed up the evidence as to the true nature of these shells, and has revised and added to the species, in a series of articles in the Geological Magazine of London, vol. viii. If we exclude the alleged Pakcorhis above referred to, all the Paleozoic Pulmonifera hitherto found are American. Since, however, in the Carboniferous age, Batrachians, Arachnidans, Insects and Millipedes occur on both continents, it is not un- likely that ere long European species of land snails will be announced. The species hitherto found in Eastern America, are in every way strangely isolated. In the plant-beds of St. John, about 9,000 feet in thickness, and in the Coal- formation of the South Joggins, more than 7,000 feet in thickness, no other Gasteropods occur, nor, I believe, do any occur in the beds holding land snails in Illinois. Nor, as already stated, are any of the aquatic Pulmonifera known in the Paleozoic. Thus, in so far as at present known, these Paleozoic snails are sepa- rated not only from any predecessors, if there were any, or successors, but from any contemporary animals allied to them. It is probable that the land snails of the Erian and Carbonif- erous were neither numerous nor important members of the faunae of those periods. Had other species existed in any considerable numbers, there is no reason why they should not have been found in the erect trees, or in those shales which contain land plants. More especially would the discovery of any larger species, had they existed, been likely to have occurred. Further, what we know of the vegetation of the Paleozoic Period would lead us to infer that it did not abound in those succulent and nutritious leaves and fruits which are most congenial to land snails. It is to be observed, however, that we know little as yet of the upland life of the Erian or Carboniferous. The animal life of the drier parts of the low country is indeed as yet very little known ; and but for the revelations in this respect of the erect trees in one bed in the Coal- formation of Nova Scotia, our knowledge of the land snails and Millipedes, and also of an eminently terrestrial group of reptiles, the Microsatiria, would have been much more im- perfect than it is. We may hope for still further revelations of this kind, and in the meantime, it would be premature to speculate as to the affinities of our little group of land snails with animals either their contemporaries or belonging to earlier or later formations, except to nrjte the fact of the little change of form or structure in this type of life in that vast interval of time which separates the Erian Period from tlie [>resent day. I