QL 
 
 |Tb 
 
 NRLF 
 
 
LIBRARY 
 
 UNIVERSITY OF CALIFORNIA. 
 
 Class 
 
 LIBRARY 
 
1836 Plate L 
 
 r 
 
 
 
 G.H.Fdel. 
 
 M.P. Parker litk. 
 
 Plank-tan of tine Faeroe Channel. 
 
1896.] ON THE PLANKTON OE THE FAEROE CHANNEL. 991 
 
 in this country, and Mr. Rothschild has stated ( Avifauna of 
 Laysan, p. 97) that Lafresnaye's type is in the Paris Museum. On 
 this point he must have been misinformed, and the specimen he 
 " carefully examined " there was probably one of the pair obtained 
 and presented by Neboux (Eevue Zoologique, 1840, p. 289), from 
 which presumably the figures in the Voyage of the ' Venus ' (Ois. 
 pi. i. figs. 1, 2) were taken. It is almost needless to remark that 
 had the present example been attainable by Mr. Wilson he would 
 never have supposed it to be specifically identical with the bird 
 which he found in Hawaii ; and I may observe that not one of the 
 five examples of the HemignatTius lucidus of Oahu at his disposal 
 two from Berlin, two at Cambridge, and one in the British 
 Museum was that of a male in full plumage. 
 
 Mr. W. B. Tegetmeier, F.Z.S., exhibited an interesting 
 application of the Rontgen rays to ornithology, in the shape of an 
 actinograph taken from a Partridge that had " towered " on being 
 shot. The actinograph seemed to show that the " towering " was 
 caused by injury done to the. lungs, and not by lesion of the brain, 
 as often supposed.^^C>| [ iroRS^^ 
 
 The following papers were read : 
 
 1. Contributions to our Knowledge of the Plankton of the 
 Faeroe Channel. No. I. By G. HERBERT FOWLER, 
 B.A., Ph.D., Assistant Professor of Zoology, University 
 College, London. 
 
 [Received November 3, 1896.] 
 (Plate L.) 
 
 Between July 29th and August 8th of this year I enjoyed the 
 great advantage of a berth on H.M.S. 'Research/ by the per- 
 mission of the Lords Commissioners of the Admiralty, extended to 
 me at the request of the Council of the Royal Society. I am glad 
 of this opportunity to tender my thanks, not only to both of these 
 bodies, but also to Capt. Moore and the other officers of the 
 ' Research ' for placing at my disposal every facility that lay in 
 their power. 
 
 My chief object on the cruise was an attempt to ascertain 
 
 /whether the intermediate zones of water between (say) 100 and 
 
 700 fathoms are characterized by definite forms of planktonic life 
 
 or not ; and if so, what temperature-limits form barriers to the 
 
 distribution of various species. The large number both of surface 
 
 and deep-water organisms obtained during the cruise will demand 
 
 so long a study that it seems best to publish results as soon as 
 
 obtained in the scant leisure of which a teaching post admits. 
 
 The present note forms, therefore, the first of a series, in which 
 
 Puoc. ZOOL. Soc. 1896, No. LXIV. 64 
 
 L v/ ivi i V t. K .-> i j i i 
 
 V OF // 
 
992 DR. G. HERBERT FOWLER OX THE [Dec. 15, 
 
 BIOLOGY 
 
 the methods employed and the general questions of distribution 
 will be left to the last paper. 
 
 SAGITTA WHAETOISTI, sp. n. 1 (Plate L. figs. 1-3.) 
 Tn external form this species resembles most nearly $. lyra 
 (Krohn), and differs from all other species yet described in the 
 approximation, almost fusion, of the paired lateral fins. Prom 
 Krohn's species, however, it is easily distinguished by the absence 
 of a constriction between body and trunk and by the numbers of 
 the teeth and cirrhi. 
 
 The head is large, 3-4 mm. wide and 2 mm. long in a specimen 
 45 mm. long. It bears on each side 8-10 stout cirrhi (Greifhaken), 
 which are strongly curved, and of which the middle three are the 
 longest. The accessory teeth (Nebenkiefer) are arranged in two 
 series, of which the more dorsal are 3-5 in number and are short 
 and stout ; the more ventral are 5-7 in number and are slighter 
 and longer. The neck is somewhat thinner than the body. The 
 body tapers without constriction to the tail ; the latter (post-septal 
 region) is less than one-fourth of the total length. The lateral 
 fins are set rather far back, the anterior being much longer and 
 narrower than the posterior. 
 
 The longest specimen measured 45 mm. The following dimen- 
 sions are taken from well-preserved straight specimens, of which 
 A was apparently uncontracted, B contracted considerably antero- 
 posteriorly : 
 
 A. B. 
 
 Total length .. 30 mm. 38 mm. 
 
 Head, 1 2 
 
 Body, 23 26 
 
 Tail, 6 10 
 
 Neck, width 1-5 3 
 
 Body, width at widest .... 2 4 
 
 Anterior fin, length 20 18 
 
 width 3 6 
 
 Posterior fin, length 10 7 
 
 width 4 9 
 
 Tail-fin, width 3 6 
 
 It is curious that this species should not have been taken by the 
 Plankton Expedition, which records 2 S. Upunctata from the north 
 of Scotland. From this it is distinguished readily by the approxi- 
 mation (continuity) of the lateral fins. 
 
 Prom S. hexaptera it is further distinguished by the size of the 
 head, by the slightly more backward position of the posterior 
 lateral fin, by the possession of more numerous cirrhi, and by the 
 absence of the five-rayed star on the accessory teeth (cf. Strodtmann, 
 loc. cit.). 
 
 1 In honour of Admiral Wharton, E.N., the Hydrographer, a steady friend 
 to oceanic research. 
 
 2 Strodtmann, "Systematik der Chaetognathen," Arch, fur Naturgeschichte, 
 hiii. Band i. pp. 333-376, pi. xvii. 
 
1898.] PLANKTON OP THE FAEROE CHANNEL. 993 
 
 Prom S. bipunctata it is readily distinguished by the number of 
 teeth in the accessory rows and the proportions of tail to body. 
 
 A row of stout processes is placed on the ventral side of the 
 rows of accessory teeth. These appear to correspond to the 
 " follicoli vestibolari " of Grassi ; but in forming a single row they 
 differ from those which he figures as characterizing S. heocaptera l . 
 
 I have been unable to detect any trace of a " corona cigliata " 
 (Eiechorgan) on the dorsal surface of the head and neck. 
 
 This species 2 appears to be present in both the " cold " and the 
 "warm" areas 3 of the Paeroe Channel, and to be a characteristic 
 component of the " Mesoplankton," i. e. the floating and swimming 
 organisms between a depth of +100 fathoms below the surface 
 and a depth of +100 fathoms from the bottom. 
 
 Horizontal distribution : 61 18' N., 4 21' W., to 59 42' N., 
 7 7' W. 
 
 Vertical distribution : 
 
 Greatest depth warm area Sta. 19 a, 480 to 350 fathoms ; 
 temp. 46 to 47 P. 
 
 Greatest depth cold area Sta. 13 #, 465 to 335 fathoms ; 
 temp. 31 to 33 F. 
 
 Least depth Sta. 13 t, 100 to fathoms ; temp. 48 to 54 P. 
 
 The least depth given above was the only occasion on which it 
 was taken anywhere near the surface, except for one doubtful and 
 broken specimen at the surface at midnight (Sta. 15). There is 
 no doubt that this species is essentially Mesoplanktonic, with a 
 very wide temperature range (at least 33 to 48 P.) ; it occurred 
 in every haul, but one, of those made between 530 and 100 fathoms 
 (i. e. in eight out of nine hauls) ; it occurred in every haul which 
 began at or lower than 300 fathoms and finished at the surface 
 (three hauls) ; and was taken, certainly, only once in a haul 
 which began at 1 00 fathoms and ended at the surface (once out of 
 twenty-two hauls). 
 
 SPADELLA (KBOHNIA) HAMATA, Mobius. (Plate L. fig. 4.) 
 
 Having obtained a large number of well-preserved specimens of 
 this species, I think it worth while to give an outline (fig. 4) of 
 the external form, since both the original figure of Mobius 4 (which 
 has been simply copied by.Hertwig 5 and by Grassi 6 ) and also the 
 
 1 Grassi, loc. cit. infra, pi. iii. fig. 6. 
 
 2 I am anxious to leave the discussion of the bathymetric limits of the species 
 taken on H.M.S. ' Research,' and of the means used to determine these limit?, 
 till the material has been more fully investigated. At, the same time, in 
 describing a new species it is necessary to provisionally indicate the depth fct 
 which it was taken ; but remarks under this heading must be for the present 
 considered as provisional, except in the case of surface forms. 
 
 3 For an explanation of these areas, see Wyville Thomson, ' Depths of the 
 Sea.' London, 1874. 8vo. 
 
 4 Jahresb. Commiss. wissenschaft. Untersuch. deutschen Meere, Jahrg. ii., 
 iii. p. 158, pi. iii. fig. 13. 
 
 5 " Die Chaetognathen," Jenaische Zeitschrift, xiv. pi. ix. fig. 7. 
 
 6 " I Chetognati," Fauna und Flora Golf. Neapel, v. pi. i. fig. 5. 
 
 64* 
 
994 DR. G. HERB BUT FOWLER ON THE [Dec. 15, 
 
 more recent figure of Strodtmann *, owing doubtless to ill-preserved 
 material, are capable of improvement in respect of the lateral fins. 
 There can be no doubt that the ' Research ' specimens are refer- 
 able to this species, since they agree with Mobius's description 
 and figures of the cephalic armature to the minutest detail. 
 
 This species appears to be an essentially northern form. It was 
 originally described by Mobius from the following localities : 
 N. of Hanstholmen, Korsfjord (twice), and N.W. of Skagen 
 (misprinted S.W., loc. cit. p. 158) during the cruise of the 
 ' Pommerania,' 1872. 
 
 It was recorded by Levinsen 2 from Greenland (Kronprinsens 
 Eiland), from 30 m. W. of Cape Farewell, and from lat. 59 N., 
 long. ? ; lat. 57 50' N., long. 48 43' W. ; lat. 57 48' N., 
 long. 43 45' W. 
 
 Strodtmann records it from the North Atlantic Drift (" Gulf- 
 stream "), Irminger (Greenland) Sea, and the Labrador Current, 
 i. e. from 60 to 50 N. latitude, as having failed in no single haul 
 made by the 'National' (Plankton Expedition) in 1889. 
 
 In the Faeroe Channel it was rarely absent from a tow-net. 
 
 The deepest haul in which I obtained this species was in the 
 warm area Sta. 19 , 480 to 350 fathoms ; temperature 46 to 
 47 F. It may be regarded as having a fairly wide range of tem- 
 perature (eury thermal), since it was obtained from the surface at 
 a temperature of 53 F. (haul 15 6), and at a temperature of less 
 than 33 F. (haul 13 #, 31 to 33 F.) in the cold area. 
 
 These four instances are, I believe, the only records of the 
 occurrence of the species. 
 
 In illustration of the ease with which one may fail to collect 
 specimens of a fairly plentiful species, may be cited two successive 
 hauls, made within an hour of each other : 
 
 Haul 19 a, 480 to 350 fm., gave 6 specimens of S. hamata. 
 19 6, 480 to 
 
 In other words, 6 were caught in towing through 130 fm. of 
 water, none in towing through 480 fm. (cf. Strodtmann, loc. cit. 
 p. 367) with the same net at the same place. 
 
 SALPA ASTMMETEIOA, sp. n. (Plate L. figs. 5-8.) 
 
 As was the case with most Salpso collected on the ' Research/ 
 the specimens of this species were considerably damaged by 
 pressure against the tow-net, owing to the heavy rolling of the 
 ship when heaved to. Not all anatomical details could therefore 
 be satisfactorily made out, but the following appear to be good 
 characters : 
 
 EXTERNAL CHARACTERS. Body ovoid, flattened, devoid of pro- 
 cesses. Apertures in solitary form terminal ; apertures in sexual 
 
 1 " Systematik der Chaetognathen," Arch. Naturgeschichte, Iviii. Bd. i. 
 pi. rvii. fig. 17. 
 
 2 " Om nogle pelagiske Annulata," Vidensk. Selsk. Skriften, (6) iii. 321. 
 
1896.] PLANKTON Otf TflE FAEROE CHANNEL. 995 
 
 form, mouth dorsal, cloaca terminal. Surface smooth. Length of 
 sexual form 12 mm. 
 
 TEST clear, transparent, thin. 
 
 MANTLE. In the sexual form the musculature exhibits an 
 asymmetry similar to that already described in S. dolichosoma- 
 viryula, musculosa-punctata, and magalhanica *. The mouth has a 
 pair of sphincters, apparently formed by splitting of two lateral 
 longitudinal muscle-slips. At least one sphincter surrounds the 
 cloacal aperture ; but the arrangement of the musculature of both 
 apertures was extremely difficult to make out, owing to the bad 
 condition of the specimens. The order, or rather the disorder, of 
 the main muscles is more easily appreciated from drawings than 
 from a description (Plate L. figs. 5, 6, a-f). In addition to these 
 there are two dorsal longitudinal muscle-slips, a dorsal sheet 
 overlying the nucleus, and a fan-like sheet on the right of the 
 nucleus. 
 
 In the solitary form, extracted with the placenta from the 
 parent, the musculature is much more regular ; it consists cf 
 eight complete bands, two large and (?) four small circum cloacal 
 sphincters (the arrangement of which could not be exactly ascer- 
 tained), a right and a left longitudinal slip of unequal length in 
 connection with the two circumoral sphincters. 
 
 ENDOSTYLE fairly long and straight. 
 
 DOESAL LAMINA large (diam. in posterior third about 5 mm. in 
 sexual form), with strongly-marked ridges. No languet was 
 detected. 
 
 DOKSAL TUBEECLE large, about 5 mm. in length in sexual form ; 
 transversely marked with fine bands of cells. 
 
 VISCEEAL MASS comparatively small, brownish yellow in life. 
 
 At first it seemed probable that one was dealing merely with a 
 specimen curiously broken, and that the asymmetry was artificial. 
 But specimens of this species were taken on many occasions, and 
 all possibility of the above explanation was destroyed when I 
 obtained several specimens which presented the same asymmetry, 
 but in a " Spiegelbild," namely the reversal which would be pro- 
 duced by a reflection in a mirror. The same reversal or " inverse 
 image " has been discussed at length by Apstein ' 2 on the basis of 
 the three asymmetrical genera cited above. 
 
 As the * Ergebnisse der Plankton Expedition ' are not readily 
 accessible to everyone, and as the point is novel and of some 
 interest, I quote Apstein' s conclusions : " Bei den iibrigen Salpen, 
 die eine synimetrische Muskulatur haben, ist Spiegelbild und 
 Kongruenz dasselbe, bei einem unsymmetrischen Korper aber fallen 
 Spiegelbild und Kongruenz nicht zusammen. Ich glaube jedocb, 
 dass bei alien Salpen in der Kette die Individuen der eine Reihe 
 gleich, d. h. kongruent sind, aber zu denen der anderer Eeihe 
 spiegelbildlich sich verhalten, aber dass dies in der Muskulatur 
 
 1 Apstein, ' Ergebnisse der Plankton Expedition : Die Thaliacea. B. Ver- 
 teilung der Salpen,' p. 17. 
 3 Apstein, loc. cit. p. 17. 
 
996 BE. a. o. cutftfiffGHAM ox ABNORMAL [Dec. 15, 
 
 meist nicht zu sehen ist, well fast alle Salpenarten sjmmetrische 
 Muskeln haben." 
 
 This adds an eighteenth species to the list of Salpse occurring in 
 the North Atlantic. It was obtained at two stations (four hauls) 
 in small quantities : Sta. 13, 60 2' N., 5 49' W. ; and Sta. 19, 
 59 42' N., 7 7' W. On these four hauls it was at the surface ; 
 in two more hauls at the same stations it was also taken from 
 uncertain horizons with an open tow-net, probably at or near the 
 surface. 
 
 EXPLANATION OF PLATE L. 
 Sagitta whartoni, sp. n. (p. 992). 
 
 Fig. 1. Ventral view. X 2. 
 
 Fig. 2. Dorsal view of head, showing some of the cirrhi, the two rows of 
 
 accessory teeth, and the row of sensory processes. Cam. Inc. X 12. 
 Fig. 3. Cephalic armature, a, end of cirrhus ; b, tooth of ventral row ; 
 
 c, tooth of dorsal row. X 210. 
 
 Spadella (Kroknia) hamata, (p. 993). 
 
 (Drawn by camera lucida.) 
 Fig. 4. Ventral view. X 2. 
 
 Salpa asymmetrica, sp. n. (p. 994). 
 
 a-f. main muscles of the mantle. en. endostyle. 
 
 at. atriopore. ne. nerve-ganglion. 
 
 cl. cloaca. nu. nucleus. 
 
 dl. dorsal lamina. pi. placenta. 
 dt. dorsal tubercle. st. stolon. 
 
 el. elaeoblast. 
 
 Fig. 5. Sexual form, dorsal aspect. X 4'5. 
 Fig. 6. Sexual form, ventral aspect. X 4'5. 
 Fig. 7. Solitary form, right side. X 16. 
 Fig. 8. Solitary form, left side. X 16. 
 
 2. On the Occurrence of a Pair of Supernumerary Bones in 
 the Skull of a Lemur and on a Peculiarity in the Skull 
 of a young Oraug. By ROBERT O. CUNNINGHAM, M.D., 
 F.L.S., F.G.S., C.M.Z.S., Professor of Natural History, 
 Queen's College, Belfast. 
 
 [Eeceived November 9, 1896.] 
 
 A short time ago, when taking part in an oral examination on 
 zoology at the Royal University of Ireland, Dublin, I was some- 
 what surprised to recognize in the skull of a common Lemur a 
 small pair of supernumerary bones intervening between the 
 f rentals, nasals, and lachrymals. As I could not find any reference 
 to such bones in any of the works on comparative anatomy at my 
 disposal, I wrote to Sir William Flower, as our highest authority 
 on the osteology of the Mammalia, to ask him if he could furnish 
 me witli any information on the point. He kindly handed my 
 letter with its accompanying sketch to Dr. Forsyth Major, who 
 showed him a skull with exactly the same bones, observing that 
 
1897.] ON THE PLANKTON OF THE FAEROE CHANNEL. 523 
 
 2. Contributions to our Knowledge of the Plankton of the 
 Faeroe Channel. No. II. By G. HERBERT FOWLER, 
 
 B.A., Ph.D v Assistant Professor of Zoology, University 
 College, London. 
 
 [Eeceived March 29, 1897.] 
 
 The following notes form a continuation of the previous paper 
 on this subject (see P. Z. S. 1896, p. 991) : 
 
 CoNCH(ECiA MAXIMA (Brady & Norman). 
 
 Twenty-five specimens, apparently referable to this Ostracod, 
 were obtained in deep-water hauls. It occurred in three hauls 
 at depths between 480 and 220 fathoms, and in three hauls which 
 began at depths greater than 300 fathoms and were finished at the 
 surface ; it did not occur in a single one of the twenty-two surface 
 hauls (100 fathoms or less, to the surface). 
 
 The only other occurrences of this species are recorded by Brady 
 and Norman l as " off Greenland in lat. 74 49' N., long. 11*30' W., 
 in a depth of 350 fathoms, and by H.M.S. 'Triton' in 1882, 
 lat. 60 20' N., long. 7 23' W., in 200 fathoms, cold area, Faroe 
 Channel." Mr. John Murray, who supplied these specimens to 
 Mr. Brady and Canon Norman, has kindly informed me that the 
 Greenland specimens "were brought home by Mr. Gray in a 
 Peterhead whaler a few years ago." 
 
 So far as the three records go, there can be little doubt that in 
 Conchoecia maxima we have a true member of the cold Mesoplank- 
 tonic fauna. The lowest depth and temperatures at which it was 
 captured on the ' Research ' were 2 : 
 
 Sta. I3g. 465 to 335 fathoms ; temp. 31 to 33 Fahr. 
 
 Sta. 19 a. 480 to 350 fathoms ; temp. 46 to 47 Fahr. 
 
 TOMOPTERIS ONISCIFORMIS, Eschscholtz. 
 
 Vejdovsk^ 3 recognizes three European species of Tomopteris : 
 onisciformis (Eschscholtz 4 ), vitrina (Vejdovsk^ 3 ), and scolopendra 
 (Keferstein 5 ). His diagnostic characters, however, seem quite 
 inadequate for sharp distinction, and fall in all probability within 
 the limits of individual variation, excepting in the case of the 
 " Flossenaugen," the remarkable structures which have been 
 variously interpreted as eyes or as phosphorescent organs. 
 According to Yejdovsk^ these are arranged as follows : 
 Vitrina, Vej. One on the notopodium, one on the neuropodium; 
 pigment yellow ; one lens. 
 
 1 Sci. Trans. Eoy. Dublin Society, (ii.) v. 687, pi. Ixi. figs. 1-8. 
 
 2 Of. Proo. Zool. Soc. 1896, p. 993 note. 
 
 3 Zeitschrift wiss. Zoologie, xxxi. p. 81. 
 
 4 Isis, 1825, p. 735. 
 
 5 Arch. Anat. Physiol., 1861, p. 360, 
 
524 DR. G. HERBERT FOWLER ON THE [May 18, 
 
 Scolopendra, Kef. One on the neuropodium only; pigment 
 dark red ; two lenses. 
 
 Onisciformis, Esch. Two on the notopodium, two on the neuro- 
 podiurn ; pigment yellow ; five lenses. 
 
 These seem good diagnostic characters, but are unfortunately 
 not entirely justified. 
 
 Taking first the number and position of these organs, and 
 accepting Vejdovsk^'s and Keferstein's account of vitrina and 
 scolopendra respectively, the alleged presence of two "Elossenaugen" 
 on each half of the parapodium in onisciformis is stated by Vej- 
 dovskf to have been observed by Carpenter and Claparede \ and 
 by Leuckart and Pagenstecher 2 . A reference to the original 
 memoirs shows, however, that the first-named authors describe and 
 figure one only on the notopodium, one on the neuropodium ; and 
 that the German authors, describing a 2 mm. onisciformis under 
 the name of quadricornis, describe and figure one only on the 
 basal part of each parapodium. Busch 3 also, in describing young 
 specimens, agrees with Leuckart and Pagenstecher. Tomopteris 
 onisciformis, therefore, like T. vitrina, has apparently one " Elossen- 
 auge " on the notopodium, one on the neuropodium, or two on 
 each parapodium ; it has probably only one in young stages, and 
 this only on certain parapodia. 
 
 Taking next the question of the pigment, its colour, yellow, 
 dark red, or brown, can hardly be reckoned diagnostic. Lastly, 
 with regard to the question of the lenses these appear, according 
 to Greef 4 , who worked on fresh material at the Canary Islands, to 
 be artificial products of the preservation fluids. Almost certainly, 
 judged by a comparison of the figures, the five lenses attributed by 
 Vejdovsk^ to Leuckart and Pagenstecher's onisciformis are the 
 same things as his " Augen-driise " cells, which appear to surround 
 the pigment-cells in a surface view. 
 
 There^ seems, therefore, to be no real specific distinction between 
 Vejdovsk^'s vitrina and onisciformis (auctt.). In my specimens of 
 onisciformis the basal joint of the second cirrhi (Borstencirrhen) 
 was sometimes longer, sometimes shorter than the first parapodium, 
 and the eye-lenses were single thus breaking down two more of 
 his diagnostic criteria. 
 
 It is possible, as Vejdovsky suggests, that T. scolopendra (Kef.) 
 may be separate from T. onisciformis C?=Briarcea scolopendra, 
 Quoy and Gaimard 5 ) ; but it is always difficult, often impossible, 
 to make certain of the " Elossenaugen " in preserved material, 
 and conceivably scolopendra may prove a Mediterranean variety of 
 onisciformis. 
 
 The largest ' E-esearch ' specimen measured 45 '5 mm. in length ; 
 
 1 Trans. Lirmean Soc., xxiii. p. 59. 
 
 2 Arch. Anat. Physiol., 1858, p. 588. 
 
 3 Arch. Anat. Physiol., 1847, p. 180. 
 
 4 Zeitschrift wiss. Zoologie, xxxii. p. 237. 
 
 5 Ann. Sciences naturelles, x. p. 235. 
 
1897.] PLANKTON OF THE FAEROE CHANNEL. 525 
 
 the second cirrhi (Borstencirrhen) were only 33 ram. long in this 
 specimen, but in smaller ones were often longer than the body. 
 The fully developed parapodia were 20 in number ; the undeveloped 
 posterior part of the body carried eight rudimentary parapodia, 
 and measured 9 mm. In the youngest specimens the parapodia 
 were proportionately fewer than in the medium-sized specimens, 
 and are again less crowded in the largest. Points like these, taken 
 with the specific uncertainty already discussed, show how necessary 
 is a renewed study of the genus on living material. 
 
 I have not found any record of a larger specimen than this, 
 but my friend Mr. E. T. Browne informs me that he has taken a 
 specimen about 55 mm. in length off Valentia. 
 
 As regards the horizontal distribution of the species, it is 
 common in northern seas, but not apparently further north 
 than the Faeroe Channel. Here it was captured by both the 
 1 Knight Errant ' and the ' Triton,' and Prof. M'Intosh * points 
 out that it appears to have been procured from very varying 
 depths ; this agrees with my experience on the 'Research'; it was 
 taken at 2 Sta. 13 cj 465 to 335 fathoms, temp. 31 to 33 Fahr., 
 and was also taken at the surface at a temperature of 54 F. 
 
 TBACHELOTEUTHIS EJISEI (Steenstrup). 
 
 I have found some difficulty in the determination of this species, 
 owing probably to the fact that Steenstrup's original description 3 
 was of the briefest. 
 
 A specimen obtained in the Faeroe Channel during the cruise of 
 H.M.S. * Knight Errant ' in 1880 was fully described by Hoyle 
 among the 4 Challenger ' Cephalopoda 4 , but he expressed himself as 
 uncertain of his determination. 
 
 The deciding characteristics of the only two species 5 known 
 appear to be the following according to Carus G (founded on Hoyle 
 and Weiss) and Steenstrup : 
 
 nisei. behnii. ' Eesearch ' spec. 
 
 Fins Rhomboid. C.,S. Rounded behind. C. Rounded behind. 
 
 Heart-shaped. 8. Heart-shaped. 
 
 = body length. C. ;> body length. C. 7 =% body length. 
 =4 bcxly length. S. 
 
 Tentacles = body length. C. =| body length. C. = body length. 
 
 Arm 4... = f length of arms 2, 3. S. = length of arms 2,3. S. =f length of 2,3. 
 
 While, then, the general dimensions of my specimen agree with 
 
 1 ' Challenger ' Rep. Zool., Annelida Polychasta, xii. p. 532. 
 a Cf. Proc. Zool. Soc 1896, p. 993 note. 
 
 3 Vidensk. Medd. Nat. Foren. Kjobenhavn, (4) iii. p. 293. 
 
 4 Chall. Rep. Zool. xvi. Cephalopoda, pp. 163-166, pi. xxviii. figs. 6-12. 
 
 5 Since the above was in type, I find that a third species, T. guernei, has 
 been described by Joubin (' Campagnes Scientifiques par S. A. le Prince do 
 Monaco,' t'asc. is.), but it is not likely to be confounded with either of the other 
 two. 
 
 6 Prodrom. Faunas Mediterr. ii. pp. 447, 448. 
 
 7 " Plus quam % pallii sequantes." Surely a mistake I 
 
 Pitoc. ZOOL. Soc. 1897, No. XXXV. 35 
 
526 ON THE PLANKTON OF THE FAEEOE CHANNEL. [May 18, 
 
 those of T. riisei, the shape of the fin is markedly that of T. behnii ; 
 
 this is well brought out by Hoyle's figure, which shows a distinctly 
 
 rhomboid fin. 
 
 A specimen of T. behnii was described by Weiss l , which agrees 
 
 almost exactly with the diagnostic characters given above for that 
 
 species. 
 
 The following table exhibits the dimensions of my specimens, 
 
 the ' Knight Errant ' specimen described by Hoyle, and the 
 
 Messina specimen described by Weiss, expressed in percentages of 
 
 mantle length : 
 
 'Research.' 'Knight Errant.' Messina. 
 Length of mantle in mm. 28 32 21 
 
 Breadth of mantle '38 -25 
 
 Length of fin -34 -40 -28 
 
 Breadth of fins -56 -59 '38 
 
 Length of arm 1 -21 -24 -14 
 
 2 -56 -56 -33 
 
 3 -47 -46 -28 
 
 4 -34 -40 -19 
 
 Length of tentacle -91 1-00 -61 
 
 So far as this goes it is fairly obvious that the ' Knight Errant ' 
 and 'Besearch' species are the same, and different from the 
 Messina species ; the dimensions further point to an accurate 
 determination by Hoyle and Weiss of their respective species. 
 
 I have therefore assigned my specimen to T. riisei, although 
 the shape of the tail-fin is distinctly that of the other species. 
 
 Dimensions in millimetres : end of body to margin of mantle, 
 23 ; breadth of body, 9 ; length of fin, 8 ; breadth of conjoint fins, 
 13 ; arm i, 5 ; arm ii, 13 ; arm hi, 11 ; arm iv, 8 ; tentacle, 21. 
 
 The animal was of an absolutely glass-like transparence, except 
 for the two staring black eyes and a black mass posteriorly (? iiik- 
 sac). When it had been killed, scattered chromatophores became 
 more obvious, notably four, symmetrically placed on the dorsal 
 surface of the head, and a line of smaller ones along the median 
 dorsal line of the mantle ; they were of a deep claret -colour. 
 
 As Hoyle 2 pointed out, and was corroborated by Jatta 3 , Trache- 
 loteuthis is a member of the subfamily Ommastrephini ; the latter 
 author refuses, however, to accept the suggested identification of 
 Tracheloteuthis with VerrilliolaEntomopsis, as the four species 
 described under these two genera are members of the Taonoteuthi. 
 
 Distribution : 
 
 (1) Faeroe Channel 60 29' N., 8 19' W., surface ('Knight 
 Errant ') 
 
 (2) Faeroe Channel 60 2' N., 5 49' W., 100 to fathoms 
 (' Besearch '). 
 
 (3) Atlantic, Mediterranean (Sttenstrup). 
 
 1 Quart, Journ. Micr. Sci. xxix. pp. 75-96. pis. viii.-x. 
 
 2 Loc. cit. 
 
 3 Fauna e Flora Golf. Neapel. I Cefalopodi (Sistematica), p. 112. 
 
P.Z.S.1897.P1.XLVII. 
 
 LL\Wl*JluliLti 
 
 G.H.F.del.J.SmitlitK 
 
 Minte rn Bros . imp . 
 
 PLANKTON OF THE FAEROE CHANNEL 
 
1897.] ON THE PLANKTON OF THE FAEROE CHANNEL. 803 
 
 H^AMBATES JOHNSTONI, sp. n. (Plate XLYI. fig. 4.) 
 
 Vomerine teeth in two small groups between the choanse. Head 
 much broader than long ; snout rounded, as long as the diameter 
 of the eye ; ihterorbital space as broad as the upper eyelid ; tym- 
 panum two tmKls the diameter of the eye. Fingers with a 
 slight rudiment dfx web ; toes half-webbed ; disks well deve- 
 loped ; inner metatarsal tubercle large, compressed, crescentic, 
 very prominent. The tibio-tarsal articulation reaches the eye. 
 Skin smooth above, granulate on the throat, belly, and lower surface 
 of thighs. Purplish or brown above, with a more or less distinct- 
 dark triangular marking on the back, the apex reaching the 
 occiput; white dots usually scattered on the back; limbs with very 
 indistinct dark cross-bars ; a white streak borders the upper lip, 
 the outer side of the forearm and hand, the anal region, the heel, 
 and the outer side of the foot ; hinder side of thighs dark brown ; 
 lower parts white. 
 
 From snout to vent 42 millim. 
 
 Closely allied to H. anchietce, Eocage, from Angola. 
 
 Three specimens from Kondowe-Karonga, and one from the 
 Nyika Plateau. 
 
 EXPLANATION OF PLATE XL VI. 
 
 Fig. 1. Lygosoma johnstoni, Blgr. Side views of head and anterior portion of 
 body and pelvic region, and upper view of head (p. 801). 
 
 2. Glypholyciis whytii, Blgr. Upper, lower, and side views of head (p. 802). 
 
 3. Arthroleptis whytii, Blgr (p. 802). 
 
 4. Hylambates johnstoni, Blgr (p. 803). 
 
 9. Contributions to our Knowledge of the Plankton of the 
 Faeroe Channel. No. III. 1 The Later Development of 
 Arachnactis albida (M. Sars), with Notes on Arachn- 
 actis bournei (sp. n.). By G. HERBERT FOWLER, B.A., 
 Ph.D., Assistant Professor of Zoology, University 
 College, London. 
 
 [Received June 15, 1897.] 
 
 (Plate XLVLI.) 
 ARACHNACTIS ALBIDA (M. Sars). 
 
 This beautiful floating Actiriian was originally described by 
 Michael Sars in 1846 (loc. cit. infra) ; it has since been taken 
 on several occasions, and has received quite a large amount of 
 attention. 
 
 The recorded occurrences and the references to descriptions are 
 most simply put in tabular form. They all refer to surface 
 captures, often in company with shoals of Salpce. 
 
 1 For Part I. see P. Z. S. 1896, p. 991 ; Part II. antea, p. 523, 
 
804 
 
 DR. G. HERBERT FOWLER ON THE 
 
 [June 15, 
 
 Arachnactis dlbida, M. Sars. 
 
 M. Sars, Fauna littor. Off Floroe Island. 
 
 Norveg. i. p. 28. 
 Forbes & Goodsir, Tr. Boy. The Minch. 
 
 Soc. Edin. xx. 307. 
 
 Vogt, Archives de Biologie, 
 viii. p. 1. 
 
 Boveri, Zeit. wiss. Zool. 
 
 xlix. p. 459. 
 Vanhoffen, Bibliotheca 
 
 Zoologica, Hft. xx. 
 
 Browne (unpublished). 
 Fowler 
 
 56 35' N., 20 19' 
 
 W. 
 Rockall to Hebrides 
 
 (' Holsatia '). 
 Faeroe Channel 
 
 (' Triton '). 
 60 N., 7 W. 
 
 Autumn & winter, 
 
 1846. 
 Aug. 1850. 
 
 Sept. 1861. 
 July 1885. 
 Aug. 1882. 
 Sept. 1893. 
 
 ?Rockall to Heb- 1889. 
 
 rides (' National'). 
 North Sea, near 
 
 Brit, coasts. 
 Valentia Island. 
 Faeroe Channel 
 
 ('Research'). 
 
 Feb. to April, 1895. 
 
 Mar. 1895. 
 Aug. 1896. 
 July 1897. 
 
 Original description 
 
 of the species. 
 Eefer to Dr. Balfour 
 
 having taken it in 
 
 1841. 
 In strong current 
 
 from N.B. 
 
 German Plankton 
 Exped. 
 
 ? A. bournei. 
 
 All recent observers of Arachnactis are agreed that it is to be 
 referred to the Cerianthidce. As regards the early development of 
 this group, Kowalewsky * traced it from the gastrulation to the 
 formation of two pairs of tentacles and one pair of mesenteries ; 
 but unfortunately obscured his information by writing in Russian. 
 Van Beneden 2 , beginning where Kowalevsky left off (and giving 
 a short abstract of his work), traced the development of an Arachn- 
 actis (apparently not A. albida, although described under that 
 name) from a stage with two pairs of tentacles and one of 
 mesenteries up to a stage with seven tentacles and four pairs of 
 mesenteries. On the later development we have also two papers : 
 Boveri 3 began with 8 tentacles and five pairs of mesenteries, and 
 carried it to a stage with 21 tentacles and 14 oral tentacles; 
 Vanhoffen 4 made sections of, and described in detail, a stage with 
 19 mesenteries. 
 
 As regards these two last papers, I am glad to say that my 
 observations bear out those of Boveri, but regret that they are far 
 from agreement with those of Vanhoffen. The latter author has 
 been drawn into a series of mistakes by an initial error, which is 
 best given in his own words : " Die Keihenfolge in der Bildung 
 der Septen ergiebt sich aus der Verfolgung der Schnitte von uuten 
 nach oben"; that is to say, he imagines that the order of develop- 
 ment of the mesenteries can be inferred from a comparison of 
 their absolute length at a late stage : and it is hardly necessary to 
 say, not only that this assumption is quite unjustifiable, but that 
 the order of development which he consequently assigns to the 
 mesenteries proves to be absolutely erroneous when tested by 
 successive stages. As Vanhoffen is the latest writer on Arachnactis, 
 
 1 Nachrichten d. Ges. d. Freunde d. Naturerkenntniss u. s. w., Moscow, 
 1873. 
 
 2 Archives de Biologie, xi. p. 115. 3 Op. cit. supra. 4 Op. tit, supra, 
 
1897.] PLANKTON OF THE FAEEOE CHANNEL. 805 
 
 it seemed to me worth while to study all the stages in my power, 
 and to endeavour to put the matter straight again. 
 
 The following stages have been drawn from ; Eesearch ' speci- 
 mens and cut into microscopic sections : 
 
 Stage. Tentacles. Mesenteries. Oral tentacles. 
 
 A 6 10 
 
 B 7 11 4 
 
 Appearance of the unpaired tentacle (5). 
 
 C 9 12 4 
 
 D 9 12 4 
 
 E 10 14 6 
 
 F 11 16 8 
 
 a 12 16 8 
 
 H 13 18 8 
 
 I ? 19 10 
 
 (First appearance of generative cells.) 
 A few older stages have also been studied. 
 
 This table, taken together with the diagram (PL XL VII. fig. 1), 
 sufficiently shows the successive development of the various struc- 
 tures, and their position in the oldest specimens. As regards this 
 diagram, the order of succession of the first four pairs of mesenteries 
 is taken from van Beneden's account of an allied species, and that 
 of the first two pairs of tentacles is inferred from his drawings and 
 descriptions. The facts implied by the remainder of the diagram 
 I have myself checked, and they will be found to differ entirely 
 from those given by Vanhoffen, and to agree with those of Boveri 
 on all points with which we both deal. The developmental order of 
 the first four pairs of mesenteries, as described by van Beneden (c, 
 a, 5, cZ), appeared at first to contradict the lettering attached to 
 the same mesenteries by Boveri (c/, a, 6, c), but the latter author 
 courteously informs me that he did not intend by these letters to 
 indicate a developmental succession : van Beneden's observed 
 order may therefore be taken to hold good for this species also, in 
 default of direct evidence. 
 
 AEACHNACTIS BOURNEI, sp. n. 
 
 There can be no doubt that the specimens from the English 
 Channel, first recorded by Bourne, and described by van Beneden, 
 tinder the name of Amchnactis albida, belong to another and 
 an unnamed species. Not only are the form, and proportions of 
 the animal quite different from those of albida, both in van 
 Beneden's drawings and in a few specimens which I received from 
 the Marine Biological Station at Plymouth in 1893, but also the 
 rate at which different sets of organs are developed is not the 
 same in the two species. This is at once apparent on a comparison 
 of my table of albida stages (given above) with the following : 
 
 Tentacles. Mesenteries.. . C ? ra ! 
 
 tentacles. 
 
 Van Beneden's oldest larva . . 7 8 
 
 Plymouth specimens (1893) . . 9 10 2 
 
 PROC. ZOOL. Soc. 1897, Xo. LIIL 53 
 
806 
 
 DR. G. HERBERT FOWLER O1ST THE 
 
 [June 15, 
 
 and while the Plymouth specimens acquire the characteristic 
 terminal pore at a stage of between 7 and 9 tentacles, it does not 
 become perforated in albida until a stage of about 8 mm. in length 
 provided with 12 oral tentacles, or, according to Boveri, 17 marginal 
 tentacles. 
 
 Until this Channel form be traced to a kno\vn adult Cerianthid 
 (?(7. lloydii, Gosse), I propose to distinguish it from A. albida by 
 associating with it the name of my friend Mr. G. C. Bourne, the 
 first Director of the Plymouth Station, under the style of Araclm- 
 actis bournei ; for although I admit that the christening of larva? 
 by specific names is a reprehensible practice, still so much tow- 
 netting is now carried out every summer all round our coasts that 
 it is advantageous that well-marked species of even larval forms 
 should have a name under which their occurrences may be 
 chronicled.^ 
 
 Arachnactis bournei, sp. n. 
 Annually \ 
 
 Bourne, J. Mar. Biol. Assoc. Plymouth area, 
 (n. s.) i, p. 321. 
 
 Described anatomically 
 t by van Beneden, 
 Entrance to English July 1889. Arch. Biol. xi. p. 115. 
 
 Channel. 
 Mclntosh, Ann. Mag. Nat. St. Andrew's Bay. June 1890. Single specimen re- 
 
 Hist. (6) v. p. 306. corded only. 
 
 Vallentin, Eep. R. Corn- Falmouth. Summer, 1890. (Not seen for some 
 
 wall Polyt. Soc. lix. years now. R. V.) 
 
 Browne (unpublished). Port Erin, Isle of Jan. 1895. 
 
 Man. 
 Valentia Island. March 1896. 
 
 1 According to Garstang, March and April are the chief months for Arachnactis 
 at Plymouth. 
 
 Prom A. albida, which is slender and tapers markedly in late 
 stages, A. bournei is recognizable by its fat cylindrical body and 
 sharply rounded end ; further, whereas in A. albida the union of 
 the swollen bases of the tentacles produces an " oral disk " much 
 greater in diameter than the body (a point better brought out by 
 Bars' than by Vanhoffeu's figure), and the tentacles are often many 
 times the length of the body, in A. bournei oral disk and body have 
 about the same diameter, and the tentacles are very short. As 
 regards the colouring, my friend Mr. E. T. Browne informs me 
 that he has taken this form on several occasions, and that in colour 
 it is yellowish or brownish all over : it thus presents a great contrast 
 to A. albida, which is of a transparent bluish-white, except for the 
 yellowish-brown tips of the tentacles ; in older specimens of albida 
 the body may also assume a brown tint, but the tentacles remain 
 transparent even in my oldest stages. The mesenteries, in all 
 specimens of A. bournei which I have been able to examine, have 
 an extremely short course, extending only about J to 5 of the 
 length of the body below the free end of the stomodseum ; in 
 A. albida they extend to ^ or g of this distance even in young speci- 
 mens, and in older ones some stretch for nearly the whole body- 
 
1897.] PLANKTON OF THE FAEROE CHANNEL. 807 
 
 length. The oldest specimens of this species at present known 
 appear to be the Plymouth specimens with 9 tentacles. 
 
 The only other forms referable to the genus at present are 
 (1) Arachnactis brachiolata, A. Agassiz *, obviously a different 
 species from either of the two already described ; (2) the larvae 
 observed by Haime 2 in the co3lenteric cavity of Cerianfhus, which 
 do not quite resemble either A. albida or A. bournei', with these 
 latter Iarva9 may perhaps be identical the forms discovered by 
 Joh. Miiller and described by Busch 3 from Trieste under the name 
 of Dianthea nobilis, which have been suggested by van Beneden to 
 be Cerianthidan. 
 
 OllIGIN OF THE MESENTER1AL ElLAMENT. 
 
 A study of the developing mesenteries of A. albida has confirmed 
 me in the belief, advocated elsewhere by myself and by others 
 before me on histological grounds, that the thickening at the free 
 edge of the mesentery, commonly known as the mesenterial fila- 
 ment, is ectodermal in origin. The mesenteries in Cerianthidce, as 
 has long been known from the researches of A. von Heider 4 , are 
 of two kinds fertile (generative) and digestive, which generally 
 alternate one with another, and, as he mentions very briefly, carry 
 two different kinds of filaments, which become differentiated about 
 stage Gr of my specimens. 
 
 The filament of a digestive mesentery (fig. 2) is of a type familiar 
 to all students of Anthozoa : it consists of densely packed gland- 
 cells of at least two kinds, among which lie nematocysts in all 
 stages of development ; this tissue abuts, quite sharply and without 
 transition, on the undoubtedly endoderrn-cells of the mesentery, 
 and agrees exactly in histological detail with the ectoderm of all 
 the stomodaeum except that of the sulcus, which has small nemato- 
 cysts, if any. 
 
 The filament of a fertile mesentery (fig. 3) is different from the 
 foregoing both in shape and in histological detail. There is a central 
 groove (often deeper than in the figure) consisting of finely granular 
 gland-cells with very strong cilia ; these cells are practically 
 identical with the ectoderm of the sulcus. The groove is flanked 
 by wings containing large gland-cells and nematocysts ; next to 
 these come three sets of simpler cells, the nuclei of the first and 
 third set staining very strongly. The last of these three sets lies 
 " unconformably " upon the vacuolated endoderrn-cells. 
 
 I venture to repeat the suggestion (due first, I believe, to von 
 Heider) that both types of filament are ectodermal downgrowths 
 from the stomodaeum along the free edge of the mesentery, on the 
 following grounds : 
 
 1. The histological structure of the chief part of both filaments is 
 
 1 Journ. Boat. Soe. N. H. vii. p. 525 (1863). 
 
 2 Ann. Sciences naturelles, (4) i. p. 341 (1854). 
 
 3 Beob. lib. Anat. u. Entwickl. einiger wirbellosen Seethiere, p. 122 : Berlin, 
 1851, 4to. 
 
 4 Sitzungsber. d. k.-k, Akad. Wiss. Wien, Ixxix. (Math.-nat. 01.) p. 204. 
 
808 DR. G. HERBERT FOWLER ON THE [June 15, 
 
 practically identical with that of the ectoderm of the stomodseum ; 
 even the ectodermal pigment granules, very distinct in borax- 
 carmine preparations on the body and stomodseum, are 'uniformly 
 present on the filaments, but are not found in the undoubted 
 endoderm. 
 
 2. Young mesenteries, which have not yet become united with 
 the stomodaeum as far down as its lower free edge, carry only a 
 thickening of obviously endoderrn-cells (fig. 4) on their iree 
 margins. 
 
 3. Mesenteries which have become united with the stomodaeum 
 as far down as its lower free edge (except the " directive " 
 mesenteries) carry one or other of the two types of mesenterial fila- 
 ment above described for some distance, but below this filament they 
 show a simple thickening of vacuolated endoderm-cells, of the 
 same character as they carried before they reached the lower edge 
 of the stomodseum (fig. 4) ; as I interpret it, the ectoderm has 
 grown down along their free margins for some distance, but not as 
 yet for their whole length. 
 
 4. The sulcus runs very much further down into the coelenteron 
 than does any other part of the stomodaeum, forming a long groove 
 of the shape indicated in fig. 6. At the point where the ectoderm 
 of the sulcus becomes continuous laterally with the endoderm, the 
 histological structure is practically the same as in the filament of a 
 fertile mesentery (fig. 5). 
 
 The only evidence, of which I know, in favour of an endoderm al 
 origin of the filament is as follows : (1) E. B. Wilson ! , in his 
 studies on the development of numerous Alcyonaria, claimed to 
 have shown that the axial (dorsal) filaments were of ectodermal, 
 the remaining six filaments of endodermal, origin. To this one may 
 reply that Alcyonaria are not Actiniaria, although closely allied to 
 them, and that the differentiation of function, with which Wilson 
 showed that the different mesenteries were correlated, does not 
 hold good in the same shape for Actiniaria. (2) The brothers 
 Hertwig - refuse to accept von Heider's suggestion of an ecto- 
 dermal origin in Cerianthus on the ground that in Sagartia para- 
 sitica the incomplete mesenteries, which do not yet touch on the 
 stomodeeum, are provided with a filament similar to that of the 
 complete mesenteries. This is certainly not the case in young 
 Araclmactis, and, I may add, the filament of Sagartia parasitica 
 seems to be in many respects of an unusual character among 
 Actiniaria. Neither the argument from Alcyonaria nor that 
 from Sagartia appears to me to be strong enough to unseat the 
 evidence given above. If these filaments are indeed ectodermal, 
 the boundary between ectoderm and endoderm is obvious enough 
 in the digestive type of mesentery ; but in the fertile type, is 
 probably at the commencement of the vacuolated endoderm-cells, 
 as there occurs at this point what I can only describe, by borrowing 
 a phrase from geology, as an unconformability of strata. 
 
 1 Mittheil. zool. Stat. Neapel, v. 1. 
 
 2 Die Actinien. Jena, 1879, 8vo. (Jen. Zeitschrift, xiii.) 
 
1897.] PLANKTON OF THE FAEKOE CHANNEL. 809 
 
 With regard to the distribution of the two types of mesenteries 
 and filaments in Arachnactis^ the "directive" pair practically carry 
 no filament; for a very few sections below the end of the sulcus 
 they have a slight thickening resembling the type of a fertile 
 mesentery, but almost immediately assume the appearance indicated 
 in fig. 4. The mesenteries next to them are of the fertile type, 
 and the next ensuing of the digestive type ; from that point 
 onwards the alternation is apparently regular : 
 
 Fertile : 3, 1, 4, 6, 8, &c. 1 Numbered in order of 
 Digestive : 2, 5, 7, 9, 11, &c. / successive development. 
 
 The differentiation of the filaments of the two kinds of me- 
 senteries in the adult Cerianthus is apparently not mentioned 
 by the brothers Hertwig l ; their figure 3, pi. viii., practically 
 unites the main features of my figures 2 and 3. Unfortunately, 
 the specimens of Cerianthus at my disposal are not very well 
 preserved, but even in them it is obvious that there is a differenti- 
 ation of the two filaments, of the same kind as, although not 
 precisely identical with, that which I have described above for 
 Arachnactis. Very young germ-cells are recognizable in both 
 types of mesentery in the adult. 
 
 I have seen nothing in Arachnactis of the small " directive " 
 mesenteries, not attached to the stomodaeum, which are mentioned 
 by von Heider as occurring in Oericmthus. 
 
 NOTE. Since the MS. left my hands, I have received a letter 
 from my friend Prof. Karl Brandt of Kiel, which informs me that 
 Prof, van Beueden has a paper in the press dealing with the 
 Arachnactis of the Plankton and other German expeditions ; this 
 will doubtless throw more light on the distribution of the various 
 species. Prof. Brandt informs me that the genus appears to have 
 been widely taken in the North Atlantic (' National ') and in the 
 North Sea (' Holsatia ' 1885, Nordsee Expedition 1895). 
 
 EXPLANATION OF PLATE XLVII. 
 
 Arachnactis albida, M. Sars. 
 
 Fig. 1. Diagram showing the order of development of mesenteries, marginal 
 tentacles, and oral tentacles (p. 805). 
 
 2. Section of the filament of a digestive mesentery, X 600 (p. 807). 
 
 3. Section of the filament of a fertile mesentery, x600 (p. 807). 
 
 4. Section of the thickened edge, presented both by a mesentery which has 
 
 not touched the ectoderm at the lower edge of the stomodaeum, and by 
 a mesentery in the lowest part of its length, X 600 (p. 808). 
 
 5. Section of the edge of the sulcus, X 600 (p. 808). 
 
 6. Outline of the sulcus in transverse section below the level of the rest of 
 
 the stomodaeum ; the azygos tentacle (5) and the directive mesenteries 
 (3) are indicated also (p. 808). 
 
 In Figs. 2,3, and 5, the arrow indicates the supposed junction of ectoderm and 
 endoderm. 
 
 1 Op. cit. supra, 
 
 PBOC. ZOOL. Soc. 1897, No.LIV. 54 
 
810 THE SECRETARY OK ADDITIONS TO TILE MENAGERIE. [Nov. 16, 
 
 November 16, 1897. 
 Dr. A. GUNTHER, F.B.S., Vice-President, in the Chair. 
 
 The Secretary read the following reports on the additions made 
 to the Society's Menagerie during the months of June, July, 
 August, September, and October, 1897 : 
 
 The registered additions to the Society's Menagerie during the 
 month of June were 178 in number. Of these 132 were acquired 
 by presentation, 15 by purchase, 14 were received on deposit, 13 
 were bred in the Gardens, and 4 were received in exchange. The 
 total number of departures during the same period, by death and 
 removals, was 137. 
 
 Amongst the additions the following are worthy of notice : 
 
 1. Two fine adult King Penguins (Aptenodytes pennanti), pur- 
 chased out of a lot of five offered for sale by a dealer, on June 23rd. 
 
 2. A young female Orang-outang (Simla satyrus}, brought home 
 from Sumatra and presented by Dr. H. Dohrn, C.M.Z.S., on 
 June 30th. 
 
 The registered additions to the Society's Menagerie during the 
 month of July were 102 in number. Of these 34 were acquired by 
 presentation, 17 by purchase, 14 were received on deposit, and 
 37 were bred in the Gardens. The total number of departures 
 during the same period, by death and removals, was 143. 
 
 Amongst the additions attention may be specially called to : 
 
 1. A young pair of Babirussas (Babirussa alfurus}, from Celebes, 
 presented by H.G. The Duke of Bedford, F.Z.S., July 3rd. 
 
 2. An example of the Thick-billed Penguin (Eudyptes pachy- 
 rhynchus), from Stewart Island, New Zealand, deposited by the 
 Hon. Walter Kothschild, F.Z.S., July 5th. 
 
 3. A very large example of Daudin's Tortoise (Testudo daudini), 
 deposited by the Hon. Walter Eothschild on July 21st. This 
 Tortoise, no doubt originally from the Aldabra Islands, is said to 
 have been kept in captivity in Mauritius for about 150 years, and 
 is believed to be the largest Land-Tortoise now living in the world. 
 It is about 4 ft. 7 inches in length, 2 ft. 10 inches in breadth, and 
 weighs about 5 cwt. 
 
 The registered additions to the Society's Menagerie during the 
 month of August were 132 in number; of these 91 were acquired 
 by presentation, 7 by purchase, 15 were received on deposit, 18 
 were bred in the Gardens, and 1 was received in exchange. The 
 total number of departures during the same period, by death and 
 removals, was 128. 
 
 Amongst the additions attention may be specially called to : 
 
 1. A male and two females of a large Deer from the Altai 
 
 Mountains, probably referable to Cerviis eustephanus, Blanford, 
 
 received on deposit on August 10th, and apparently different in 
 
 species from any Deer previously exhibited in the Society's series. 
 
PLATE XLIV. 
 
 Fig. 1. Siderastr&a clavus, x 2J, p. 525. 
 
 2. Pavonia repens, X 2, p. 531. 
 
 3. Pavonia intermedia, X 2, p. 531. 
 
 4. Pavonia calicifera, X 2, p. 532. 
 
 PLATE XLV. 
 
 Fig. 1. Psammocora naimiana, x 2, p. 536. 
 
 2. Psammocora superficialis, X 2, p. 537. 
 
 3. Psammocora profundacella, x 2, p. 537. 
 
 4. Psammocora savigniensis, x 2|, p. 538. 
 
 3. Description d'un Genre nouveau d'Ophidiens, 
 Geatractus. Par ALFRED DUGES, M.D. 1 
 
 [Eecehed June 6, 1898.] 
 
 J'ai decrit t figure dans le Journal Mexicain ' La Naturaleza ' 
 (2 a serie, t. ii. 1897, pag. 455) un Ophidien nouveau sous le nom 
 de Qeophis tecpanecus. 
 
 Caracteres generaua, Aspect de Calamarien et de Coronellien. 
 Noir a reflets bleus ; <iix barres blanches dorsales, courtes et 
 transversales ; un collier blanc passant sur la joue et la majeure 
 partie de la gorge. Sept supralabiales, 3 feme et 4& me touchant 
 1'oeil, la 5 feme la plus grande. Preoculaire unique, tres petite, au 
 dessus d'une freno-oculaire. ''Deux postoculaires. Temporales 
 1 + 2 + 2 (mal rendues sur la figur^). Queue extremement courte, 
 robuste et obtuse. Quinze rangs Nj'ecailles pourvues en general 
 de deux pores apicaux. Une preamle. Tete O f 025 m., queue 
 0*023 m., longueur totale 0'50 m. Le& vertebres dorsales portent 
 une hypapophyse tres nette. 
 
 Mr. Gr. A. Boulenger a fait de ce serpent un Atractus (Zool. 
 Kec. 1896, Hept. pag. 25), mais les Atractus n'ont pas d'bypa- 
 
 1 Communicated by Mr. G. A. BOULENGER, F.Z.S. 
 
4. Contributions to our Knowledge of the Plankton of the 
 Faeroe Channel. No. IV. l Report on the Copepoda 
 collected by Dr. G. H. Fowler from H.M.S. ( Research' 
 in the Faeroe Channel in 1896 and 1897. By ISAAC 
 C.THOMPSON, F.L.S. (With an Appendix by Dr. FOWLER.) 
 
 [Eeceived June 18, 1898.] 
 
 The material upon which this Report is based was collected in 
 34 out of the 41 hauls (omitting 12 /, the depth of which was not 
 recorded). The Plankton had been immediately preserved in 
 formalin, corrosive sublimate, or picric acid, and kept in 5/ formalin 
 The Copepoda were picked out from the mass by Dr. Fowler, and 
 sent to me in bottles labelled with the number of the station and 
 letter of the haul whence the material was obtained. 
 
 By means of messengers in 1897 and of a screw-propeller in 
 1896 (see pp. 570-575), the mid-water tow-nets were opened and 
 closed at will, enabling the depths to be almost accurately ascer- 
 tained, the limit of error being dependent upon the possibly impeded 
 rate of fall of the messenger or upon the accelerated rate of the 
 screw-propeller in a very heavy sea. 
 
 The accompanying distribution table records the soundings, the 
 depths at which the various hauls were taken, the temperature (Fah- 
 renheit) at those depths, the number of meshes per inch of the net 
 used, and the occurrences of each species. It will be seen that all 
 the Copepoda collected are free swimmers, with one remarkable 
 exception, that of Aryulus, referred to later on. 
 
 The collection furnishes some interesting facts as to the influence 
 of depth upon distribution. By far the commonest Copepod in the 
 collection, and probably the most widely distributed species known, 
 Calanusfinmarchicus, occurs abundantly in 32 out of the 34 hauls, 
 
 1 For Part I. see P. Z. 8. 1896, p. 991 ; Part IT., P. Z. S. 1897, p. 523 ; 
 Part III., P.Z. S, 1897, p. 803. 
 
1898.] PLANKTON OF THE FAEBOE CHANNEL. 541 
 
 and appears to be equally prevalent at all depths. But probably 
 no other known species exhibits this ubiquitous feature to anything 
 like the same extent. A reference to the distribution table will 
 show that several species, such as Heterochceta dbyssalis, were not 
 found at a less depth than 100 fathoms ; while others, such as the 
 well-known and beautifully coloured Anomalocera patersoni, usually 
 remain about the surface, sometimes congregating ia vast numbers. 
 
 The relative sizes of the same species at opposite depths is to a 
 considerable extent seen in Calanus finmarchiciis, the deep speci- 
 mens being considerably larger than those found near the surface. 
 Among our British Copepoda the largest known species is 
 Euchceta norvegica, but I am not aware that it has ever been taken 
 in our waters at less than 80 or 100 fathoms, at which depth I have 
 taken it in quantities in Loch Eyne, where it probably forms an 
 important item in the diet of the herring. 
 
 The vertical distribution of Copepoda is doubtless to a consider- 
 able extent subject to climatic influences. During a contiruance 
 of stormy weather they often altogether desert the near surface 
 and go very deep ; while in fine warm weather many species 
 love to gambol on the actual surface, presenting much the appear- 
 ance of the " play " of the herring in miniature. 
 
 The size of mesh in the tow-net used is of considerable import- 
 ance, and the apparent scarcity of such minute forms as Oithona 
 spinifrons and Ectinosoma atlanticum is probably to be explained from 
 the fact of a large mesh having been generally used ; while the 
 comparatively few tow-nets in which the above species were found 
 were of a fine texture and probably might with advantage have 
 been more generally employed. 
 
 Five out of seven species of Copepoda found by Dr. Brady in 
 material from theEaeroe Channel (Exploration of the Faeroe Channel 
 during the summer of 1880 in H.M.'s hired ship ' Ejr'ght Errart ' 
 by Staff-Commander Tizard, E.N., and John Murray) occur in this 
 collection, viz. : Eucalanus attenuatus, Centropayes typicus, Anomalo- 
 cera patersoni, Acartia longiremis, and Oithona spinifrons. 
 
 The following species, viz., ^Etidius armatus, Euchirella pulchra, 
 Heterochceta abyssalis, which occur sparingly in the collection, have 
 never before been recorded north of the Mediterranean, this fact 
 indicating a considerable extension of their distribution. 
 
 CALANUS HTPERBOEETJS Krbyer. 
 
 A number of what I took to be specially large specimens of 
 Calanus finmarchicus were found among the specimens from 20 d. 
 Careful examination clearly proves them to be identical with 
 G. hyperboreus, now recognized by Giesbrecht as a distinct species. 
 The nipple-shaped lateral terminations of the cephalothorax, the 
 large first abdominal segment, and the shape and position of the 
 teeth on the basal joint of the 5th feet appear to be the chief points 
 which separate C. hyperboreus from C. finmarchicus. Giesbrecht 
 says that joint 19 of the anterior antennae is as long as joints 23 
 and 24 together ; but none of the very few specimens I found with 
 ZOOL, Soc,1898, No. XXXVI, 36 
 
542 
 
 MB. T. C. THOMPSON ON THE 
 
 [June 21, 
 
 
 1 
 
 oS 
 
 1 
 
 c 
 a 
 .2 
 
 Sounding in fathoms. 
 
 Depth of haul in fathoms. 
 
 Temperature (Fahr.). 
 
 Meshes per inch of net. 
 
 Calanus Jinmarchicus Gunner. 
 
 Eucalanus attenuatus Dana. 
 
 Rhincalanus cornutus Dana. 
 
 Rhincalanus gigas Brady. 
 
 & 
 
 1 
 
 Euchirella pulchra Lubbock. 
 
 Euckceta barbata Brady. 
 
 
 
 11 
 
 203 
 
 100-0 
 
 48-54 
 
 25 
 
 VA 
 
 
 
 
 
 
 
 
 
 00 
 
 116. 
 
 
 o 
 
 54 
 
 180 
 
 A 
 
 
 
 
 
 
 
 
 
 s 
 
 
 " 
 
 30-0 
 
 49-54 
 
 36 
 
 VA 
 
 
 
 
 
 
 
 
 
 O 
 
 ^3 
 
 126. 
 
 502 
 
 10-0 
 
 53 
 
 36 
 
 VA 
 
 
 
 
 
 
 
 
 
 1 
 
 12 c. 
 
 
 o 
 
 53 
 
 180 
 
 F 
 
 
 
 
 
 
 
 
 
 
 12 d. 
 
 " 
 
 150-+0 
 
 43-53 
 
 
 VA 
 
 8 
 
 
 
 
 
 
 
 
 +1 
 
 13 i. 
 14 a. 
 156. 
 
 558 
 610 
 
 100-0 
 
 
 o 
 
 48-54 
 54 
 53 
 
 36 
 180 
 36 
 
 C 
 VA 
 A 
 
 F 
 
 ... 
 
 ... 
 
 's 
 
 F 
 
 ... 
 
 ... 
 
 
 -2 
 
 15 d. 
 
 
 o 
 
 53 
 
 
 A 
 
 
 
 
 
 
 
 
 
 1 
 
 16 6. 
 16 c. 
 
 18 a. 
 
 398 
 645 
 
 
 4-0 
 3-0 
 
 53 
 
 53 
 53 
 
 36 
 36 
 
 VA 
 A 
 
 VA 
 
 
 
 
 
 
 
 
 
 OS 
 
 19 c. 
 
 595 
 
 4-0 
 
 54 
 
 36 
 
 A 
 
 F 
 
 
 
 
 
 
 
 
 Oi 
 
 19 d. 
 
 
 10-0 
 
 54 
 
 36 
 
 
 
 
 
 
 
 
 
 
 m 
 
 20 f. 
 
 560 
 
 
 
 52 
 
 180 
 
 
 
 
 
 
 
 
 
 
 
 20 a. 
 
 
 40-0 
 
 52 
 
 36 
 
 A 
 
 
 F 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 11 
 
 31 
 
 12 e. 
 13d 
 
 502 
 575 
 
 450-320 
 400 270 
 
 30-32 
 32 38 
 
 25 
 
 25 
 
 A 
 A 
 
 F 
 C 
 
 F 
 
 
 ... 
 
 
 F 
 
 
 
 _ " 
 
 13 e 
 
 
 400-270 
 
 32-38 
 
 25 
 
 A 
 
 F 
 
 
 F 
 
 
 
 
 
 
 2 * 
 
 13 a 
 
 558 
 
 465 335 
 
 31 33 
 
 05 
 
 c 
 
 F 
 
 
 
 
 
 
 
 
 O ^ 
 
 16 a i 
 
 398 
 
 350 220 
 
 31 37 
 
 25 
 
 VA 
 
 
 
 
 
 
 
 
 
 1 1 fl 
 
 
 
 300-170 
 
 33-44 
 
 25 
 
 A 
 
 
 
 
 
 
 
 
 
 HjJ 
 
 186. 
 
 645 
 
 530-400 
 
 31-47 
 
 
 A 
 
 
 
 
 
 
 
 
 
 8 
 
 19 a 
 
 595 
 
 480-350 
 
 46-47 
 
 25 
 
 c 
 
 F 
 
 
 
 
 
 8 
 
 
 
 5 r-* 
 
 20 a. 
 206. 
 20 c 
 
 560 
 
 200-100 
 300-200 
 400-300 
 
 39-46 
 33-39 
 31-33 
 
 40 
 40 
 40 
 
 A 
 A 
 A 
 
 
 ... 
 
 ... 
 
 s 
 
 F 
 
 8 
 
 ,s 
 
 
 ... 
 
 
 1.1 
 
 20 d. 
 
 " 
 
 500-400 
 
 30-31 
 
 40 
 
 C 
 
 F 
 
 F 
 
 ... 
 
 s 
 
 S 
 
 
 
 
 i 
 
 12f 
 
 502 
 
 ?10-0 
 
 ?53 
 
 
 A 
 
 o 
 
 P 
 
 
 
 
 
 
 
 
 12 a 
 
 
 +350-150 
 
 +31-43 
 
 25 
 
 VA 
 
 
 
 
 
 
 
 
 
 -H 
 
 13 ab 
 
 575 
 
 300-0 
 
 33-54 
 
 25 
 
 VA 
 
 o 
 
 c 
 
 
 
 
 
 
 
 1 
 
 15 c. 
 196. 
 
 610 
 595 
 
 530-0 
 480-0 
 
 30-53 
 46-54 
 
 25 
 25 
 
 A 
 
 n 
 
 
 
 S 
 
 ... 
 
 ... 
 
 ... 
 
 S 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1898.] 
 
 PLANKTON OF THE FAEEOE CHANNEL. 
 
 543 
 
 
 Euchceta gigos Brady. 
 
 5 
 
 1 
 
 Euchceta marina Prestandrea. 
 
 Euchceta norvegica Boeck. 
 
 Phaenna spinifera Claus. 
 
 ! 
 
 1 
 
 o 
 
 3 
 
 .CO 
 
 p 
 
 t 
 1 
 
 Metridia longa Lubbock. 
 
 -% 
 
 "i 
 
 1 
 
 1 
 1 
 
 
 .03 
 
 ^ 
 
 e 
 | 
 
 53 
 
 H 
 
 00 
 
 3 
 
 f3 
 
 '1 
 1 
 
 1 
 
 Heterochceta abyssalis Griesbrecht. 
 
 Candace truncata Dana. 
 
 Anomalocera patersoni Templeton. 
 
 Acartia clausii Giesbrecllt. 
 
 Oithona spinifrons Boeck. 
 
 Ectinosoma atlanticum Brady & 
 Eobertson. 
 
 ArguhisJ'oliaceus Linnaeus. 
 
 
 
 
 
 
 
 
 
 F 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 F 
 
 
 
 
 
 
 
 
 A 
 
 
 
 
 
 
 ... 
 
 
 
 F 
 
 
 ... 
 
 F 
 
 F 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 A 
 
 f! 
 
 
 
 
 ... 
 
 ... 
 
 ... 
 
 C 
 
 
 
 
 C 
 
 f! 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 S 
 
 
 
 
 O 
 
 
 
 
 
 
 
 
 VA 
 
 c 
 
 s 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 F 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 A 
 
 
 
 
 ^ 
 
 
 
 
 
 
 
 
 o 
 
 
 
 
 
 
 
 
 F 
 
 
 
 ! 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 s 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 s 
 
 
 
 
 
 
 
 
 
 
 
 8 
 
 
 
 
 
 
 
 
 
 F 
 
 
 
 
 
 
 
 f! 
 
 
 
 
 
 
 \ 
 
 
 
 
 
 
 F 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ... 
 
 ::: 
 
 s' 
 
 C 
 F 
 
 
 ..-. 
 
 ... 
 
 ... 
 
 C 
 
 O 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 C 
 
 o 
 
 ... 
 
 ... 
 
 
 c 
 c 
 
 C 
 
 F 
 
 
 ... 
 
 S 
 
 
 
 
 8 
 
 
 
 
 B 
 
 ... 
 
 ... 
 
 c 
 o 
 
 
 
 ... 
 
 c 
 
 n 
 
 
 
 
 
 
 
 
 
 
 
 
 ... 
 
 C 
 
 c 
 
 fl" 
 
 
 ... 
 
 c 
 
 c 
 
 \ 
 
 S 
 
 
 
 
 
 F 
 
 
 
 
 
 
 
 A 
 
 
 
 
 
 A 
 
 
 
 
 
 
 
 F 
 
 S 
 
 
 
 
 
 
 
 
 
 
 
 S 
 
 s 
 
 
 
 
 
 
 
 
 
 
 
 S 
 
 S 
 
 ... 
 
 F 
 
 ... 
 
 ... 
 
 ... 
 
 A 
 
 F 
 
 
 S 
 
 ... 
 
 S 
 
 - 
 
 F 
 
 
 
 
 
 ... 
 
 ... 
 
 C 
 
 6 
 
 S 
 
 
 
 F 
 
 
 
 
 
 S 
 
 
 
 
 
 
 
 
 
 
 D 
 
 
 
 
 
 
 
 
 
 
 
 o 
 
 
 
 
 
 
 
 
 A 
 
 F 
 
 
 
 
 
 A 
 
 
 
 s 
 
 
 
 
 
 
 
 
 8 
 
 
 F 
 
 
 
 
 
 
 n 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
544 DR. G. H. FOWLER ON THE [June 21, 
 
 perfect antennae agree with this description. JN"or, curiously enough., 
 does Giesbrecht's own exquisitely drawn figure (pi. vi. fig. 6, 
 Pelagischen Copepoden des Golfes von Neapel &c.) bear it out. 
 
 Giesbrecht's grounds for making this a distinct species from 
 C. finmarcliicus, and not a mere variety, seem to me scarcely 
 adequate. It is extremely likely that a species so widespread and 
 living under so varied conditions should possess corresponding 
 modifications such as we find here. 
 
 The very remarkable occurrence of three specimens of Argulus 
 foliaceus in 15 d gathering is phenomenal ; this species, so far as I 
 am aware, having never been previously recorded except from fresh 
 water, in which it is commonly found parasitic upon the stickleback, 
 carp, and other fish. In this instance it appears to have been 
 taken by the tow-net as a free-swimmer ; and the only conclusion 
 I can come to is that these three specimens became detached from 
 a fish which had recently found its way into the sea from some 
 stream, They in all particulars agree with A. foliaceus, differing 
 markedly from any of the known marine species of Argulus. 
 
 [Notes to Table of Distribution. 
 
 (1) Stations 11 to 19, 1896. Station 20, 1897. 
 
 (2) The temperatures given for Station 20, hauls a to d, were not actually 
 observed there, but are taken from the serial observations at Station 16 ; 
 the difference between the two is probably trifling. The serial tempera- 
 tures of the 1896 cruise are published in the Report of Proceedings &c. 
 in the Faeroe Channel made by Capt. W. U. Moore, R.N., to the Hydro- 
 graphic Office in 1896. 
 
 (3) For the reason of the exclusion of Calanus hyperboreus from the table 
 
 see p. 541. 
 
 (4) VA=Very abundant. = Common. 
 
 A = Abundant. F=Few. 
 
 S= Scarce. 
 
 G. H. F.] 
 
 Appendix to the foregoing Report. By G. HERBERT 
 FOWLER, B.A., Ph.D., Assistant Professor of Zoology 
 in University College, London. 
 
 Mr. Thompson's Eeport brings out some very interesting 
 features, from the oceanographic standpoint, with regard to the 
 distribution and bionomics of Copepoda. The most salient 
 feature is, as he points out, the apparent indifference of Calanus 
 finmarchicus to temperature and pressure. Like Spadella 
 (Krohnia) hamata, discussed for the Faeroe Channel in an earlier 
 paper of this series 1 , and on a wider basis by Steinhaus 2 and 
 Chun 3 , it is apparently equally happy whether at the surface under 
 
 1 G. H. Fowler : Proc. Zool. Soc. 1896, p. 993. 
 
 2 O. Steinhaus : Verbreitnng der Chsetognathen ; Inaug. Dissert., Kiel, 1896. 
 8vo. 
 
 3 0. Chun : Beziehungen zwischen dem arktischen und antarktischen 
 Plankton. Stuttgart, 1897. 
 
1898.] PLAtfKTOtf OF THE PAEBOE CltANtfEL. 545 
 
 pressure of 14 Ibs., or at 500 fathoms under a pressure of half 
 a ton, whether in bright light at a temperature of 54 F., or in 
 utter darkness at a temperature of 30-32 F. Not only so, but 
 it ranges apparently all over the globe (although not in such quan- 
 tity 1 as in the Arctic Seas), except for the fact that it has not 
 been recorded for the Equator and the hottest parts of the tropics, 
 nor south of Cape Horn. In the Antarctic regions according to 
 Chun 2 its place is apparently taken by Calanus propinquus ; but 
 Mr. Thompson informs me by letter, that in a recent examination 
 of Antarctic Plankton he finds Calanus finmarchicus to be one of 
 the commonest species. Its general distribution is cited by 
 G-iesbrecht 3 . 
 
 In discussing the Plankton of the Faeroe Channel it must be 
 remembered that we are dealing with a * Mischgebiet/ for which I 
 would suggest the term ' Frontier/ a district in which the North- 
 easterly continuation of the North Atlantic Drift (the so-called 
 Gulf Stream), carrying a warm-water fauna, is constantly warring 
 with a Southerly set of Arctic water carrying a cold-water fauna 4 . 
 Both in 1896 and 1897 a succession of north winds had given a 
 distinctly northern character to the fauna : and although, for 
 example, fanthina-sliella and PhysopTiora liydrostatica have in some 
 cases been swept by the North Atlantic Drift as far north as the 
 Lofoten Islands through the Faeroe Channel, I have not so far 
 come across a single characteristically warm-water surface species in 
 the ' Eesearch' collections of either year from the Faeroe Channel. 
 
 Taking now the 34 hauls in which Copepoda were captured, we 
 have 17 Epiplankton 5 hauls of less than 100 fathoms, and 13 
 Mesoplaukton 5 hauls (including 12 a, in which the depth was not 
 so approximately known as in the other deep hauls, but which 
 
 1 With the view of testing the Prince of Monaco's suggestion, that a tow-net 
 could be made to pro vide food for shipwrecked boat's crews, we tried this species, 
 raw, in the ward-room of the ' Research.' The Officers voted it excellent food, 
 like "delicate shrimp-paste" ! 
 
 2 C. Chun, op. cit. p. 48. 
 
 3 W. Giesbrecht : Pelagische Copepoden des Golfes von Neapel, 1892, p. 89. 
 
 4 Compare Chun, Beziehungen zwischen d. arktischen u. antarktischen 
 Plankton, pp. 7-10. Stuttgart, 1897. 8vo. 
 
 5 In my lectures on Oceanography at University College, I have felt the 
 need of simple terms to express briefly the Oceanic zones, and have used the 
 following : 
 
 Epiplankton : to + 100 fathoms below surface. 
 
 Mesoplankton : + 100 fathoms below surface to 100 fathoms above 
 
 bottom. 
 
 Hypoplankton : +100 fathoms above bottom to bottom. 
 Epibenthos: high-water mark to the mud-line (generally at + 100 fathoms 
 
 depth) = fauna of the continental shelf. 
 Mesobenthos : the mud-line ( + 100 fathoms) to + 500 fathoms = fauna 
 
 of the continental slope. 
 
 Hypobenthos : over 500 fathoms = abyssal fauna. 
 
 This is not the place in which to discuss the justification of these terms : 
 their intention will be apparent to all who have followed the recent progress of 
 oceanic zoology. Two of them may be queried : (1) the Hypoplankton, under 
 which I reckon those floating and swimming animals (Crustacea, Fish, &c.) 
 which, for nutrition and for other reasons, are more intimately connected with 
 
546 b&. GL H. FOWLER Otf THE [June 21 , 
 
 certainly finished below the 100 fathoms), in all 30 hauls, with 
 which to deal. Eegarding, then, only those species which were 
 captured six times, or in 20 / of the hauls, as affording a sufficient 
 basis for discussion, we find that the occurrences of seven species 
 work out thus, expressed in percentages of hauls made above and 
 below 100 fathoms : 
 
 Epiplankton. Mesoplankton. 
 
 Calanus finmarchicus 88'2 % lOO'O % 
 
 Eucalanus attenuatus 17'6 46*1 
 
 Euch&ta norvegica 1T7 
 
 Metridia longa 23*5 
 
 Pleuromma abdominale 5'8 
 
 Acartia clausii 35 '2 
 
 Temora longicornis.... , 35'2 
 
 76-9 
 69-2 
 61-1 
 15-3 
 0-0 
 
 Prom this table it would appear (1) that Calanus ^finmarchicus is 
 essentially eurythermal and eurybathic, i. e. has a wide range both 
 of temperature and of depth ; (2) that Eucalanus attenuatus, 
 Euchceta norvegica, Metridia longa, and Pleuromma abdominale show 
 a distinct preference for the deep water and low temperature of 
 the Mesoplankton, although occurring more sparingly in the 
 Epiplankton; (3) 1hat Acartia clausii belongs rather to the 
 Epiplankton than to the Mesoplankton ; (4) that Temora longicornis 
 is essentially a member of the Epiplankton. We may now com- 
 pare these results, based unfortunately on but scanty data, with 
 those recorded by others. 
 
 In the first place, Calanus finmarchicus, as mentioned above, 
 has been recorded from most varied temperatures (latitudes), and 
 is now definitely shown to extend to considerable depths (Sta. 18 6, 
 530-400 fm.). It does not occur among the Mesoplanktonic forms 
 in Griesbrecht's list (op. cit. p. 788), and its vertical distribution in 
 the Eaeroe Channel is therefore worth recording. It is not at 
 present safe to suggest a maximum temperature, as expressed 
 by mean annual isotherms, for this species ; it is, however, possible 
 that its non-occurrence in the Equatorial region may indicate a 
 maximum of 75 or 80 E. as its temperature limit. 
 
 In the second place, it is noteworthy that of the five species of 
 Copepoda recognized by Chunks essentially Arctic types (Leit- 
 formen), one is missing from the ' Research' collections (Calanus 
 cristatus) ; one, regarded by Mr. Thompson as a species of doubtful 
 
 the bottom than with the Mesoplankton ; (2) the Mesobenthos, which seems on 
 statistical and other grounds to have certain marked features, both faunistic 
 and physical, which distinguish it from the zones below and above it ; although 
 it shares many species with other zones, still, according to the ' Challenger ' results 
 (J. Murray, Summary of Scientific Results, Exped. H.M.S. Challenger, part ii. 
 p. 1430, table 1), no less than 74 per cent, of its fauna is confined to it, and 
 does not spread into other zones. 
 
 These six words, with the addition of the terms " oceanic" and "neritic" as 
 applied respectively to the plankton of the open ocean and of the continental 
 region, have been found in practice to serve sufficiently well for descriptive 
 purposes. 
 
 1 C. Chun, op. cit. p. 28. His list is a condensation from that of OHesbrecht, 
 op. cit. p^). 776-7. 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 547 
 
 value, occurred rarely (C, hyperboreus) ; one, Pseudocalanus elon- 
 gatus, is only represented three times, and cannot therefore be 
 further discussed; two, Metridia longa Lubbock (= armata 
 Boeck) and Euchaeta norvegica, are well represented. Both of 
 these species exhibit, in the table of percentages above given, that 
 preference for a mesoplanktonic existence which one would expect 
 of an Arctic species in a Frontier district. For if the law be true, 
 which was enunciated first, I think, by Moebius, that the area of 
 distribution of a Planktonic organism is bounded at the surface by 
 an isotherm and below by an isothermobath of the same number 
 of degrees, we should expect Arctic forms to sink to lower (colder) 
 depths as they approached lower latitudes (warmer surface-water). 
 The southernmost points recorded in Griesbrecht's lists for these 
 two species at the surface are the northern part of the North 
 Sea for Euchceta norvegica, and Concarneau for Metridia longa. 
 We are probably safe in assigning a maximum mean annual tem- 
 perature * of 50 F. for Metridia longa, and a slightly lower mean 
 annual for Euchceta norvegica. In the very interesting collections 
 made by Prof. Herdman in his traverse of the North Atlantic 2 , 
 the eight captures of ^Metridia longa were all near the mean annual 
 isotherm of 50 F. ; Euchceta norvegica was not captured at all. As 
 regards the vertical distribution of Euchceta norvegica, the Norwegian 
 North Atlantic Expedition failed to capture this species at tbe sur- 
 face 3 , but it certainly comes to the surface in the Faeroe Channel, 
 even in broad daylight (Sta. lie). 
 
 The other two forms, which, according to the table of per- 
 centages given above, exhibit an apparent preference f or the Meso- 
 plankton Eucalanus attenuatus and Pleuromma abdominale, 
 are united in having a very wide superficial range in the Atlantic 
 and Pacific Oceans ; both occur in Griesbrecht's list of mesoplank- 
 tonic Copepoda, Eucalanus attenuatus being credited with 1000 m. 
 = + 550 fms., Pleuromma abdominale with 4000 m.= +2200 fms. 
 Both these species must be regarded as eurythermal and eurybathic ; 
 and it is not at present possible to suggest a maximum or minimum 
 temperature for either of them. Their apparent preference for 
 the Mesoplankton in my collections must therefore be attributed 
 to some other cause than temperature ; but it is in no way incon- 
 sistent with what we already know of their habits. 
 
 Temora longicornis appears to be confined to the North Atlantic, 
 except for two records from the Mediterranean which Griesbrecht 
 appears to doubt 4 . So far as I am aware, it has never been 
 recorded from any considerable depth, and with this my results 
 accord : we may fairly regard it as a member of the Epiplankton ; 
 
 1 The mean annual temperatures are adopted from Buchan, Ohall. Rep. 
 Phys. Chem. ii. Atmospheric Circulation. 
 
 2 W. A. Herdman, I. C. Thompson, and A. Scott: Trans. Liverpool Biol. 
 Soc. xii. 33. 
 
 3 G-. O. Sars: Crustacea of the Norwegian N. Atlantic Expedition, i. p. 240. 
 
 4 W. Giesbrecht, op. cit. pp. 328-330. Mr. Thompson informs me by letter 
 that this species occurs also in a collection made at Muscat by Staff-Surgeon 
 Bassett-Smith, E.N., of H.M.S. 'Cossack.' 
 
548 Dit. G. fi. FOWLER our THE [June 21, 
 
 and if it occurs between Newfoundland (mean annual isotherm 
 35 F.) and Muscat (mean annual isotherm 80 F.), it is remarkably 
 eurytherrnal for an epiplanktonic animal. 
 
 As Mr. Thompgon has mentioned, the occurrence of Euchaeta 
 marina so far north is remarkable. It has been recorded hitherto, 
 according to Griesbrecht and Brady, in both Atlantic and Pacific 
 Oceans, northwards from 47 S. (?) across the tropics, but with a 
 northern limit in the Mediterranean. In Giesbrecht's list of meso- 
 planktonic species, it figures as from 4000 m. = 2200 fms. to the 
 surface. According to Brady \ "it would seem to be the most 
 abundant and most widely distributed of all the pelagic Copepoda," 
 a description which it deserves more than ever, now that its range 
 has been extended to the Faeroe Channel. In Prof. Herdman's 
 traverse it was " found in the majority of the collections taken 
 between mid-ocean and Quebec," i. e. across the mean annual iso- 
 therms of 35 to 50 F. Its extension northward in our longitudes 
 is therefore by no means surprising. 
 
 The occurrence of Euchaeta barbata and Euchaeta gigas in the 
 Faeroe Channel is most extraordinary. Both species have hitherto 
 been taken only once, and then only together, viz. off Buenos Ayres 
 (Challenger Sta. 325, 36 44' S., 46' 16' "W., down to 2650 fathoms). 
 Their reappearance, still together, in northern latitudes makes it 
 fairly safe to prophesy that the use of deep-water tow-nets in inter- 
 mediate latitudes will prove them to be mesoplanktonic species of 
 wide distribution. 
 
 Euchaeta hessei (Q-. S. Brady), which, as Griesbrecht suggests, 
 is perhaps identical with Euchirella rostrata (Glaus), is known 
 sparingly from both Atlantic and Pacific Oceans ; its distribution 
 is considerably extended by its occurrence in the ' Research ' 
 collections. 
 
 Euchirella pulchra has been recorded, according to Griesbrecht, 
 only from the Gulf of Guinea, N.W. Africa, and South America. 
 Phaenna spinifera, Leuckartia flavicornis, and Heterochaeta spini- 
 frons, according to the same authority, are known only from the 
 Mediterranean (including the Canaries) and from the tropical 
 Pacific ; only the last of these occurs among the species taken in 
 Prof. Herdman's traverse of the Atlantic ; their range is now 
 extended northwards to the Faeroe Channel. They illustrate well 
 how impossible it is at present to draw distributional areae for most 
 Copepoda; this group of Crustacea will probably rival the Eadiolaria 
 in the width of its distributional areae, owing to the hardiness and 
 tenacity of life 'of many of its members. But if we bear in mind 
 that this is a Frontier district, i. e. one where a heavy slaughter of 
 the Plankton occurs at the meeting of warm and cold currents, as 
 is evinced by the abundant formation of glauconite and phosphatic 
 nodules in the bottom deposits 2 , and by the wealth of the benthos, 
 
 1 G. S. Brady, Chall. Eep. Zool. viii. Copepoda, p. 62 (Euchata prestandrea). 
 
 2 For the glauconite, see Tizard and Murray, Proc. Hoy. Soc. Edinburgh, 
 i, pp. 671 et seqq. "There were no very large phosphate nodules, but numerous 
 
 small ones, with phosphates in varying quantities," in a letter from Sir John 
 Murray. 
 
1898.] PLATOON OF THE FAEROE CHANNEL. 549 
 
 it is not a little suggestive that the above four species (to which 
 may perhaps be added Eachceta hessii and Candace truncata), which 
 appear to have wandered north of their usual habitat, were only 
 taken in the 'Research' from the Mesoplankton, and in all cases 
 marked by Mr. Thompson as " Scarce." All six occurred once 
 only, except Euchceta marina, which was captured twice. It seems 
 at any rate possible that these wanderers had either been killed by 
 a reduced temperature, or at any rate so numbed by cold as to be 
 gradually sinking to the bottom. 
 
 Acartia clausii of Giesbrecht has been separated by that author 
 from A. (Dias) longiremis of Lilljeborg ; he uses the latter specific 
 name for species from the Baltic and Sound only. Assuming his 
 view to be correct, the area of A. clausii has been somewhat ex- 
 tended northwards by the 'Research' collections: it reaches south- 
 wards to the Canary Islands, including the Mediterranean. I 
 gather, however, from Mr. Thompson that he himself would prefer 
 to regard the Baltic and North Atlantic forms as varieties of one 
 species. 
 
 A. clausii appears to have been known hitherto as an epiplank- 
 tonic form only x . Possibly its occurrence in deep water, at Station 
 20, may be due to dead or numbed specimens sinking from the 
 surface ; but it was so regular in its appearance on that occasion 
 (in three out of four mesoplankton hauls), that, if the above 
 explanation be correct, a very large swarm of this species must 
 have succumbed to cold recently. As it did not occur in my meso- 
 plankton hauls in 1896, I should prefer to leave the question 
 open. 
 
 Rhincalanus cornutus and Aetidius armatus have been sparingly 
 recorded from both Atlantic and Pacific Oceans, but not, so far as 
 I know, from as far north as the Faeroe Channel. 
 
 As regards the remaining species in Mr. Thompson's list, there 
 does not appear to be anything of mark connected with their 
 appearance in the ' Research ' collections, with the exception of 
 Argulus (cf. p. 544). 
 
 The following conclusions as to vertical distribution appear to 
 be justifiable on a comparison of the ' Research' collections with 
 other records : 
 
 Calanus finmarchicus is eurythermal and eurybathic. 
 
 Metridia armata and Euchceta norvegica, two essentially Arctic 
 types, tend to descend to the Mesoplankton on reaching lower 
 latitudes. 
 
 Eucalanus attenuates and Pleuromma abdominale are apparently 
 eurythermal and eurybathic. 
 
 Temora longicornis and Anomalocera patersoni are apparently 
 confined to the Epiplankton. 
 
 1 F. Dahl, Verhandl. deutschen zool. Gesellsch. 1894, p. 64. 
 
550 MR. KTT.I.HOLT ON TEE [June 21 
 
 5. Contributions to our Knowledge of the Plankton of the 
 Faeroe Channel. No. V. 1 Report on a Collection of 
 very young Fishes obtained by Dr. G. H. Fowler in 
 the Faeroe Channel. By ERNEST W. L. HOLT. 
 
 [Eeceived June 18, 1898.] 
 (Plates XLVI. & XL VII. ) 
 
 My friend Dr. G. H. Fowler has asked me to name, if possible, 
 the fishes taken in his vertical self-closing tow-net in the Faeroe 
 Channel. My task is rendered the easier by the fact that the greater 
 number of them prove to belong to one species. Individually some 
 of the stages represented could hardly be definitely identified, even 
 generically, but the series is practically complete and has enabled 
 me to add considerably, as I venture to suppose, to our knowledge 
 of the developmental phases of deep-sea forms. Incidentally the 
 species in question, Scopelus glacialis, is definitely added to the 
 British fauna, though that is a matter of no great importance. In 
 the case of a pelagic egg and some early Iarva3 of very elongate 
 form, I have only been able to point out the possible affinities. 
 Two other larvae, those of Sebastes norvegicus arid Gadus ceglefinus, 
 have already received attention at the hands of other observers, 
 but the collection furnishes a stage of G. ceglefinus that has not 
 hitherto been adequately described. The importance of a really 
 efficient self-closing net, even from the point of view of the mere 
 ichthyologist, can hardly be overrated. 
 
 SEBASTES NORVEGICUS Ascan. Norway Haddock. 
 
 Sebastes marinus, Collett, Norw. N. Atlant. Exped,, Fish. 1880, 
 p. 15, pi. i. figs. 3, 4. 
 
 Collett refers to this species a number of Iarva3 or fry which 
 were taken at the surface " in mid-ocean, some nearly 400 kilom. 
 from land," off Beeren Island and Spitsbergen. His examples 
 measured from 9*5 to 19 mm., and two, illustrating the extreme 
 terms of the series, are figured. In the brief description appended 
 the character of the interorbital space and other obvious points of 
 distinction from Scorpcena dactyloptera are not mentioned ; but we 
 are not entitled to suppose that so careful an observer would have 
 overlooked the possibility of confusion between the two forms. 
 
 Dr. Fowler's specimen, 12-5 mm. in length (inclusive), corresponds 
 so closely to Collett's figures (allowing for the difference in 
 dimensions) that it is unnecessary to illustrate it. It appears to 
 be nearly identical in development with a North Atlantic specimen 
 of 12 mm., but the bony ridge of the nape terminates in a single 
 instead of in a double spine. The interorbital space is, in 
 the Faeroe Channel larva, very wide and flat, a character in which 
 
 1 For Part I. see P. Z. S. 1896, p. 991 ; Part II., 1897, p. 523 ; Part III., 1897, 
 p. 803 ; Part IV., antea, p. 540. 
 
P.Z.S.1898.P1.XLVI. 
 
 2.X3-3 
 
 3.X5-3 
 
 EW.L.H.ael.EJ.Smit Hth. 
 
 5.xlO 
 
 PLANKTON OF THE FAEROE CHANNEL 
 
 MnterlvBi-os . imp. 
 
vw. 
 
 UNIVERSITY 
 
 
P.Z.S.1898.P1.XLVII. 
 
 10.X2-25 
 
 9.x 4-5 
 
 12.X10-8 
 
 E W.L H.del.P J.Smit Htk . Mmtern.Bros. imp . 
 
 PLANKTON OF THE PAEROE CHANNEL. 
 
OFTHF 
 
 UNIVERSITY 
 
 OF 
 
1898.] PLAffKTON Otf 0?HE tfAEROE CHANNEL. 551 
 
 the adult S. norvegicus differs most strikingly from S. dactyloptera. 
 I infer, from the condition of young examples of 40 mm., that the 
 approximation of the eyes manifests itself, in the last-named species, 
 at a very early stage. 
 
 The specimen occurred at 60 2' K, 5 49' W., 100 to fath. 
 Fragments of a little fish, taken at 60 16' N., 5 49' W., 200 to 
 100 fath., seem to have belonged to a member of this species, about 
 20 mm. long. 
 
 Collett records examples of 62 to 143 mm. from the bottom at 
 120 to 150 fathoms. If I have correctly identified Dr. Fowler's 
 larger specimen, it would appear that the younger stage occurs in 
 mid-water as well as at the surface. 
 
 G-ADUS ^GLEFINTJS Linn. Haddock. (Plate XLYII. fig. 12.) 
 
 Gadus ceglefinus, GL O. Sars, Rep. Cod Fish. Lofod. (1866, 1867), 
 in Cornm. Rep. U.S. Comni. Fish. Fisher. (1877), 1879, p. 590; 
 Mclntosh, 15th Rep. Fish Bd. Scot. 1897, p. 196, pi. v. 
 
 The collection contains only one Gadoid, viz. a Gadus measuring 
 8 mm. without the caudal rays aud terminal process of the urochord. 
 It is in a good state of preservation, and may be identified with 
 approximate certainty as a young Haddock. The eggs and very 
 early larvae of this fish are well known l , and later stages, from 19 
 mm. upwards, have been well figured by Mclntosh. Intermediate 
 conditions have received less attention. Such were known to 
 G. O. Sars, who probably studied them exactly : but, in the only 
 account which lhave seen, the Norwegian observer simply remarks 
 that they are distinguishable from corresponding stages of the Cod, 
 G. morrhua, by their shorter and stouter shape. Mclntosh describes 
 very briefly some specimens of 7 to 8, 11, 12-5 and 19 mm., which 
 he attributes to the Haddock. He supposes that the smaller of 
 the series correspond to the stages taken by Sars. 
 
 My figure (Plate XLVIL fig. 12) shows what I suppose to be 
 the essential features of the Faeroe Channel specimen. The 
 proportions and conformation being accurately drawn, need no 
 elaborate description. As in the case of the young Haddock 
 studied by Sars, the form is much more massive than in the Cod. 
 This is seen at once on comparing my drawing with Prince's figure 
 of a Cod, '33 in., 8*25 mm. c.a. The total length is about the same, 
 but the larval Cod is much more slender and appears less advanced 
 in general development. The eye is also smaller. Probably 
 whatever postmortem shrinkage may have occurred in one specimen 
 is compensated by a similar condition in the other, and even if the 
 Cod were drawn from a living specimen the difference in confor- 
 mation is too striking to be entirely explained by a possible 
 distortion of the supposed Haddock. In the latter the pelvic fins 
 are indicated, if at all, by a very slight prominence of the thoracic 
 region. The dorsal and anal fins are indicated by the inflections 
 of the embryonic fin, but only a few of the permanent fin-rays are 
 
 1 Vide Mclntosh and Prince : Trans. E. S. Edin., xxxv. 1890, p. 822. 
 
552 ME. E. w. L. HOLT ON THE [June 21, 
 
 in visible process of development. The caudal fin shows features 
 of interest. The extremity of the notochord forms the axis of a 
 lanceolate mass ; its extremity is bent up at an obtuse angle, and a 
 considerable part projects freely, being succeeded, to the margin of 
 the fin, by fine embryonic rays. Dorsally occur 12 rays, or 11 
 and a mass of embryonic rays dividing the last true ray from the 
 urochord. None of these show any distinct basal element. Below 
 the urochord is a roughly trigonal hypural lobe bearing five rays. 
 Anteriorly are three smaller oblong lobes, the most posterior 
 bearing two, the others one ray each. In front occur 6 rays. 
 None of these caudal rays are perfectly formed, the anterior rays, 
 dorsally and ventrally, being but little different from the embryonic 
 rays in front of them. The notochord is still imperfectly segmented, 
 and the myomeres cannot be counted with accuracy. These 
 characters, therefore, like the fin-ray formula, are not available as 
 aids to specific determination. Preserved in formol the specimen 
 naturally possesses no yellow pigment, if any ever were present. 
 The black chromatophores have the distribution shown in my 
 figure on the left side. On the right side there are in addition a 
 few scattered chromatophores. The roof of the peritoneum is seen 
 to be densely black when the specimen is clarified. Mclntosh 
 makes DO mention of the caudal pigment-bar which is such a 
 prominent feature in the Faeroe Channel Gadus. The chromato- 
 phores above the insertion of the pectoral in the latter probably 
 correspond to " a very distinct area of pigment-points behind the 
 pectorals " in Scottish larvae of 11 mm., and ultimately perhaps to 
 the more posteriorly situate spot of the adult. The development 
 of pigment in Teleostean larvae is undoubtedly influenced to some 
 extent by conditions of light and, apart from this, is variable in 
 individuals. Probably such differences of coloration as may exist 
 between the Faeroe Channel specimen and those attributed to the 
 Haddock by Professor Mclntosh are explicable in this way, but the 
 information afforded, both as to pigment and conformation, in the 
 case of the latter only permits of a conjecture as to their identity. 
 The Scottish examples of 24 mm. and upwards, which are figured 
 and adequately described, are undoubtedly Haddock, and appear to 
 be certainly derivable from such a stage as is exemplified in the 
 larva from the Faeroe Channel. 
 
 Dr. Fowler's specimen was taken at 60 2' N., 5 49' W., at 100 
 to fathoms. I have myself recorded the capture of spawning 
 Haddock at 154 fath., off the W. coast of Ireland, while Grirnsby 
 line-fishermen have told me that they frequently take the species 
 at depths of more than 100 fath. on the wide area which they include 
 in the Faeroe Bank. 
 
 SCOPELUS GLACIALIS Eeinh. (Plate XLVI. figs. 1-5 ; XL VII. 
 figs. 6, 7.) 
 
 S. glacialis, Giinther, Chall. Eep., Zool. xxii., Deep-Sea Fishes, 
 p. 196 ; Liitken, Spol. Atlant., Scopel. 1892, p. 30 (250). 
 
 Myctophum glaciale, Smitt, Hist. Scand. Fish. ed. 2, ii. p. 941. 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 553 
 
 ? S. scoticus, Griinther, Chall. Eep., Zool. xxxi., Pelagic Fishes, 
 p. 31. 
 
 S. mulleri, Collett, Norweg. N. Atlant. Exped., Zool., Fish, 
 p. 158. 
 
 Benihosema mulleri, Goode & Bean, Ocean. Ichth. p. 76. 
 
 Young, imperfectly characterized stages of the Scopelidce have 
 been a source of much labour to the various observers who have 
 had occasion to name collections of this group, since it has been 
 quite impossible to determine, in the absence of sufficient material, 
 whether certain differences have a 'systematic or merely a develop- 
 mental value. I think I am right in saying that the reproduction 
 is quite unknown, and I can find no description of the early larvae 
 of any species. With regard to one, the efficiency of Dr. Fowler's 
 vertical net appears to have supplied this want, as I find in his 
 collection what appears to be a nearly complete series of Scopelus 
 glacialis. 
 
 Though the method has its disadvantages, it appears necessary in 
 the present instance to describe the different stages in the inverse 
 order, commencing with the most advanced. This is a specimen 
 of 58*5 mm., exclusive of the lower jaw and the caudal fin-rays 1 . 
 It has the adult characters peculiar to the species and, except that 
 most of the scales have gone and some of the fin-rays are broken, 
 is in good preservation. No description is necessary except for 
 ontogenetic comparison. The radial formula is D. 13, A. 18. 
 The eye is nearly three times as long as the snout, and is T %- of the 
 length of the head (12 mm.), which is equal to the height of the 
 body at the shoulder and a little more than 4- of the total length. 
 The anal commences nearly opposite the middle of the dorsal. 
 Adequate figures of the adult stage, which is practically exemplified 
 in this specimen, are given by G-oode and Bean and by Smitt, but, 
 in some copies of the Hist. Scand. Fishes the printing is very 
 imperfect. A clear diagram of the photophores is given by Liitken. 
 
 Figures 1 to 7 (Plates XLVI. & XL VII.) represent younger 
 stages in Dr. Fowler's collection. The most advanced of these, 
 fig. 1, measures only 14'5 mm., and has no scales ; but the condition 
 of another specimen indicates that the body is covered under 
 natural conditions with dark-coloured scales. The part shaded in 
 my drawing remains, in formol, a bluish grey. The photophores, 
 having the formula of S. glacialis, are intact. The radial formula 
 is D. 12 or 13, A. 18. The proportions of the head, eye, and snout are 
 respectively as 31 (= 4 mm.), 10, 7. The eye is thus much smaller, 
 relatively, than in the specimen of 58*5 mm., arid the snout longer. 
 Considered in the light of the ordinary ontogenetic changes of 
 these parts in Teleosteans, this condition would appear to prove 
 that the two individuals belong to different species, since as 
 a general rule the eye decreases and the snout increases as develop- 
 ment advances. In Scopdus, as I shall show, this condition is 
 reversed during some part of the metamorphosis of the larva. 
 
 1 This limitation is implied in all measurements of total length in this paper, 
 
554 MB. E. W. L. HOLT ON THE [J Ulie 21, 
 
 A specimen of 13*5 mm. does not differ greatly from the last. 
 It was evidently fully clad, in life, with dark-coloured scales. The 
 radial formula is D. 11 or 12, A. 15 or 16. I can see no certain 
 indication that any rays have been entirely lost. 
 
 A specimen of 12 mm. (fig. 2) has the radial formula D. 14 ca., 
 A. 18. There are no signs of scales. The photophores are in- 
 complete, but such as are present correspond in position to those 
 of fig. 1 and of S. glacialis. A low wrinkled ridge of skin occurs 
 along the back from the nape to the first dorsal fin. The pro- 
 portions of the head, eye, and snout are as 25 ( = 3'5 mm.), 7, 6. 
 There is thus a further reduction in the eye and increase in the 
 snout as compared with the 14*5 mm. stage ; but I think it will 
 be conceded that the two specimens (figs. 1 and 2) are specifically 
 identical. A vertical from the commencement of the anal passes 
 a little behind the front of the dorsal. The base of the adipose is 
 more extended than in the last stage. 
 
 Fig. 3 shows a specimen of 11'5 mm. The radial formula is 
 D. 14 ca.,A. 18 c#., the rays being rather indistinct in the posterior 
 parts of the fin. The adipose is continued forward by a fold of 
 membrane, beset with numerous embryonic rays, reaching nearly 
 to the base of the dorsal, but its permanent region is indicated 
 by an interneural prominence of the dorsal contour. The 
 proportions of head, eye, and snout are as 25 ( = 3 mm.), 7, 6, 
 a further reduction of the eye being thus indicated. The 
 specimen is drawn in a rather oblique position. Viewed in exact 
 profile, the top of the eye does not quite reach the cephalic contour. 
 No photophores appear to be fully developed, but one is indicated 
 at the lower extremity of the preoperculum, while some pigment 
 on the mandibles seems to be representative of others. A patch of 
 pigment occurs on the isthmus. Except in the eyes no other 
 external pigment is visible ; but internally a black mass in the 
 postero-dorsal part of the abdominal cavity, visible when the 
 specimen is clarified, is probably associated with the air-bladder. 
 The greater part of the abdominal cavity is occupied by a volumi- 
 nous intestinal tract beset with transverse ridges. The liver is 
 comparatively small, and occurs below the basal part of the 
 pectorals. Posterior to this line the whole cavity, so far as I can 
 see, is occupied by the intestine, which passes by a slight con- 
 striction into the pyriform rectum. The mouth is smaller than 
 in the more advanced stages, a condition familiar in the ontogeny 
 of the Salmon. 
 
 The most remarkable feature of the larva is a large bladder-like 
 expansion of the skin of the dorsum between the head and the 
 dorsal fin. In the present condition of the specimen it is some- 
 what collapsed and flattened, its edges projecting from the upper 
 part of the sides. Pigs. 3 and 4 show this structure from different 
 points of view, the true dorsal contour being indicated in the 
 profile drawing by a dotted line. It is obviously identical with the 
 wrinkled fold already noted in the 12 mm. stage, which is the 
 degeneration of what is evidently a larval organ. In the specimen, 
 
1898.] PLANKTON OF THE FAEB.OE CHANNEL. 555 
 
 of 11*5 mm., the cavity contains an amorphous plasma, which 
 disappears in a clarifying medium. The larvae of many Teleosteans, 
 e. g., Gadus, Solea, are characterized in the vitelligerous condition 
 by an expansion of the anterior part of the dorsal marginal fin, 
 the walls of which are separated and form a sinus of varying size 
 filled by a'transparent fluid 1 . The fluid being lighter than the body 
 and yolk, enables the larva to maintain a vertical position, as 
 I have been able to note by watching larvae of Gadus luscus, in 
 which the sinus is well developed. Larvae not furnished with such 
 a sinus in the vitelligerous stage are seldom vertical in position 
 when at rest, except in the case of large vigorous forms from 
 demersal ova, in which the organs of locomotion are far advanced 
 at the time of hatching. I regard the structure noted in our 
 Scopelus larvae as homologous with the sinus of early Gadoid and 
 other larvae. It may be, as Eyder supposes, a lymph-space, having 
 nothing in common except contiguity and continuity with the 
 embryonic fin-fold, but I think its function is primarily connected 
 with equilibrium. The most remarkable feature is its persistence, in 
 Scopelus, to a comparatively advanced stage of the general develop- 
 ment. In Gadus &c. it appears after hatching and attains its 
 greatest development at about the end of the vitelligerous period or a 
 little after (as in G. morrhua, teste Eyder), but disappears, so far 
 as my experience goes, before the permanent median fins commence 
 to appear. 
 
 [(Note added Aug. 1898.) My friend and teacher, Professor Howes, 
 has called my attention to the possibility of an homology between 
 the dorsal sinus of the young Scopelus and a peculiar pad-like 
 process at the anterior end of the dorsal marginal fin of the larva 
 of Rana alticola, described by Mr. Boulenger in his Catalogue of 
 the Batrachia. Through the kindness of the last-named observer, 
 I have been able to examine a larva of R. alticola. In both cases 
 the structures are continuous with the walls of the marginal fin, 
 but they appear, at present, to have little else in common. In 
 Rana the median pad is associated with paired organs of a similar 
 nature, and all three are solid and (teste Boulenger) glandular. In 
 Scopelus the thin-walled sinus is probably devoid of well-developed 
 glandular matter, but the material is too valuable to be submitted 
 to the arbitry of the microtome. 
 
 Although Dr. Fowler's youngest examples of Scopelus are too 
 much injured to admit of an exact determination of the extent of 
 the sinus, it appears probable that the latter covers an area 
 sufficiently extended to include the sites of all the glandular pads 
 of R. alticola. It is possible that the sinus is an organ of extreme 
 antiquity, of which the isolated pads of Rana may be modern 
 derivatives.] 
 
 In a specimen of about the same stage of development as that 
 
 1 Vide Eyder, Kep. Comm. Fish. U. S. A. for 1885 (1887), p. 496, pi. i. This 
 author does not regard the sinus as part of the larval fin-fold, though its walls 
 are continuous with that of the latter. 
 
556 ME. E. w. L. HOLT ON THE [June 21 
 
 last described, the dorsal sinus is collapsed and flattened from side 
 to side, having therefore the appearance of a skinny median ridge. 
 A similar condition appears to have almost certainly furnished 
 the most striking feature of Vaillant's genus Anomalopterus 
 (Exp. Sci. Travaill. Talism., p. 160, pi. ix.), which is founded on a 
 specimen of 60 mm. having a kind of adipose fold (" re'pli, sorte 
 d'adipeuse") occupying the entire length of the back from the head 
 to the dorsal fin. Presuming in an allied family such a develop- 
 mental increase in the size of the eye as we have seen to occur in 
 Scopelus, it appears to me quite possible that Anomalopterus 
 pinguis is only a young stage of Baihytroctes, the dorsal fold 
 being merely a larval sinus *. 
 
 A younger stage of Scopelus is represented in the Eaeroe 
 collection by a larva of 8 mm. (as slightly bent), shown in fig. 5. 
 The general conformation appears to clearly associate it with the 
 stage last described. The proportions of head, eye, and snout 
 appear to be as 15, 4, 3, but the posterior boundary of the head is 
 ill-defined and may be farther back than is indicated by my 
 measurements. Relatively to the snout the eye is certainly a little 
 larger than in the last stage. There is a continuous marginal 
 fold, ampullated in the anterior dorsal region, the walls of the 
 sinus extending some little way on to the sides. The dorsal 
 is represented by a prominent interspmous ridge, beset with 
 embryonic rays, but destitute of definite permanent rays. The 
 rest of the dorsal fold bears embryonic rays, the adipose being 
 merely indicated by a prominence of the dorsal contour. Com- 
 paring the various stages observed, it would seem that the 
 development of the adipose proceeds on the same lines as the 
 first dorsal and anal, since in th$ 12 mm. stage (fig. 2) there is 
 an indication of the formation of true rays, which, however, is 
 never consummated. The caudal is in an advanced stage of the 
 familiar metamorphosis, the tip of the urochord projecting very 
 slightly. The anal, more developed than the dorsal, already shows 
 the proximal parts of 16 true rays. Thickened processes of the 
 body-wall external to the origin of the rectum probably represent 
 the developing pelvic fins. The alimentary viscera appear to be 
 in much the same condition as at 11 mm. The anterior part of 
 the abdominal tract is masked by the base of the pectoral and the 
 liver. The rest of the cavity is occupied by a voluminous intestine 
 lined with well-marked annular or spiral ridges. There is little 
 or no black pigment in the peritoneal roof. Externally black 
 pigment is distributed as shown in fig 5. An aggregation near 
 the lower end of the preopercular ridge and another above the 
 middle of the anal fin appear to represent photophores, though no 
 supra-anal photophore is indicated in the more advanced stage of 
 11 mm. There are about 33 myomeres, of which about 11 or 12 
 
 1 In Vaillant's plate (loc. cit.) is a figure of B. melanocephalus above that of 
 A. pinguis. Allowing for developmental changes on the lines indicated above 
 the two are much alike, but the radial formulas given in the text are not quite 
 in harmony. 
 
1 898.] PLANKTON OF THE FAEROE CHANNEL. 557 
 
 are abdominal. The posterior region of the tail is imperfectly 
 segmented. 
 
 Two less advanced larvee, 6-5 and 4'5 mm. in length, may be 
 taken together. The smallest, fig. 7, has about 31 myomeres, 
 some 14 overlying the alimentary tract. The tail is practically 
 diphycercal. The specimen of 6-5 mm., fig. 6, has the caudal 
 metamorphosis more advanced, and shows an early condition in the 
 development of the anal fin. The alimentary canal is much alike 
 in both, but in the smaller the anterior part is nearly straight. In 
 the larger there is a slight post-cesophageal dilatation, presumably 
 the stomach. This is followed by a (pyloric ?) constriction, distal 
 to which the gut at once expands and is slightly bent towards the 
 left side in front. Posteriorly it tapers to the region of the 
 rectal valve. I cannot detect distinct transverse ridges, but there 
 are some indications of a folding of the lining membrane of the 
 wider anterior part, and I think that this condition may well 
 represent an earlier stage of the voluminous intestinal tract of 
 the more advanced larvae. A large stellate chromatophore in the 
 abdominal roof, about midway between the supposed pylorus and 
 the anus, apparently overlies a small vesicle, not very clearly 
 outlined. This may represent the air-bladder, and there are 
 indications of its connection by a duct with the anterior part of 
 the alimentary canal. In both specimens the marginal fin-fold is 
 much abraded, but is certainly ampullate in its anterior region. 
 
 I have not attempted in my drawings to restore it to what may 
 be presumed to be the natural proportions. The teeth are small 
 and not very numerous. The proportions of the head, rather 
 injured in both specimens, are, I think, correctly represented in 
 the drawing 1 . 
 
 The general conformation, proportions of abdomen, and a sufficient 
 harmony in the number of myomeres seem to reasonably connect 
 these Iarva3 with the smallest (8 mm.) of the series of Scopelus 
 glacialis' 2 . It may be objected that in the undoubted Scopeli of 
 
 II mm. and upwards, the proportions of snout and eye have been 
 shown to change in a manner inverse to that which obtains in the 
 two smallest larvae. I think, however, the increase of the eye is 
 a secondary condition of comparatively recent establishment. In 
 the earliest stages I imagine that the eye and snout retain the 
 proportional metamorphosis common in the development of 
 Teleosteans, the snout gradually elongating as development pro- 
 ceeds. This would go on until the attainment of a condition 
 roughly corresponding to that shown in fig. 5. Thereafter the 
 eye commences to increase in size until the adult proportions are 
 attained. Such a condition appears to me more natural than an 
 entire inversal of the metamorphosis whereby the ordinary pro- 
 portional growth of eye and snout would be reversed from the 
 earliest stage of larval development. In Arnoylossus laterna the 
 
 1 The specimen of 6'5 mm. has only one eye, which, whether naturally or 
 otherwise, is oblique in position. 
 
 - For an intermediate specimen, see note on p. 560. 
 
 PROC. ZOOL. Soc. 1898, No. XXXVII. 37 
 
558 ME. E. W. L. HOLT OX THE [June 21, 
 
 eye of the male is known to enlarge as a secondary sexual 
 character associated with the development of other structural 
 changes ; while according to Grassi * the Common Eel (Anguilla 
 vulgaris) acquires large eyes in deep water and in the Roman 
 cloacae. The secondary enlargement of the eye in Scopelus is 
 thus not without parallels. Scopelus is, I suppose, a form driven 
 from littoral regions to a pelagic and bathybial mode of life, 
 involving an enlargement of the visual apparatus. 
 
 Among the pelagic fishes enumerated by Giinther in -his 
 ' Challenger ' monograph (vol. xxxi.) are mentioned a number of 
 small Scojpeli tnken by the ' Triton 'in the Faeroe Channel (loc. cit. 
 p. 31). While recognizing the close resemblance which these 
 forms bear to &. glacial is, the author considers that certain 
 characters deserve specific distinction, and has accordingly de- 
 scribed them under the name of 8. sections. 
 
 The largest specimen measures 14-5 mm., that is, exactly the 
 same as the S. glacialis shown in figure 1. In the dimensions of 
 the eye (naturally considered by Giinther, in the absence of any 
 information of the developmental changes of this organ, of 
 importance) the two forms are in practical agreement. The 
 contour of the snout apj ears to agree with the corresponding 
 stages in Dr. Fowler's collection. The posterior margin of the 
 preoperculum is described as vertical in S. scoticus, it is rather 
 oblique in S. glacialis. In the characters of the maxilla the two 
 forms agree. The photophore formula is described as identical 
 with that of S. glacialis. In S. scoticus the origin of the dorsal is 
 nearer to the root of the caudal than to the tip of the snout, and 
 is behind that of the pelvics. In S. glacialis of 14-5 mm. the dorsal 
 arises midway between the snout and the caudal ; in a specimen of 
 11 mm. it is a little nearer to the latter ; and comparison of the 
 several young stages suggests that in relation to the two points 
 named there is during development a. slight variety in the position 
 and perhaps- a developmental migration of the fin. It is behind 
 the base of the pelvics even in adults. Younger stages do not 
 differ in any important detail described from those in Dr. Fowler's 
 collection, but specimens of 9 mm. are stated to have the fin-rays 
 perfectly differentiated. In this case the length given appears 
 from the context to include the caudal fin. One specimen of 8 mm. 
 (without caudal) has the rays of the dorsal still unclifferentiated. 
 Individual variation in the degree of development at a given size 
 is, however, x a common feature in Teleostean ontogeny. The 
 radial formula of S. scoticus is stated as D. 10/11, A. 16. That of 
 S. glacialis is, according to Goode and Bean, D. 12-14, A. 16-18. 
 In Dr. Fowler's specimens the formula, as we have seen, is D. 12 
 or 13 to 14 (?), A. 18 and 18 ca., with the exception of one which 
 has only D. 11 or 12, A. 15 or 16. This last specimen is one of 
 the most advanced, in good preservation, and of nearly the same 
 size as another, from which it differs in no detail except the 
 number of fin-rays. I believe that all Dr. Fowler's Scopeli can 
 1 Q. J. M. S. xxxix. 1896, p. 385. 
 
1898.] 
 
 PLANKTOX OF THE FAEROE CHANNEL. 
 
 559 
 
 safely be assigned to S. glacialis, and am strongly inclined to 
 consider that S. scoticus must be relegated to the synonymy of that 
 species. 
 
 In all 15 specimens were obtained on the 'Research/ 
 
 Sta. 
 
 Depth in 
 fathoms. 
 
 Temp. 
 Fahr. 
 
 Spec. 
 
 Length in mm. 
 
 136. 
 
 300-170 
 
 
 1 
 
 14-5 ca. 
 
 13 e x . 
 
 400-270 
 
 32-38 
 
 \l 
 
 6-0, 6-5 ca. 
 11-0 to 14 ca. 
 
 IS 9. 
 
 465-335 
 
 31-33 
 
 
 14-0 ca. 
 
 13 . 
 
 100-0 
 
 48-54 
 
 3 
 
 4-5, 7'5, 8-0. 
 
 1.5.0. 
 
 50-30 
 
 30-53 
 
 1 
 
 58-5. 
 
 16 a. 
 
 350-170 
 
 31-44 
 
 {? 
 
 12ca. 
 la*rger injured. 
 
 19 a. 
 
 480-350 
 
 46-47 
 
 1 14-5. 
 
 20 c. 
 
 400-300 
 
 31-33 
 
 1 13-5. 
 
 1 13 e is suspected of having closed nearer to the surface than the depth here 
 recorded; till all its contents have been identified, it is to be regarded as 
 doubtful. G. H. F. 
 
 Many of these specimens have been more or less injured, but 
 all can be clearly associated with the series which I have described. 
 Giinther, Collett, and Goode and Bean agree in regarding S. <jlaci- 
 alis as a truly bathy trial species ; but Dr. Fowler's self-closing net 
 furnishes us with the first certain evidence of its vertical 
 distribution. It extends evidently to at least 350 fath., the 
 specimen taken at 480 to 350 fath. being one of the most 
 advanced of the series (fig. 1). This latter specimen enables us 
 to add S. glacialis to the British list, the locality lying within 
 Norman's British Area (Ann. Mag. Nat. Hist. 1890, v. p. 345). 
 All the other specimens occurred just outside this area as did also 
 the ' Triton ' specimens ($. scoticus) ; the latter were taken in the 
 Eaeroe Channel " partly with a surface-net at night, partly with 
 the tow-net, which with a line of o50 and 600 fathoms was 
 worked at various depths " in the Cold Area. 
 
 S. glacialis is known from the Northern coasts of Norway, 
 coast of Greenland, Arctic Ocean, and various localities in the 
 American North Atlantic. 
 
 [With regard to the vertical distribution of this species, in the 
 first place, it appears to be essentially a cold-water form. Collett * 
 records it as having been taken by the * Voringen ' once " found 
 floating," and once (three specimens) from 1110 fathoms west -of 
 Hammerfest. Previously to this expedition it had been known 
 only from Greenland and Northern Norway. It has since been 
 taken by the 'Blake' 2 , at considerable depths only, off the coasts of 
 New England and South Carolina, in the cold undertow which 
 passes under the Gulf Stream and whose upper edge forms the 
 Labrador current and its continuation southward. 
 
 1 Norweg. North Atlantic Exped., Fishes, p. 112. 
 
 2 Goode & Bean : Bull. Mus. Comp. Zool. Harvard, x. p. 222 (1883). 
 
 ' 37* 
 
560 Mil. E. W. 3,. HOLT OX THE [J 11118 21, 
 
 Secondly, like many other cold-water forms, it appears to be 
 eurybathic in high latitudes ; the difference in temperature between 
 the superficial and deeper water being comparatively small, and 
 offering no marked thermal barrier to its descent. 
 
 Lastly, a,s regards the Faeroe Channel, it is noticeable that no 
 specimens, larval or adult, were taken at the actual surface in 
 twenty-five hauls ; that the smallest specimen of all was captured 
 nearest to the surface, between 100-0 fathoms (Sta. 13 {.) that 
 other larvae were taken in six out of the thirteen deep hauls, and 
 may thus fairly be ranked among Mesoplankton. One (?) adult 
 specimen was taken in a haul which began at 530 fathoms and 
 finished at the surface ; this unfortunately gives us no help. 
 Although none of the ' Research ' specimens were captured at the 
 surface, still if, as Mr. Holt suggests, Dr. G anther's Scopelus 
 scoticus is identical with these larvae, some larvae come to the 
 surface at night in the Faeroe Channel. 
 
 Though more observations are required for confirmation, still it 
 seems probable that Scopelus glacialis, at any rate as regards the 
 Faeroe Channel, falls into the category of animals which have an 
 early epiplanktonic stage, but frequent greater depths when adult 
 (cf. p. 578, infra). Even in higher latitudes the adult has been 
 most frequently recorded either from considerable depths, or as 
 dead and floating if at the surface. Gr. H. F.] 
 
 [Note added Aug. 1898. The stages shown in figs. 5 & 6 are 
 connected by an intermediate specimen of 7*5 mm., received too 
 late for description in the text. The proportions of the head, eye, 
 and snout are as in the specimen of 8 mm., but the general form 
 is more slender. E. W. L. H.] 
 
 IMPERFECTLY CHARACTERIZED LARVA with very elongate abdo- 
 men. ? MALLOTUS VILLOSUS Miiller. Capelin. (Plate XLV1I. 
 figs. 8-11.) 
 
 These very elongate larvae have at first sight much the 
 appearance of young Eels, but closer inspection soon dispels this 
 illusion. They measure respectively 17, 19 (ca.), and 24'5 mm., 
 from the snout to the extremity of the notochord. I have figured 
 the most advanced, which on the whole is the most perfect 
 specimen of the series. The others differ little in general 
 conformation, but the smallest has the caudal extremity still 
 practically diphycercal, and the marginal fin terminates, without 
 spatulate expansion, in a sharp lanciforin process. The propor- 
 tionate lengths of the abdominal and caudal regions are shown in 
 Plate XL VII. fig. 8 ; it will be seen that the abdomen is about 
 twice as long as the tail, the rectum being thus given off at a point 
 far posterior to median. The fore-brain extends but little in 
 front of the eye, which is only of moderate proportions. The 
 considerable bluntly-rounded rostral region is occupied anteriorly 
 by a large olfactory pouch. The angle of the jaws is opposite the 
 front of the eye. The pectorals are small. The pelvics are 
 indicated by a pair of membranous lobes supported anteriorly by 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 561 
 
 a thickened fleshy rim. They are situate at about the middle of 
 the total length of the larva, and well behind the middle of the 
 abdominal region. The liver occurs as a small pyriform mass 
 shortly behind the clavicle. The alimentary canal, apparently 
 wide and thin-walled in the thoracic region, is soon constricted 
 and thickened. Its ventral wall shows a downward crenulation 
 (about halfway between the clavicle and the pelvics) which may 
 be accidental. At the pelvic region commences a well-marked 
 intestinal tract lined with transverse (annular, perhaps spiral) 
 ridges. The short and rather voluminous rectum leaves the 
 trunk in an oblique direction. 
 
 There are 47 abdominal (counted to the origin of the rectum) 
 and 20 caudal myomeres visible : others may probably be seen 
 at a later stage, but the total number will not be much greater 
 than 67. Black pigment is present in a series of ventral spots, 
 seven in number, distributed at regular intervals from the 
 clavicular region backward. These consist for the most part of a 
 single chromatophore on either side of the gut, but at the shoulder 
 there are several, as also at the region of the rectal valve. The 
 pre-peduncular spot of the tail consists of two ventral and one 
 lateral chromatophore. The caudal fin, both as to the embryonic 
 and permanent parts, is rather profusely decorated with small 
 black dots. The eyes are deeply pigmented. The dorsal marginal 
 fin is wide. Anteriorly it is rather imperfect in the specimen 
 figured. In that of about 19 mm. the fin appears to be ampulla! e 
 anteriorly, and this is probably the natural condition in the others 
 also. There are no signs of the permanent dorsal and anal fins, 
 but embryonic rays occur in the postanal region. 
 
 On comparison of the three examples it would appear that the 
 ventral spots become reduced as development advances. Though 
 identical in number those of the largest individual are relatively 
 considerably smaller than those of the younger. 
 
 I have noticed elsewhere (p. 565 infra) the occurrence in 
 Dr. Fowler's collection of a pelagic egg, which, as far as may be 
 judged from the preserved condition, appears to be practically 
 identical with Baffaele's species No. 7 (Mitth, zool. Stat. Neap, 
 viii. 1888, p. 69). In conformation and in distribution of: pigment 
 the form which we are now dealing with bears a striking likeness 
 to the larva of Sp. 7 (op. cit. tav. v. fig. 9). The ventral spots are 
 numerically equal, and there is an indication in the Faeroe larva of 
 the large " rhomboidal " supra-cephalic sinus described in Sp. 7. 
 The latter is stated to have 59 or 60 abdominal segments, a 
 condition which indicates that the total number is considerably 
 in excess of that present in the much more advanced Faeroe larva, 
 and so disposes of the possibility of the formula being harmonized 
 in the two forms by a developmental migration of the anus. The 
 marginal fin, though wider in the Faeroe larva), terminates, in the 
 youngest example, as in Sp. 7 ; and in the anterior dorsal region 
 appears to be inflated alike in both forms. But none of the 
 Faeroe larvae show any trace of the prodigious buccal armature of 
 Sp. 7. The teeth, on the contrary, are quite small.! 
 
562 MB. E. w. L. HOLT ox THE [June 21 , 
 
 Sp. 7 is one of a group of ova and larvae which liaffaele 
 considered to exhibit Muraenoid affinities ; and Grassi has practically 
 confirmed the correctness of this view in the case of at least one 
 species, No. 10, which he has connected with Anguilla vulgaris. 
 Moreover it appears probable that all Muraenid larvae pass through 
 a Leptocephalus-st&gQ, losing the buccal armature of what Grassi 
 terms the pre-larval condition. I imagine that it is impossible to 
 connect the Eaeroe larvae with either end of a Leptocephaline 
 metamorphosis ; while the condition of the intestine and the 
 caudal fin suggest for them affinities which are not Muraenoid. 
 The presence of pelvic fins can hardly be held to prove that they 
 are not Muraenoids ; at least until Grassi shall have found that 
 such structures never occur as vestigial phenomena in the 
 development of Eels l . 
 
 In 1893 my friend Captain F. Klotz, s.s. ' Dominican,' brought 
 me a number of young fish which he had taken at the surface off 
 the West Horn of Iceland on the 27th July. They range in size 
 from 36 to 57 mm., and in general shape have much the 
 appearance of Sand-eels (Ammodytes). The collection is suffi- 
 ciently serial to show that only one species is present, while the 
 largest appear to associate themselves with the Gapelin, Mallotus 
 villosus. I have figured the head of the smallest (fig. 9), a 
 specimen of 42-5 mm. (fig. 10), and the largest (fig. 11). The 
 radial formula of the largest appears to be D. 12 (or a few more), 
 A. 21. This specimen has 64 myomeres (perhaps more, as the 
 pectoral region is lacerated) exclusive of the peduncular part of 
 the tail, where a few others are probably present, though not 
 sufficiently defined to be counted. About 49 are abdominal. 
 From the ocular region backward the head is distinctly trigonal 
 in section, the upper surface being flat while the sides approach 
 each other ventrally. Though this is rather less marked in the 
 buccal region, there is a distinct approach to the conformation (a 
 three-sided pyramid) described by Sinitt (Hist. Scand. Fish. ed. 2, 
 p. 877) as characteristic of the head of the adult Capelin. The 
 sides of the body are compressed and flattened, while the dorsum 
 is also rather flat. Mallotus has the radial formula D. 12-16, 
 A. 18-25 ; the vertebrae are from 65 to 70. In general proportions 
 and in the relative position of the fins the oldest Iceland specimen 
 is in agreement with Mallotus (compare Sinitt's figures of the 
 latter, op. cit. pi. xli. with my figure 11). The Iceland specimens 
 are a good deal damaged and none have any scales on the body, 
 but there are traces of them on the gill-cover of the largest. The 
 teeth are small, and there is no distinct notch in the premaxillary 
 region for the reception of the mandibular extremity. 
 
 Beyond a few remarks of Collett's, quoted by Smitt, I have not 
 found any description of the young stages of Mallotus. Our 
 
 1 Liilken (" Spol. Atlant , Changements de forme chez IPS Poissons," Vid. Selsk. 
 Skr. 5. Ksekke, 1880, p. f>94) considers that pelvic fics probably exist in the 
 young of all species of Trichiurtis, though their presence is only indicated in 
 the adult of one species. 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 563 
 
 Iceland forms show a certain resemblance to the genera Paralept* 
 and Sudis. Paralepis borealis is known from Greenland, Iceland, 
 and the North-American coast. Apart from other differences, the 
 excessive number of anal rays and the large size of the teeth (vide 
 Groode & Bean, Ocean. Ichth. p. 119, fig. 148) serve to separate 
 it from the forms before us. P. coregonoides has occurred in the 
 Mediterranean and on the American Atlantic coast, and may well 
 exist in Boreal European waters. It appears to agree better than 
 the last with the Iceland forms, but has the generic character of 
 very large teeth. P. sphyrcenoides, from the Mediterranean and 
 Madeira, has 30 anal rays. I cannot ascertain the vertebral 
 formula of any of these species. Under the name of Sudis 
 atlanlicus Smitt gives a brief account, derived from Krb'yer, of 
 a fish washed ashore at the Skaw. It had 20 anal rays, and so 
 far as I can judge its young stage might bear some resemblance to 
 the Iceland specimens. The balance of probability,' however, 
 appears to me to favour the association of the latter with Mallotus 
 villosus x , although, so far as I know, the Capelin has never been 
 recorded from Iceland. 
 
 The smallest Iceland specimens bear a considerable resemblance 
 to the largest of Dr. Fowler's larvsB. In the latter (fig. 8) the 
 snout is obtuse aad rounded except at the extremity. In the 
 former (fig. 9) the snout is more pointed, but still somewhat 
 rounded superiorly. A depression behind the eyes indicates the 
 collapse of a sinus over the hind-brain, such as seems to have been 
 also present in the Faeroe larvae. The specimen 36 mm. long has 
 the greatest height of the body only 2*5 mm. ; the form being thus 
 extremely elongate. The gradual increase in height is illustrated 
 in figs. 10 and 11. 
 
 Most of the Iceland forms have only a few chromatophores 
 scattered along the ventral surface, but one, about 42 mm., has a 
 number rather widely diffused over the general surface of the head 
 and body. How far the generally unpigmented condition is 
 natural I cannot say. 
 
 A size-interval of 11*5 mm. separates the largest of the Faeroe 
 larvae from the smallest of the Iceland series. Since in the former 
 the isolated vspots of the ventrurn appear to be in process of 
 reduction, their absence in the latter is not necessarily a bar to 
 the association of two series. The Faeroe larva? have certainly a 
 a smaller eye than the Iceland forms, but we have evidence of a 
 developmental increase in the size of this organ in Scopelus which 
 may well be repeated in other fishes of similar environment. In 
 the Iceland series the proportions of the eye are variable ; but in 
 the larger and more perfect examples an increase is associated 
 
 1 Dr. Gunther considers that a number of larval forms, corresponding to 
 Kichardson's genus Prymnothonus (vide Chall. Rep., Zool. xxxi. Pelag. Fish. p. 39, 
 pi. v.), " represent larval conditions of fishes belonging to Paralepis or Siidis or 
 of genera allied to them." T venture to suggest that in the genera named the 
 abdomen will be found to be much more elongate, from the earliest stages, than 
 in Prymnothonus. 
 
564 MR. E. W. L. HOLT ON THE [JuU6 21 , 
 
 with advance of general development. In the number of myomeres 
 both Faeroe and Iceland forms agree well enough with Mallotus. 
 
 The latter has not been recorded from any point nearer to the 
 Faeroe Channel than the coast of Norway, but appears to be a fish 
 of pelagic habit, approaching the coast only for the purpose of 
 spawning. The ova are demersal, and it may be objected that our 
 Faeroe larvae are too young to be found so far from land. This 
 objection depends for its validity on a knowledge of the rate of 
 growth, which is not forthcoming. 
 
 Although I think I have demonstrated the possibility of 
 connecting the Faeroe larvse, through intermediate stages as 
 represented by the Iceland series, with the adult form of Mallotus 
 villosus, I do not think we are justified in considering the question 
 settled. The fact is that we know next to nothing of the 
 development of many marine forms and especially of the pelagic 
 and bathybial species, nor can it be supposed likely that a few 
 sporadic cruises have furnished us with an even approximately 
 complete list of the fish-fauna of the Faeroe Channel. In all proba- 
 bility there is a strong resemblance between the larvse of many 
 pbysostouious fishes, however widely they may be separated in the 
 adult condition. Of the method of reproduction of bathybial 
 fishes, whether by pelagic or demersal ova, we are in most cases 
 ignorant. The characters of the Faeroe larva, though probably 
 sufficient to exclude it from the Mura3iiida3, are such as might 
 occur equally in a Salrnonoid, Scopeloid, or Clupeoid. Any 
 Clupeoids known as inhabitants of the region may be eliminated, 
 since we know the larval stages of all of them. The same remark 
 applies, as I think, to Argentina spliyrcma ; specimens of 37 mm. 
 have already acquired the adult conformation 1 , though only about 
 13 mm. longer than the Faeroe example, which is still practically 
 undifferentiated. The size-interval does not appear sufficient, and 
 1 imagine that this species of Argentina has a shorter larva, with, 
 of course, fewer myomeres. A. situs has 65 to 68 vertebras and 
 is a much larger fish. It may conceivably pass through a larval 
 stage like the Faeroe form if its pelvic fins undergo an anterior 
 migration. Among the Scopeloids Stomias is an elongate form, 
 and S. ferox has been recorded by Giirither from the Faeroe 
 Channel (Chall. xxxi. op. cit. p. 31). 
 
 However, the example in question, though capable of even 
 specific determination, was again only 37 mm. in length ; \i hile I 
 can find in the Faeroe larva of 24-5 mm. no trace of the barbel 
 and enlarged teeth of Stomias. I have already referred to the 
 characters of the Paralepidce, and the enumeration might be 
 prolonged but always without bringing us, for the present, any 
 nearer to a definite conclusion. 
 
 Dr. Fowler's specimens were taken as follows : 
 
 13 i. 60 2' N., 5 C 49' W. 100 to fathoms. Two, 19 and 
 24'5 mm. 
 
 20 c. CO C 16' K, 5 49' W. 400 to 300 fathoms. One, 17 mm. 
 
 1 Holt & Calclerwood, Trans. E. Dubl. Soc. ser. 2, v. 1895, p. 5C9, fig. J. 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 565' 
 
 If they prove to be young Mallotus it will have been shown 
 that form is capable of descending below the 300-fathom line. 
 The localities are just outside the British area. 
 
 A PELAGIC EGG, resembling Eaffaele's species No. 7. 
 
 ?Eaffaele, Mittheil. zool. Stat. Neap. viii. 1888, p. 69, tav. 5. 
 Undetermined species no. 7. 
 
 Dr. Fowler's collection contains only one egg, which is quite 
 unlike any that has been recorded from British or Northern 
 European coasts. Preserved in a weak solution of formaldehyde, 
 it was not sufficiently transparent for an exact determination of 
 the internal structure. It was therefore passed through the 
 usual reagents into oil of cloves, a process which unfortunately 
 involved a complete collapse of the zona radiata. An attempt to 
 remove the latter without injury to the contents was only partially 
 successful. The characters, as observed during the whole process 
 of manipulation, appear to be as follow : 
 
 The diameter is 3-5 inm., the shape approximately spherical. 
 The zona is thin and probably without any distinctive feature, 
 since some bubble-like markings present on one part appear to be 
 due to the adherence of a thin layer of yolk-matter. The peri- 
 vitelline space is certainly large, but the exact dimensions of the 
 yolk had been obscured by rupture either in the net or by the 
 action of formaldehyde. The embryo remains attached to a 
 pyriform yolk-mass 1*19 mm. by '90 mm., the narrow end under- 
 lying the head. The yolk is divided throughout into small rounded 
 segments of irregular size, and appeared to possess, as seen in 
 formaldehyde, a number of small oil-globules aggregated together. 
 The embryo is advanced and has a considerable free tail, closely 
 apposed to the yolk. Its total length may be estimated at about 
 2-40 mm. There appears to be no pigment. Any distinctive 
 characters which may have been present could not be observed 
 before the removal of the zona ; and the specimen was too much 
 injured in this process to admit of a reliable observation of the 
 embryo. 
 
 Sufficient, however, has been noted to show that the egg agrees 
 very closely, both in dimensions and other characters, with 
 Eaffaele's species no. 7. Grassi's researches * have confirmed 
 Eaffaele's suggestion of a Muraenoid parentage for at least some 
 of the group of evidently allied ova to which no. 7 belongs, one of 
 them, no. 10, having been connected in a practically conclusive 
 manner with the Common Eel (Anguilla vulgaris). 
 
 No observer has yet described the perfectly ripe egg of the 
 Conger (C. vulgaris), nor has any attempt been made to identify 
 with this abundant and rather valuable form any egg taken 
 in the tow-net. It appears from Cunningham's description 
 (Q. J. M. S. xl. p. 155) that the ripe egg probably differs from 
 that of Anguilla in possessing one or more oil-globules, and 
 therein agrees with Eaffaele's sp. 7 and with the egg from the 
 1 Q. J. M. S. xxxix. p. 371. 
 
566 ON THE PLANKTON OF THE FAEROE CHANNEL. [June 21, 
 
 Faeroe Channel. In eggs characterized by a large perivitelliue 
 space, such as those of Hippoglossoides and some species of Clupea, 
 the expansion of the zona is known to be accomplished after 
 deposition. The difference of dimension of the yolk-mass, as 
 between sp. 7, the Faeroe Channel egg, and the largest eggs 
 obtained by Cunningham from the Conger *, does not appear to be 
 considerable. The specific identity of the three appears at least 
 possible. 
 
 On the other hand, it may well be that Baffaele's group of eggs 
 belongs in fact to more than one family of physostomous fishes. 
 I have described from Dr. Fowler's collection a series of larvae, 
 which are apparently not Eels, but which in conformation and 
 pigment agree rather closely with the larva of Baffaele's no. 7, 
 though they entirely lack the peculiar buccal armature of the 
 latter. Such armature is, in the Eels, a very temporary pheno- 
 menon, the leptocephaline condition being devoid of it. 
 
 To attempt to connect the Faeroe egg with the elongate larva 
 from the same region were simply an unprofitable speculation ; 
 but it may be suggested that the characters of segmented yolk 
 and large perivitelline space, common to Mursenidse and Clupeidae, 
 may be equally present in the ova of Scopeloids and of such, it' 
 any, Salmonoids as propagate by means of pelagic eggs. In point 
 of attenuation I know no larvae more eel-like than some of the 
 Clupeoids. I do not suppose that the egg with which we are 
 dealing is that of a Clupeoid, but, whether it be identical with 
 Baffaele's no. 7, or different, our knowledge of the development 
 of the pelagic and bathybial members of the other groups 
 mentioned is hardly such as to permit us to definitely assign it to 
 any one of them. Mallotus, which I have suggested as a possible 
 parent of the elongate larva, is known to deposit ova which are 
 demersal in littoral waters. If any description of their structure 
 exists I have not seen it. 
 
 EXPLANATION OF THE PLATES. 
 
 PLATE XLVI. 
 Fig. 1. Scopelus, glacialis, 14'5 mm., p. 552. Formol. 
 
 2. ,, ,, 12mm. Formol. 
 
 3. irSmm. Formol. The larval sinus in front of 
 
 the dorsal fin rather collapsed. 
 
 4. Dorsal view of the same specimen. Formol. 
 
 5. 8. glacialis, 8 mm. Oil of cloves. 
 
 PLATE XLVII. 
 Fig. 6. S. glacialis, 6'5 mm., p. 552. Oil of cloves. 
 
 7. ,, 4'5 mm. Oil of cloves. 
 
 8. Larva with elongate abdomen, 24'5 mm., p. 560. Oil of cloves. 
 
 9. Head of young Mallotus villosus ?, 36 n.m., p. f60. From Iceland. 
 
 Alcohol. 
 
 10. Young M. villows?, 42'5 mm., p. 560. From Iceland. ^Iccl ol. 
 
 11. ,, 57 Him. From Iceland. Alcohol. Natural size. 
 
 12. Young Gadus ceglefmus, 8 mm., p. 551. Formol. 
 
 1 Cf. Journ. M. B. A., n. s. ii. 1891, pp. 24 25. 
 
1898. J ON THE PLANKTON OF THE FAEROE CHANNEL. '567 
 
 6. Contributions to our Knowledge of the Plankton of the 
 Faeroe Channel. No. VI. 1 Description of a new Mid- 
 water Tow-net. Discussion of the Mid-water Fauna 
 (Mesoplankton). Notes on Doliolum tritonis and 
 D. nationalist and on Parathemisto abyssorum. By G. 
 HERBERT FOWLER, B.A., Ph.D., Assistant Professor of 
 Zoology, University College, London. 
 
 [Eeceived June 18, 1898.] 
 
 In the first paper of this series, I proposed to leave the de- 
 scription of the mid-water nets used, and the discussion of the 
 general question of the existence of a mid-water fauna or Meso- 
 plankton, until the collections made on the ' Research ' had been 
 thoroughly investigated. The net which I used last year proved 
 so successful in actual working, that it now seems to me better 
 to describe it at once for the information of other investigators, 
 who might give it a further trial ; the more so since my leisure 
 for research work is but small, and the collections cannot be 
 completely finished for some months to come. 
 
 It is unnecessary to describe here the numerous and varied forms 
 of apparatus which have been devised for the capture of animals at 
 known mid- water depths without admixture of the fauna from other 
 zones. References to them will be found, by those interested, 
 in the papers of Hoyle 2 , H.H. the Prince of Monaco 3 , and 
 Agassiz 4 ; since the appearance of the last-named, a full description 
 of the 'National' apparatus has been published by Hen sen *. 
 Agassiz, in the paper cited, has subjected the earlier forms of net 
 to a searching criticism, with which I agree on the whole ; except 
 that of the Prince of Monaco and that of the ' National/ none 
 appear to exclude satisfactorily animals from undesirable zones. 
 Even that of the Prince of Monaco does not appear to have 
 worked satisfactorily on the * Pola'; and the modification of Chun's 
 net used on the ' National'' was uncertain in its action 5 . 
 
 When desirous to study for myself the question of a mid-water 
 fauna or Mesoplankton 6 , I feared that both the nets last quoted 
 were too expensive, and the * National ' net too complicated for 
 use in such heavy seas as are generally to be found in the Faeroe 
 Channel, the only deep-water readily accessible to me. Returning 
 therefore to Chun's 7 original ingenious design as a starting 
 
 For Part I., see P Z. S. 1896, p. 991 ; Part II., P. Z. S. 1897, p. 523 ; Part 
 III., P. Z.S. 1897, p. 803 ; Part IV., antea, p. 540; Part V., antea, p. 550. 
 - Proc. Liverpool Biol. Soc. iii. 100. 
 
 3 OR. Congres international de Zoologie, Paris, 1889, p. 133. 
 
 4 Bull. Mus. Comp. Zool. Harvard, xxiii. 1. 
 
 5 Ergebnisse d. Plankton Exped. : Methodik der "Tntersuchungen p. 103 
 et seqq. (1895). 
 
 6 For the explanation of this and similar new terms used here, seep. 54o ante. 
 ~ C. Chun : Bibliotheca Zoologica, i. 1 
 
568 DE. G. H. FOWLER ON THE [June 21, 
 
 point, I endeavoured to introduce into it such improvements as 
 would obviate what appeared to me to be its weaknesses, namely : 
 (1) The position of the wires when the net had shut, which 
 necessitate the mouth being always slightly open ; (2) the lack of 
 power to keep the net-mouth shut in a roll of the ship or a check 
 on the line, as the attachments of the wires by which it then hangs 
 are so close together; (3) the speed at which the whole structure 
 must be towed in order that the screw-propeller, and the rod to 
 which it is fixed, may overcome the frictional resistance offered by 
 the rings on which the weight of the net is hanging. 
 
 I decided to construct a net for vertical and not for horizontal 
 use, because it seems to me, on the basis of my small experience, 
 impossible to be certain of the depth at which a net is being towed 
 horizontally. The usual method for this is to lower the net 
 vertically, and to begin towing with the rope straight up and down ; 
 then to observe the angle made by the rope with the horizon by 
 means of a quadrant, and to calculate the vertical depth of the net 
 by traverse tables on the assumption that the towing-line is the 
 hypotenuse of a right-angled triangle. Unfortunately for this 
 method, however, the towing-rope is not a hypotenuse, but 
 forms an unknown catenary, which varies with the weight of the 
 net, its resistance to the w ? ater, and the pace of towing ; this forms 
 an increasing source of error, the greater is the length of towing- 
 warp out. As an example of the uncertainty of this method, I 
 struck bottom at 398 fathoms in the Faeroe Channel, when by 
 quadrant and traverse tables the net should have been at 300 
 fathoms with 450 fathoms of rope out. There are so many forces 
 at work as to make it impossible for any but a highly skilled mathe- 
 matician to calculate the probable position of the net, and this 
 only after tedious experiment. 
 
 Description of the Apparatus. 
 
 This consists of the net, the net-frame and chains, and the 
 locking-gear. As the first of these were used both in 1896 and 
 1897, they will be described in detail ; the locking-gear of the 
 
 1896 pattern will only be sufficiently sketched to enable future 
 workers in this field to profit by my experience of failures ; the 
 
 1897 pattern will be fully described. 
 
 The net is made of Swiss Silk Boulting Cloth, by far the best 
 material known to zoologists for every form of tow-net ; it was 
 supplied by Messrs. Staniar of the Manchester Wire Works ; this 
 material will stand almost any fair pull, but, as it is very liable to 
 be cut by anything sharp, when coming inboard, the actual net 
 is surrounded by a loose case of common mosquito-netting. A net 
 with a twenty-inch square mouth, tapered to a four-inch diameter 
 cod-end, and six feet in length, was found to be a good working 
 size. It should be sewn throughout by hand, not by machine; 
 and with strong sewing-silk, not thread. If washed nightly in 
 fresh water and dried in the air, a net of this sort will last for a 
 very long time. 
 
1898.] PLANKTON OF THE FA.EROE CHANNEL. 
 
 569: 
 
 FiC. 3* 
 
 G. H, F. del. 
 
570 DR. G. H. FOWLER OTf THE [June 21 , 
 
 As a mid-water net has to be drawn up by a steam-winch more 
 rapidly than is usual with a surface tow-net, even when the winch 
 is going its slowest, boulting cloth of twenty-five (1896) and forty 
 (1897) meshes to the inch was selected ; of these the second is 
 stronger and more efficient. If the winding-drum can be run dead 
 slow by gearing, 50 or even 60 meshes to the inch might be used. 
 A calico band at the mouth pierced by lacing-holes, and a calico 
 band at the cod-end, with a tape by which the collecting zinc pot 
 is tied in, complete the net. The tape should run in loops outside 
 the calico band, it is there much easier to untie with cold wet 
 fingers. 
 
 The net-frame (fig. 1, where it is represented as half open) 
 consists of two ( ! | shaped phosphor-bronze castings BB' hinged 
 together on a solid brass axle C ; on to the latter is also hinged, 
 outside BB', a wrought iron | | shaped piece A, which is rather 
 larger than the other two. The arms bb of BB' are drilled to take 
 shackle-bolts from which chains pass upward to the locking-gear; 
 two holes are also drilled at aa for similar shackle-bolts and chains. 
 The net-frame in its descent is suspended from bb, and is therefore 
 tightly closed by its own weight (about 15 Ibs.) and by any additional 
 weight that may be hung on the axle, the arms pressing BB' firmly 
 together ; when the chains from bb are slacked by the locking-gear, 
 the net falls for a short distance, the weight is caught on to the 
 chains from aa, and the net-mouth either falls open, or opens on 
 the slightest pull in towing. The whole apparatus is then 
 hauled upwards through the zone which it is desired to investigate 
 (generally 100 fathoms). The chains from aa are then slacked by 
 the locking-gear, the net falls a second time, and the weight, being 
 caught on the chains from bb, again closes the net effectively. 
 
 In fig. 2 the sectional dimensions of A, B, B' are given, the net- 
 frame being represented as closed. The upper end of the net 
 itself, laced inside the frame, is compressed into the space between 
 B and B' ; the dotted lines indicate the lacing-holes drilled 
 through the frame at intervals of an inch. When it is closed, only 
 a Protozoan could get through the net-mouth, and even that would 
 find a difficulty. B and B' when open form a mouth twenty inches 
 square (inside measurement) ; A is | inch outside them when closed. 
 The arms bb are seven inches long, and effect a good leverage for 
 closing the net. They form one of the most important improve- 
 ments on the original pattern. Even shaking the frame violently 
 up and down when held by the chains does not open the net. 
 
 [The locking-gear of the 1 896 pattern was arranged as follows : 
 Through the chains from aa and bb were passed the hammers of 
 two reversed gun-lock movements, the hammer rising when fired ; 
 the lock of the bb chains was placed vertically below that of the 
 aa chains. Parallel to the vertical between these two ran a long 
 steel rod, tapped with a screw-thread : at the lower end of the 
 steel rod was a screw-propeller, arranged so as not to revolve 
 during the descent of the apparatus. When hauled upwards, 
 however, the propeller began to revolve, travelled up the steel rod. 
 
1898.] PLANKTON OP THE EA.EROE CHA.TSTXEL. 571 
 
 and fired the trigger of the lower lock-movement, thus slackening 
 the bb chains and allowing the net frame to fall open ; still 
 travelling upwards, as the apparatus was hauled in, the propeller 
 presently fired the trigger of the upper lock-movement, slacked 
 the aa chains, and the net then closed. The whole apparatus was 
 prevented from spinning in its descent, and thus causing the 
 propeller to begin travelling too soon, by being suspended from a 
 swivel which worked on ball-bearings. 
 
 This arrangement worked successfully in about three hauls out 
 of four, the failures being generally due to one or both chains 
 hanging on the hammer, even when the lock-movement had been 
 fired, owing to the great friction of the chains on the hammers. 
 A further disadvantage in the apparatus was the difficult ad- 
 justment of the distance between the triggers, which determined 
 the distance in fathoms for which the net remained open ; th's 
 further had a tendency to vary somewhat with the rate of 
 hauling in.] 
 
 In designing the locking-gear of the 1897 pattern I therefore 
 abandoned the propeller in favour of messengers, which I had 
 originally avoided on the grounds of others' experience with the 
 light messengers of deep-sea thermometers. There seems, how- 
 ever, to be no objection to the use of heavy messengers on any 
 well-stretched rope (hemp or wire) which hangs free of the 
 bottom, and in which kinks are thus avoided by the maintenance 
 of a steady strain. 
 
 Photographs of the whole apparatus are given on pnge 572. 
 Details of the locking-gear are furnished by figs. 3 a, 3 b (p. 569), 
 which are sectional drawings at right angles to one another. They 
 are carefully drawn to scale, about one-seventh of the real size. 
 
 Four vertical pillars of teak l T, connected below by two cross- 
 pieces of the same material T', and strengthened by iron plates at 
 the angles, form a rigid frame ; on to this is screwed a brass 
 casting D, to which a second casting E is screwed. The rope by 
 which the machine is slung passes through a hole in the centre of 
 D into the space R between D and E, and is kept there by being 
 worked into a broad knot. 
 
 Two brass cylindrical rods or pins FF (fig. 3 ) run in two good 
 bearings through D and are rigidly bolted into a cross-piece which 
 carries a third shorter pin a, travelling in bearings through the 
 centre of E. The pin a is passed through the chains from aa on 
 the net-frame, and is kept in place by springs (not drawn) between 
 the hooks shown in fig. 3 a with a pull of about 10 Ibs. If a weight 
 be dropped on to the pins FF, it will overcome the springs, depress 
 the pin a, and let go the chains from aa. 
 
 A second pair of pins GGr (fig. 3 b~) run in bearings through D, 
 and through another casting H which is bolted to TT. They are 
 rigidly bolted to a cross-piece which carries a third pin b, travelling 
 in bearings through the centre of H ; this pin is passed through 
 
 1 Teak is one of the few woods that will resist the enormous pressure at 
 great depths ; less closely grained woods warp and split. 
 
DR. G. H. FOWLER ON THE 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 573 
 
 the chains from bb on the arms of the net-frame, and is kept in 
 place by springs (rubber loops) between the hooks shown in 
 fig. 3 b, with a pull of about 10 Ibs. If a weight be dropped on to 
 the pins GG, it will overcome the springs, depress the the pin b, 
 and let go the chains from bb. 
 
 The apparatus is worked thus : The whole machine is lowered 
 with the locking-gear in the position drawn in figure 4, the chains 
 aa held on the pin a, but not carrying the weight of the net 
 and frame ; the chains bb held on the pin b, and holding the net- 
 frame tightly closed by its own weight. When the machine is at 
 the bottom of the zone which it is desired to study, the first 
 messenger is despatched down the rope ; this, being small, drops 
 into the nest N, striking on the pins GG, and freeing the chains 
 bb ; the net-frame falls 6 inches, and opens, the weight being 
 caught with a jerk on the chains aa. 
 
 The machine in this condition (fig. 5) is hauled upwards for a 
 hundred fathoms ; the second and larger messenger is despatched, 
 which, striking on the pins FP, frees the chains aa ; the net 
 falls 15 inches, the weight is caught again on the chains bb ; the 
 net-frame closes, and can be then hauled in-board without any 
 admixture with the fauna of higher zones (fig. 6). 
 
 The chains of course are not let go altogether, as the net and 
 frame would then be lost ; each chain has a large link in it to go 
 over its pin, and beyond this a short length by which it is bolted 
 to T or a shackle-bolt in the centre of T'. 
 
 Chains aa. Chains bb. 
 
 From net-frame to pin 33 in. 23 in. 
 
 Prom pin to T 9-5 in. 
 
 From pin to central bolt of T' 12 in. 
 
 The messengers used in 1897 were clumsy and unnecessarily 
 heavy, and will not be described here. Probably weights of 4 Ibs. 
 for the smaller arid 6 Ibs for the larger are amply sufficient on 
 rope : smaller weights would do on wire, since the friction is less. 
 
 The apparatus was tested in 1897 on H.M.S. ' Research/ but, 
 unfortunately, owing to heavy weather, we were only able to spend 
 one day in the deep water of the Faroe Channel ; the apparatus 
 was tried four tiroes, and seemed to work perfectly. The only 
 improvement which suggested itself was that a weight should be 
 hung from the axle C into the middle of the net, heavy enough to 
 prevent the net in its descent from washing up into the machinery 
 (which happened once, but without serious consequences) ; the 
 additional weight at this point will also serve to shut the net- 
 mouth more closely, and can also be arranged to prevent the sides 
 of the net compressing the contents when closed. Should the 
 first messenger strike FF before GG, the net would simply come 
 up empty, having been open only for a few seconds. 
 
 Weight of net-frame 16| Ibs. ; of locking-gear and chains 33 Ibs. ; 
 of messengers used in 1897 (7| + 10) 17| Ibs. ; of messengers for 
 . ZOOL. Soc. 1898, No^ XXXVHI, 38 
 
574 DE. G. H. FOWLER ON THE [June 21, 
 
 future use (4+6) 10 Ibs. ; suggested above to be added at T'T', 
 10 Ibs., and to be hung on C, 10 Ibs. : total about 80 Ibs. 
 
 At the conclusion of the four hauls, the net was sent down to 
 100 fathoms, and hauled up without the messengers having been 
 despatched ; it came up empty, although it had passed through 
 the stratum where life w T as probably most plentiful. I am unable 
 to see any source of error in the working of this apparatus, but 
 hope that it may be given a further trial before long *. Of course, 
 with an apparatus half a mile away from one in water, one cannot 
 see what is actually occurring ; one can only take precautions 
 against every possible source of error, and may judge of their 
 success to some extent by the character of the animals obtained. 
 
 Conclusions of Prof. Agassiz : the Azoic Zone. 
 
 In discussing the general results of the ' Albatross ' Expedition in 
 1891 2 , Prof. Agassi/, reviewed the apparatus used and conclusions 
 attained by earlier naturalists who had attempted a solution of the 
 question of a Mesoplankton. His own views are based on experi- 
 ments made during the cruises of the ' Blake' (1877-80) and the 
 * Albatross ' (1891). On the first of these vessels he used the gravi- 
 tating-trap 3 invented by Lieutenant-Commander (now Captain) 
 Sigsbee, which not only failed to catch living organisms between 100 
 and 150 fathoms, but apparently missed even the corpses of the dead 
 surface fauna ! The machine is only stated to have been tried on 
 two occasions, and only to a depth of 150 fathoms ; from this 
 Agassiz concluded 4 (p. 37) that " these experiments serve to 
 prove that the pelagic fauna does not extend to considerable 
 depths, and that there is at sea an immense intermediate belt in 
 which no living animals are found, nothing but the dead bodies 
 which are on their way to the bottom." On the ' Albatross ' a 
 new apparatus was tried, the invention of Captain Tanner, which 
 is fully described and figured by Prof. Agassiz. On the basis of 
 this he states 4 (p. 55) : " Our experience in the Grulf of Cali- 
 fornia with the Tanner self-closing net would seem to indicate 
 that in a comparatively closed sea, at a small distance from the 
 land, there may be a mixture of the surface species with the free- 
 swimming deep sea bottom species, a condition of things which 
 certainly does not exist at sea, in deep water, in an oceanic basin at 
 a great distance from shore, where the surface pelagic fauna only 
 
 1 The cost of the apparatus should come to about 10, now that the patterns 
 for casting have been made. If any zoologist will give it a further trial, I shall 
 be glad to superintend its manufacture. 
 
 Sirce the above was written, my net has been taken for a further trial by 
 the German Expedition which sailed on August 1st under Prof. Chun's 
 direction, and Prof. Max Weber has ordered a net for the Dutch East-Indian 
 Expedition. 
 
 2 Bull. Mus. Comp. Zool. Harvard, xxiii. 1. 
 
 3 Bull. Mus. Comp. Zool. Harvard, xiv. 36 (=' Three Cruises of the Blake,' 
 vol. i. p. 36, London, 1888, 8vo). 
 
 4 Bull. Mus. Comp. Zool. Harvard, xxiii. 1, 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 575 
 
 descends to a comparatively small depth, i. e. about 200 fathoms, 
 the limits of the depth at which light and heat produce any con- 
 siderable variation in the physical conditions of the water. The 
 marked diminution in the number of species below 200 fathoms 
 agrees fairly with the results of the * National ' Expedition." 
 
 The other experiments with the Tanner net, made in an oceanic 
 basin on the way to Acapulco from the Galapagos, and to the 
 G-alapagos from Cape San Francisco, " seem to prove conclusively 
 that in the open sea, even when close to the land, the surface 
 pelagic fauna does not descend far beyond a depth of 200 fatho ns, 
 and that there is no intermediate pelagic fauna living between 
 that depth and the bottom, and that even the free-swimming 
 bottom-species do not rise to any great distance, as we found no 
 trace of anything within 60 fathoms from the bottom, where it 
 had been fairly populated." 
 
 Prof. Agassiz therefore admits the existence of a deep Meso- 
 plankton near land, but does not state how far from land and in 
 what depth of water his generalization of an Azoic zone begins to 
 hold good. I do not know of any later pronouncement by this 
 eminent oceanographer on the question. Since then, Captain 
 Tanner has improved his original pattern in detail \ but the prin- 
 ciple of his net remains the same. It is rash, and perhaps a little 
 ungracious, to criticize the working of a net which one has never 
 seen ; but I venture to suggest, on the basis of the drawings and 
 description of the Tanner nets, that a weak point in them is the 
 way in which the tripping lines are suspended ; it seems that it 
 would be so very easy for them to slip oif from the tumbler and 
 c. ] ose the net before they were intended to do so, under the alter- 
 nate strain and slackening of the warp as the ship rolls ; it also 
 seems likely, and indeed Captain Tanner himself admits, that the 
 angle made sometimes by the net-frame in turning would practically 
 close the net's mouth. As regards the Sigsbee gravitating trap, 
 there can, I think, be little doubt that it w r as too small and too 
 violent to throw much light on the question of an Azoic zone. 
 
 Conclusions of the ' Challenger' and other Naturalists: 
 the Mesoplankton. 
 
 Prof. Agassiz may be regarded as the chief representative of the 
 school of naturalists which refuses to accept the alleged existence 
 of a Mesoplankton. The chief supporters of the opposite view 
 are the ' Challenger ' naturalists (a distinguished band, of whom 
 Sir John Murray is alone left), Prof. Chun, and Profs. Hensen 
 and Brandt of the c National ' staff. 
 
 The ' Challenger ' naturalists arrived at their belief from a com- 
 parison of serial tow-nets, stopped at intervals along the dredge- 
 rope. As all the tow-nets were open throughout their course, the 
 presence of particular species in the deep nets only seemed to 
 indicate thai: these species occurred in the deep water only. The 
 
 1 Z. L. Tanner, Bull. U.S. Fish Commission, xiv. p. 148. 
 
576 DR. G. it. FOWLER ON THE [June 21, 
 
 method is theoretically excellent *, but is not certain enough for 
 use as an argument against the negative observations of the ' Blake ' 
 and 'Albatross.' 
 
 While I am fully in agreement with Professor Chun's results, it 
 must be admitted that the original pattern of his net was not 
 devoid of sources of error, which Agassiz was not slow to point 
 out. Chun reported 2 an abundant fauna from all depths in the 
 Mediterranean, but, this being a warm closed sea with a uniform 
 temperature of 55 or 56 E. from. 100 down to 2400 fathoms and 
 more, no thermal barriers are here set to the vertical descent of an 
 organism. It is not therefore possible to argue from this case to 
 that of the great oceans, the temperature of which decreases with 
 the depth until 30 F. or even less is reached. 
 
 Three hauls made by Prof. Chun on a voyage to the Canary 
 Islands 3 revealed a Mesoplankton at great depths, the general 
 character of which agreed with the similar captures of the ' Chal- 
 lenger ' and ' National. ' The net used was an improvement on 
 the Mediterranean pattern: open nets were also employed in 
 other hauls. 
 
 As regards the ' National ' net, a modification of Chun's pattern, 
 Prof. Agassiz expressed suspicion of the locking arrangement which 
 closed it. Prof. Brandt was kind enough to show it to me some 
 years ago in Kiel ; it is extremely ingenious in mechanism, but, as 
 Prof. Hensen 4 admits, it is most uncertain in its action ; and, if I 
 may judge from my own experience of a screw-propeller, it would 
 not give very exact information of the depth ; for the rate at which 
 the propeller travels (i. e. the time-intervals from first hauling to 
 opening, and from opening to shutting) varies so much with the 
 rate of the steam-winch (an inconstant) and with the rolling of the 
 ship. If there is any swell, the strain on the line as the ship rolls 
 to leeward sends the propeller round at a greatly increased rate. 
 While, however, venturing to criticize the method, I accept the 
 positive results without any reserve, so far as they are published. 
 They have been most recently summarized by Prof. Brandt 5 , and 
 show a mesoplanktonic fauna which rapidly diminishes in numbers 
 below 100 fathoms, together with a large number of dead organ- 
 isms which are slowly settling to the bottom. Prof. Hensen 6 
 
 1 Though theoretically perfect and simple, this method of investigating Meso- 
 plankton appears to me to present two practical objections to its use : the one, 
 that such an enormous amount of material must be collected as will take years 
 for its proper identificaiton, before a comparison of surface and deep nets can 
 be instituted ; the other, that much of the deep material must inevitably be 
 reduced to soup by pressure against the open tow-net in its long passage upwards ; 
 only forms with a strong skeleton (Eadiolaria, Copepoda, &c.) can be expected 
 to arrive fairly unbroken. In a closed net the resistance of the water does not 
 appear to press the contents of the net against the meshes in the same way. 
 
 2 0. Chun: Bibliotheca Zoologica, i. 
 
 3 C. Chun: Bibliotheca Zoologica, vii., and SB. Akad. Belin, 1889, p. 519. 
 
 4 V. Hensen, Ergebn. d. Plankton Expedition, MethodikderTJntersuchungen, 
 p. 106. 
 
 5 K. Brandt : Verb.. Gesellsch. deutschen Naturforscher und Aertze fiir 
 1895, Liibeck, p. 107. 
 
 6 V. Hensen : Keisebeschreibung der Plankton Expedition, p. 28. 
 
1898.] PLANKTON OF THE FAEBOE CHANNEL. 577 
 
 maintains the accurate locking of his net as against Prof. Agassiz's 
 criticism, and makes a very pregnant remark on the point : " Das 
 Netz ist aber nur das Mittel urn beweisende Fange moglichst rein zu 
 erhalten, der wirkliche Bevveis ist die Beschaffenheit des Fanges." 
 The above summary represents briefly the results and conclusions 
 of the chief writers who have studied the question experimentally : 
 in the case of Prof. Agassiz, negative results have led to the 
 assertion of an Azoic zone ; in the case of the * Challenger,' the 
 4 National,' and Prof. Chun, positive observations have led to the 
 conclusion of the existence of a Mesoplankton, but in these cases 
 the mechanism of locking the net has not been sufficiently certain 
 to escape the criticisms of the opponent school. With their 
 results the less extensive experiments of the Prince of Monaco 
 (' 1'H.irondelle '), the ' Pola,' and the ' Gazelle ' are in general accord. 
 
 Results of the Cruises of the ' Research,' 1896 and 1897. 
 
 In commencing to work at this question, I attempted to construct 
 a locking-gear with which not even Prof. Agassiz could find fault ; 
 with the view, firstly, of finally settling the question of the existence 
 of a Mesoplankton, secondly, of endeavouring to ascertain definitely, 
 in a small area and on a small scale, what animals habitually lived 
 in, and what animals descended to, the mid-water strata (matters of 
 very great importance from the standpoint of oceanic distribution). 
 
 I venture to submit that, as long as the Law of Gravity holds 
 good, the absolute closure of my net is indisputable, for it is 
 effected by gravity. It is not only certain in the actions of opening 
 and shutting (gravity being here also the motive power), but, when 
 shut, the net-frame closes so tightly that nothing larger than the 
 net-mesh (1 mm. or -75 mm.) can get into it, either going down 
 or coming up. 
 
 This being so, my observations agree on general lines with those 
 of Chun and the ' National,' and directly contradict the purely nega- 
 tive observations of the ' Blake ' and ' Albatross ' on which Agassiz 
 bases his theory of an Azoic zone. I encountered animals at every 
 depth down to 500 fathoms, the deepest water available. 
 
 The Faeroe Channel was indicated as a suitable district by the 
 thermal conditions ; the depth is small when compared with the 
 great oceans, but the extremely low temperatures met with in the 
 district are those of the greatest depths in open oceans. As regards 
 every thing but pressure, which appears to be an unimportant factor 
 in determining distribution, the conditions of life at 500 fathoms 
 in the " cold area " of the Faeroe Channel seem to be those of the 
 greatest midwater depths known l . 
 
 The Faeroe Channel is certainly a " closed sea " in the technical 
 
 1 The Faeroe Channel was further indicated by the fact that H.M.S. 'Eesearch' 
 was surveying in the Orkney district. I cannot sufficiently express my obliga- 
 tions for the assistance rendered to me on so many sides the recommendation 
 of the Council of the Eoyal Society, the assent of the Lords Commissioners of the 
 Admiralty, the suggestions of Admiral Sir William Wharton and Captain 
 Tizard of* the Hydrographic Office, and the uniformly patient help of Captain 
 Moore and the other Officers of the ' Eesearch ' in both years. 
 
578 DR. G. H. FOWLER OK THE [June 21, 
 
 sense of the word ; but it is not a closed sea like the Mediterranean 
 or Gulf of California, in which high temperatures are maintained to 
 such a depth thafrthere is practically no thermal limit to the descent 
 of a surface organism. It is a closed sea on one side only, open to 
 the Arctic Ocean on the North-east, with the isothermobath of 
 35 F. at about 250 fathoms, and in many places with a tempe- 
 rature of 30 F. at 500 fathoms. One is far from land nowhere in 
 the Faeroe Channel ; the single station of 1897 (Sta. 20) being only 
 about a hundred miles from Cape Wrath, but far enough to be 
 beyond the range of continental influence, in a case where the 
 continental slope (100 to 500 fathoms) is steep, and no rivers 
 discharge into the sea. The water at these depths is directly 
 derived from the open Arctic ocean, and is practically unaffected 
 by continental influence. 
 
 I would urge therefore, as against Prof. Agassiz, that planktonic 
 animals can and do flourish at greater depths than 200 fathoms, 
 even under oceanic and not neritic conditions : that they apparently 
 flourish in utter darkness, at a temperature of 30 to 32 P., and at 
 a depth of at least 500 to 400 fathoms. 
 
 The animals captured in the mid-water appear to fall into at least 
 five categories : (1) Organisms which range indifferently over all 
 depths (eurybathic) ; of these, at any rate so far as the Faeroe 
 Channel is concerned, Galanus finmarchicus may be taken as an 
 example (p. 544 ante) : (2) those which live habitually at great 
 depths, and rarely or never appear at the surface, if at all, generally 
 at night ; of these characteristically mesoplanktonic animals, the 
 Tuscarorida of the ' Challenger' Expedition, the deep-sea Schizopoda 
 of Prof. Chun, Sagitta whartoni and Conchoecia maxima of the 
 1 Research ' collections 1 may be cited : (3) those which spend their 
 earlier life at or near the surface, but of which adults are almost 
 or quite confined to deep water, such as Nyctiphanes norveyica : 
 
 (4) those which when adult inhabit the surface, but spend their 
 larval life at considerable depths, such as Chun's Ctenophora : 
 
 (5) the corpses of any of the foregoing classes, and of purely epi- 
 plunktonic animals, such as Temora longicornis (p. 546, table, ante). 
 
 With regard to this latter class, it will no doubt be urged by some 
 naturalists that the capture of organisms in the Mesoplankton 
 points, not necessarily to the fact of their living at great depths, 
 but to their having been killed at the surface by unfavourable 
 physical conditions and their subsequently sinking through the 
 deeper strata towards the bottom. In many cases this is no doubt 
 the true explanation of their presence in deep water : I have sug- 
 gested this as the explanation of a particular haul of Doliolum (p. 583 
 infra), and of the presence of six species of Copepoda (pp. 548-9, 
 supra) in the ' Research ' collections from the Mesoplankton. 
 
 (1) In cases where numerous observations on successive days in 
 the same district show numerous specimens of a species in the 
 upper strata, but only a few specimens are rarely, not constantly, 
 taken in the lower zones, this explanation probably holds good, 
 especially in a Frontier district (p. 545) such as the Faeroe 
 1 Proc. Zool. Soc. 1896, p. 992 ; 1897, p. 523. 
 
1898.] PLANKTON OF THE FAEBOE CHANNEL. 579 
 
 Channel, where hotter and colder surface currents are constantly 
 at war. 
 
 (2) This explanation may probably be further extended to cases 
 such as those of the six Copepoda already mentioned (pp. 548-9) ; 
 they appear to be southern (warm-water) forms, driven by the 
 North Atlantic Drift into higher latitudes (colder temperatures) 
 than they can bear. Although southern forms, none of them were 
 taken at the surface in 17 hauls, five were captured once and one 
 twice in 13 Mesoplankton hauls ; all six were few in numbers. 
 
 (3) A different explanation seems reasonable in the case of species 
 which are taken in numbers and with regularity at considerable 
 depths, but appear rarely or never at the surface (if at all, then 
 generally at night). It is to me inconceivable thai; the destruction 
 of such a small surface population should produce dead spe- 
 cimens in such abundance and with such regularity in the deeper 
 strata. Euchwta norvegica, Metridia longa, and Pleuromma abdo- 
 minale (pp. 543 and 547) are examples of this distribution ; they 
 seem to be forms which, at any rate in these latitudes, exhibit a 
 preference for a mesoplauktonic existence, but which can and do 
 exist at the surface also under certain circumstances. Two of the 
 species are Arctic type-forms, which in these latitudes seek deeper 
 (colder) water, and may perhaps eventually be taken very much 
 further south as Mesoplankton than they have as yet been recorded 
 in surface collections. 
 
 (4) When a species is taken in equal abundance and with equal 
 regularity both in Mesoplankton and Epiplankton, it seems fair to 
 infer that it is eurythermal and eurybathic ; it does not seem 
 possible that all the deeper specimens are deep merely because they 
 are dead and sinking. .For example, the list of the captures of 
 Galanus Jinmarchicus on the * Eesearch ' (p. 542) seems to exclude 
 such a possibility. 
 
 It seemed worth while to cite these instances of criteria, which 
 may be applied in dealing with collections of Plankton from various 
 zones, if the observations are numerous enough and sufficiently 
 near together in time and place to permit of any general conclusions 
 at all being drawn. Most mcsoplanktonic specimens are dead when 
 they arrive inboard ; the sudden alterations of pressure and tempe- 
 rature, and the damage by the net itself, are most fatal ; further, 
 decay is so retarded at low temperatures in sea-water, that not 
 even microscopical examination can be relied on as evidence of 
 the life or death of the organism at the moment of capture. The 
 criteria applied above may be expressed thus :- 
 
 Specimens at surface Specimens below Species belongs to 
 
 Numerous, constant. None, or occasionally Epiplankton. 
 
 a few. 
 Numerous, constant. Numerous, constant. Epiplankton and 
 
 Mesoplankton. 
 
 None, or occasion- Numerous, constant. Mesoplankton. 
 ally a few. 
 
580 DB. G. H. FOWLER ON THE [June 21, 
 
 The table on pp. 542-3 showing the vertical distribution of the 
 ' Research ' Copepoda in the Faeroe Channel, seems to me to offer 
 convincing proof of the existence of a living Mesoplankton. If 
 the forms which I caught at great depths were all dead, there 
 would be more dead species in the district than live ones, which 
 seems absurd ; the average number of species per haul is *88 in 
 the Epiplankton and 1'3S in the Mesoplankton. Further, the deep 
 water would contain an abundance of dead specimens of a species, 
 such as Eucliceta norvegica, of which there were practically no 
 specimens at the surface to be killed ; which also seems absurd. 
 Again, if the destruction at the surface is so extensive as the death- 
 hypothesis would imply, some specimens at least of Temora lonyi- 
 cornis, and of all such forms as are abundant at the surface, ought 
 to be captured in the lower strata ; yet this species was not onpe 
 taken in the Mesoplankton. 
 
 In concluding this discussion of the general question, I would 
 strongly urge that any attempt, seriously to investigate the Meso- 
 plankton in future, should be made, not at random stations all over 
 the ocean, but in a limited area, one which presents as far as pos- 
 sible uniform conditions throughout, and may be presumed to 
 contain a similar fauna throughout ; for only by numerous successive 
 hauls at all depths can that careful comparison be made, which will 
 enable the observer to assign to each organism the proper signifi- 
 cance of its occurrences. 
 
 DOLIOLUM (DoLioLETTA Borgert ') TKITONIS, Herdm. 
 = D. denticulatum Herdman 2 . 
 
 This species presented no new anatomical features for record. 
 As Herdman points out 2 , some specimens are cylindrical rather 
 than of the characteristic barrel-shape ; he assigns this to imperfect 
 preservation. A comparison of my specimens from different 
 stations with specimens of other animals from those stations, leads 
 me to believe that the alteration in shape is due to damage in the 
 tow-net by pressure. The smallest sexual specimens which still 
 carried the stalk of attachment to the " Pnegethier " were about 
 5 mm. ; it had been lost in one of 7 mm. length. 
 
 The horizontal distribution of this species was enormously ex- 
 tended by the ' National' (Plankton Expedition) ; till 1889 it had, 
 I believe, only been taken in the Faeroe Channel, the North Sea, 
 and off the Hebrides ; the ' National ' captured it in that year over 
 nearly the whole of their course, from the Labrador Current right 
 down to the South Equatorial Drift. 
 
 The appearance of huge swarms of sexual forms of D. iritonis 
 
 1 A. Borgert; Thaliacea der Plankton Expedition. C. Vertheilung der 
 Doliolen. 1894. 
 
 W. A. Herdman : Trans. Roy. Sue. Edinburgh, xxxii. p. 101, 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 581 
 
 in the Faeroe Channel is very perplexing. On the second and last 
 days out of eight in 1896, they were at or near the surface in enor- 
 mous quantities (96 to 140 specimens in a haul of 10 to 15 
 minutes) ; on the other six days, they were not only scarce or 
 absent at the surface, but could not be found even by the deep- 
 water net. Our position was altered several times between the two 
 days of their swarming. This seems to imply that D. tritonis 
 occurs in patches, with a few outliers in between the patches. 
 Similar swarms of this species were observed in the Faeroe Channel 
 by the ' Triton ' in 1882 l , by the 'Holsatia' in 1885, by the 'National' 
 in 1889. 
 
 Brandt 2 , in an interesting discussion of swarms such as these, 
 seems to incline to the view that they are produced by wind and 
 current action ; but it is a little difficult to imagine how the effect 
 of these agents would gather scattered organisms into a broad swarm 
 in the open sea, except in an eddy or backwater ; although they 
 might make "wind-rows " in the open sea, or swarms in a closed 
 area such as the Mediterranean. Further, if wind and current- 
 were the main direct agents in collecting swarms of D. tritonis, 
 other organisms of the same powers of locomotion ought also to 
 swarm at the same time ; this is not my experience, nor, so far as 
 1 know, have other observers recorded this as a feature of the case. 
 
 I should prefer for the present to regard a swarm of D. tritonis 
 mainly as the result of a period of great reproductive activity. In 
 the case of an organism with a rapid power of multiplication and 
 definite reproductive periods (whether due to food, temperature, or 
 other causes), a very large number of individuals will soon be pro- 
 duced nearly simultaneously ; if they have but little power of self- 
 locomotion, as long as they lie in the track of fairly uniform wind 
 and current, such as the North Atlantic Drift ("Gulf Stream"), 
 there seems to be no reason why they should be parted one from another. 
 In an eddy, such as the Sargasso Sea, where there are no con- 
 stant winds or constant currents, the tendency will probably be 
 for every little shift of wind to part them. The swarms of various 
 organisms met by the ' National ' were apparently all in the track 
 of great ocean-currents, and were conspicuously absent from the 
 Sargasso Sea. 
 
 If my suggestion is correct, then in still or steadily moving 
 water a few Uoliolum " Ammen," fairly close together, will produce 
 a crop of " Pflegethiere " by asexual generation more numerous 
 than themselves ; and although we do not know the rate of 
 reproduction of the "Amme" in throwing off "Pflegethiere," 
 still that each "Pflegethier" may throw off an enormous number 
 of sexual forms is obvious from the hundreds of buds on the 
 stolon of each Pflegethier. The rate of reproduction is extremely 
 rapid ; and I see no reason to believe that in a constant current 
 the family would not move forwards as a whole. 
 
 1 " .At times the Doliolum appeared to be in vast banks, where they were very 
 numerous ; between these banks there were always a few stragglers." (Murray 
 in Herdman, op. cit. p. 112.) 
 
 - Brandt : in Eeisebeschreibung der Plankton Expedition, p. 356 (1892). 
 
 PROC. ZOOL. Soc. 1898, No. XXXIX. 39 
 
582 DR. G. H. FOWLER ON THE [June 21, 
 
 It would appear also that the reproduction (throwing off) of 
 sexual forms is periodic, from the following facts : 
 
 The ' Research ' specimens consisted of very numerous fully- 
 grown sexual forms, a few much smaller sexual forms, and a few 
 large ' Pflegethiere." Other observers x have recorded much the 
 same for the same time of year (July, August ). 
 
 Taking this in conjunction with the fact that, in my collections 
 at any rate, sexual specimens of intermediate size, between the 
 less than 5 mm. and the more than 9 mm. specimens, were very 
 scarce, it would appear that the swarms were due to a period of 
 simultaneous throwing off of numerous sexual forms ; their 
 existence and growth being, naturally, only possible when, as 
 Borgert suggests, the conditions of food, temperature, &c. are 
 favourable. 
 
 The above remarks apply to the 'Besearch' collections of 1896. 
 In 1897 we were able to collect on one day only. On this 
 occasion Doliohim was rare at the surface (like everything else), 
 and the bulk of the catch was at a considerable depth. The small 
 specimens were, proportionately to the large, very much more 
 numerous at the surface than in the collections of ] 896 ; the 
 larger forms seemed to have sunk, like almost everything else, 
 under the influence of very cold and somewhat boisterous weather. 
 The following table gives the numbers taken : 
 
 Sta. Haul in fathoms. Temperature. Specimens. 
 
 20 e. 16 large -, 4 small 
 
 20/. 4 
 
 20 g. 40toO ] 25 
 
 20 a. 200 to 100 
 
 206. 300 to 200 11 
 
 20 c. 400 to 300 3 
 
 20 d. 500 to 400 130 
 
 As they were almost absent from the Mesoplankton during 
 the 1896 cruise, I should not like to suggest, without more 
 extended observations, that the deeper specimens were at so great 
 a depth and so low a temperature, of their own free will. It 
 seems to me probable, although there was nothing in their 
 appearance either to suggest or to contradict it, that, in the haul 
 20 d, the net si ruck a swarm which had been killed by cold or 
 other unfavourable circumstances, and was slowly settling to the 
 bottom. The only differences between the specimens from 20 c 
 and 20 d, and those surface-specimens which were living when 
 brought on board, was that the digestive coil was blue in the 
 deep-water specimens, brown or reddish in the surface specimens. 
 Experiment would easily determine whether this was a post- 
 mortem change or not. 
 
 1 " Such vast numbers with a very few exceptions of much the same 
 
 size " (no Pflegethiere noticed) ; Herdman, op. cit. p. 111. " Erst bei genauerer 
 Durchsicht fand ich unter ihnen, wenn gleich in weitaus geringerer Zahl, 
 Pflegethiere und auch Ammen"; Borgert, op. cit. p. 61. " Ammen " were not 
 observed among the ' Research' specimens. 
 
 2 Three were "Pflegethiere." 
 
1898.] PLANKTON OF THE FAEEOE CHANNEL. 583 
 
 ON THE OCCUEEENCE OF Doliolum nationolis (Borgert) IN 
 BEITISH WATEES. 
 
 By the courtesy of Mr. E. T, Browne and of Mr. E. J. Allen, 
 the Director of the Plymouth Laboratory, I have been able to 
 examine specimens o the alleged Doliolum tritonis from Yalentia 
 and Plymouth. These southern specimens prove to be D. nationalis 
 Borgert ] ; they differ from D. tritonis not only in their much 
 smaller size, but in the point of origin and attachment of the 
 branchial lamella. A further difference between the species, not- 
 discussed by Borgert, is shown by the relations of the intestine ; 
 in D. tritonis (correctly figured by Herdman 2 ) this is short, thick, 
 and sharply curved on itself ; in D. nationalis (correctly figured 
 by Borgert, pi. v. fig. 4) it is long and slender, and, after a nearly 
 straight course posteriorly, it is only slightly curved forwards, 
 often not so much so as he has figured. 
 
 D. nationalis appears to be a southern and warm-water form,, 
 It has only been described hitherto from the collections of the 
 * National' (German Plankton Expedition) in 1889 ; it was absent 
 until the ' National ' struck the true Gulf Stream (37 N. 59 W., 
 surface temperature 79 Eahr.) ; from there it occurred with 
 greater or less regularity through the Sargasso Sea, North 
 Equatorial, Counter Equatorial (" Guinea Current "), and South 
 Equatorial Drifts, right up to the mouth of the English Channel 
 (49 7' N., 5 8' W., surface temperature 52 Fahr.), where one 
 specimen only was captured. It appears to be only an occasional 
 visitor to our shores, probably under the influence of prevalent 
 south-westerly winds and warm weather ; it occurred at Plymouth 
 and Valentia in 1893 3 and 1895 4 . 
 
 PAEATHEMISTO ABYSSOBUM (Boeck). 
 
 This species according to Hansen 5 and Sars 6 is probably identical 
 with Hyperia oblivia Kroyer ; a view now accepted by Bovallius ? . 
 H. ollivia Speuce Bate, appears to be not identical with either of 
 the above. 
 
 Its distribution vertically and horizontally is a little perplexing, 
 so far as our information goes at present. 
 
 i. It lives in cold water, apparently at the surface, in Greenland 
 seas (Kroyer 8 and Hansen 5 ), and in the Murmanske Hav, North 
 of Russian Lapland (Hansen 9 ). 
 
 ii. It lives in cold water at great depths from 1710 to 160 
 
 1 Op. cit, p. 581 supra. 
 
 Op.cit. p. 581 supra, pi. xx. fig. 1. 
 
 W. Garstang : Journ. Mar. Biol. Assoc. iii. p. 222. See also p. 210 for an 
 account of the weather that year. 
 
 E. T. Browne : Journ. Mar. Biol. Assoc. iv. p. 171. 
 
 Hansen : Malacostraca marina Groenlandise occidentals, 
 
 G. O. Sars: Crustacea of Norway, vol. i. p. 11. 
 
 Bovallius: Kongl. Svenska Vetenskaps-Akad. Hdlg. xxi. p. 251. 
 8 Kroyer : " Gronlands Amfipoder," Vidensk. Selsk., nat.-math. Afh.vii. p. 229. 
 3 Hansen*. Dijmphna Togtets zool.-bot. Udbytte, 1886, Krebsdyr, p. 28. 
 
584 DR. G. H. FOWLER ON THE [June 21, 
 
 fathoms at 6 stations of the Norske Nordhavs Expedition * ; all 
 along the West Coast of Norway up to Finrnark from 100 to 200 
 fathoms (Sars 2 ) ; in the cold area of the Faeroe Channel 
 (H.M.S. ' Eesearch,' 1896, 530 to 220 fath.). 
 
 iii. It appears to come up to the surface from great depths at 
 night, in the Faeroe Channel (H.M.S. l Eesearch,' 1896, 
 Station 15 d) ; it has been taken off the Shetlands 3 , and in the 
 Faeroe Channel by the ' Triton ' in 1882. 
 
 iv. It has been recorded from shallow waters round our coasts : 
 from Banff (Edwards 4 ) ; from the Forth 5 ; once, a single specimen, 
 from the Clyde (Bobertson) 6 ; oft' St. Andrews (Mclntosh) ; from 
 Valentia, where what appeared to be very young specimens of this 
 species were taken in profusion by Messrs. A. O. Walker and 
 E. T. Browne. Mr. Walker also informs me that he has received 
 specimens 5 mm. in length from off Galley Head, co. Cork. 
 
 Now the curious fact about the specimens from Valentia, Galley 
 Head, and the Firth of Forth is that they are all very small, 
 ranging from 2 to 5 mm. : whereas in the Faeroe Channel they 
 are mostly about 7-10 mm. in length, and specimens from the 
 Norwegian North Atlantic Expedition reached the length of 
 17 mm. The length of the Banff specimens is not given. In all 
 probability the small size of the British specimens of this sub- Arctic 
 form indicates either (1) that the species attains a smaller size 
 under increased temperature ; or (2) that the larger adults are 
 oceanic, and come inshore to breed, dying or retreating again to 
 the open sea afterwards (this is Mr. Walker's suggestion) ; or (3) 
 that the small and apparently young specimens of our coasts nor- 
 mally live in the open sea but nearer the surface than the adults, 
 and are only driven on to our shores in heavy weather, or by a 
 southerly current. 
 
 I have nothing to adduce either for or against the first suggestion. 
 Against Mr. Walker's suggestion, it may be urged that the adult 
 forms have not been recorded from inshore waters, and would 
 surely have been noticed if they arrived in great numbers to breed. 
 For, one feature of the appearance of this species on our coasts is 
 that it generally arrives in enormous numbers (Firth of Forth, 
 Banff, Yalentia in 1896 ; they were less numerous, but plentiful 
 at Valentia in 1897) : this would imply the presence at some time 
 of numerous parents, which have never been recorded. 
 
 The third suggestion appears to me to be likely to prove the 
 correct solution ; namely, that both young and adults normally 
 inhabit open water, the young living nearer the surface and being 
 brought to our shores as occasional visitors under special circum- 
 stances of weather and current. The clue is to be found in an 
 
 1 G. O. Sars : Norske Nordhavs Expedition, Crustacea, vol. ii. p. 37- 
 - G. O. Sars: Crustacea of Norway, vol. i. p. 11. 
 
 3 A. M. Norman : Kep. British Association for 1868, p. 287. 
 
 4 Edwards : Journ. Linn. Soc. ix. p. 166. 
 
 5 Sir John Murray kindly sent me a sample of these. 
 
 t; Robertson : Trans. N. H. SOP. Glasgow, n. s. ii. p. 69 (1890). 
 

 1898.] FROM THE SOUTH PACIFIC. 1015 
 
 Tribe THALASSINIDEA. 
 Family CALLIANASSIDJD. 
 Genus CALLIAKLDEA H. M.-Edwards, 1837. 
 29. CALLIAKEDEA TYPA H. M.-Edwards, 1837. 
 
 Gallianidea typa, H. M.-Edwards, H. ]ST. Crust, ii. p. 329, 
 pi. XXN. bis, figs. 8-14 (1837). 
 
 Erom Rotuina six specimens ; from. Funafuti six specimens. 
 
 EXPLANATION OF THE PLATES. 
 PLATE LXIII. 
 
 Fig. 1. Metapen&us commensalis, n. sp., p. 1001, side view. X 1- 
 la. ,, head from above. X 2. 
 
 1 b. ,, 3rd maxilliped. 
 
 2 a. Stenopus hispidus (Olivier), p. 1002, 1st abdom. append, of . 
 26. 1st abdom. append, of tf . 
 
 3. Caradina vitiensis, n. sp., p. 1003, side view. X 4. 
 
 3 a. ,, head from above. 
 
 4. Periclimenes dancs (Stimpson), p. 1001, side view. X 8. 
 
 4 a. head from above. X 10. 
 
 4 6. ,, 3rd maxilliped. 
 
 5. Periclimenes rottimanus, Borradaile, p. 1005, side view. X 5. 
 
 5 a. head from above. X 5. 
 
 5 b. 3rd maxilliped. 
 
 PLATE LXIV. 
 
 Fig. 6. Periclimenes vitiensis, Borradaile, p. 1005, side view. X 3. 
 Qa. ,, head from above. X 3. 
 
 6 b. ,. 3rd maxilliped. 
 
 7. Coralliocaris brevirostris, Borradaile, p. 1006, side view. X 4. 
 head from above. X 4. 
 
 x4. 
 
 Fig. 9. Athanas sulcatipes, n. sp., p. 1011, $ 
 9 a. ,, head from above. 
 
 96. 3rd maxilliped. 
 
 9 c. ,, ,, 2nd maxlliped. 
 
 9d. ,, 1st maxilliped. 
 
 9 e. ,, 2nd maxilla. 
 
 9/. 1st maxilla. 
 
 9<7. mandible. 
 
 9 h. 1st antenna. 
 
 Qi. smaller leg of 1st pair of . 
 
 10. Alpheus funafutensis, n. sp., p. 1013, side view. X 4. 
 
 10 a. , head from above. X 4. 
 
 i ,> 
 76. 
 7c. 
 Id. 
 8. Palcemonella trider 
 8 a. 
 86. 
 80. 
 
 ucau IIULU auuvo. /N ^t. 
 
 3rd maxilliped. 
 chela of 2nd pair, 
 dactyle of 3rd leg. 
 tata, n. sp., p. 1007, side view, 
 head from above. X 4. 
 2nd maxilliped. 
 mandible. \ 
 
 PLATE LXV. ' 
 
 106. 
 10 c. 
 10 d. 
 10 e. 
 10/. 
 10 ff. 
 10'h. 
 
 3rd maxilliped. 
 
 2nd maxilliped. 
 
 1st maxilliped. 
 
 2nd maxilla. 
 
 1st maxilla. 
 
 mandible. 
 
 smaller leg of first pair. 
 
 
DR. G. HERBERT FOWLER ON THE [Dec. 13. 
 
 6. Contributions to our Knowledge of the Plankton of the 
 Faeroe Channel 1 . No. VII. A. General Data of the 
 Stations. JB. The Protozoa. C. The Medusse. By G. 
 HERBERT FOWLER, B.A./Ph.D., Assistant Professor of 
 Zoology, University College, London, 
 
 [Eeceived December 6, 1898.] 
 (Plate LXVI.) 
 
 A. GENERAL DATA OF THE STATIONS. 
 
 In the table now exhibited (see p. 1019) will be found the chief 
 details of the successive collecting stations of H.M.S. ' Eesearch'in 
 the Faeroe Channel, 1896 and 1897: Stations 11 2 to 18 being in 
 the " Cold Area," between July 30 and Aug. 6, 1896 ; Station 19 
 in the " Warm Area," Aug. 7, 1896 ; Station 20 in the " Cold Area," 
 July 7, 1897. 
 
 The physical conditions of the Channel have been fully dealt 
 with in the R-eports of the various exploring expeditions 3 which 
 have surveyed this classic district, of which it is not an exaggeration 
 to say that the very beginnings of modern oceanography were made 
 in its somewhat troubled waters. 
 
 DETERMINATION or THE HORIZONS. 
 
 The horizons through which the Mesoplankton net remained 
 open in 1896 were thus determined. In the first place, experi- 
 mental hauls were made near the surface, to determine the number 
 of fathoms through which the net must be towed at an approxi- 
 mately constant speed in order that the propeller (1) might 
 open the net, (2) might shut it again. Of these experimental 
 hauls, the contents of which were mostly not kept, the last oue 
 retained was 12 d. 
 
 1 Owing to the scanty leisure at my disposal, the series of papers under this 
 title has been unavoidably disconnected. 
 
 The first three numbers dealt with some conspicuous and interesting species ; 
 the fourth, by Mr. I. C. Thompson, with the Copepoda ; the fifth, by Mr. E. 
 W. L. Holt, with the fish-larvse ; the sixth furnished a description of the 
 special nets used for the Mesoplankton, and a short discussion of the general 
 question of a midwater fauna. This and the future papers will discuss the 
 organisms captured, group by group, and show their horizons by tables when 
 necessary. 
 
 The references to previous papers of the series in the Society's Proceedings 
 are : _No. I., 1896, p. 991 ; No. II., 1897, p. 523 ; No. III., 1897, p. 803 ; 
 No. IV., 1898, p. 540 ; No. V., 1898, p. 550; No. VI., 1898, p. 567. 
 
 2 Stations 1-10 were collecting-grounds in the neighbourhood of Kirkwall 
 and do not concern the 'Research' cruises. 
 
 3 C. Wyville Thomson : ' Depths of the Sea.' London, 1873, 8vo (H.M.S. 
 ' Lightning ' and ' Porcupine '). T. H. Tizard and J. Murray : " Exploration of 
 the Faeroe Channel in 1880." Proc. Roy. Soc. Edinb. xi. p. 638 (H.M. hired 
 ship ' Knight Errant'). T. H. Tizard : " Soundings and Temperatures obtained 
 in the Faeroe Channel during the Summer of 1882." Proc. Roy. Soc. xxxv. 
 p. 202 (H.M.S. ' Triton '). 
 
P.Z.S.1898.P1.LXVI. 
 
 Mixitern Bros 
 
 PLANKTON OF THE FAEROE CHANNEL 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
 CAl 
 
1898.] 
 
 PLAffKTOS OF THE FAEROE CHAXftTEL. 
 
 1017 
 
 The procedure was then as follows : The net and machinery, 
 weighted up to 100 Ibs., were lowered overboard, and a number of 
 fathoms run out, slightly greater than that of the sounding in the 
 case of the lowest horizon ; the angle made by the line when taut 
 was approximately measured, and a calculation made from Traverse 
 Tables in the ordinary way as to the depth which the net had 
 reached. As I have pointed out already \ this, the usual method, 
 is most fallacious ; for the towing-line does not form the hypo- 
 tenuse of a right-angled triangle (as presupposed by this method), 
 but an unknown catenary, which is practically uncalculable except 
 
 CIIAKT OP THE FAEROE CHANNEL, 
 
 Showing the collecting-stations of H.M.S. ' Kesearch ' in 1896 and 1897. The 
 contour-lines have been roughly plotted from the Admiralty Chart and 
 from the soundings taken on these cruises : they are dotted where the 
 soundings are far apart. (Station 20 (1897) is N. of Station 13.) 
 
 by tedious experiment in order to obtain the necessary data. The 
 fallaciousness of this method was brought home to me by striking 
 bottom at 398 fathoms (Station 16 a i) with 450 fathoms of warp 
 out, though by quadrant and traverse tables the net should only have 
 reached 300 fathoms. Fortunately all the details of the previous 
 hauls had been kept ; and as there was sufficient evidence, from 
 
 1 Proc. Zool. Soc. 1898, p. 568. 
 FEOC. ZOOL. Soc. 1898, No. LXYII. 
 
 67 
 
1018 DR. G. HERBERT FOWLER ON THE [Dec. 13, 
 
 the condition of the paint and the small quantity of bottom-deposit 
 in the collecting- tin, that the net had not more than touched 
 bottom without dragging on it, I was able to get, from this 
 accident, data for the correction of the other deep-water hauls. 
 "While, therefore, the horizons of the Mesoplankton hauls may 
 perhaps be understated (if the net had rested long on the bottom 
 in haul 16 a i), the depth is certainly not exaggerated. 
 
 That the calculation of the depth reached in this manner was 
 a very close approximation to the truth, can fortunately be shown 
 in another way. During the 1896 cruise, Captain Moore and the 
 other Officers were engaged in taking serial temperatures 1 ; and a 
 minimum thermometer was sent down on the locking-gear of my 
 net with every haul after 12 e. A comparison of the temperatures 
 thus recorded on the net, arid of the temperatures independently 
 observed or interpolated on a curve by the Officers, is given 
 below, where column I. shows the station number and haul letter ; 
 column II., the probable depth reached by the net (about 50 
 fathoms below the point at which it opened) as calculated from the 
 data furnished by Station 10 ai when the net struck bottom; column 
 III., the temperature recorded by the thermometer on the. net, after 
 correction ; column IV., the temperatures for the depth given in 
 column II., as independently observed or interpolated in the curves 
 in Captain Moore's Report. 
 
 I. II. III. IV. 
 
 13 a 180 47-0 47'0 
 
 136 356 32-6 33-0 
 
 13 d 445 32-0 31-25 
 
 13 e 445 32-0 31-25 
 
 13 </ 516 3075 31-0 
 
 15 c 578 31-0 30-75 
 
 16 a i 400 30-6 30-9 at 380 fath. 
 16 a ii 356 31-0 31-5 
 
 18 1 578 31-0 31-0 at 600 fath. 
 
 19 a 534 46-0 46-8 at 550 fath. 
 
 Considering the different times of day, and the slightly different 
 positions owing to the ship's drift, at which the two sets of observa- 
 tions were made, their approximation is very close. 
 
 With the net of the 1897 pattern, which presented less resistant 
 surface and less buoyancy than the other, no calculation of the 
 depth was required : the line hanging vertically to the surface, the 
 number of fathoms paid out indicated the depth sufficiently 
 accurately. As to the rate of travel of the messengers, had time 
 (i.e. weather) permitted, this would have been carefully worked into 
 a curve : as it Was, the impact could be felt at the less depths, and 
 had to be guessed (good margin being allowed) for the greater 
 depths. That the messengers travelled very rapidly was shown 
 by the deep dints that they received on striking the locking-gear. 
 
 1 W. U. Moore : Eeports of Proceedings in connection with Investigations 
 into the Physical Conditions of the Water of the Faeroe Channel. Hydro- 
 graphic Department, Admiralty, 1896, 4to. 
 
1898.] 
 
 PLANKTON OF THE FAEROE CHANNEL. 
 
 1019 
 
 TEMPERATURES. 
 
 The temperatures given iu the table are compiled from the 
 readings of the thermometer on my net, and from the observations 
 and interpolations published by Captain Moore (op. cit. supra). 
 
 
 
 CO 
 
 .S 
 
 
 
 1 
 
 L 
 
 <u 
 
 dt 
 
 s 
 
 o 
 
 1 
 
 S~^ O 
 
 "1 
 
 -s s 
 
 "P 
 
 ^ 
 
 r2 
 
 g'^lf 
 
 
 S 33 
 
 00 
 
 ^ 
 
 Q^ 
 
 
 ' 
 
 12 
 
 "2 
 
 M 
 O 
 
 i 
 
 1 
 
 Hi 
 
 i, 
 
 
 1 
 
 I 
 
 ""O 
 
 o 
 
 02 
 
 .|-s 
 w^ 
 
 ^ 
 
 H 
 
 i 
 
 VH 
 
 lla ... 
 
 61 N., long. 
 
 203 
 
 100- +0 
 
 48-54 
 
 25 
 
 11 6 
 
 > 
 
 99 
 
 
 
 54 
 
 180 
 
 lie ... 
 
 M 
 
 
 30-0 
 
 49-54 
 
 36 
 
 12 a ... 
 
 61'N.,8W. 
 
 502 
 
 +350- +150 
 
 31-43 C 
 
 25 
 
 126 ... 
 
 n 
 
 
 10-0 
 
 53 
 
 36 
 
 12c 
 
 9) 99 
 
 
 
 
 53 
 
 180 
 
 12 a! 
 
 
 
 130- +0 
 
 44 -53 
 
 25 
 
 12 c .'.'. 
 
 99 99 
 
 
 450-320 
 
 30-32 
 
 25 
 
 12f ... 
 
 
 
 ?10-0 
 
 ?53 
 
 ?36 
 
 13 ab ... 
 
 60 N., 5 W. 
 
 575 
 
 300-0 
 
 33-54 
 
 25 
 
 13 c ... 
 
 ?> 
 
 
 2-0 
 
 54 
 
 36 
 
 13d ... 
 
 >? 
 
 
 400-270 
 
 32-38 
 
 25 
 
 13 e ... 
 
 > 
 
 
 400-? 
 
 32-? 
 
 25 
 
 13 / .. 
 
 5 
 
 
 
 
 54 
 
 180 
 
 13# ... 
 
 ? 
 
 558 
 
 465-335 
 
 31-33 
 
 25 
 
 is* ... 
 
 ' 
 
 
 
 
 54 
 
 180 
 
 13* ... 
 
 
 
 100-0 
 
 48-54 
 
 36 
 
 13k ... 
 
 > 
 
 624 
 
 2-0 
 
 53 
 
 36 
 
 13 / ... 
 
 > 
 
 
 
 
 53 
 
 180 
 
 14 ... 
 
 55 
 
 
 
 
 
 54 
 
 180 
 
 15a ... 
 
 61 N., 4 W. 
 
 610 
 
 2-0 
 
 53 
 
 36 
 
 156 ... 
 
 55 
 
 J9 
 
 
 
 53 
 
 36 
 
 Ibc ... 
 
 5> 
 
 
 
 530-0 
 
 31-53 
 
 25 
 
 15 d ... 
 
 
 
 
 
 53 
 
 13 
 
 16a i ... 
 
 60 N., 5 W. 
 
 398 
 
 350-220 
 
 31-37 
 
 25 
 
 16 aii. 
 
 s 
 
 
 300-170 
 
 33-44 
 
 25 
 
 166 ;;; 
 
 J> 
 
 n 
 
 
 
 53 
 
 36 
 
 16c? ... 
 
 55 55 
 
 55 
 
 4-0 
 
 53 
 
 36 
 
 17 ... 
 
 
 
 
 
 53 
 
 13 
 
 18 a ... 
 
 60'N. ; 6 W. 
 
 645 
 
 3-0 
 
 53 
 
 36 
 
 186 ... 
 
 
 
 M 
 
 530-400 
 
 31-?32 
 
 25 
 
 19 a 
 
 59 N., 7 W. 
 
 595 
 
 480-350 
 
 46 47 
 
 25 
 
 196 '.'.'. 
 
 99 99 
 
 39 
 
 480-0 
 
 46-54 
 
 25 
 
 19 c ... 
 
 99 99 
 
 
 4-0 
 
 54 
 
 36 
 
 19 d ... 
 
 
 
 10-0 
 
 54 
 
 36 
 
 20 a ... 
 
 60 N., 5 W. 
 
 560 
 
 200-100 
 
 39-46 
 
 40 
 
 206 ... 
 
 M 
 
 9 
 
 300-200 
 
 33-39 
 
 40 
 
 20 c 
 
 
 
 400-300 
 
 31-33 
 
 40 
 
 20 <z !!.' 
 
 
 
 500-400 
 
 30-31 
 
 40 
 
 20* ... 
 
 55 
 
 j 
 
 
 
 52 
 
 36 
 
 20/ ... 
 
 )5 
 
 ( 
 
 
 
 52 
 
 180 
 
 
 J) 
 
 ' 
 
 40-0 
 
 52 
 
 36 
 
 
 
 
 
 
 
 67 1 
 
1020 DR. G. HERBERT FOWLER ON THE [Dec. 13 
 
 CLASSIFICATION OF THE HAULS. 
 
 In the first table (p. 1019) the hauls are arranged in succession 
 of number and letter, in order to facilitate reference ; but 
 in the subsequent tables of species they will be classified as Epi- 
 plankton (0 to +100 fathoms); Mesoplankton ( + 100 fathoms 
 from surface to +100 fathoms from bottom); and "doubtful 
 hauls," in which the net failed to shut at the expected horizon, or 
 in which the contents of two hauls were accidentally mixed. On 
 comparing these tables of species with that given in Mr. Thompson's 
 paper on the Copepoda 1 , it will be found that a few changes have 
 been made. No. 12 a has been moved from among the " doubtful " 
 to the Mesoplankton hauls, because it certainly closed somewhere 
 near 100 fathoms, although perhaps not so low as 150; 12 / 
 proves, by the character and condition of its contents, to have been 
 made very near the surface, and has been put with the Epiplankton 
 hauls ; 13 e, about which I entered a note of suspicion in the 
 station-book when it arrived inboard, proves to contain several 
 essentially epiplanktonic organisms which do not occur in any 
 other Mesoplankton haul, and has therefore been relegated to the 
 " doubtful " category : in all probability one of the chains hung on 
 the trigger for some time after the net should have completely 
 closed ; the details of this haul will be given later. 
 
 B. THE PEOTOZOA. 
 
 It was not to be expected that this group would yield much 
 information with regard to the special object of the cruise, the 
 Mesoplankton fauna. For the efficient study of the Protozoa, the 
 nets must be extremely fine, so fine that they must be towed 
 very slowly ; and if they are towed slowly, a large part of the 
 other constituents of the catch will escape. Special hauls with 
 special nets, or a special arrangement inside the large mesoplaukton 
 net (which I hope to try shortly), are requisite for successful 
 captures. On the other hand, some of my hauls show that certain 
 Phaeodaria live at great depths, although they do not show that any 
 species are confined to the Mesoplankton. 
 
 As regards the surface Protozoa, no special attempt was made 
 to collect them, for they were not required for comparison with 
 the Mesoplankton fauna ; and, further, my finest net, the only one 
 suitable for Protozoa, was almost entirely devoted in 1896 to the 
 capture by Dr. Stericker, B.N., of vegetable plankton for the 
 Scottish Fishery Board. A few new and interesting forms of 
 considerable size were, however, obtained. 
 
 Two things are apparent on a glance at the table of Protozoa 
 the one, the epiplanktonic character of the three Peripylaria ; the 
 other, the way in which several species are aggregated in the same 
 haul, while other hauls show few or no Eadiolaria. They seem to 
 
 1 Proe. Zool. Soc. 1898, pp. 542-3. 
 
1898.] PLANKTON OE THE FAEROE CHANNEL. 1021 
 
 appear and disappear together in accordance with varying external 
 conditions. 
 
 Only those species appear in the table, the horizons of which 
 seem to be in any way significant ; the horizons of the rest will be 
 simply recorded in the text. 
 
 EADIOLARIA PEBIPYLAEIA. 
 THALASSICOLLA sp. 
 
 A. number of specimens of this genus, taken chiefly at the 
 surface, could not be assigned with certainty to any species already 
 described. As with Collozoum, observations on living material 
 seem to be necessary in order to determine the specific position. 
 The following characters are enumerated here in order to assist 
 future recorders in identifying the form from this locality : The 
 striated calymma is very thick and colourless, the alveolar layer 
 internal to this is also very thick and colourless, with large alveoli ; 
 the extracapsular pigment is generally yellowish, occasionally 
 dark in colour; the central capsule is dark and considerably 
 thicker than in T. nudeata ; in specimens of which sections were 
 made, the membrane of the central capsule appeared to be divided 
 up into numerous small polygonal arese, with a single large pore 
 in the centre of nearly every area ; the nucleus is circular, with a 
 thickish nuclear membrane and irregular nucleolus ; intracapsular 
 inclusions ? 
 
 The proportion of central capsule to nucleus, often utilized as 
 a specific character, does not appear to be trustworthy for this 
 purpose. The table below gives this proportion in a number of 
 specimens, apparently all referable to the same species : column I. 
 shows the total diameter in millimetres, arranged in order of size ; 
 column II. shows the diameter of the central capsule expressed as 
 a percentage of the total diameter. 
 
 I. II. 
 
 3-38 29 
 
 3-29 19 
 
 2-10 40 
 
 1-96 21 
 
 1-96 21 
 
 1-90 30 
 
 1-75 22 
 
 1-70 22 
 
 1-68 41 
 
 1-61 21 
 
 I. II. 
 
 1-27 38 
 
 1-26 33 
 
 1-23 28 
 
 Ml 33 
 
 1-09 32 
 
 1-09 32 
 
 1-07 21 
 
 93 37 
 
 92 30 
 
 77 26 
 
 1-47 23 -63 36 
 
 1-44 22 
 
 The proportions of striated calymma, alveolar layer, and central 
 capsule showed similar variations. 
 It seems highly probable from the table that this Tkalassicolla is 
 
1022 
 
 DR. G. HERBERT FOWLER ON THE 
 
 [Dec. 13, 
 
 
 Station Number and 
 Haul Letter. 
 
 Horizon in fathoms. 
 
 Thalassicolla sp. 
 
 Collozoum sp. 
 
 G " 
 1 d 
 
 r-^ QQ 
 
 ^ ^J 
 
 I"- 8 
 
 95 
 
 Aulacantha Icevis- 
 sima Hkl. 
 
 i 
 1 
 
 a 
 
 ^ 
 
 Aulographis moor- 
 en-sis, sp. n. 
 
 Auloceros trigeminus 
 Ilkl. 
 
 
 
 11 a. 
 
 100- +0 
 
 
 
 
 
 
 
 
 
 
 116. 
 
 
 
 4- 
 
 4- 
 
 4. 
 
 
 
 
 
 
 
 lie. 
 
 30-0 
 
 4 
 
 4- 
 
 
 
 
 
 
 
 
 126. 
 
 10-0 
 
 
 
 
 
 
 
 
 
 
 12c 
 
 
 
 
 
 
 
 
 
 
 
 
 12 d. 
 12/. 
 
 150-+0 
 ?10-0 
 
 
 
 
 
 
 
 
 
 
 13 c. 
 
 2-0 
 
 
 4- 
 
 
 
 
 
 
 
 
 13d 
 
 
 
 
 
 
 
 
 
 
 
 fc 
 
 13 h. 
 13 1. 
 13 k. 
 
 
 100-0 
 2-0 
 
 + 
 4- 
 
 + 
 4- 
 
 4- 
 f 
 4. 
 
 4- 
 
 ... 
 
 ... 
 
 ... 
 
 
 M 
 to 
 
 13 1. 
 14. 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 gi 
 
 s 
 
 15 a. 
 156. 
 15 d. 
 166. 
 
 2-0 
 
 
 
 
 4- 
 
 4- 
 
 
 
 
 
 
 
 
 16 c. 
 
 4-0 
 
 
 4^ 
 
 
 
 
 
 
 
 
 17. 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 18 a. 
 
 3-0 
 
 4. 
 
 4- 
 
 4- 
 
 
 
 
 
 
 
 19 c. 
 
 4-0 
 
 
 
 4- 
 
 
 
 
 
 
 
 19 d 
 
 10-0 
 
 
 
 
 
 
 
 
 
 
 20 e. 
 
 
 
 
 
 
 
 
 
 
 
 
 20/. 
 
 
 
 
 
 
 
 
 
 
 
 
 20 a. 
 
 40-0 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 12 a. 
 
 + 350- + 150 
 
 
 
 
 
 
 
 
 
 I 
 
 
 
 12 e. 
 13 d. 
 13<7- 
 16 a i. 
 16 a ii. 
 
 450-320 
 400-270 
 465-335 
 350-220 
 300-170 
 
 4- 
 
 ... 
 
 ... 
 
 + 
 
 ... 
 
 ... 
 
 4- 
 
 
 ^ 
 
 186. 
 
 530-400 
 
 
 
 
 
 
 
 
 
 1 
 
 
 19 a. 
 20 a. 
 
 480-350 
 200-100 
 
 
 
 
 4- 
 
 + 
 
 4- 
 
 4- 
 
 
 ^ 
 
 206. 
 
 300-200 
 
 
 
 
 
 
 
 
 
 
 20 c. 
 
 400-300 
 
 
 
 
 
 
 
 
 
 
 20 d. 
 
 500-400 
 
 + 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 i 
 
 13 a 6. 
 13 e. 
 15 c. 
 
 300-0 
 400-? 
 530-0 
 
 4- 
 
 + 
 
 + 
 
 4- 
 
 4- 
 
 ... 
 
 + 
 
 
 a 
 
 196. 
 
 480-0 
 
 
 4- 
 
 + 
 
 4- 
 
 
 ... 
 
 
 
1898.] 
 
 PLA.XKTON Oi 1 THE FAEKOE CHANNEL. 
 
 1023 
 
 
 Aulocoryne zetesios, 
 gen. et sp. n. 
 
 Aulosphcera flexuosa 
 Hkl. 
 
 Ccelodendrum ramosis- 
 simum Hkl. 
 
 Cceloplegma mur- 
 rayanum Hkl. 
 
 Lizzia biondina 
 Forbes. 
 
 S 
 
 Solmaris sp. 
 
 PH 
 
 
 Aglantha ? rosea 
 Forbes. 
 
 Aglantha ? digitalis 
 0. F. M. ' 
 
 t 
 
 s 
 
 s 
 
 1 
 
 s 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 + 
 
 -f 
 
 
 
 4- 
 
 
 
 
 ... 
 
 ... 
 
 
 4- 
 
 4. 
 
 
 
 
 
 
 
 
 
 
 
 
 4. 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 + 
 
 
 4- 
 
 
 
 
 
 
 ... 
 
 4- 
 
 4- 
 
 4- 
 + 
 
 
 ... 
 
 4- 
 4- 
 
 4- 
 
 
 4- 
 
 
 
 
 
 
 
 
 4- 
 
 4. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 -}- 
 
 4. 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 ... 
 
 ... 
 
 + 
 
 + 
 
 
 
 + 
 4- 
 
 4- 
 
 
 
 
 
 
 
 
 
 -f 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 + 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4. 
 
 
 
 ? 
 
 + 
 
 ... 
 
 + 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 ... 
 
 ... 
 
 
 + 
 
 ... 
 
 ... 
 
 ... 
 
 4- 
 
 
 4- 
 4- 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 4. 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 "? 
 
 4- 
 + 
 
 ... 
 
 + 
 + 
 
 -f 
 
 ... 
 
 ... 
 
 + 
 4- 
 
 4- 
 
 ... 
 
 4- 
 
 4- 
 4- 
 
 
 
 
 
 
 
 
 
 
 
 
 
1024 DR. G. HERBERT FOWLER ON THE Dec. 13, 
 
 an epiplanktonic form; it was plentiful at the surface, but in 
 and 20 d onl y single specimens were captured, which were probably 
 dead or dying and sinking to the bottom. 
 
 For the horizons of capture, see the table on p. 1022. 
 
 COLLOZOUM spp. 
 
 Of this genus there were apparently two separate species 
 represented in my collections, neither of which could be attributed 
 to Collozoum inerme from the warm Atlantic, or to C. ellipsoides, 
 described by Haeckel from the Eaeroe Channel. In the one type 
 the largest spherical zooids of the colony measured about '05 to 
 07 mm. in diameter, in the second type about *09 to '16mm.; 
 both had about *2 to *28 mm. of calymuia and alveoli outside the 
 zooids. In the first type there was a considerable thickness of 
 alveolar calymma in the centre of the colony, as in the ordinary 
 G. inerme; but in the spherical or lenticular colony of the second type 
 the zooids were so closely aggregated in the centre of the colony 
 as all but to touch one another, and were surrounded by a thick 
 alveolar layer and a thick radiately striate calymma, exactly as a 
 Thalassicolla. 
 
 Although I have no doubt that at least one undescribed species 
 of Collozoum occurs in these waters, I do not feel justified in 
 naming and describing it without a detailed examination of living 
 material. 
 
 Both types were confined to the Epiplankton, except for a few 
 specimens in haul 13 , which appears to have remained open 
 through higher horizons than was intended or nt first believed, 
 and is now included with the doubtful hauls. As the Collozoum 
 occurred in 30/ of the Epiplankton hauls, and in no undoubted 
 Mesoplankton haul, I think we are justified in regarding it as 
 essentially epiplanktonic. 
 
 For the horizons of capture, see the table on p. 1022. 
 
 LAMPOXANTHIUM MURRAYANUM, sp. n. 1 
 
 Definition of the Species. Spicules of the skeleton numerous, 
 geminate-radiate, with a short axial rod, from each of which 
 spring three or four acute shanks, devoid of branches or forks 
 (sometimes three shanks at one end, four at the other). Both rod 
 and shanks smooth and straight ; shanks two to three times the 
 length of the rod. Calymma full of large alveoli. Diameter of 
 calymma 3'5 mm. ; diameter of central capsule 1 mm. 
 
 This large and beautiful species is undoubtedly referable to 
 Haeckel's genus Lampoxantliium ; but I am unable to place it with 
 certainty in any of his subgenera, and it agrees with none of his 
 species. In addition to the geminate -radiate spicules there are 
 
 1 I have great pleasure in dedicating this species to Sir John Murray, 
 K.C.B., F.E.S., who is specially associated with the Faeroe Channel by his part 
 in the exploration of the district in the ' Knight Errant' (1880) and ' Triton ' 
 (1882). 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 1025 
 
 also a few which may be radiate, or may be only broken off from 
 the end of a geminate-radiate spicule. 
 
 The horizon of capture was doubtful ; one specimen was taken 
 at 13 , one at 13 ab. 
 
 SIPHONOSPH^RA (HOLOSIPHONIA) TizARDi, sp. n. 1 (Plate LXVI. 
 fig. 1.) 
 
 Definition of the Species. Colony spherical (? always), up to 
 about 2 mm. diameter. Zooids with a single spherical lattice-shell 
 about '15 mm. in diameter, which is beset all over by short broad 
 tubes. The tubes are very thin-walled and fragile, their walls 
 slightly convergent, '010 to '018 mm. in diameter, and about 
 005 mm. high ; there are five to seven tubes on the half meridian. 
 Endosarc with very numerous nuclei ; oil-globules? ; zooxanthellae 
 very numerous, both inside and outside the shell, and also scattered 
 through the calymma between the zooids. 
 
 In some hauls large numbers of the zooids had apparently 
 broken away from the calymma, and appeared as solitary organisms 
 referable to the family Liosphssrida. As a warning to describers 
 of Liosphserida, I may say that I had actually identified them as 
 EtJimosphcera leptosiphonia, described by Haeckel from the Eaeroe 
 Channel, before I found them united in a colony. 
 
 So far as the evidence goes, the species is purely epiplanktonic ; 
 as it is a very conspicuous form, and it occurs with fair regularity 
 at the surface (23 % of epiplankton hauls), and never with 
 certainty in mesoplankton hauls, I think we are justified in 
 accepting the evidence as fairly conclusive. 
 
 For the horizons of capture, see the table on p. 1022. 
 
 EADIOLAEIA ACANTHARIA. 
 
 Acanthometron catervatum Haeckel (=A. brevispina Hkl.) was 
 present in most hauls with the fine-meshed net in 1896, often 
 in sufficient quantity to give a red tinge to the contents of the 
 tow-net. In 1897 (Station 20) it was practically absent from the 
 surface, like most things. A similar abundance and scarcity were 
 recorded by the ' Knight Errant ' in 1880 in this district 2 . 
 
 BADIOLARIA PH^ODAEIA. 
 
 This interesting group of Iladiolaria was well represented in 
 the ' Research ' collections, but not so well as in the ' Triton ' 
 collections made by Sir John Murray in 1882. 
 
 The data afforded by my captures show the extreme danger of 
 drawing conclusions as to the vertical distribution of a species 
 from a few observations at a single " station." I have already 
 pointed out 3 that adequate data for this work can only be obtained 
 
 1 I have pleasure in associating with this species the name of Captain T. H. 
 Tizard, R.1S., who explored the Faeroe Channel in command of the 'Knight 
 Errant' (1880) and of H.M.S. 'Triton' (1882), to whom I am indebted for 
 much valuable help. 
 
 2 T. N. Tizard and J. Murray, Proc. Koy. Soc. Edinburgh, xi. p. 654. 
 
 3 Proc. Zool. Soc. 1898, pp. 578-580. 
 
1026 DR. G. HEltBEBT tfOWLEB ON TUE [Dec. 13, 
 
 by numerous observations at all depths on successive days in a small 
 area, and even these cannot be safely applied to a species unless 
 it occurs constantly and in fair number in a large percentage of the 
 hauls. The table of Phseodarian captures given on pp. 1022-3 
 would seem at first sight to point to about 100 fathoms as the 
 upper limit of all the species except Codoptegma murrayanum ; but 
 the weakness of such an inference would lie in the fact that none 
 of them were captured with anything like regularity in the Meso- 
 plankton. That the argument would be false is shown by the 
 i'act that two of them were taken by Sir John Murray at the 
 surface from H.M.S. ' Triton ' in the same waters. 
 
 All the conclusions that can be drawn for the Faeroe Channel, 
 from so few observations as those in the table, are : 
 
 (1) That Godoplegma murrayanum is both epiplanktonic and 
 mesoplanktonic, extending to at least 350 fathoms (19 a) and 
 a temperature of 33 Fahr. (13#). The large number of specimens 
 taken at 13 g and 19 a, and the small number taken at or near the 
 surface, showed that the deep specimens were not merely dead 
 and sinking to the bottom. 
 
 (2) That Aulacantha Icevissima and Aulosphcera flexuosa may 
 occur at considerable depths in the Mesoplankton ; since the 
 ' Triton' results showed them to exist at the surface also, they 
 are, like Codoplegma murrayanum, to be regarded as epiplanktonic 
 and mesoplanktonic. Though not present in such numbers as the 
 first species, they were plentiful enough to make it extremely 
 improbable that the specimens were dead and sinking. 
 
 (3) That Aulographis moorensis and Auloceros triytminus, var., 
 occur in the Mesoplankton, but it does not appear whether they 
 are confined to it or not. 
 
 AULACANTHA L^EVISSIMA Haeckel. (Plate LXVI. fig. 3.) 
 
 The youngest specimens referable to this genus in the ' Eesearch ' 
 collections agreed entirely with Haeckel's description of A. Icevis- 
 sima, except for the presence of a few extremely minute teeth on 
 the larger spines. Larger specimens, however, with a central 
 capsule about *4 mm. in diameter, and spines at least *9 mm. in 
 length and calymina about 2 mm. in total diameter, exhibited a 
 distinct denticulation (Plate LXVI. fig. 3). As A. Icevissima has 
 been described only from the Faeroe Channel, it is probable that 
 my specimens belong to the same species as those of Haeckel. I 
 have therefore retained the name for " the smoothest " species 
 described up to the present. 
 
 For the horizons of capture, see the table on p. 1022. 
 
 AULOGRAPHIS (AULOGRAPHONTUM) MOORENSIS \ Sp. n. (Plate 
 
 LXVI. figs. 2, 4.) 
 
 Definition of the Species. Eadial tubes rounded proxitnately, 
 
 1 With this new species I am glad to associate the name of Captain W. 
 Usborne Moore, E.N., of H.M.S. ' Eesearch,' to whose help I owe no small part 
 of such success as my midwater experiments attained. 
 
1898.] PLANKTON OF THE EAEEOE CHANNEL. 1027 
 
 equally broad for most of their length, but then tapering slightly 
 towards the distal end, at which the tube expands suddenly into a 
 broad circular cushion. The margin of this cushion bears two 
 verticils of radially divergent, slightly curved, terminal branches, 
 about 10 to 16 in number ; these are about twice as long as the 
 inflated end of the tube is broad. Each branch is armed with two 
 lateral rows of numerous recurved denticles, and bears a terminal 
 spathiUa of 5 to 8 recurved teeth (Plate LXVI. fig. 4). 
 
 One specimen : 480-350 fathoms, 46-47 Fahr. (Station 19 a). 
 
 AULOCEEOS (AULOCEE^EA) TEiGEMixus Haeckel, Var. nov. 
 
 A few shattered specimens, of what is probably only a variety 
 of the species above named, exhibited a verticil formed by the 
 twice-repeated dichotomous branching of the radial tubes, each 
 verticil thus consisting of eight tynes. 
 
 The type species is known only from the ' Challenger ' Station 
 353, between St. Vincent and the Azores, at a probable depth of 
 2965 fathoms (open tow-nets). 
 
 For the horizons of capture, see the table on p. 1022. 
 
 AULOCOEYNE zETESios \ gen. et sp. n. (Plate LXVI. figs. 5, 6). 
 
 Aulocoryne (Family Aulacanthida) : Radial tubes without 
 lateral branches, terminating in a club-shaped expansion which 
 carries numerous fine radiating spines. 
 
 Aulocoryne zetesios : The spines of the terminal club are thin, 
 tubular, at first straight or slightly curved, then regularly zigzag, 
 lastly straight ; they are finely denticulate, and terminate in a 
 spathilla of about 8-10 recurved teeth (Plate LXVI. fig. 6). 
 
 A single specimen only of this species was captured. Although 
 so broken that not a single head was left on the radial tubes, 
 many heads had been fairly well preserved with the calymma, and 
 there could be no doubt as to its structure. The fine spines cf 
 the terminal club are of the same character as the tangential 
 spines of Cannorhaphis spathillata and the radial spines of Ccelo- 
 drymus anchoratus: the same types of growth recur again and 
 again in the various families of Phteodaria, first as scattered 
 spicules, then as tubes radiating from the central capsule, then 
 bound together in a coherent skeleton. 
 
 Unfortunately, the exact record of the horizon was lost ; it was 
 captured in either 13 e or 13 g. 
 
 CCELODENDEUM (CcELODENDEIDIUM) RAMOSISSIMDM 
 
 This species was fairly plentiful at Station 13 i. It has been 
 described as cosmopolitan, from various stations and depths, but 
 not, I think, from so far north as the Faeroe Channel. 
 
 C(ELOPLEGMA MUEEAYANUM-TEITONIS 
 
 These species of Haeckel are the extremes of a series of very 
 1 avXos, Kopvvrj, tubular club ; ^r^ffic, in honour of H.M.S. ' Eesearch.' 
 
1028 DR. G. HERBERT EOWLER Otf THE [Dec. 13, 
 
 varying forms, all terms of which were represented in the ' Research' 
 collections. The range in depth is now extended to 480-350 
 fathoms ; the lowest temperature to 31-33 F. It has not been 
 recorded except from the Faeroe Channel. 
 
 For the horizons of capture, see the table on pp. 1022-3. 
 
 FORAMITQFERA. . 
 
 GLOBIGERINA spp. 
 
 1. A very small species, probably a dwarfed 61. bulloides, was 
 fairly plentiful whenever the finest net was used at the surface. 
 The specimens were spinous when captured \ 
 
 2. On the occasion when the Mesoplankton net touched bottom, 
 a very small quantity of bottom deposit was found in it, containing 
 minute spineless Globigerinse, which seemed to be referable to the 
 species G. bulloides and G.pachy derma. It is very noticeable in balsam 
 mounts of this sample that most of the supposed G.pachyderma are 
 quite filled with what looks like brownish protoplasm, as are most 
 of the bottom-living Foraminifera, but that most of the thin-shelled 
 G. bulloides are clear and empty. The brownish material, while 
 yellowing slightly with nitric acid, does not give the brilliant tint 
 of the usual xanthoproteic reaction. It would seem to be of a clayey 
 nature, and is possibly, as Sir John Murray suggests, a stage in the 
 formation of glauconite. It is extremely soft and friable, and when 
 stained is almost indistinguishable from the similarly stained proto- 
 plasm of surface specimens. 
 
 The dependence of the formation of glauconite upon the presence 
 of protoplasm has been pointed out in detail by Sir John Murray 
 and the Abbe Renaud (Chall. Rep., Deep-Sea Deposits, pp. 385- 
 390). If this material be of a glauconitic nature, its method of 
 occurrence would seem to indicate that G. pachyderma on reaching 
 the bottom contains more protoplasm than G. bulloides, and in that 
 case probably lives nearer to the bottom. It is very desirable 
 that voluminous samples of the bottom deposit should be taken in 
 the Faeroe Channel in order to test this suggestion, and for the 
 following reason. 
 
 The whole discussion as to whether Globigerina was a purely 
 planktonic form, or could both float and creep at the bottom 
 indifferently, would probably have been settled by the acceptance 
 of t he first alternative years ago, had it not been for an observation 
 by Dr. Carpenter during the third cruise of the ' Porcupine ' 2 
 which was recorded in his general discussion of the Globigerina 
 question in 1875. This was to the effect that samples of water 
 taken from immediately above the Globigerina ooze at 500-750 
 fathoms, in the Faeroe Channel, yielded on filtration " multitudes 
 of young Globigerince" plentiful and small enough to make the 
 water appear turbid. 
 
 The " cold area " of the Faeroe Channel is apparently the 
 
 1 Cf. Brady : Proc. Boy. Soc. Edinburgh, xi. p. 717. 
 
 2 W. B. Carpenter : Proc. Eoy. Soc. xxiii. p. 235. 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 1029 
 
 southernmost limit 1 for the occurrence of G. pachy derma in bottom 
 deposits ; it is abundant in Arctic deposits, but has never been 
 recorded alive from the surface. G. bulloides, on the other hand, 
 is only known to occur at the surface, although dead shells are 
 plentiful in the deposits of the Faeroe Channel. 
 
 I venture to suggest that Dr. Carpenter's observation as to 
 the presence of very small living Globigerince just above the bottom 
 may be harmonized with the generally accepted view that most, if 
 not all, Globigerince are essentially planktonic organisms, by the 
 supposition that G. pachyderma is a mesoplanktonic form, at any 
 rate in the Paeroe Channel. It is quite possible that it may occur 
 at the surface farther north, but it would escape capture by any 
 but the finest nets (diameter of the shell *3 mm., according to 
 Brady ; my largest specimens were about *15 to '2 mm.). 
 
 SlLICOFLAGELLATA . 
 DlCTYOCHA Sp. 
 
 A fair number of spicules referable to this genus of Ehrenberg 
 occurred in one or two surface-hauls, notably 13 h. They agreed 
 on the whole with the spicules of D. stapedia and rhombus 
 (Haeckel), but no sign of the protoplasmic body was traceable. 
 Prof. Cleve 2 records D. fibula and D. speculum (Ehrenberg) for the 
 same cruise. 
 
 DlNOFLAGELLATA. 
 
 In reporting on the vegetable Plankton of the cruise of the 
 ' Kesearch ' in 1896, Prof. Cleve 3 records the following species of 
 Dinonagellata : 
 
 Ceratium tripos Duj. 
 
 Ceratium furca Duj. 
 
 Ceratium tripos Ehrenb. ; var. baltica Schiifct ; var. macroceros 
 Ehrenb. = var. scotica Schiitt ; var. longipe* Bail. = var. tergestina 
 Schiitt ; var. horrida Cleve. 
 
 Peridinium divergens Ehrenb. 
 
 Pyropliacus horologium Stein. 
 
 With the exception of the last, with which I did not meet, all 
 these occur in all hauls with the finest net, many of them in great 
 abundance. 
 
 CILIATA OLIGOTBICHA. 
 
 DICTYOCYSTA ELEGANS Ehrenberg. 
 
 A beautiful species of this genus was fairly plentiful in some 
 hauls, notably 13 h. According to Moebius 4 all the various forms 
 of Dictyocysta are referable to Ehrenberg's species elegans, an 
 
 1 H. B. Brady : Cball. Eep. Zool., ix. Foraininifera, p. 600 (of. pp xii-xiv). 
 
 2 ' Fifteenth Annual Eeport of Fishery Board for Scotland/ part iii. p. 302. 
 
 3 P. T. Cleve ; Fifteenth Annual Eeport of Fishery Board for Scotland, 
 1896, part iii. p. 297. 
 
 4 O. Moebius : Fiinfter Jahresbericht d. Commission z. wiss. Untersuch. d. 
 deutschen Meere, 1887. 
 
1030 DK. G. HERBERT FOWLER ON THE [Dec. 13, 
 
 opinion which, I think, is not likely to be accepted by the next 
 monographer of the group. My own specimens agreed exactly 
 with Moebius's figure 28, pi. viii., and showed no signs of variation 
 in the direction of other species. As regards the structure of the 
 shell, I can confirm von Daday l as against previous observers in 
 the belief that the neck (Aufsatz) consists of a meshwork, but that 
 the body of the shell (Wohnfach), although appearing at first sight 
 to be also a meshwork, is really a closed chamber. My specimens 
 seem to show that the inner membrane of the " Wohnfach " is 
 continuous everywhere except at the mouth, but that the outer 
 membrane ceases at the so-called pores. 
 
 C. THE MEDUSA. 
 
 My friend Mr. E. T. Browne has been kind enough to look 
 over the few Medusae of my collections. Of all groups this seems 
 to suffer most in capture at sea. Near shore, or from an open 
 boat, in fairly still water, the tow-net can be handled delicately ; 
 but on board ship in open water the characteristic sense-organs 
 and delicate tentacles are broken by pressure against the tow-net, 
 whether in the rolling of the ship or in the hauling of a meso- 
 plankton net by steam-power from considerable depths. 
 
 In 1897 I tried to lessen the damage to surface forms, both by 
 diminishing the net-mouth in proportion to the surface-area of 
 the net, and by attaching the net-warp to a single-strap 
 ' accumulator ' of india-rubber ; these certainly diminished, but 
 did not avoid, damage. Only in a few cases was Mr. Browne able 
 to assign a specific name ; his list is as follows : 
 
 1. Lizzia blondina Forbes. 5. Solmaris (possibly) two spp. 
 
 2. Pkialidium sp. 6. Solmundella sp. 
 
 3. Sarsia sp. 7. Aglantha roxea Forbes. 
 
 4. Sarsia gemmipara Forbes. 8. Aglantha digitalis Haeckel. 
 
 9. Trachynema sp. 
 
 Of these the first five are probably purely epiplanktonic. Lizzia 
 blondina was often present in such numbers as to tinge the 
 contents of the tow-net. 
 
 Phialidium sp. (14) and Sarsia spp. (several hauls) presented no 
 special features. 
 
 Solmaris sp. is almost certainly confined to the Epiplanktou. 
 A single specimen occurred in 20 e (400-300 fathoms) ; but as it 
 occurred in 53 % f Epiplankton hauls, often in great profusion, 
 and only a single specimen in one Mesoplankton haul, the 
 presumption is that the latter specimen was dead and sinking 
 to the bottom 2 . 
 
 As to Solmundella, my captures do not afford any evidence of 
 its vertical distribution. 
 
 1 E. von Daday : Mittheil. zool. Station in Neapel, vii. p. 486. 
 
 2 Compare Proc. Zool. Soc. 1898, p. 579. 
 
1898.] PLANKTON OF THE FAEROE CHANNEL. 1031 
 
 What appeared to be broken specimens of Aglantlia rosea of 
 Forbes occurred in small numbers in three surface hauls. 
 The eighth species, 
 
 AGLANTHA DIGITALIS (0. F. Miiller, Haeckel pars), 
 
 represents such of HaeckeFs A. digitalis as remains after the 
 restoration of Forbes's A. rosea, and the removal of A. digitalis var. 
 occidentalis Maas J . In his great monograph Haeckel 2 put Forbes's 
 A. rosea with eight marginal vesicles, and the old A. digitalis of O. F. 
 Miiller and Fabricius with four marginal vesicles, under the single 
 species A. digitalis. Since then both species have been confused, 
 until again separated by Browne 3 . It is consequently at present 
 impossible to detail accurately the distribution of these two species, 
 but it seems to be certain that A. digitalis occurs off Greenland and 
 Northern Norway, and that A. rosea occurs as a neritic form round 
 the British coasts (Valentia, Shetland, Heligoland). The one is 
 certainly an Arctic form, the other a southern, even though they 
 may overlap to a greater extent than we at present know. 
 
 This being so, it is not without significance that Mr. Browne, 
 when going over my specimens without knowing the horizons, 
 separated the Aglanthce into two groups, A. rosea and A. digitalis, of 
 which, on comparison with the station list, all the A. rosea were found 
 to come from surface hauls, all the A. digitalis from deep hauls 4 . 
 As A. digitalis was captured in 66 / of Mesoplankton hauls, and 
 never at the surface, the presumption is that it has, like other 
 Arctic surface forms, sunk to deeper strata on reaching lower 
 latitudes (warmer surface water). 
 
 Unfortunately the results of the ' National ' do not throw any 
 further light on the distribution of these two species, horizontally 
 and vertically, for Maas (op. cit. supra) accepted Haeckel's 
 fusion. 
 
 TBACHYNEMA sp. 
 
 A few specimens of a large medusa were apparently referable 
 to this genus. Hemispherical in shape (15 mm. diain., 12 mm. 
 high), its eight radii showed the heavy transverse musculature of 
 Trachymedusce. The eight tentacles were stumpy and thick, one 
 at the end of each radial canal. The sense-organs had disappeared. 
 The manubrium was about 5 mm. long, devoid of a " Magenstiel," 
 and provided with four very small oral lappets. What seemed 
 to be rudiments of generative organs were placed on the upper 
 third of the radial canals. 
 
 1 O. Maas: Ergebnisse d. Plankton-Expedition. Die craspedote Medusen 
 24 
 
 2 E. Haeckel : System der Medusen, i. p. 272. 
 
 3 E. T. Browne : Proc. Zool. Soc. 1897, p. 833. 
 
 4 One small specimen of Aalantha, too much damaged for reference to either 
 species, was taken at 166. In the table it has been placed as a query under 
 A. rosea. 
 
1032 ON THE PLANKTON OF THE FAEROE CHANNEL. [Dec. 13. 
 
 It is the ooly Trachynema which approaches T. funer curium Hkl. 
 in size ; but its proportions, and the position of the generative 
 organs, are against its being a young form of this species. In 
 most recognizable points it lies between T. octonarium Hkl. and 
 T. eurygaster Hkl. ; but it agrees exactly with neither. The eight 
 radial canals and manubrium were of a strong brick-red. 
 
 It occurred in deep or doubtful hauls only. 
 
 EXPLANATION OF PLATE LXVI. 
 
 Fig. 1. Siphonospkeera tizardi, sp. n., p. 1025. A single individual is repre- 
 sented by half the shell and by half a section of the central capsule : 
 outside the latter are zooxaiithellse. Cam. Inc. 
 
 Fig. 2. Aulographis moorensis, sp. n., p. 1026. Termination of a radial tube. 
 Cam. luc. 
 
 Fig. 3. Aulacantha Icsvissima Haeckel, p. 1026. Termination of a radial tube 
 in optical section, showing the denticulations. Cam. luc. 
 
 Fig. 4. Aulographis moorensis, sp. n., p. 1026. A single terminal branch of a 
 radial tube, showing the denticulations and spathilla. Cam. luc. 
 
 Fig. 5. Aulocoryne zetesios, gen. et sp. n., p. 1027. Termination of a radial tube, 
 showing the club covered with zigzag spines. This beautiful drawing 
 is due to the skill of Miss Mabel Green. 
 
 Fig. 6. Aulocoryne zetesios, gen. et sp. n., p. 1027. A single zigzag spine. 
 Cam. luc. 
 
1903.] ON THE PLANKTON OF THE FAEROE CHANNEL. 117 
 
 8. Contributions to our Knowledge of the Plankton of the 
 Faeroe Channel. No. VIII. 1 By Gr. HERBERT FOWLER, 
 B.A., Ph.D., F.Z.S. 
 
 [Received December 20, 1902.] 
 (Text-figures 13-17.) 
 
 The present paper contains notes (in some cases due to the 
 valued help of friends) on Beroe, Arachnactis, Podon, the Ostracoda, 
 the Copepoda, the Amphipoda, and the Schizopoda, captured by 
 H.M.S. Research' in 1896 and 1897 in the Faeroe Channel. 
 
 CTENOPHORA. 
 BEROE CUCUMIS Fabricras. 
 
 This species, characteristic of cold Arctic currents 2 , was taken in 
 the following hauls : 
 
 16 a ii., 300 to 170 fathoms, seven specimens. 
 
 13 e, 400 to ? fathoms, one fragment. 
 
 20<:Z, 500 to 400 fathoms, one specimen. 
 
 Most. specimens showed the characteristic brick- red or rose tint, 
 and though much battered and in some cases inverted, were 
 referable with a fair amount of certainty to this species. 
 
 ANTHOZOA. 
 ARACHNACTIS ALBTDA M. Sars. 
 
 Some information as to the developmental succession of the 
 mesenteries in this form was given in No. III. of this series. 
 Since its publication, I am glad to say that it has been substanti- 
 ally corroborated by Prof, van Beneden 3 . 
 
 He agrees with my suggestion to separate the Channel and 
 North Sea Arachnactis from albida of the Faeroe Channel, and 
 describes it under the name of lloydii, under the idea, which is 
 probable, but at present unproved, that it will be shown eventu- 
 ally to be the larva of Cereanthus lloydii. Till this has been 
 proved, I venture to think it better to retain my provisional name 
 of bournei for this form. 
 
 The occurrences of A. albida are shown in the table (p. 118) : 
 it occurred in over 61 per cent, of epiplankton hauls, never in a 
 mesoplankton haul, and may fairly be taken to be a purely 
 epiplankton form. It was present in considerable quantity, as 
 many as 50 specimens having been taken in one haul. 
 
 1 The references to previous papers in the Society's Proceedings are : No. I., 1896, 
 p. 991; No. II., 1897, p. 523 ; No. III., 1897, p. 803 ; No. IV., 1898, p. 540; No. V., 
 1898, p. 550; No. VI., 1898, p. 567 ; No. VII., 1898, p. 1016. I regret that various 
 circumstances, mostly beyond my control, have caused so great a lapse of time 
 between this paper and No. VII. 
 
 2 Chun : ' Die Ctenopboren der Plankton-Expedition,' p. 26. 
 
 3 Van Beneden : ' Anthozoaires de la Plankton-Expedition.' 
 
118 
 
 DR. Q. HERBERT FOWLER ON THE 
 
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1903.] 
 
 PLANKTON OF THE FAEROE CHANNEL. 
 
 119 
 
 
 Eucalanus attenuatus 
 Dana. C/ note p. 123. 
 
 Euchceta norvegica 
 Boeck. 
 
 Metridia longa 
 Lubbock. 
 
 Pleuromma abdominale 
 Lubbock. Cy.n.p. 123. 
 
 Acartia clausii 
 Giesbrecht. 
 
 Temora longicornis 
 Miiller. " 
 
 Thysan. longicaudata, 
 adult. 
 
 Thysan. longicaudata, 
 larvae & sublarvae. 
 
 P 
 
 Thysanopoda microphth. 
 Ortrnaim. 
 
 Parathemisto oblivia 
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120 
 
 PR. G. HERBERT FOWLER ON THE 
 
 [Feb. 3, 
 
 PHYLLOPODA. 
 
 PODON INTERMEDIUS Lilljeborg. 
 
 My friend the Rev. T. R. R. Stebbing, F.R.S., was kind enough 
 to identify and count the specimens of this species. It would no 
 doubt have occurred in more of the surface hauls had not my 
 finest tow-net been devoted to the collection of Diatoms for the 
 Scottish Fishery Board. It is no doubt a purely epiplanktonic 
 form in the Faeroe Channel ; a single specimen only was taken at 
 20 d (500-400 fathoms) as against about 106 specimens in 7 hauls 
 at the surface ; the single deep specimen was probably a sinking 
 corpse. 
 
 This species is, I believe, known only from the surface l ; it 
 ranges over the Baltic, Norwegian coast up to Yadso, Denmark, 
 Boulogne, Concarneau, Trieste. 
 
 OSTRAGODA. 
 
 The representatives of this order belonged exclusively to the 
 Halocypridse, and were mostly taken in the mesoplankton. Only 
 one species, Concho&da maxima, occurred sufficiently often to allow 
 of a generalization as to its horizon. 
 
 The identification of a Halocyprid is rarely satisfactory without 
 dissection of the mouth-parts, which means destruction of the 
 specimen. I have, however, dissected a considerable number, and 
 feel at all doubtful only in the case of C. porrecta ; I have pre- 
 ferred, however, to leave the specimens under this species rather 
 than create a new species on the strength of slight differences 
 in the armature of tjie mandible. 
 
 The table following shows those surface and deep-water hauls, 
 made by Professor Chun between Finistere and the Canary Islands 
 with open vertical nets 2 , which contained the same species as 
 
 
 
 a 
 
 
 1 
 
 
 . 
 
 
 
 sl 
 
 
 
 hSJ . 
 
 2 . 
 
 K^ 
 
 Haul. 
 
 Horizon in fathoms. 
 
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 11 
 
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 II 
 
 11 
 
 .C 555 
 
 II 
 
 11 
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 II. 
 
 546 to 
 
 
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 I 
 
 
 III. 
 
 819 to 
 
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 * 
 
 IV. 
 
 646 to 
 
 
 
 * 
 
 
 
 
 
 
 VII. 
 
 873 to 
 
 
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 rt 
 
 
 
 Surface. . 
 
 ... 
 
 
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 * 
 
 
 1 J. de Guerne : Bull. Soc. Zool. France, xii. 341 (1887). W. Lilljeborg 
 * Cladocera Suecise,' Upsala, 1900, 4to. 
 
 2 Chun : SB. kon. preuss. Akad. Wisscnsch. (1889 xxx. Claus : * Die Halocy 
 priden,' Wien, 1891, 4to. 
 
1903.] PLAXKTON OF THE FAEROE CHANNEL. 121 
 
 were captured by the ' Research ' in the Faeroe Channel ; they 
 are cited in the text by Roman numerals. 
 
 CONCHCECIA MAXIMA Brady & Norman. 
 
 As I have previously pointed out *, this species appears to be 
 purely mesoplanktonic, in the latitude at any rate of the Faeroe 
 Channel. It occurred in 50 per cent, of the mesoplankton hauls, 
 and in three hauls which began at or over 300 fathoms and finished 
 at the surface ; it was not captured once in hauls between 100 
 fathoms and the surface (cf. table, p. 118). The species was 
 fairly common. 
 
 The record of previous captures was cited in the second paper of 
 this series \ and also indicated a mesoplanktonic habit in subarctic 
 regions, but it is not surprising that in yet colder waters it should 
 appear at the surface. At 84 32' N., 76 E., it was captured 
 with a surface-net by the ' Pram ' 2 , and is recorded as abundant in 
 most of the samples of Crustacea from this voyage 3 . 
 
 CONCHCECIA HYALOPHYLLUM Claus. 
 
 Twelve specimens in haul 13 i, 100 fathoms to surface. Five 
 specimens too small for satisfactory identification, but perhaps 
 referable to this species, occurred in hauls 20 c and 20 d. 
 
 Claus 4 records as other occurrences Chun's haul IV., Ischia at 
 492 fathoms, Orotava at the surface. 
 
 ? CONCHCECIA PORRECTA Claus. 
 
 Numerous specimens from 20 a bod and one from 13 i. Claus 
 (op. cit.) records it from Chun's hauls II., III., IV., VII. 
 
 CONCHCECIA BOREALIS G. O. Sars. 
 
 A single specimen in haul 19 a, 480 to 350 fathoms. Recorded 
 previously from 250 to 300 fathoms at the Lofoten Islands 5 , and 
 from Trondhjem Fjord at 150 fathoms 6 . This appears to be a 
 purely cold-water form. 
 
 PARACONCHCECIA OBLONGA Claus. , 
 
 Six specimens in haul 20 c, four in 20 d. Claus (op. cit. p. 64) 
 cites this species as from Chun's hauls III. and IV. ; and states 
 that it also occurs at the surface, but without giving authority or 
 details. He remarks on the probable identity of this species with 
 G. W. Miiller's variabilis 7 , a suggestion with which Miiller seems 
 to agree 8 . This would extend the distribution considerably, as 
 Miiller 7 records it, from the * Vettor Pisani ' collections of 
 
 1 Proc. Zool. Soc. 1897, p. 523. 
 
 2 F. Nanseu : Norwegian North Polar Expedition. G. 0. Sars : Crustacea, p. 11. 
 
 3 Id. ibid. p. 137. 
 
 4 C. Claus, op. cit. p. 61. 
 
 5 G. O. Sars : Forh. Vid.-Selsk. Christiania (1865), vol. 1866, p. 120. 
 
 6 G. S. Brady & A. M. Norman : Trans. Roy. Dublin Soc. (2) v. p. 686. 
 
 7 G. W. Miller : " Ueber Halocypriden," Zool. Jahrb. Syst. v. p. 273. 
 
 8 G. W. Miiller : ' Ostracoden des Golfes von Neapel,' p. 229. 
 
122 DR. G. HERBERT FOWLER ON THE [Feb. 3, 
 
 Chierchia, as occurring at various points in the tropics at depths 
 between 382 and 546 fathoms; it occurs also in the Gulf of 
 Naples. Brady l records it as having been taken by the ' Chal- 
 lenger ' Expedition off Kandavu, Fiji, and between Marion and 
 Crozet Islands at unrecorded depths. 
 
 HALOCYPRIA GLOBOSA Glaus. 
 
 Six specimens in haul 1 3 i. 
 
 This species is known from the surface and at various depths 
 in the Atlantic 2 , and is recorded from Gibraltar as taken by the 
 ' Yettor Pisani ' 3 . Of specimens taken by the ' Challenger/ the 
 record was in one instance lost 4 ; other specimens were captured 
 at the surface between Api and Cape York 5 . It seems to be a 
 form widely distributed both vertically and horizontally. 
 
 CONCHOSCILLA DAPHNOIDES ClauS. 
 
 Only three complete specimens, and one empty carapace, refer- 
 able to this genus were obtained. The specimens on which Glaus 
 founded the genus (with this single species) were all young males : 
 larger specimens of the genus, including females, were obtained by 
 Sir John Murray on H.M.S. 'Triton' in 1882, from the Cold 
 Area of the Faeroe Channel, and were described by Canon 
 Norman and Dr. Brady under the specific name of lacerta, not 
 without the " suspicion that they may perhaps belong to the adult 
 form of C. daphnoides " 6 . My own specimens were too few to 
 settle the point ; but as the two smaller specimens most resembled 
 in outline the figure of Glaus, and the two largest that of Brady 
 and Norman, I have left them provisionally under the older specific 
 name. 
 
 In addition to Chun's hauls III. and IY., it has been captured 
 at 200 fathoms off Achill Head (daphnoides), the Faeroe Channel 
 as above (lacerta), and off Kandavu, Fiji, at an unrecorded depth 7 
 (daphnoides). 
 
 COPEPODA. 
 
 Mr. I. C. Thompson was kind enough to report on the 
 Copepoda in No. IY. of this series of papers 8 . Since that date, 
 the arrangement of three then doubtful hauls has required modi- 
 fication : 1 2 a, which was suspected at the time of capture to have 
 remained open too long, proves to have no apparent contamination 
 of undoubted surface forms, and has been moved to the Meso- 
 plankton ; 13 e was also suspected, in this case with justice, as 
 
 1 G. S. Brady : " Myodocopa of the ' Challenger ' Expedition," Trans. Zool. Soc. 
 xiv. p. 95. 
 
 2 C. Glaus, op. cit. p. 79. 
 
 3 G. W. Muller : Zool. Jahrb. Syst. v. p. 270. 
 
 4 G. S. Brady & A. M. Norman : Trans. Roy. Dublin Soc. (2) v. p. 705. 
 
 5 G. S. Brady : Trans. Zool. Soc. xiv. p. 97. 
 
 6 G. S. Brady & A. M. Norman : Trans. Roy. Dublin Soc. (2) v. p. 697. 
 ^ G. S. Brady : Trans. Zool. Soc. xiv. p. 95. 
 
 8 Proc. Zool. Soc. 1898, p. 540. 
 
1903.] PLANKTON OF THE FAEROE CHANNEL. 123 
 
 containing several undoubtedly epiplanktonic species (e. g. Arach- 
 nactis albida), and has been relegated to the " doubtful" category, 
 closure of the net not having taken place at the proper time ; 
 12/ was known to be epiplanktonic, although there was some 
 doubt as to the exact depth at which it had been towed. I have 
 therefore reprinted in the table (pp. 118, 119) the captures of the 
 seven forms which were taken at least six times, sufficiently often 
 to give approximate data for an estimate of their vertical distri- 
 bution. In discussing this question, I gave a short table on 
 p. 546 showing the occurrences of these seven species expressed 
 in percentages of those Epiplankton and Mesoplankton hauls 
 which contained Copepoda ; this can now be amended as follows, 
 omitting the four doubtful hauls from the calculation : 
 
 Total hauls containing Copepoda. 
 
 Epiplankton. Mesoplankton. 
 
 Calanusfinmarcliicus occurred in 83 % and in 
 
 l Eucalanus attenuatus 22 
 
 Euch&ta norvegica 11 
 
 Metridia longa 22 
 
 1 Pleuromma ab dominate 5 
 
 Acartia clausii 33 
 
 Temora longicomis 33 
 
 The amended table is in harmony with the conclusions drawn 
 from the former, as to the vertical distribution of these forms, 
 except in the case of Acartia clausii, the question of which was 
 expressly reserved (op. cit. p. 549). 
 
 Since the publication of Mr. Thompson's report, I found that 
 Dr. R. Norris Wolfenden was making an exhaustive study of the 
 fauna of the Faeroe Channel, and naturally placed my collection 
 at his disposal. He has been kind enough to furnish the following 
 notes on new and other species, with some of which he has 
 already dealt briefly elsewhere 2 . Exact data of depth &c. were 
 riot always available, as by the time that Dr. Wolfenden received 
 the specimens all the epiplankton hauls of a station had in many 
 cases been put together in one bottle, all the mesoplankton hauls 
 in another, for economy of space. 
 
 PLEUROMMA ROBUSTUM Dahl, Zool. Anzeig. v. p. 16 (1893). 
 
 " This is the common Pleuromma of the Faeroe Channel, and 
 was found to be present in considerable numbers in Dr. Fowler's 
 collection, PI. abdominale occurring much more rarely. In these 
 northern latitudes it almost entirely replaces the latter species. 
 It is readily distinguishable by the horseshoe- shaped mass of red 
 pigment which is present in the anterior and inferior portion of 
 the head at the base of the mouth-organs, and in the male by 
 
 1 Dr. Wolfenden points out that as, according to his wide experience, TSucalanns 
 attenuatus is nowhere met with in the Faeroe Channel, unless perhaps quite 
 exceptionally, these figures probably refer to Eucalanus elongatus. Similarly, for 
 the species Pleuromma abdominale should probably be substituted PL robustum. 
 
 2 R. N. Wolfenden : Journ. Marine Bio!. Assoc. (1902), vi. p. 344. 
 
124 DR. G. HERBERT FOWLER ON THE [Feb. 3, 
 
 the clasping antenna being on the left side, and the pigment- 
 spot invariably on the right side. The secend feet in both 
 male and female have the characteristic notch and hook on both 
 limbs. Length 3-4 mm. Haul 20 a, (200 to 100 fms.)and several 
 others." 
 
 HETEROCH^TA ZETESIOS S , Wolfenden, op. cit. p. 367. 
 
 " The head is like H. papilligera Gbt. Though the end joints 
 of both anterior antennae were broken off, the 19 joints left had 
 a length of over 4 mm., with the geniculation between the 18th 
 and 19th segments. The anterior antennae were therefore much 
 longer than the whole animal, which was 3*5 mm. There was 
 considerable asymmetry of the furcal segments, that on the left 
 being much the longest and broadest. The anterior foot-jaw had 
 one thick hooked bristle on the 5th lobe, but no " tooth-comb " 
 bristle, and the 5th feet were peculiar and unlike those of any 
 other ffeterochceta, displaying an upright and stiff process of the 
 2nd basal joint, armed with fine stiff hairs on the inner aspect 
 (like a " tooth-comb "), and the proximal inner margin of the 1st 
 joint of the exopodite with a protuberance armed with 4 teeth. 
 The 2nd basal joint of the foot of the opposite side is armed distally 
 with short stiff bristles. It could be only the male of H. grimaldii 
 or of H. longicornis, neither of which is yet known, or of H. major 
 (Dahl). The latter and H. grimaldii are very large (5-10 mm.), 
 and though H. zetesios resembles II. longicornis in some points, it 
 is perhaps better for the present to distinguish it as a new species. 
 Only one example was met with in Dr. Fowler's collection, in 
 haul 20 a (200 to 100 fathoms)." 
 
 ATLANTICUS Wolfenden, op. cit. p. 364. 
 
 " The occurrence of an example of this genus in the Faeroe 
 Channel is remarkable. This specimen was found in the collection 
 made by Dr. Fowler as 20 a (200 to 100 fathoms). It had a 
 total length of 1*45 mm., a 6-segmented anterior antenna with 
 very long and peculiar sensory processes. It has distinct differ- 
 ences from JEg. mucronatus or JEg. aculeatus Gbt., and also from 
 the species described by Scott from the Gulf of Guinea as 
 JEgisthus longirostris." 
 
 LUCICUTIA MAGNA Wolfenden, sp. n. J 
 
 "A single specimen found in Dr. Fowler's collection from 19 a 
 (480 to 350 fathoms), of 3*54 mm. length, was apparently new. 
 The anterior antennae were larger than the whole body, by the 
 terminal one and a half joints. The endopodite of the 1st foot 
 was two- jointed. The right 5th foot has a strong spiny process 
 on the inner side of the 2nd basal and the exopodite of two seg- 
 ments ; the endopodite and exopodite of the left 5th foot being 
 each of three segments. The size alone distinguishes it from the 
 males of any other known species, only L. grandis being larger." 
 
1903.] PLANKTON OF THE FAEROE CHANNEL. 125 
 
 AUGAPTILUS ZETESIOS Wolfeiiden, op. cit. p. 369. 
 "One specimen only was found, in the bottle marked 19 a. c. 
 Another specimen occurred in the sample marked 20." 
 
 EUCALANUS CRASSUS Gbt. 1888, Atti Ace. Line., and 1892, Fauna 
 u. Flora Neapel, v. p. 19. 
 
 " This species was of not infrequent occurrence, especially in 
 the bottles marked B 1 and 13 k (2 to 0) and 13 i (100 to 0). 
 
 " The writer also has frequently noted its occurrence in the 
 Faeroe Channel." 
 
 GAETANUS MAJOR Wolfenden, sp. n. 
 
 " Two examples of this genus (Gaetanus) were found in 
 Dr. Fowler's collection marked 19 a (480 to 350 fathoms). The 
 copepod very greatly resembled Gaetanus armiger Gbt., but the 
 anterior antennae were longer, reaching beyond the f urea by the 
 length of the last joint ; the spines of the last thoracic segment 
 were comparatively shorter, the 1st abdominal segment and the 
 anal segment shorter, and the furcal segments only as long as 
 broad (longer than broad in G. armiger), and each abdominal 
 segment had a row of pectinations on the posterior border. The 
 saws of the swimming-feet possessed more teeth ; the abdomen 
 was not nearly half the length of the cephalothorax, and the 
 whole length of the animal was 5' 3 mm. In all these points it 
 differed from the typical G. armiger, the size of which reaches 
 only about 3 mm., and justifies its being made into a separate 
 species." 
 
 GAIDIUS Gbt. 1895, Bull. Mus. Harvard. 
 
 " A good many examples of this genus occurred in the deep- 
 water collections of Dr. Fowler, e. g. in the bottle marked Meso- 
 plankton 20 (500 to 100 fathoms). 
 
 There is no doubt that in the Faeroe Channel there are two 
 kinds of Gaidius one agreeing in every particular with the 
 Gaidius pungens of Giesbrecht ; the other, a larger species, also 
 differing in the segmentation of the 1st and 2nd feet. Gaidius 
 pungens Gbt. has the exopodite of the 1st foot with only two 
 segments and the endopodite of the 2nd foot with only one seg- 
 ment ; whereas the northern species has a 3-jointed exopodite 
 of the 1st foot and a two- jointed endopodite of the 2nd foot. 
 There are other minor differences. In size the northern species is 
 much larger ; Gaidius pungens Gbt. being 4^ mm., as compared 
 with about 3 mm. The Chiridius tenuispinis of G. 0. Sars is the 
 same species, all being characterized by the peculiar series of 
 lamellar appendages of the basipodite of the 4th foot." 
 
 PSEUDAETIDEUS ARMATUS Wolfenden. 
 
 " Some examples of this species occurred in Dr. Fowler's col- 
 lection. It was drawn and described (in MSS. only) before the 
 
126 DR. G. HERBERT FOWLER ON THE [Feb. 3, 
 
 writer became acquainted with the recent work of Prof. G. 0. Sars, 
 who figured and described the species as Chiridius armatus. The 
 writer has published reasons why this generic name should not 
 be used (see E-ep. of the Brit. Assoc. 1892, " A proposed Revision 
 of the Subfamily Aetidiince "), as it is not a Chiridius" 
 
 EUCHIRELLA CARINATA Wolfenden, op. cit. p. 366. 
 
 " One example of this species, measuring 3'54 mm. in length, 
 was found in Dr. Fowler's collection in the bottle marked 20. 
 
 " These new species will be described in full, along with the 
 drawings, in the writer's monograph which is in hand." 
 
 AMPHIPODA. 
 
 I am indebted to the Rev. T. R. R. Stebbing for help in the 
 determination of some of these forms. Only one species occurred 
 in sufficient quantity and with sufficient frequency to enable 
 deductions as to its habitat in the Faeroe Channel being drawn, 
 namely 
 
 PARATHEMISTO OBLIVIA Kroyer = abyssorum Boeck. 
 
 I have already discussed the distribution of this form at some 
 length x ; to the records there given must be added two stations 
 of the 'National' expedition N. of the Hebrides, and S.W. of 
 Iceland 2 and 1 2 stations along the route of the ' Fram ' 3 . Canon 
 Norman ajso cites Bonnier as having taken it at 950 metres in 
 the Bay of Biscay 4 . 
 
 It is apparent from the table (p. 119) that the species is a 
 true member of the Mesoplankton in this locality, having been 
 captured in 66 per cent, of the deep hauls ; it rises to the surface 
 at midnight, the only occasion out of 26 Epiplankton hauls being 
 at that hour (haul 15 d). 
 
 CYCLOCARIS GUILELMI Chevreux. 
 
 Two specimens of a Cyclocaris were obtained in haul 20 <Z, 
 between 500 and 400 fathoms. Mr. Stebbing informs me that 
 they agree undoubtedly with the above species, captured in a net 
 sunk to 600 fathoms near the Lofoten Islands by the * Princesse 
 Alice ' 5 , the largest of the six specimens being about 1 2 mm. in 
 length. My largest specimen, a female, would have measured 
 about 20 mm. if straight. 
 
 Another species of this genus, Cyclocaris tahitensis Stebbing, 
 was described 6 from a single specimen taken by the ' Challenger ' 
 off Tahiti, apparently at the surface 7 . 
 
 1 Proc. Zool. Soc. 1898, pp. 583-585. 
 
 2 J. Vosseler : Arnphipoden der Plankton-Expedition, p. 80. 
 
 3 F. Nansen : Norwegian North Polar Expedition. Crustacea, by G. 0. Sars, 
 p. 14. 
 
 * A. M. Norman : Ann. Mag. N. H. (7) v. p. 131. 
 
 6 E. Chevreux : Bull. Soc. Zool. Prance, xxiv. (1899), p. 148. 
 
 T. E. R. Stebbing : Chall. Hep. Zool., Amphipoda, p. 661, pi. xvii. 
 
 5 J. Murray : Chall. Rep., Summary of Results, p. 1077. 
 
1903.] PLANKTON OF THE FAEROE CHANNEL. 127 
 
 Mr. Stebbing points out "that this species has been again 
 figured in great detail by Professor Sars *, and that Dr. Norman 2 
 has with almost equal fulness represented his Cyclocaris faroensis. 
 In Mr. Stebbing's opinion the differences between the two sets of 
 figures are purely casual, depending on individual or accidental 
 conditions of the specimens examined. Further, while accepting 
 provisionally the distinction between the boreal form and the 
 4 Challenger ' C. tahitensis, he agrees with the view thus expressed 
 by Dr. Norman, 'so remarkable is the resemblance, that the 
 differences seem scarcely varietal ; but I hesitate to unite a form 
 found in the Faroe Channel with one from so distant a locality as 
 Tahiti.' " 
 
 Canon Norman does not appear to have known of M. Chevreux's 
 name (which apparently has priority) ; his specimens were captured 
 by the 'Triton' in the Faeroe Channel in 1882, at a depth of 
 640 fathoms. Professor Sars's specimens were apparently from 
 various depths along the course of the ' Fram,' the smallest 
 specimens at the least depths. 
 
 This species (omitting tahitensis as specifically distinct) is 
 evidently a Polar and deep-water form. 
 
 TRYPHANA MALMI Boeck. 
 
 A single specimen, from haul 13 i, 100 fathoms to the surface, 
 was identified by Mr. Stebbing. The previous records of its 
 occurrence are: Hardangerfjord, 100 fathoms 3 ; from Nansen- 
 f jord to Hardangerfjord 4 ; Folgero, Sunde, Foldenf jord, 80 to 
 100 fathoms 5 . Sars 5 regards T. nordenskioldi Boeck and T. boecki 
 Stebbing as being the males of T. malmi. Of these the former 4 
 was described from the Sofia Expedition as off the Faeroe Islands 
 at 65 N., the latter 6 from 18 8' N., 30 5' W., at the surface. 
 
 EUTHEMISTO sp. indet. 
 
 A number of specimens too much broken for recognition 
 occurred in the haul 15 d at midnight. 
 
 EUTHEMISTO BISPINOSA Boeck. 
 
 Occurred in 15 c (530 to fathoms) and 15 d (surface, at mid- 
 night). The records of this species were exclusively Arctic, till 
 it was captured by the ' National ' expedition in the Sargasso Sea 
 between 218 fathoms and the surface. 5 
 
 EUTHEMISTO COMPRESSA Goes. 
 
 A single specimen at 12 e (450 to 320 fathoms). This also was 
 believed to be exclusively an Arctic form, but has now been 
 
 1 F. Nansen : Norwegian North Polar Expedition. G. O. Sars : Crustacea, p. 20, 
 pis. ii. & iii. 
 
 2 A. M. Norman : Ann. Mag. N. H. (7) v. p. 197, pi. vi. 
 
 3 Boeck : ' Skandinaviske og Arktiske Amphipoda,' 1872, p. 92. 
 * C. Bovallius : Vega-Exped. Vetensk. lakttag. iv. p. 573. 
 
 5 Sars: Crustacea of Norway; Amphipoda, i. p. 17 (1890). 
 
 6 T. R. Ii. Stebbing : Chall. Kep. Amphipoda, p. 1539. 
 
 OF THE 
 
 UNIVERSITY 
 
 OF 
 
128 DR. G. HERBERT FOWLER ON THE [Feb. 3, 
 
 recorded from the Antarctic region, as well as from the Gulf- 
 Stream proper, the Sargasso Sea, and South Equatorial Drift l . 
 
 EUTHEMISTO LIBELLULA Mandt. 
 
 A single specimen in haul 1 5 d at the surface at midnight. It 
 is widely distributed over the Arctic Seas, but, unlike the two 
 foregoing species, was not taken in southern waters by the 
 ' National.' 
 
 SCINA BOREALIS G. 0. Sars. 
 
 A single specimen from 13 g (465 to 335 fathoms) was acci- 
 dentally included among the Gopepoda sent to Mr. Thompson 
 and identified by Mr. A. O.Walker. According to Canon Norman 2 , 
 the distribution of this species is mesoplanktonic, mostly northern, 
 but also in the Bay of Biscay (960 metres). It reaches to about 
 80 N. 3 
 
 SCHIZOPODA. 
 
 The Schizopoda captured belong exclusively to the Euphausiacea, 
 and are referable to only three species. Several forms which 
 might have been reasonably expected among the captures were 
 absent. A list of the British species with their distribution is 
 given by Canon Norman, in his paper on British Lophogastrida3 
 and Euphausiidae 4 . 
 
 THYSANOESSA LONGICAUDATA Krb'yer. 
 
 A considerable number of specimens of this species were 
 captured : it appeared to be the commonest Schizopod of the 
 Faeroe Channel at the time. The synonymy appears to be 
 Thysanopoda longicaudata Kroyer = Thysanoessa tenera Sars = 
 Thysanoessa longicaudata of Hansen, Norman, Ortmann, &c. 
 
 The species ranges from the "West Coast of Norway right across 
 to Greenland and into the Labrador current ; the * National ' 5 ceased 
 to take it (after almost daily captures up to that moment) from 
 the date of entering the warm water of the Gulf -Stream (' Florida- 
 strom '). Sars 6 , who described the species from deep water in 
 the Yaranger Fjord, records it also as from the surface at four 
 stations between Norway and Jan Mayen on the cruise of the 
 < Voringen ' 7 . It appears, therefore, to be essentially a cold- 
 water species, an Arctic type-form, and was captured by the 
 'Frarn' 8 . 
 
 It has, however, been recorded twice from British coasts 9 . 
 
 1 Vosseler : Amphipoden der Plankton-Expedition, p. 86. 
 f A. M. Norman : Ann. Mag. N. H. (7) v. p. 135. 
 ^ F. Nan sen, op. cit. p. 19. 
 
 4 A. M. Norman : Ann. Mag. Nat. Hist. (6) ix. p. 454. 
 
 5 A. Ortmann : ' Decapoden und Schizopoden der Plankton-Expedition,' p. 14. 
 
 16 G. O. Sars : Forhandlinger Videnskabs-Selskahet (Christiania), 1882, no. 18, p. 53. 
 < G. O. Sars : Norwegian North Atlantic Expedition (Crustacea), pt. ii. p. 13. 
 s F. Nansen : Norwegian North Polar Expedition. G. O. Sars : Crustacea, p. 14. 
 y A. M. Norman : Ann. Mag. Nat. Hist. (6) ix. p. 463 ; and the papers there cited. 
 
1903.] PLANKTON OF THE FAEROE CHANNEL. 129 
 
 Once it occurred in enormous quantity in St. Andrew's Bay in 
 company with Nyctiphanes norvegica, once at Redcar with a 
 similar swarm of Euthemisto compressa, the latter being also an 
 Arctic type-form l . In both these cases it is probable that the 
 creatures had been driven down the North Sea by a strong southerly 
 current, in the manner which I have already suggested 2 for 
 Parathemisto oblivia ; and it has therefore no more right to be 
 regarded as a " British " species than an occasional Velella or 
 lanthina brought up by the North Atlantic Drift to our shores. 
 According to Ortmann (op. cit.), the ' National ' hauls gave no 
 indication of the vertical distribution of this species. 
 
 It will appear from the table (p. 119) that the ' Research ' was 
 more fortunate, and the hauls point to its having a distinct 
 preference for the mesoplankton in the Faeroe Channel. Like 
 (at any rate some) other mesoplanktonic species, it rises to the 
 surface at night. Specimens with adult characters were captured 
 in 1 9 per cent, of epiplankton hauls, but in 66 per cent, of meso- 
 plankton hauls. On the other hand, larval and post-larval stages, 
 apparently referable to this species, were obtained in 38 per cent, 
 of epiplankton hauls, but only in one mesoplankton haul, and 
 that one terminating near the 100 fathoms. The species, there- 
 fore, appears to be epiplanktonic when young, mesoplanktonic 
 when adult, so far as these observations go and in the Faeroe 
 Channel at this time of year. In seeking deeper (colder) water 
 in this locality, it follows what appears to be the practice of other 
 Arctic type-forms when they meet the warmer water of the North 
 Atlantic Drift. That this was not apparent from the results of 
 the ' National ' is probably due to the fact that f rom the Hebrides 
 almost up to the moment of coming into the Gulf -Stream the 
 vessel was in far colder surface-water than that of the Faeroe 
 Channel in summer. 
 
 The larvae mentioned above ranged from an early Calyptopis 
 stage up to the adult condition. It was not, of course, possible to 
 derive them all with certainty from Thysanoessa longicaudata ; but 
 the majority may be safely referred to this species, not only 
 because the adults captured were far in excess of any other 
 Euphausid, but also because the larvae could be traced gradually 
 through successive stages back to the Calyptopis. The meta- 
 morphoses of this species follow the lines indicated by Sars 9 for 
 Nyctiphanes, Euphausia, and Thysanopoda. 
 
 As Paul Mayer 4 has shown, the spination of the telson of 
 Malacostracan larvae yields a character important both for phylo- 
 geny and for diagnosis. It has not as yet, I think, been pointed 
 out that the condition of the telson in Euphausiidse affords a 
 further argument for the view maintained by Boas 5 and others, 
 
 1 C. Chun : ' Beziehungen xwischen dem arktischen und antarktischen Plankton,' 
 Stuttgart, 1897, 8vo, p. 30. 
 
 2 Proc. Zool. Soc. 1898, p. 583. 
 
 3 G. O. Sars : Chall. Rep. Zool. xiii. (Schizopoda). 
 
 4 P. Mayer : Jenaische Zeitschrift, xi. (1877), p. 246 et seqq. 
 
 5 J. E. V. Boas : Morphologisches Jahrbuch, viii. p. 486. 
 
 PROC. ZOOL. Soc. 1903, VOL. I. No. IX. 9 
 
130 DR. G. HERBERT FOWLER ON THE [Feb. 3, 
 
 that this family takes its origin very near to the root of the 
 Decapodan stem, and that it has far closer affinities with the 
 latter than with the Mysidse. In N't, tiphanes 1 and Euphausia 2 , 
 and possibly in other genera also, the youngest Calyptopis-l&YvsQ 
 show seven spines on each side of the telson ; unlike all other 
 Schizopoda, so far as is known, except perhaps Lophogaster, they 
 are thus in absolute accord with the " urspriingliche Borstenzahl 
 7 + 7" which Mayer attributes to the primitive Macruran and 
 Brachyuran. In Euphausia, Nyctiphanes, Thysanopoda, and 
 Nematoscelis according to Sars (op. cit.), and in Thysanoessa, 
 the number is increased at later stages by a median terminal 
 spine, which, like the others, is jointed to the telson. Accepting 
 Mayer's enumeration of the spines from the middle line outwards, 
 and styling the median azygos spine of the Euphausiidse as 0, 
 spines 7 are found in the adult Thysanoessa about one-third of 
 the length of the telson from the root ; spines 6 at about two- 
 thirds of its length from the root ; spines 5 are lost ; spines 4 
 persist as the large lateral jointed spines near the end of the adult 
 telson 3 ; and spines 3, 2, 1, disappear altogether in the course 
 of development. On page 131, I have illustrated four stages in 
 this reduction omitted by Sars, of which fig. 15 does not quite 
 bear out his description : these show the disappearance of the 
 median spine 0, and the commencement of a new unjointed 
 growth of the telson backwards, to form the lanceolate tip of the 
 adult. The character of the telson and the presence of this 
 median spine will apparently form a good criterion for the 
 separation of Euphausidan larvae (at stages later than the Meta- 
 nauplius) from other Schizopodan and from Decapodan larvae. 
 
 The earliest Calyptopis-l&rvsd captured by the ' Research ' 
 resembled closely those figured by Sars (op. cit.) for other genera, 
 except for the facts that the carapace was much more globular 
 anteriorly and was devoid of spines or processes. 
 
 NYCTIPHANES NORVEGICA M. Sars. 
 
 This form was captured on only six occasions. Although a 
 North Atlantic type, it is not an essentially Arctic type like 
 Thysanoessa longicaudata : it is of constant occurrence in certain 
 localities on our own coasts, and has been recorded from as far 
 south as Portugal. The various records of its occurrence are cited 
 by Canon Norman 4 , but unfortunately the size of the individuals 
 and the depth from which they were derived are only rarely noted. 
 I am informed by Sir John Murray that, in his experience, large 
 adult specimens are taken only in deep water. 
 
 1 G. 0. Sars : Chall. Rep. Zool., xiii. Schizopoda, pi. xxvii. fig. 6. 
 
 2 C. Glaus : Untersuch. Crustaceen-Systems, pi. i. fig. 2, Wien, 1876, 4to. 
 
 3 With regard to these, Boas (op. cit. p. 623, note 5) has suggested that they may 
 be homologous with the long caudal appendages of Nebalia and many Phyllopods. 
 This possibility is rendered considerably more remote by their being merely two 
 persistent spines out of a series which is not represented in the forms cited by him. 
 
 4 A. M. Norman : Ann. Mag. Nat. Hist. (6) ix. pp. 459-460 (1892). 
 
1903. 
 
 PLANKTON OF THE FAEROE CHANNEL. 
 
 131 
 
 Text-fig. 13. ov . 
 
 Text-fig 15. 
 
 Text-fig. 17. 
 
 Telsons of larvae attributed to Thysanoessa longicaudata, showing reduction of the 
 primitive seven pairs of spines and formation of the median unjointed spine 
 of the telson. 
 
 Fig. 13. Early Calyptopis, 1'5 mm. long. 
 
 14. Furcilia, 4'5 mm. long. 
 
 15. Cyrtopia, 5 mm. long. 
 
 16. Late Cyrtopia, 5 mm. long. 
 
 17. 4 mm. long. 
 
 9* 
 
132 ON THE PLANKTON OF THE FAEROE CHANNEL. [Feb. 3, 
 
 The same distribution was noted by Vallentin and Cunning- 
 ham 1 : " The adult, so far as our information allows of a 
 decision, lives on the bottom, and never swims far from the 
 ground [90-95 fathoms in this instance], while the young, up to 
 half or three-quarters the size of the adult, occur abundantly at 
 the very surface and at all intermediate depths. As mentioned 
 above, Mr. Murray found swarms of individuals at the surface in 
 the Faroe Channel, but none of these were full-grown, and very 
 few more than half the adult size." 
 
 I have no doubt that this generalization will prove true for 
 greater depths : I took adult specimens, over 35 mm. in length, 
 only between 350-220 fathoms, 400-300 fathoms, 500-400 
 fathoms: the remaining specimens varied from 9 to 17 mm. in 
 length. In other words, Nyctiphanes norvegica is apparently 
 mesoplanktonic when adult. 
 
 A few larvae, larger for their stage of development than those 
 attributed to Thysanoessa, were taken at the surface, and may 
 perhaps belong to Nyctiphanes : they have not been included in 
 the tables. 
 
 THYSANOPODA MICROPHTHALMA Ortmann. (? = Thysanopoda 
 microphthalma G. 0. Sars.) 
 
 Three specimens, recognizable as young forms by the character 
 of the second maxilla and gills, and by the spination of the telson, 
 of about eight, twelve, and fourteen mm. in length, appear to be 
 referable to the same species as specimens recorded in quantity 
 by the ' National ' in 60 3' N., 27 0' W., at a probable depth of 
 between 218 and 328 fathoms. These were referred by Ortmann 2 
 to Thysanopoda microphthalma of Sars 3 , a species founded on two 
 specimens from the surface at 26 21' N., 33 37' W., and 7 N., 
 23 W. respectively. The identity of the ' National ' specimens 
 with those described by Sars seems to me rather doubtful : firstly, 
 because it is not very likely that a rare form such as this should 
 occur as adult both at the surface near the Equator and also at 
 218-328 fathoms in the Greenland Sea, or at 500-400 fathoms 
 in the yet colder water of the Faeroe Channel ; secondly, because 
 Ortmann himself indicates some points of difference between his 
 specimens and those of Sars. My own specimens agree with 
 Ortmann's figure, and differ from Sars's description, in the shape 
 of the antennal scale, and in the absence of a spine from the 
 second joint of the first antenna. The telson was not hispid, 
 probably owing to immaturity ; the eye was somewhat flatter than 
 in Ortmann's figure, and showed slight signs of a constriction 
 such as is characteristic of Thysanoessa. The matter cannot be 
 settled in default of further specimens, owing to the fact that 
 Sars gave only a woodcut of the entire animal, and no figures of 
 the detailed anatomy. 
 
 1 R. Vallentin & J. T. Cunningham : Quart. .Tourn. Micr. Sci. xxviii. pp. 325-6. 
 
 2 A. Ortmann : ' Decapoden und Schizopoden der Plankton-Expedition,' p. 9. 
 
 3 G. O. Sars : Chall. Rep. Zool., xiii. Schizopoda, p. 106. 
 
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 LIBRARY 
 
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