a ay ued hit wr, san eae le tetas a) HA A dst ty rig a et 4 Leek Vv Aly Wick ity) Hoe y Uae, Perce na elt Ha iG ) as Y Athy say y pF Bei eRe Pyotr a Ved uf 4% he AN aan Wh a hay : oy cass a (oe i f ae Hote te tS > Y 9 iA ne i ud i i ee , id i! # * ignorant} Maen ‘ a) vid toy We unindetiiys i Cen as % oie Yh it qe tbk yet if 169 ARES ton pene hiby Pe knislonnnr tne tet Mere PA sale AY? Reh: a ee i : . ete Wists. hose 43" $ 4 4 #5, si ee J fs a) ag Ault 4) th 7 T58 » Jaks a * hate Ve aye is BESET hg aa rye ae scout i mi i ai aa ae , ant Gael ncaeh Ge oH ‘ Ye beasts Vincents oe uy hel Sih ee: en tty be HNGietanare ns Eade td ‘ts rag as Re ae at ar pee si “ Wt . ca Arle eG 8 PROCKEDINGS TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. NOt XOX Val: aa | Sar, Agsonian Institge=n ae Se “Up ~ ‘ “/) owe , | fle rd \ LIAL Ss 5 J TATE SESSION 1912-1913. LIVERPOOL: C. Trnuine & Co., Lrp., Printers, 538, VICTORIA STREET. LOS. i ogni, Mh A 674. 0642 $ YY pws CONTENTS. I.—-PRocEEDINGS. _ Office-bearers and Council, 1912-1913 . Report of the Council . Summary of Proceedings at the Meets List of Members . Treasurer’s Balance Sheet IIT.—TRANSACTIONS. Presidential Address—‘“‘ Bergson’s Philosophy of the Organism.’’ By J. Jounstone, B.Sc. . Twenty-sixth Annual Report of the Liverpool Marine Biological Committee and _ their Biological Station at Port Erin. By Prof. W. A. Herpman, D.Sc., F.R.S. é Observations on Marine Algae of the L.M. B. C. District (Isle of Man Area). By R. J. Harvey-Gisson, M.A., F.L.S., Professor of Botany; Marcrery Kyicur, B.Sc., Assistant Lecturer in Botany; and H1zpa Cozury, B.Sc., Hartley Botanical Laboratories, University of Liverpool : The Harly Days of Coe eacsties Aves By F. J. Corn, D.Sc., Professor of Zoology, University College, Reading . : Report on the Investigations carried on during 1912, in connection with the Lancashire Sea-Fisheries Laboratory, at the University of Liverpool, and the Sea-Fish Hatchery at Piel, near Barrow ; By Prof. W. A. Hurpmay, D.Sc., F.R.S., ANDREW Scort, A.L.S., and James JonnstTone, B.Sc. L.M.B.C. Memoir on ‘‘ Eupagurus.’”’ By H. G. Jackson, M.Sc. : 5 , : 30 123 148 177 495 PROCEEDINGS OF THE OFFICHE-BEARERS AND COUNCIL. Ex- Presidents : 1886—87 Pror. W. MITCHELL BANKS, M.D., F.R.C.S. 1887—88 J. J. DRYSDALE, M.D. 1888—89 Pror. W. A. HERDMAN, D.Sc., F.R.S.E. 1889—90 Pror. W. A. HERDMAN, D.Sc., F.R.S.E. 1890—91 T. J. MOORE, C.M.Z.S. 1891—92 T. J. MOORE, C.M.Z.S. 1892—93 ALFRED O. WALKER, J.P., F.L.S. 1893—94 JOHN NEWTON, M.R.C.S8. 1894—95 Pror. F. GOTCH, M.A., F.R.S. 1895—96 Pror. R. J. HARVEY GIBSON, M.A. 1896—97 HENRY O. FORBES, LL.D., F.Z. 1897—98 ISAAC C. THOMPSON, F.L. S. palit R. 1898—99 Pror. C. S. SHERRINGTON, M. 1899—1900 J. WIGLESWORTH, M.D., F.R. C. 1900—1901 Pror. PATH RSON, M.D., M T.R.C.S 1901—1902 HENRY C. BEASLEY. 1902—1903 R. CATON, M.D., F.R.C.P. 1903—1904 Rey. T. S. LHA, M.A. 1904—1905 ALFRED LEICHSTEHR. 1905—1906 JOSEPH LOMAS, F.G.S. 1906—1907 Pror. W. A. HERDMAN, D.Sce., F.R.S. 1907—1908 W. IT. HAYDON, F.L.S. 1908—1909 Pror. B. MOORE, M.A., D.Sc. 1909—1910 R. NEWSTEAD, M.Sc., Fr. ES. 1910—1911 Pror. R. NEWSTEAD, M.Sce., F.R.S. 1911—1912 J. H. OCONNELL, L.R.C.P. SESSION XXVII., 1912-1913. President: JAMES JOHNSTONH, B.Sc. Vice- residents : Pror. W. A. HERDMAN, D.Sc., F.R.S. J. H. OCONNELL, L.R.C.P. Hon. Creasurer : Hon. Librarian : W. J. HALLS. MAY ALLEN, B.A. Hon. Secretary: JOSEPH A. CLUBB, D.Sc. Council : HENRY C. BEASLEY. | W. 8S. LAVEROCK, M.A., B.Sc. G. ELLISON. | Pror. B. MOORE, M.A., D.Sc. H. B. FANTHAM, DSc., B.A. Prom. R. NEWSTEAD, F.R.S. OULTON HARRISON WM. RIDDELL, M.A. W. T. HAYDON, F.LS. Pror. SHERRINGTON, F.R.S. DOUGLAS LAURIE, M.A. E. THOMPSON. Representative of Students’ Section : R. ROBBINS, B.Sc. (Miss), Vill LIVERPOOL BIOLOGICAL SOCIETY. REPORT of the COUNCIL. Durine the Session 1912-13 there have been seven ordinary meetings and one field meeting of the Society. The communications made to the Society at the ordinary meetings have been representative of almost all branches of Biology, and the various exhibitions and demonstrations thereon have been of great interest. By invitation of the Council, Prof. F. J. Cole, D.Se., of University College, Reading, lectured before the Society, at the February Meeting, on “The Early Days of Comparative Anatomy,” and the paper has been published in the Transactions. The Library continues to make satisfactory progress, and additional important exchanges have been arranged. The Treasurer’s statement and balance-sheet are appended. The members at present on the roll are as follows :— Ordinary members - - - - - = 650 Associate members” - - - - - - 6 Student members, including Students’ Section, about 35 Total - = Onl SUMMARY OF PROCEEDINGS AT MEETINGS. 1X SUMMARY of PROCEEDINGS at the MEETINGS. The first meeting of the twenty-seventh session was held at the University, on Friday, October 11th, 1912. The President-elect (James Johnstone, B.Sc.) took the chair in the Zoology Theatre. 1. The Report of the Council on the Session 1911-1912 (see “‘ Proceedings,’ Vol. XXVI., p. vill.) was submitted and adopted. 2. The Treasurer’s Balance Sheet for the Session 1911- 1912 (see ““‘Proceedings,’’ Vol. XXVI., p. xvii) was submitted and approved. 3. The following Office-bearers and Council for the ensuing Session were elected :—Vice-Presidents, Proms eherdman. DLSes, HRS: and “J. EH: ©;Connell, LA.C.P.; Hon: Treasurer, W. J. Halls; Hon. Librarian, May Allen, B.A.; Hon. Secretary, Joseph A. Clubb, D.Se.; Council, H. C. Beasley, G. Ellison, H. B. Fantham, D.Sc., B.A., Oulton Harrison, W. T. Haydon, F.L.S., W. S. Laverock, M.A., B.Sc., Douglas Laurie, M.A., Prof. B. Moore, M.A., D.Sc., Prof. Newstead, MESca LeRS.- W.- daddelll)>) McA.; Prof. Sherrington, F.R.S., and E. Thompson. 4. James Johnstone, B.Sc., delivered the Presidential Address on ‘‘ Bergson’s Philosophy of the Organism ”’ (see ‘‘ Transactions,’’ p. 3). Hy ———_— SA 1 ees [aes dl ~ 116 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. NOTES. [Explanation of the numbers on the chart opposite will be found in the 14th Annual Report of the L.M.B.C. (1900) at page 52.] 117 MARINE BIOLOGICAL STATION AT PORT ERIN. 2 Ss | | 2 | fcsorse eS 5 a9 eel “2 L soe ae .) iI Sot $46) Kepocs 2 ** Slip VOAOV LS HL 40 NOLLASRLLSIG SHL ONIMOHS AVa NING LHOd 1i8 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. NOTES. [Explanation of the numbers on the chart opposite will be found in the 14th Annual Report of the L.M.B.C. (1900), at page 54. ] Lis) ORT ERIN. AT FP NE BIOLOGICAL STATION ARI M fm. & 87 pie care as ia) VWOSN'TION AHL 40 NOLLAGIYLSIC AHL ONTMOHS AVG NIMS LHOd 4OWUVHO 120 TRANSACTIONS LIVERPOOL BIOTOGICAL SOCIETY. NOTES. [Explanation of the numbers on the chart opposite will be found in the 14th Annual Report of the L.M.B.C. (1900), at page 57.] £2 : } a / » : isi De ol g 121 rea ise 3 Sy a es 818 at cr ot Wet or lest ob \ OH SL OL WHE SUL 3 si aay ee = a — STATION = ; y } wel | ‘ £ : : i ( é : \ | | | oe ee \ ee ee 4 Ds oO i Oo S) = ) = as) & A iH ae} $9 Tubercular lesions in a Cod (Gadus caliarias). A fairly large cod landed at Fleetwood in March, 1912, exhibited this condition. Part of the fish was sent to me by Mr. T. R. Bailey, Port Sanitary Inspector. The piece sent, all that behind the origin of the second dorsal fin, showed that it was a spawning male in apparently good condition. There were some copepod parasites, Anchorella uncinata, on the vertical fins, and the flesh seemed to be healthy and unaffected. There were numerous lesions on the skin, the tail and the dorsal and ventral fins. These took the form of little rounded, slightly raised, pigmented nodules in the integument. They were hard to the touch, particu- larly on the fins. Asa rule, they occurred singly, when they were about 5 mm. in diameter, and were raised above the general surface of the integument about 4 to 1mm. The pigment was sometimes reddish-black when the fish was fresh, sometimes grey-black. After preservation in formalin the reddish pigment disappeared and all the nodules became black, particularly at their margins. The central parts were sometimes creamy- yellow in colour, with some very fine pigment spots (see fig. 2, Pl. III). -SEA-FISHERIES LABORATORY. 197 Although these nodules occurred singly for the most part, there were patches of skin where they were grouped, and here the lesion was a distinctly ramifying one, sometimes even dendritic in appearance. This was more particularly the case on one side of the fish, and on both sides between the beginning of the third dorsal fin and the root of the tail fin. In some places quite consider- able areas of skin were involved. Over the nodular lesions the epidermis had quite disappeared and there were no traces of scales, but elsewhere the skin was apparently normal in structure. On slicing away the surface of these little nodular masses a cheesy-white substance was disclosed, and sometimes this could be apparently ‘‘shelled-out,’’ when it appeared as _ little granular masses of various shapes and sizes. Some of these were stained and cleared up, but they showed no obvious indications of structure. In my absence from the laboratory the fish was preserved in formalin. It was first of all examined, as above described, for the possible presence of worm parasites, but nothing of the kind was found. Rough smears were then made from the substance in the nodules, to see if fungoid or protozoan organisms were present, but again with negative results. Sections through the nodules were then made, and were stained in various ways, methyl-blue-eosin, iron-haematoxylin followed by eosin, Khrlich’s haematoxylin and eosin, and Mallory’s stain. On examining the sections so prepared it was at once seen that morbid tissue formation had taken place, and what was seen indicated the presence of an infectious granuloma of some kind. Prof. Glynn, of the Patho- logical Department, to whom I showed the sections and specimens, at once noticed their resemblance to tuberculous lesions, and suggested staining for acid-fast 198 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. bacilli. This was done,* and the nature of the lesions then became apparent. They were evidently tubercular, and the whole was a spreading infection of the integu- ment forming lesions, most of which were in the process of healing. Fig. 1, Pl. II, represents a section through one of the smaller nodules which had been stained with methyl-blue-eosin. It includes a part of the normal integument on the right-hand side, where a scale is shown cut in section. The epidermis has disappeared everywhere, but the loose areolar connective tissue lying beneath it is shown. Beneath the scale is a thick layer of coarse connective tissue fibres, and beneath this again loose areolar tissue; none of the underlying systemic muscles are shown. It will be seen that the lesion involves only the integument, and that it is the thick layer of coarse connective tissue fibres that has been affected. Under the surface of the nodule this has almost entirely disappeared, though in the sections which have been Mallory-stained little groups of these fibres or isolated fibres can be seen, owing to their peculiar staining reaction. The characteristic structures displayed by the sections are, however, the parts which are darkly stippled in the drawing. These stain deeply with * Staining reactions. Sections fixed on the slide were stained for five minutes in the Ziehl-carbol-basic-fuchsin liquid, the latter being hot: some were also stained in the cold for 24 hours. They were decolourised with 20 % sulphuric acid for at least ten minutes, when the stain remained in the bacilli. Sections were stained in the hot liquid for ten minutes, and in the cold liquid for 24 hours, and then placed in 25 % sulphuric acid for 24 hours, washed, cleared and mounted in balsam: in these also the bacilli retained the stain. In these latter preparations the beaded appearance of the bacilli was not evident. Smears made from the substance of the nodules were stained and decolourised as above, but the bacilli could not always be seen. Sections were stained in carbol-thionin for a few minutes and then treated with Gram solution in the usual way : the bacilli did not retain the stain. Smears and sections were stained in carbol-gentian-violet and in thionin in the cold for a few minutes: the bacilli did not stain, SEA-FISHERIES LABORATORY. 199 methyl-blue-eosin, and it is here also that the bacilli are massed together. Some of these darkly-staining parts appear to he inside small cavities, which are bounded by fine fibrous tissue arranged concentrically, and it is these large masses which appear to shell-out when the superficial part of the nodule is cut away. It is very probable that the cavity shown in the figure is an artificial one, that is, it is produced by the action of the preservative. But in many of the smaller nodular masses there are also indications of the formation of this concentric fibrous tissue, though there may be no space between the bacilli-loaded centres and the fibrous invest- ment. What we see here is doubtless the encapsulation of the tuberculous centres. But there are also many darkly-staining parts of the section evidently densely packed with organisms, and round these there are no traces of capsules: the darkly-staining tissue passes without any discontinuity into the ground tissue of the section. Fig. 3, Pl. II, represents a small part of one of these smaller tubercular centres as seen under an oil- immersion lens. It will be seen that there are distinct traces of a capsule, in that fibrous tissue is arranged concentrically round the mass. This rather loose capsular tissue, and some relatively coarse fibres, with large and small connective tissue nuclei, are all the histological elements which can easily be recognised. Besides these there are some rather large patches, staining deeply and without much differentiation with methyl-blue-eosin ; and in these are some rounded bodies, staining blue, and containing numerous granules, but no evident nuclei. These present a certain resemblance to the “ giant-cells ’’ of typical tuberculous lesions, though, of course, it would be hazardous so to identify them. 200 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. In the Mallory preparations most of these obscure bodies stain orange, just as do the nuclei of the red blood corpuscles in other parts of the section where capillaries are present and can be recognised, and in the sections stained with carbol-fuchsin these parts take the stain very intensely. They, therefore, consist mainly of broken-down red blood corpuscles, connective tissue fragments, and masses of bacilli densely aggregated together. The remainder of the substance of the lesion between the nodular masses consists of fibrous connective tissue with blood capillaries. It is not richly vascular, but the capillaries with their contents can easily be recognised. It is a granulomatous, or scar, tissue, and doubtless represents the tubercular lesion in process of disintegration and absorption. It contains pigment- melanin granules without much indication of arrange- ment. Here and there this pigment appears in a stellate form, as if it were contained in richly branching cells, but as a rule it is present as small round bodies or discrete granules. All the darkly shaded parts in fig. 1, and especially the darkly stippled parts, are the loci of the bacilli staining acid-fast with carbol-fuchsin. The deeply stippled areas represent places where the bacilli are densely clumped. ‘These clumps are spherical masses of various sizes in which the organisms lie densely packed together without any definite arrangement. Out- side them the organisms le loose in the tissues, and never arranged in chains. They have the form regarded as typical of the tubercle bacillus, that is, they are relatively long, slender, slightly curved rods, and for the most part they present a richly-beaded appearance, due to the vacuolation of their cell bodies. Round all these SEA-FISHERIES LABORATORY. 201 clumped masses of organisms there is a diffuse pink staining, as if some substance had been excreted by the bacilli into the surrounding tissues, and this had taken the stain in the same way as the organisms themselves. The lesion is then obviously the result of an infective disorder, and the general similarity of structure of the nodules with those produced in warm-blooded animals by the tubercle bacillus justifies us, I think, in describing it as a case of piscine tuberculosis. The pigmentation of the skin is a frequent feature in lesions of many kinds in fishes: it is to be associated with inflammatory processes, and has no particular signi- ficance. Piscine tubercle is of course known,* but, so far as I can find, only from fresh-water species, and it is of interest to find so typical a condition in a fish living in the open, and not at all likely to have become infected by land drainage. The detailed bacteriology of these lesions is described by Dr. Alexander on page 219. Ovarian Cysts in Angler (Lophius piscatorius). A female Angler, about 5 feet in length, was sent to the Laboratory last May by Captain Wignall. On dissecting it with a view to the discovery of worm parasites, 1t was noticed that the wall of the ovaries contained rounded cyst-like bodies. The fish was a spent one: the ovaries were quite empty, and their wall was represented by a germinal epithelium containing practically only one layer of very small ova. The cysts were usually attached to the external surface of this: they were of various sizes, the largest being about 23 by 14 cms. in diameter, and the smallest being about +cm. Their shapes varied, some being almost spherical, * See Hofer, Handoduch der Fischkrankheiten. Stuttgart, 1906. 202. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. other ellipsoidal, other again quite irregular and constricted, as if they were made up of several smaller cysts coalescing together. In one case a group of four were attached together, and were suspended from the ovary by a single pedicel. The wall of these bodies was, as a rule, thin and almost transparent, but in some cases the cyst was constricted about its middle, and one-half of the whole structure would possess a thin clear wall, while the wall of the other half would be thick and opaque. On preservation in formalin the whole structure swelled shghtly and its walls became tense, doubtless by endosmosis. On opening the cyst an albuminous fluid exuded, but after preservation it was sometimes possible to open the cyst and “‘ shell-out’’ the contents as a clear semi-solid mass. As a rule, this showed no structure when looked at under the microscope, except a kind of froth appearance, due doubtless to incipient coagulation of the contents. Fig. 1, Pl. III, is a photograph of several of these bodies, nearly natural size. One compound cyst is shown, and several smaller ones. Some of the cysts showing a dense wall are also photographed, and a piece of germinal epithelium, showing a cyst on the internal surface, 1s also represented. At first sight these structures appeared to resemble cysticercoids; but no traces of a scolex could be seen on dissection, nor any trace of calcareous corpuscles, when the thin wall was examined microscopically without preparation. Sections were then made, and it was seen that they were mucoid cysts, somewhat similar to the bodies described in pathological works as ovarian cysts. Fig. 5, Pl. I, represents a section through the wall of one of the translucent cysts. It is thin, about SEA-FISHERIES LABORATORY. 2.03 0°06 mm. thick, and consists of several fairly well marked layers. Next the external surface is a thin layer of dense connective tissue fibres, and then a layer of rather loose areolar tissue containing round cells. Next the internal surface is an epithelium consisting for the most part of rounded cells, in places suggesting a cubical epithelium. For the most part it is broken down, but here and there are indications of the presence of mucous cells. Two such are shown in the figure containing large ‘“‘goblets.’’ This layer doubtless represents the remains of an epithelium which has secreted the mucus filling the cyst, and has been almost entirely disintegrated by the shedding of its products. Between these two layers is a broad one consisting of connective tissue fibres running round the cyst. Some of these are straight, but the majority are greatly twisted. Fig. 6, Pl. I, represents part of a section through one of the cysts possessing a thick opaque wall. The structure is obviously entirely different from that of the thin-walled cysts. The most prominent element in it is the mucous epithelium lining the interior—this is thrown into folds and prominences resembling the villi of a mammalian intestine. Part of one of these folds is represented in fig. 7 as seen under an oil-immersion lens, and fig. 8 represents a villus cut near its tip in transverse section. The epithelium is a columnar one, as is seen on the right in fig. 7. As a general rule, little of the layer exists in this condition, but here and there are relatively large patches of the unmodified columnar cells. For the most part, however, the appearance is that suggested by fig. 7, that is a ‘* goblet- cell’ epithelium. The “ goblets’’ are about 0:04 high, and are quite typical in structure: one of them is shown in fig. 7 with the section passing through its aperture. 9204 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The columnar cells are high and slender, and have their nuclei at the extremities away from the cavity of the cyst. Their free extremities are banded: a densely staining zone forms the free edge of the cell, and then next to this is a lightly staining zone. The external layer of the wall resembles that of the thin-walled cysts already described, and next to this . is a layer composed mostly of smooth connective tissue fibres. In this, however, there are numbers of unstriated muscle fibres, all running in one direction. Between this and the layer of columnar epithelium is a layer consisting mainly of loose areolar tissue. Elastic fibres, however, pass from the denser layer through this into the interior of the villus-like structures. There are some rather remarkable glandular bodies in this areolar layer : these are represented by the darkly stippled patches in fig. 6, and they are also shown in fig. 11 as seen under an immersion lens. They consist of groups of cells, sometimes arranged irregularly, but as a rule grouped round a small but most distinct lumen or cavity. The cells are rather of the ‘‘eosinophilous’’ type, finely granular in structure, and with small darkly staining nuclei near their outer extremities. These glandular bodies do not seem to be connected together, nor do they open into the cavity of the cyst. Blood vessels are very few in either the thick- or thin-walled cysts, but there are cavities in the thin- walled bodies which are filled with small lymphocytes. The cysts do not, then, appear to resemble any structures figured in pathological works. Yet they are undoubted morbid growths. A Phycomycetous Fungus in a Mackerel (Scomber scomber). A mackerel caught by Mr. A. Scott off Walney Island in July last, proves to have been infected by a SEA-FISHERIES LABORATORY. 205 fungus. It was at once apparent on opening the fish that the viscera were in a morbid condition. The liver was hard to the touch and granular in appearance, the whole surface being marked by slight rounded elevations from + to 1 mm. in diameter. The substance of the organ was friable and easily broken down. The kidneys presented a somewhat similar appearance, and the spleen was also affected. The fish was a spent female, and on slitting open the ovaries minute opaque bodies were seen on the folds of germinal epithelium. The peritoneum covering the pyloric caeca, particularly where it connected these tubules, contained great numbers of small opaque spherical bodies, varying in diameter from 0°32 to 0:05 mm. On dissecting these away they were seen to be attached together by delicate strands of peritoneal tissue. Cleared in clove oil they were seen to contain small round, granular masses about 0°04 to 0°06 mm. in diameter, each surrounded by a very distinct structureless capsule, while round that again was a fibrous capsule of variable thickness. The larger bodies usually contained several (from two to eight) of these spherical structures, each with its own capsule, while the aggregate was also enclosed in a capsule; exceptionally a much larger number was contained in the same com- pound capsule, but the usual number was small. A group of these bodies is represented in fig. 4, Pl. IT. Sections were made from parts of liver, renal organ and ovary. The infection is very intense in the liver, so much so that about three-fourths of the hepatic tissue has disappeared. Three main kinds of foreign bodies are to be seen. (1) Structures like that shown in fig. 1, Pl. I, possessing a very distinct fibrous capsule, and varying greatly in size. The larger ones are essentially similar to that represented in the figure, but in the 206 TRANSACTIONS LIVERPOOL BIOLOGICAL SGCIETY. smaller ones the capsule is much less distinct. (2) Groups of bodies like those represented in fig. 4, Pl. I. Some of these are capsulated, but in others there is no distinct boundary between them and the surrounding liver tissue. (3) Other bodies similar to the larger ones shown in fig. 4, Pl. I, each enclosed in a very distinct capsule, with an outer investment of — fibrous tissue. Between all these foreign bodies is the hepatic tissue, perfectly normal and well preserved in spite of the formalin fixation. The infection of the ovaries is relatively slight. In these organs the germinal epithelium is thrown into deep longitudinal folds projecting into the cavity of the organ. The epithelium itself is very thin and the ova are on its internal surface—within the folds. Among the ova, sometimes apparently attached to the epithelium, but in other cases lying quite loosely, are foreign bodies essentially similar to that shown im fie, 1) Pia They are, however, few in number, but still abundant enough to show up clearly when the organ was examined by means of a hand-lens. Fig. 1, Pl. I, represents a part of a section of the renal organ. For the most part the foreign bodies in this organ are of the type figured here. A fairly thick fibrous capsule surrounds a mass of tissue containing very numerous small nuclei. In the centre of this there is usually a thick, densely staining, structureless capsule, which is sometimes crumpled or collapsed, and usually empty. Sometimes, however, this capsule contains a round body like those shown in fig. 4. As a rule the nuclei are imbedded in a granular mass of no very definite structure, but sometimes they appear to be the nuclei of small cells lying fairly distinctly from each other. In most cases the intrusive bodies in the renal organ consist SEA-FISHERIES LABORATORY. 207 of this strong fibrous capsule, an ill-defined layer repre- senting the nucleated tissue of fig. 1 and the central capsule.. In many cases the body within the central capsule has burst the latter and has begun to exhibit vegetative reproduction. In figs. 2 and 3, Pl. I, such a case 1s represented—doubtless the beginning of formation of a mycelium. The tissues of the renal organ apart from these bodies are quite normal. Several excretory tubules are repre- sented in fig. 1 surrounded by small lymphocytes—all this is perfectly normal, and the fixation of the tissue is quite satisfactory. In a number of places both in the liver and renal organ, “‘nests’’ of bodies exist, lying almost loosely in the general renal or hepatic tissue. Such a “‘nest’’ is shown in fig. 4, Pl. I. It contains a number of small spherical bodies, each surrounded by a rather delicate, structureless capsule, and the whole lies quite loosely among the liver parenchyma. In some cases these capsules burst, and the contained body appears to be proliferating or budding. This is shown in fig. 2, in its first stage. In fig. 4 there is undoubtedly the beginning of a mycelium, and this is still more clearly shown in fig. 3, which represents part of a section of the renal organ. We have clearly a case of the infection of the fish by a fungus, and the growth of the latter within the organs. Dr. H. M. Woodcock, to whom I showed these sections, has drawn my attention to a paper by Plehn and Mulsow,* in which the causes of the disease called “ Taumelkrankheit,’’ by Hofer, are investigated. This is a disease attacking fresh-water fishes, chiefly trout, *Plehn and Mulsow, ‘‘ Der Erreger der ‘ Taumelkrankheit’ der Salmoniden.” Centralbl. f. Bakt. LIX Bd., 1911, Originale, pp. 63-68, 1 pl. 208 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. and characterised by lack of co-ordination in the swim- ming movements of the animal. It lasts for some weeks and usually leads to the death of the fish. Hofer found* that various organs in the animal were infected by an organism which he regarded, provisionally, as a sporozoan. They were contained in rounded or oval cysts, many of which skowed proliferation, or vegetative growth. Plehn and Mulsow were successful in isolating these bodies and cultivating them in artificial media, when a typical mycelial growth was produced. The appearance of this is represented in their figures. ‘They were able to show that it was a Phycomycete fungus belonging to the group Chytridinae, and they called it Ichthyophonus Hofert. Now I think there can be no doubt that the parasite here described from the mackerel is very closely allied to the species of Plehn and Mulsow, if it is not identical, but in the absence of fresh material capable of setting up cultures it is, of course, impossible to be certain, and I hesitate to make the identification. A closely similar condition was described by me in 1905.¢ Plaice living in captivity in the spawning pond at Port Erin Fish Hatchery became subject to an epidemic disease, characterised by extensive ulceration and death of the fish. Some of these fish examined by me proved to be infected by a fungus which I identified as a genus of Entomophthorineae, near to the form Conidiobolus. The appearance of the organism in these plaice was rather different from that written about here. A mycelium was established in the liver, and this growth was much more massive than that found in Mr. Scott’s mackerel. I attributed the disease and death of these * Hofer, Handbuch der Fischkrankheiten. Stuttgart, 1906, pp. 286- 289, Text-figs. 177-181. + Johnstone, ‘‘ Internal parasites and diseased conditions of fishes.” Ann. Rept. Lancashire Sea Fisheries Laboratory for 1905. In Trans. Liverpool Biol. Soc, Vol. XX, 1906, pp. 295-329, Pl. XVI., figs. 3-7. SEA-FISHERIES LABORATORY. 209 plaice to the effects of this fungus, but later cases of epidemic disease occurred at Port Erin, and the fish that died had all the appearance of those studied by me in 1905. An epidemic of this kind was studied by Riddell and Alexander in 1911.* Extensive ulceration of the fish was found, and an invasion of the body by certain bacteria. There were, however, no traces of a fungus in any of the internal organs. It is therefore likely that the fungus invasion and the ulcerative condition of the fishes studied by me were concomitant conditions; as in the case of the Saprolegnia disease among salmon. The ulceration and _ consequent weakening of the fish would predispose it to infection by the fungus, spores of which were no doubt widely distributed. In the case of the mackerel described here, there are, however, no external lesions, so that fungal invasion may therefore occur apart altogether from any wound of the outer surfaces of the fish’s body. Fibromatous Tumour from a Halibut (Hippoglossus vulgaris). In July last, Mr. T. R. Bailey, Port Sanitary Inspector at Fleetwood, sent me part of a tumour taken from the body cavity of a halibut landed by a steam trawler. The fish was about 4 feet 6 inches in length and was in fair condition, apparently quite unaffected by the presence of the tumour. The piece of the latter sent weighed about 1,250 grams, and was rather less than half of the entire growth. It was evidently a soft fibroma, and had developed from the peritoneum covering the viscera of the fish, where, precisely, is not certain from the appearance of the structure. It was fairly soft, easily torn, clean and compact on its outer surface, which was lobulated, the diameters of the individual * «Note on an ulcerative disease of the Plaice.’’ Ann. Rept. Lancashire Sea-Fisheries Laboratary for 1911, pp. 85-91, Pls. I. & II. O 210 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. lobules varying from about 14 inches to + inch. It came to the laboratory in the fresh condition, and parts were immediately fixed in Zenker’s fluid, cut and stained in various ways. Figs. 9 and 12, Pl. I, represent parts of the sections stained in Mann’s methyl-blue-eosin. The latter figure represents the most characteristic tissue present in the erowth—that is loose fibrous tissue, containing small rounded cells. The fibres run straight in the part figured, but throughout the section are places where they run in all directions. The nuclei shown in the figure are of two kinds: small elongated nuclei belonging to the connective tissue fibres, and larger rounded nuclei with a minimum of cell substance. These belong to small cells lying between the fibres. This is, of course, quite the typical structure seen in these tumours. Fig. 9, however, shows something rather different. This figure is drawn from a section made through one of the smaller nodular masses. Here © the predominant tissue consists of small rounded cells rather closely packed together, and with very few fibres. There are few blood vessels among these cells, but here and there throughout the part of the section nearest to the surface of the tumour are tubular structures. One of these is shown in the section. The internal wall consists of a layer of typical columnar cells, and outside this is a rather thick layer of coarse connective tissue, the fibres of which run concentrically round the vessel. Outside, there is no sharp distinction between the wall of the vessel and the surrounding cellular tissue. The fibres become looser and cells begin to appear between them. ‘These vessels are quite numerous in the outer part of the tumour. ‘They are, of course, a quite unusual feature in the histology of growths of this kind. ——— SEA-FISHERIES LABORATORY. Hel LT Melanotic Sarcomata in Skates (Raia batis). Several interesting cases of this condition may be recorded. On October 15th, 1912, Mr. T. R. Bailey sent me part of the wing of a skate affected by a sarcoma. The growth occurred on the dorsal surface of the left wing. It was very nearly circular in shape and very flat, so that it looked like a large pigment patch. On closer examination, however, it was seen that the growth was slightly raised up—one or two mm., and that it was surrounded by an area of pigmentation fading rather quickly into that normal to the skin of the fish. On 2dth October, Mr. Bailey sent me a further specimen which illustrates the condition of melanotic sarcoma production better than any specimen I have yet seen. The fish was caught by a liner off the coast of Ireland, 45 miles N.W. from “‘ Rathlin-a-Milley,”’ in 70 fathoms depth. It was a skate measuring about 150 cms. (nearly 5 feet) across the body. The wings only were sent. The fish was in very poor condition, the flesh being very soft, and the fish thinner than usual. It smelt very strongly of ammonia. Mr. Bailey, however, informs me that this 1s not uncommon in the stale,’’ ee case of skates or rays which have gone rather though I had not noticed it in any specimens of these fish hitherto examined, nor in any skates or rays dissected in the laboratory by the students, fish which are certainly very ‘‘stale’’ at times. This ammoniacal odour occurs ‘only in Hlasmobranchs, under decomposition. Doubt- less it 1s to be related to the fact that urea occurs in relatively large quantities in the blood of these fishes, and this urea may undergo conversion into ammonia compounds. The flesh of this fish was full of melanotic tumours. There was a very large one on the dorsal surface close to 912 TRANSACTIONS LIVERPOOL BIOLOGICAI, SOCIETY. the postpterygial cartilage. This measured about 15 cms. to 7 cms. in diameter, and it was raised up about 2 to 3 cms. It was very soft to the touch, having all the appearance of an enormous blister. On cutting into it a dense black fluid exuded, and the growth partially collapsed. The part of the fish containing the tumour was then cut out and hardened, and it was seen that it was a very large melanotic growth reaching down to about 6 to 7 cms. below the surface of the skin. Most of its interior was liquid, having evidently under- gone extensive necrosis. There were two other large tumours on the dorsal surface, measuring approximately about 5 to 6 cms. in diameter, and raised up 1 to 2 cms. above the general surface of the skin. They were dense black in colour, and without any appearance of integument on their upper surfaces. They were surrounded by black pigmented annular areas of skin. There were several smaller tumours, apparently without any pigmentation, about 2 to 3 cms. in diameter and projecting about 1 cm. above the surface of the skin. On cutting through these they proved to be large melanotic growths beneath the integument, which was unaffected. They were nearly spherical in shape. Several other pigment spots on the skin also proved to be similar growths in the muscle substance beneath the integument. Even in other parts of the fish, where there was no external pigmentation or other morbid indications, the tissues immediately beneath the skin proved to be affected. In these cases, when the flesh was cut into, there were irregular patches of dense black matter, some- times extending along the fibrous tissue sheets separating the muscle bundles, and sometimes even diffusing into the SEA-FISHERIES LABORATORY. 213 muscle bundles themselves. In text-fig.1, A represents the appearance of one of these larger nodular masses, natural size, and B in the same figure represents the appearance of one of the more diffuse growths. It will be seen that in A the tumour does not affect the epidermis and immediate subjacent layers, nor is the tumour raised up above the level of the skin. The muscle bundles Text-Fic 1. Melanotic Sarcoma in the Skate. Hand sections of part of the pectoral fin. Natural size. are pushed to each side, but it is evident that the intrusive tissue, although it may have spread along the connective tissue, intermuscular septa, has invaded the substance of the muscles themselves. In the neighbour- hood of these larger subcutaneous growths there may be a slight infiltration of the muscles with black pigment. This is not necessarily the growth of the sarcoma, but may merely be due to the breaking down of the latter, -214 ‘TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. and the presence of melanin granules in the lymph or blood vessels. It is evident, then, that in this specimen we have to deal with a generalisation of the affection, since most parts of the flesh of the wings show the presence of the tumour. That this generalisation was affecting the health of the fish was very apparent from the general, bad condition of the flesh. Unfortunately, the fish had, as usual, been gutted at sea, so that there was no opportunity of examining the viscera. The minute structure of the tumours presents several features of interest. In any specimens of skates and rays, presenting sarcomatous conditions, which I had seen before, the morbid growth affected only the integumentary connective tissues. It is true that this growth may have been massive, that is an extra- ordinary hypertrophy of the connective tissues may have occurred; still the underlying muscles have always been free from the morbid growth. In this specimen, however, large blocks of muscular tissue have disappeared, and their places have been taken by the sarcomatous tissue—as in Text-fig. 1. Fig. 2, Pl. II, represents a section through the margin of one of the smaller tumours—such a section as is shown to the left in the lower figure in Text-fig. 1. On the right, in fig. 2, we see the almost unaltered muscle fibres cut in transverse section, and on the left a relatively massive aggregation of sarcomatous tissue. Even in the latter there are spaces, and these spaces contain isolated muscle fibres. On the right, the malignant tissue, indicated by its melanin contents, is seen invading the connective tissue between the fibres. In the same section of which fig. 2 is a part, the central part of the tumour is entirely free from any SEA-FISHERIES LABORATORY. 215 remains of muscle fibres, and consists entirely of the sarcomatous elements. _ Fig. 6, Pl. II, shows very much the same condition, except that in this case the muscle fibres are cut longitudinally, the section is part of the edge of such a massive tumour as is represented in the upper figure (Text-fig. 1). It shows the hypertrophy of the con- nective tissue lying between the muscle fibres. The darkly-stippled part represents the fully-developed sarcomatous tissue: although the morbid connective tissue growth is taking place in the inter-fibrillar connective tissue, the latter. is not yet loaded with melanin. Fig. 5, Pl. II, represents some of the cells in a fully-developed part of one of the larger tumours. The structure is very obscure, but apparently consists of small rounded cells, some of which stain deeply with eosin and are very coarsely granular, while others are loaded with melanin granules. Along with these cells are masses of granules of melanin, resulting evidently from the breaking down of the pigment-containing cells. When treated for some days with hydrogen peroxide the melanin is bleached, but the cell body then stains with ‘ difficulty or not at all, and in most cases only the outer cell membrane remains visible after such prolonged bleaching. EXPLANATION OF THE PLATES. 7 PrAre ih. Fig. 1. Section through the renal organ of a mackerel infected with phycomycetous fungus. Large cyst with thick fibrous wall. On the left some renal tubules and lymphoid cells. The longitudinal diameter of the cyst is about 0°28 mm, 216 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Fig. 2. The liver of the same fish; a developing spore; about 0°127 mm. in diameter. Fig. 3. The liver of the same fish. Commencing mycelial growth of the fungus. Fig. 4. Part of a section of the liver of the same fish. Spore-like bodies, the largest of which is about 0°065 mm. in diameter. Fig. 5. Ovarian cysts in Lophius. Section of part of the thin wall of a cyst. Fine fibrous tissue with discharged goblet cells. The thickness of the wall is about 0°06 mm. Fig. 6. Ovarian cysts in Lophius. Section of a thick- walled cyst. Mucous epithelium with closely-crowded goblet cells. Goblet cells about 0°04 mm. in height, Fig. 7. Ovarian cysts in Lophius. Part of the section represented in fig. 6 seen under greater magnification. Fine columnar epithelium with large goblet cells. Fig. 8. Ovarian cysts in Lophius. Section through one of the villus-like projections on the internal wall of a cyst. Goblet cells cut mostly at right angles to their greatest diameter. Diameter of the “villus” about 0°1 mm. Fig. 9. Fibromatous tumour in Halibut. Tubular structure from the tumour. Thick fibrous capsule surrounding the tubule, the wall of which is composed of columnar epithelium. Outside the tubule small rounded cells. Diameter of the tubule about 0°135 mm. Fig. Fig. Fig. Fig. Fig Fig. 10. ate 12. 3. SEA-FISHERIES LABORATORY. GA Fibromatous tumour in Halibut. Small, gland-like tubule from the tumour. Diameter about 0°06 mm. Ovarian cysts in Lophius. Gland-lke structures from the submucous layer of one of the thick-walled cysts. Diameter about 002 mm. The darkly-stippled area in the submucous layer in fig. 6 shows the positions of these structures. Fibromatous tumour from Halibut. Part of the tumour showing its generally fibrous nature. Apochromatic lens, Zeiss, 1°5 mm. Prate If. Tubercular nodules in Cod. Section of the integument passing through a lesion. The oblique, dark, thick line is a scale. The darkly-stippled area is the tissues crowded with acid-fast bacilli. The thickness of the skin at the regions of the nodule is about 1°2 mm. . 2. Sarcomatous tumour from Skate. Part of the body musculature infected by the morbid growth. The light bodies are muscle fibres cut in section. The darkly-stippled area shows the locus of the sarcomatous tissue. Tubercular nodules in Cod. Section of a nodule stained with methyl-blue-eosin. Zeiss apochromatic 13mm. Thick fibrous tissue surrounding nodules of obscure structure. The finely-stippled parts are the loci of the bacilli. Fig. Fig. ‘Fig. Fig. Fig. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 4. Phycomycetous fungus in Mackerel. A group of small cysts attached to the peritoneum over the pyloric caeca. The remains of the peritoneum are represented by the fibrous structures connecting the cysts. The diameter of the largest cyst is about 0:04 mm. Sarcomatous tumour in Skate. Section of a fully-developed tumour. Rounded cells with melanin granules. Rounded cells with clear granules, or almost homogeneous cell substance. Broken-down cells and diffuse melanin granules. Zeiss apochro- matic 2 mm. Sarcomatous tumour in Skate. Section of the edge of one of the larger tumours—the elongated - bodies are muscle fibres in longitudinal section. The finely-stippled parts are the hypertrophied connective tissue; the darker-stippled parts represent the tumour. Zeiss AA. PLATE Ta. Ovarian cysts in Lophius. Natural size. Cod with tuberculous lesions in the skin. Half natural size. Sarcomatous tumour from Skate. Hand section through part of a pectoral fin showing tumour in situ. Natural size. Photos. by A. Scott. Pirate J. MORI DV STOLOCT TOE ISHES: Pais IL MORBID HISTOLOGY OF FISHES. RG. B Puce aL. Prare. LET: MORBID HISTOLOGY FISHES. Photos. by A. Scott. SEA-FISHERIES LABORATORY. 219 A REVIEW OF PISCINE TUBERCLE, WITH A DESCRIPTION OF AN ACID-FAST BACILLUS FOUND IN THE COD. By D. Moorr Auexanper, M.D., Assistant Lecturer in Bacteriology, The University, Liverpool. The literature concerning the occurrence of tuber- culosis amongst cold-blooded animals is extremely scanty, and with one exception relates to the inhabitants of fresh water. . In 1897 Bataillon, Dubard and Terre published an account of an organism found in a granulomatous tumour , of a carp, and Terre, in 1902, reported more fully upon the subject. This bacillus was non-motile and acid-fast, its optimum temperature of growth lay between 23°-25° C., though it would grow at 12°C.; it belonged to the streptothrix family, as it showed branched forms, and in most respects agreed with the characteristics associated with the tubercle bacillus. Apparently identical with this organism is one isolated by Moller from the spleen of a blind-worm which had been infected a year previously with the sputum of a tuberculous patient. Mdller’s bacillus has an optimum temperature of 22°C., development ceasing at 28° C. It grows upon ordinary agar to form a glistening white growth. In broth and upon albumen- free media it shows branching of its filaments. It is non-pathogenic for, and non-transmissible to, rabbits. Kuster (1905) found tuberculosis in three frogs out of 200 examined. The organism grew well at 28° C., was pathogenic for frogs and other cold-blooded animals, and was toxic, but not pathogenic, for warm-blooded animals, 220 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Weber and Taute (1906) isolated from fresh frogs, from aquarium mud, and from moss 36 strains of acid-fast bacilli, all of which were pathogenic for cold- blooded animals and harmless for warm-blooded animals. A large amount of experimental work has been done attempting to prove, firstly, that the organism affecting cold-blooded animals is a changed tubercle bacillus; and secondly, that it is possible, experimentally, by passage through animals, to cause the tubercle bacillus of the human or bovine type to undergo a metamorphosis into the cold-blooded or piscine type. Terre (1902), without success, injected and fed fish and frogs with cultures of human and avian tuberculosis. Dieudonné and Herzog (1903) showed that frogs inoculated with tubercle bacilli do not die of tuberculosis, but may contain tubercle bacilli in their organs as long as 60 days after the experimental infection. They also showed that an emulsion of these organs can cause the death of a second frog, and an emulsion of its organs frequently produces a typical miliary tuberculosis when injected into a third animal. If these bacilli be now cultivated they show all the characteristics of the bacillus of piscine tubercle, being pathogenic for cold-blooded animals, but no longer for warm-blooded animals, and grow readily at room temperature. It has, however, not been possible up to the present to restore the human or bovine characteristics to these organisms, for failure has resulted from all attempts to successfully immunize a rabbit against them. Bertarelli has produced tuberculosis in Varanus by sputum injection. Hormann and Morgenroth, Nicolas and Lesieur fed fish (fresh-water) with human sputum containing tubercle SEA-FISHERIES LABORATORY. 921 bacilli without result. No tubercular lesions were ever produced in the fish, but these authors showed that acid- fast organisms were to be found in the tissues and organs of these experimental fish, and were viable for a month at least after the feeding experiments had been _ stopped. The relationship between the various types of organisms characterised by the acid-fast staining reaction and isolated from cold-blooded animals, and those organisms which belong to the well-known human, bovine or avian types has been the subject of much study by many authors. The question has not as yet reached a final settlement. Two authors alone of the many engaged in this research have succeeded in producing an organism, originally isolated from a cold-blooded animal, which they could accustom to grow at a temperature of 387°— the optimum temperature for organisims isolated from human sources. Friedmann’s bacillus isolated from the lung cavity of turtles grew well at 37°, and Aujesky, after much trouble, obtained a strain of the bacillus of fish tuberculosis which would grow at the temperature of the body-heat of a warm-blooded animal, and was even pathogenic for the smaller laboratory animals. Dubard, Bataillon and Terre believe that the bacilli of fish tubercle can become human tubercle bacilli. Morya, Auche and Hobbs, Lubarsche, Sion and Herr do not believe that fish tubercle bacilli are produced by the passage of human tubercle bacilli through cold-blooded animals. Sorgo and Suess have proved to their own satisfaction that human tubercle bacilli can be transmuted into the bacillus of fish tubercle. From the point of view of this note, it is to be 229, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. remarked that no close relationship between human and piscine tubercle has yet been proven, and that no work has been quoted as yet bearing upon acid-fast bacilli in salt-water fish. Only one paper has been found bearing on this point, by. von Betegh, of Fiume, and his communication deals with experimental fish, and not with the natural occurrence in fish. | He injected varying amounts of an emulsion of a virulent culture of fish tubercle bacilli into six salt-water fish intraperitoneally or intramuscularly. The, fish chosen were three Sparus annularis, two Mugil cephalus and one Servanus gadus. One Sparus annularis injected intramuscularly with 02 c.c. of the tubercle emulsion twenty-two days after the inoculation presented a small tumour at the site of injection. When this was incised it was found to consist of a sinus of pus and blood ‘containing acid-fast bacilli in large clumps. At the bottom of the sinus a tubercular nodule was found showing giant cells. The Serranus gadus injected intraperitoneally with 0°2 c.c. of the emulsion developed tuberculosis of the swim bladder. All the other organs were found to be normal. None of the other fish mjected showed any symptoms. PRESENT INVESTIGATION. In November, 1912, a portion of a cod obtained at Fleetwood was sent for bacteriological examination. The surface of the fish presented six dark-coloured areas suggestive of lupus in the human subject, and varying in size from a threepenny-piece to that of a florin. After a thorough washing with sterile saline, an aseptic instrument was employed to scrape the patches thoroughly. The resulting débris was deposited in three bottles labelled A, B and C. ee SEA-FISHERIES LABORATORY. OS Bottle A.—The contents of this bottle were covered with 20% antiformin solution, which consists of equal parts of soda chlorinata and 15% lyuor sodae, and possesses the property of destroying all other organisms but those which are acid-fast. After remaining in this sohition for one hour the deposit was thoroughly washed with sterile saline to remove the antiformin, and then inoculated into twelve tubes of Dorset’s egg medium, and incubated at room temperature. Bottle B.—The contents of this bottle were treated as in Bottle A, but after thorough washing were injected into two guinea-pigs subcutaneously. Bottle C.—The contents of this bottle were emulsified in sterile saline and injected into two guinea-pigs subcutaneously. Some large pieces of tissue which could not be broken up into a satisfactory emulsion were inserted under the skin of the abdomen of two guinea- pigs. Since the bacillus of tuberculosis found in cold- blooded animals rarely possess any pathogenicity for the ordinary laboratory animals, there was no expectation that generalised tuberculosis would result in the guinea- pigs. These animals were inoculated in the hope that they would serve as an incubator, and were examined every few days for glandular enlargements and for any lesion at the site of inoculation. Only the two animals inoculated with large portions of tissue, untreated with antiformin (Bottle C), showed any reaction. A week after inoculation both animals presented a swelling at the point of injection about the size of a broad-bean. The examination of the two. guinea-pigs was conducted on different lines. G.P. 37. Thirteen days after inoculation the swelling burst, discharging a creamy caseous pus, and 994 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. showed a tendency to form an ulcer. The animal was in good health. It was killed, and a thorough post mortem made after smears and cultures had been made from the pus. All the internal organs were healthy. The pus was found to consist almost entirely of polymorphonuclear leucocytes. Many of these were filled with acid-fast bacilli congregated in clumps or bundles consisting of from twenty to forty separate individuals. The microphotograph shows the arrangement of these clumps, and also a few organisms lying outside the leucocytes. The second animal inoculated from Bottle C (G. P. 38) with actual masses of the fish-material showed no tendency to ulceration, and was kept under observation for five weeks. The swelling at the site of inoculation showed at no time any tendency to burst, and soon diminished in size until on the 38th day after inocula- tion, when the animal was killed and examined, no trace of the injection except a small nodule of scar tissue was to be found. This scar tissue on section presented the SEA-FISHERIES LABORATORY. 225 appearance of chronic inflammatory fibrous tissue, and no acid-fast bacilli were present. No internal lesions were found. The other four guinea-pigs (G. P. 34, 35, 36, 43) inoculated from the emulsified contents of Bottles B and C at no time showed symptoms, were killed on the 38th day after inoculation and presented no lesions. The cultural results have been unsuccessful in that a pure culture of the organism has not been obtained, and hence it has been impossible to study fully its relationship to human tubercle and the other acid-fast bacilli. The organism has been kept alive, but only in a symbiosis with a Gram-positive coccus. When dilutions are attempted to produce a pure culture the organism dies out at once. CoNncLUSIONS. It has been shown that an acid-fast bacillus is present in a skin affection of a cod resembling lupus and containing typical tubercles. The organism is non- pathogenic for the guinea-pig, and does not grow at 387°C. It grows at room temperature, but so far only in symbiosis with a coccus. 226 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. BIBLIOGRAPHY Dubard, Bataillon and Terre. Cent. f. Bakt., XII, p. 61; Compt. rend. Soc. Biol., 1897, p. 446. Terre. “‘ Essai sur la tuberculose des vertébres 4 sang froid.” Dijon, 1902. Hormann and Morgenroth. Hyg. Rundschau, 1899, p. 857. Kolle and Wassermann, Vol. II, p. 130. Nicolas and Lesieur. Compt. rend. Soc. Biol., 1899, p. 714. Moeller. Cent. f. Bakt., Abt. I, Ref. XXXII, p. 619. Sorgo and Suess. Cent. f. Bakt., Abt. I, Orig. Bd. XLITI, 1907, pp. 422- 547, Morya. Cent. f. Bakt., Abt. I, Orig. Bd. XLV, p. 422, 1907; Bd. LI, p. 480, 1909. Kral and Dubard. Rev. de la Tub., 1898, p. 129. Dubard. Bull. acad. de med., 1897, p. 580. Friedmann. Deutsche med. Wochenschr., 1903, Nr. 2. Bertarelli. Cent. f. Bakt., Abt. I, Orig. XX XVIII, p. 405. Dieudonné and Herzog. Minch. med. Wochenschr., 1903, p. 48 ; Cent. f. Bakt., Abt. I, Orig. XX XI, p. 84. Kuster. Miinch. med. W ochenschr., 1905, p. 57. Weber and Taute. Arb. aus dem Kaiserl. Gesundheitsamt, 1906. Auche and Hobbs. Compt. rend. Soc. Biol., 1897, p. 929; 1898, p. 13; 1899, p. 816. Lubarsche. Cent. ft. Bakt., Bd. XXVIII, p. 421, 1900. Sion. Cent. f. Bakt., XXVIII, p. 710, 1900. Herr. Zisch. f. Hyg., XX XVIII, p. 198, 1901. Retegh. Cent. f. Bakt., Abt. I, Orig. LIII, Hft. 4, 1912. SEA-FISHERIES LABORATORY. 227 REPORT ON THE HYDROGRAPHIC, PLANK- TONIC AND OTHER PERIODIC CRUISES OF THE “JAMES FLETCHER” IN 1912. By W. Rippet1, M.A. The positions of the various Stations are shown in the chart on page 234. Surface temperatures and water- samples were taken at all Stations. At Stations 5, 6, and 7, water-samples and tempera- tures were also taken, except where the contrary is stated, at 30 metres and near the bottom. For the deep samples, the Nansen-Pettersson insulated water-bottle was used in the earlier cruises. Since September the Ekman reversing water-bottle has been used. The plankton samples were taken with the Nansen vertical net of No. 20 silk and with surface horizontal tow-nets. MAY, 1912. Quarterly hydrographic cruise. May 7th.—Worked Stations 1-7. At Station 7 samples were obtained only at surface and 30 metres. A vertical plankton haul was made at Station 6. Surface temperatures were also taken at Piel Gas Buoy, at the Skerries, and between the Stations. May 8th.—Stations 8-13. Surface temperatures between Stations, and at Carmel Point, Middle Mouse and Point Lynus. Ran to West of Isle of Man, and trawled 7 miles W. of Contrary Head; townetting while trawling. May 9th.—Stations 14-21. Surface temperatures between Stations, also off Piel and in Ramsey Bay. 998 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. May 10th.—Stations 22-24. Also surface tempera- tures between Stations, and at Bahama Bank Lightship and Lune Buoy. JUNE, 1912. Monthly hydrographic cruise. June 3rd. Piel Gas Buoy and between Stations. June 4th.—Stations 5-7. Plankton hauls at each Station and half-way between Stations. Surface Stations 1-4. Surface temperatures at temperatures between Stations, and off Douglas Head and Langness. June 5th, Buoy. 212 fish marked, ranging in size from 19 to 36°5 em. June 6th. haul of plaice measured. Trawling and marking plaice off Nelson Trawling off Selker Lightship; large JULY, 1912. Monthly hydrographic cruise. July 1st. Piel Gas Buoy and between Stations. July 2nd.—Stations 5-7. Plankton hauls at each Station. Surface temperatures between Stations and Stations 1-4. Surface temperatures at off Douglas Head, Langness, Skerries and South Stack. Townetting in Carnarvon Bay while trawling. July Srd.—Shear-net plankton hauls at various localities in Carnarvon Bay and Cardigan Bay. July 4th. Cardigan Bay. Ordinary surface haul while trawling. Shear-net hauls at various localities in JULY, 1912. Quarterly hydrographic cruise. July 29th. Piel Gas Buoy, between Stations, and off Langness. July 30th.—Stations 5-13, omitting 8 and 9. Plankton hauls at 5, 6 and 7. Surface temperatures Stations 1-4. Surface temperatures at SEA-FISHERIES LABORATORY. 229 between Stations, off Skerries, and on course from Station 13 to Ramsey. July 31st. between Stations, off Point of Ayre, and at Lune Buoy. SEPTEMBER, i912. Monthly hydrographic cruise. September 10th. tures between Stations, at Piel Buoy and off Langness. September 11th.—Stations 5-7. Plankton hauls at each Station. Surface temperatures between Stations and off Skerries. September 12th. Bay and Cardigan Bay. September 12th.—T'rawled off Liverpool Bar. Good haul. 2038 plaice measured. Stations 14-24. Surface temperatures Stations 1-4. Surface tempera- Shear-net hauls in Carnarvon OCTOBER, 1912. Monthly hydrographic cruise. October 7th. between Stations, at Piel Buoy and off Langness. October 8th.—Stations 5-7. Plankton hauls at each Station. Surface temperatures between Stations, off Calf of Man, off Skerries and off South Stack. Shear- net haul in Cardigan Bay. October 9th.—Trawled in Red Wharf Bay. Fair haul. 68 plaice measured. October 10th. 1,200 plaice measured. FIRST LUCE BAY TRIP. October 21st. October 22nd.—Trawling in Luce Bay; 13 hauls. Put 230 fish in tanks. October 23rd.—Landed 100 fish at Port Erin for Hatchery; remainder taken on to Piel and landed in evening. Stations 1-4. Surface temperatures Trawled in Conway Bay. Big haul. Ran from Piel to Luce Bay. 230 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. NOVEMBER, 1912. Quarterly cruise. November 4th.—Stations 1-4. Surface tempera- tures at Piel Buoy and between Stations. November 5th.—Stations 5-7. Plankton hauls at each Station. Surface temperatures between Stations and off Douglas Head, Langness and Skerries. November 6th.—Stations 8-13. Surface tempera- tures between Stations, and at Carmel Point, Middle Mouse, Point Lynus and Douglas Head. November 7th.—Stations 14-21. Surface tempera- tures between Stations, and at Point of Ayre. November 8th.—Stations 22-24. Surface tempera- tures between Stations, and at Maughold Head and Piel Gas Buoy. SECOND LUCE BAY TRIP. November 19th.—Fleetwood to Luce Bay. Trawled on Bahama Bank; fish scarce. November 20th.—Trawled in Luce Bay; 10 hauls. Put 171 fish in tanks. November 21st.—Landed fish at Port Erin. Ran to Red Wharf Bay and trawled; fish scarce. DECEMBER, 1912. Monthly hydrographic cruise. December 3rd.—Stations 1-4. Surface temperatures between Stations, and at Piel Gas Buoy and off Langness. December 4th.—Stations 5-7. Surface tempera- tures between Stations, and off Skerries. Plankton hauls at each Station. December 5th.—Trawled in Red Wharf Bay, Conway Bay, and off Rhyl Patches. Fish very scarce. JANUARY, 1913. Monthly hydrographic cruise. January 7th.—Stations 1-4. Surface temperatures between Stations, and at Piel Buoy. SEA-FISHERIES LABORATORY. 931 January 8th.—Stations 5-7. Plankton haul at each Station. Surface temperatures between Stations and at Douglas Head, Langness and Skerries. January 9th.—Trawled off Point Lynus and in Red Wharf Bay; fish scarce. January 10th.—Trawled off Colwyn; few fish. FISH-ECC CRUISE. January 20th.—Trawled 10 miles East of Point Lynus; tow-net out while trawling. Townetted off Carnarvon Bay Lightship. January 2ist.—Trawled off Penkilan Head, using tow-net. Townetted in Tremadoc Bay, and 223 miles S.S.W. from Bardsey Island. January 22nd.—Trawled, using tow-net, off Patches Buoy and off New Quay Head. January 23rd.—Trawled and townetted 25 miles W.N.W. from Piel Buoy and off Maughold Head. FEBRUARY, 1913. Quarterly hydrographic cruise. February 3rd.—Left Fleetwood, but owing to wind had to-shelter in Piel. February 4th.—Stations 1-4. Surface tempera- tures between Stations and at Piel Gas Buoy. Trawled and townetted 25 miles W.N.W. from Piel Buoy. February 5th. deep samples taken owing to heavy sea. Surface tempera- Surface samples at Stations 5-8. No tures between Stations, and at Douglas Head, Langness and off Skerries. February 6th. between Stations. February 7th.—Stations 14 and 17-21; Stations 15 and 16 were omitted owing to bad weather Surface Stations 9-13. Surface temperatures temperatures between Stations. 232, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. February 8th.—Stations 224-244, from 1 to 2 miles away from Stations 22-24, on line from Maughold Head to Piel Gas Buoy. Surface temperatures between Stations, and at Maughold Head and Piel Gas Buoy. FISH-ECG CRUISE. February 18th.—(Mr. Ray was in charge of the scientific work on this trip.) Trawled 25 miles W.N.W. from Piel Gas Buoy, and on line between Bahama Bank and Selker Lightship (three hauls). Vertical hauls were taken with a coarse plankton net at Morecambe Bay Lightship, between this and Bahama Bank, at Bahama Bank, between Bahama Bank and Selker Lightship, and at Selker Lightship. Surface hauls were taken at the same Stations, and also when trawling. February 19th.—Trawled 5 miles W. by S. from Selker Lightship, using surface tow-net while trawling. Landed fish at Piel. February 20th.—Used shrimp-net on Blackpool grounds, using surface tow-net at same time, also 1 mile S. of Blackpool grounds. February 24th.—Trawled and townetted at follow- ing places: —Duddon Buoy, 1 mile 8. of Duddon Buoy, and 10 and 12 miles W. from Duddon Buoy. February 25th.—Trawled and townetted 20 miles N.W. 1/2 N. from Piel Gas Buoy, and 24 miles W.N.W. from same. Landed fish at Piel. February 26th.—Trawled and townetted 10 and 15 miles S.W. from Morecambe Bay Lightship; also tow- netted 10 miles N. of Great Orme’s Head. MARCH, 1913. Monthly hydrographic cruise. March 3rd.—Trawling for fish for Piel. Trawled and townetted 15, 18 and 22 miles W.N.W. from Piel Gas Buoy. Fish scarce. Landed fish at Piel. SEA-FISHERIES LABORATORY. 933 March 4th.—Surface samples and temperatures at Stations 1-4. Surface temperatures at Piel Gas Buoy and between Stations. March 5th.—Stations 5-7. Plankton hauls at each; . catch at Station 5 lost by tearing of silk on bucket of net. Surface temperatures between Stations, and off Langness and the Skerries. March 6th.—Trawled and townetted 5 and 10 miles E. of Point Lynus. Fish scarce. The plankton samples of these cruises will be reported on by myself in a separate paper below. The water-samples and temperature observations will be discussed by Mr. Johnstone and Professor Bassett. The records of marked and other fish will also be dealt with elsewhere in this report. [Chart showing stations over page.| 934 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Neve nieko ie D ito SI wo $5 Pyar) ne pate ER TN es cots SEA-FISHERIES LABORATORY. Dow REPORT ON THE PLANKTON OF THE PERIODIC CRUISES OF THE “JAMES FLETCHER” IN 1912-13. By W. Rippett, M.A. The plankton observations made on the “‘ James Fletcher ’’ during the year may be divided into two series. There are first the routine vertical hauls made with the Nansen closing net, 35 cm. in diameter, of number 20 silk. These hauls are made regularly on the hydro- graphic cruises at the following Stations; (see chart on p. 234); at Stations 5, 6 and 7 on all cruises, and at Station 14 on the quarterly cruises The net is lowered to 20 fathoms and then hauled vertically to the surface. There are also a considerable number of horizontal hauls made either with the ordinary surface tow-net of book- muslin, or with a shear-net of embroidery canvas. ‘These have been taken at various places throughout the district. Nansen Net OBSERVATIONS. Unfortunately we have not as complete a series of these as we had wished for. Owing to various causes involved in the starting of a new scheme, and especially to unavoidable delay in obtaining the new nets from the manufacturers, we were not able to use a standard net until the second quarterly cruise, which was carried out during the end of July and beginning of August. Various temporary substitutes were used on the earlier cruises, but these, while giving some indication of the nature of the plankton present, cannot be used for comparison with the later hauls. Further, the weather during the cruise at the beginning of February, 1913, was so bad that we were unable to use our nets. 236 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. We have thus only 22 hauls which are strictly comparable, 2 hauls at Station 14, 7 each at Stations 6 and 7, and 6 at Station 5. If we consider first the two hauls at Station 14, in the northern part of our district, we shall see that they show a marked difference. 31st July, | 7th Nov., Station 14. 1912. 1912. Calanus) finmarchicus®) -2.c2.-2-ceeees-sseee ee eee eee ee 50 17 Pseudocalanus elongatus — ............scceceeseeeee eee 1,400 1,450 Acartia) clausi. << s.os<-52.tesasdeesesseee~nd-2 2s sssmeensent 950. | 200 QOithonaysimilis eioecs2 22. ses sos oc pea soesessncee-cece esses 550 300 Wemora longicorais: fc. te eec see sects ers- sence eee ee 250 | <> == ampli: oss ct ee et ne A 3,100 | 1,350 Sacitbasbipurictatas an. sss eee neta eee sees 80 | 2 omopteris hel golandicayeres--eceeeee tree ee =e eee cece pi _ Polychactilarvaer: s-etos seer tee eet eer amas esseere — 100 Med usoidS)}: 52.2 Jascccaqsocseat ease sceeeesraaseebocessonecee 8 ] Pleurobrachia) pileusigy-s-s--sscssese ease eee oe eee — 1 Pintinmidae. 2325.32 LFA... ashes see eee cee acess cos eeeeeee — 1,450 INoctilucagmiliarish) ec sre-ce-s1soee erence eee ase cece — 100 Orkopleutardioicavesseses-c-ceeeese reese eee eee eee 150 — BReridiniumdivercens |. os-cssesceseereceree sheen essere 160% — Ceratium: Pura cscs 25 1.cese sc sesscsescctsesteece ee eoneeer | 150 100 i TUSUS Ge vesccd Sucscaacesceatessenecteess sevens 5,300 100 oe Intermedium) csssncsac eee es eee shee nee eee 4,700 | 725 Asterionella, japonica ites. --.--teeeeseeenee eee se ee ee eee = 300 Biddulphia regia* ssc ccs- on -c-eeae este eens sect eceeeee = =, °950 AS SINGNSIS) Wo Sosenke See ese tee nce gece ace seuss esse = ; 520 Chaetocéras' debile = .:2,<:5.cssce esse eceeeeeteseeeeee see — - 625 ‘ GEGIPICNS) \5.¢.uisccceess-cecounenensrss scene — 2,800 55 GENSUM: 2.25 scescdec tates tees cosa ascent 450 400 = Gidiyantimnay «252 see noes eee nee see cee ace — 500 A schiittii — 4,150 Coscinodiscus | concimmnus)-sseeseseseaee se eee eee eee = 100 = TACGIAGUS”. | ci cooncestenoeeeceecs Goce aaeee _ 600 625 Ditylrmybrichtwel litte soessscesteene eaeeee essere == 200 Guinardtayilaccid ais. si-sss sce: eee see eee 8,000 — Rhizosolenia semis pla aessetes ese see eee eee een eee 3,750 — 3 shrubsolet. osc. sAecse secon se ecsene ores 11,400 — is Stolteriobhit. Sess eae eee cence 224.700 = Streptotheca/thamensis.2-2-.4-ess---eeeeeenecse-ee eee = 400 Thalassiosira @favida ..27.2cte$e- seen eo eee eee _— | 1,150 * This does not imply that this form is to be regarded as a distinct species from B. mobiliensis. The haul on the 31st of July shows a well-marked autumn plankton, consisting mainly of Copepods, SEA-FISHERIES LABORATORY. WT Dinoflagellates, and Rhizosolenia. On November 7th there is a decrease in the numbers of Copepoda, and a marked decrease in the Dzinoflagellates, while Rhizosolenia has disappeared and been replaced by other Diatoms. We may note here that a surface haul in Luce Bay on October 22nd showed Rhizosolenia still present in the inshore waters in fair numbers, but other forms, Biddulphia, Chaetoceras, Ditylium and Thalas- siosira, had also made their appearance. This succession of forms in autumn corresponds to what has been observed at Port Erin. If we contrast these two hauls with those taken at the more southerly Stations (5, 6, 7) on corresponding dates, we shall see that while there are some points of resemblance there are also some marked distinctions. As regards Copepoda the result is much the same, the drop in numbers being, however, more marked at the southern Stations. At both localities Pseudocalanus is the most common Copepod in November, while Zemora has disappeared. Sagitta also shows a_ correspondence. Rhizosolenia, however, is different, being still present at the southern stations in November. But the most marked difference is in the Dino- flagellates; here the two localities show directly opposite conditions. At the southern Stations Dinoflagellates, except Peridinium, were absent at the end of July, while in November they appear to be at their maximum. They are still present in March. The Tintinnidae also show some resemblance. At Station 14 these were absent in July, and present in fairly large numbers in November. At the southern Stations they were present in July at Station 5 only, and in comparatively small numbers. In November they are present in large numbers, though they appear to have 238 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Sept. 11th, 1912. LD EI eAR aaa Sn Ra oho aadonebadsoacodcocreaddueboaadoocone July 30th, 1912. lation: Sisssacancaries somes cose cmec terlenkinseeace tee 5 6 7 5 6 Calanusiinmarchicus) sssescessson se senesedeeeeees eee 600 | 130 14 45 40 Pseudocalanus elongatus, ......-..-c.c+.scessseeseeaeceoraces 4600 | 3500 | 300 | 6000 | 2600 Terenas NernesteeMS scosdoeeoogacn00p00b00s000000080900u0000000 3750 | 1150 | 200 | — — WNCATtIa ClAUISIP -ape sonneiccsmemicgee aman sev saaseeenece eee cee nee 5600 | 2300 | 200 | 3000 | 900 Oithona iSimiillts! csceece alesse sonelcememelesisaisievisttesemeiseeiee ss 400 | 200} — 450 | 300 INDO, _Seoccodsgedcedsdea4eq000060000090000 2008 oGoDKIEG0C0adNsa0000 12700 | 8800 | 2700 | 4000 | 3400 Rodonsimbermecium\preere-recesee ree eeee ee eceece eee eee retrace a — — 150 | — WecajodManvac meres ceeeaccceetec ec erectseeeer eee crs — 1 DNGTOIMEROENC! NEVPWEV conacaoso0n0 sa a00000noD00nC0De0Hs00N00000000000 — — SHUG, LOCI, cescosnnoocnsnncobanstics ocosoooN050000003000 32 22 12 23 12 omopterisuielsolandteayeererersrerestcrres creer rece rtes = = 3) = 1 Rolychaetylanvale ercsec-cesececr science cree merrier — 205 = Hehinodermiyplutenmer crete secesecesscaceeece se see ee ease reece — 100 | — a0) | == Medusoid gonophores .........-.cessecsceeereeseeeeeceeeseneees LON 2 = Noctilucapmulianismasense recreate reece ect eeeeeneer — — 100 | — = MIAtIMMIGASL: Lasoes qqenes doses ical erie otaissemencee setsost site 400 | — — | 6250 | 1700 DGi@E Nes TOE, ccocageconsnuancc00cncoc0annsqsH5000000000050006 — — — — — ikoplemmayGioicay —hsctaseceacges secon lane seme teosesee semen 100} 300; 100; 300] 300 Bericiniuml Sposa soe see soseese sm esce nes eesecscecsccsces a 830 | 100) — — = IDO AVES AOU, o66 coc onnonsossscodcoecnsnsboson0Ha0K00n0000000 — -— — — — Ceratiumeturca: Acuy.pemce cacectinnsistietesinls voecebeeeteosce — — Pes FUISUS doecicccenod cea ee uaobs dae sete eaadasaronsacsererece — — — — — és Intermechivn” >» s.ssbasees cheese nck pastiddsweeedces — — — 150 | — ah TOTTI TES, coc cgononconcnsunccousvscasc0c0psAd 000000000008 — — a = = oD (AY TOScaddsosagadocuocwsoscsascbonsoqcossocd0cedoos009006 — — Actinopiychuspundulatus jeeecsceeeceesssssseee smectic — Asiieriornellll, Ty NOTICE, conocopsoodcnnbeon ab cD0q5000Danc0GG00N000 — — — = 300 Bacillaria paradOxa) <....6..0:2+.scccscsee me snerce reece sensee = — — = = TByiGlslUNfO AME, TBI, — cagacooooc0s ons nn0s6n0000GK500s00000006000000 = a AMODUTENSIS ween eree eeeeee ee eee nee — a — = — . PO DLA! per ige sins se/eelscises ee apien wecltoaree se deaaens — — — 150 150 i SIMENMSISY | seeeierecets sere eeeeictontemee nau sae ee oeieer — —- — — — Chaetocerasscontortumiy epee eee cece eee eeeee ee _ — — — — es Guo oorilowin coocobsoosscscsnsoona009sa0q50090000000 — — x Gk cill Ere ans gochoaauscnehdardauncauadhvohanovancanascs — — _— — — “5 GECIPIENS ) ose capisree seen aepostsiesenecacisaact eee — = 1350 — 1850 aS oVeyatsnb bith autem MeHEn ER Ue ban saasoRan akananDaocdosbodds — |13400 | 1600 | 4400 | 6750 5 (ol tuoynmibes We | edonemanaconaorcocoruccciobodessacocaso — —_— — — — 35 SOCIBIS? bo 1c) S.S. ‘* James Fletcher.” 3 hauls by police cutter ‘‘ Piel Castle,’ Fleetwood Station. 257 SEA-FISHERIES LABORATORY. TOYO] Soumve ,, ‘Gg Aq s_ney ano Tf SEI G61 a ii = 6 ae I G a7 6 I OT i OT G G 7 OT OT ol 0G 9 Il 8 €1 L G 9 OT L 8 L 6 Li i OI G Il 8 a7 9T I ST 6 €1 G al I OT ARIA, judy “yueg e[AoH 389 0K “290, | £| | | |-sess | 86 86 Ill —— I i — [ —< —_—— G —= —_ G — — G I = I T = € I = — I = == [ = I G I —o — € T = I L € cs II I 8 61 I 6 9g G GI 66 G GI LIT II él POL 96 al | GG &@ II 6&1 GT L GZI GL I €9 I — 7 I “ony “ATE ‘oune qudy ‘jeuuvy) 9sa0H] “UOT}RIG UOJYPSUG MON ..“[[ UYOR ,, 1099n0 doOg ‘ydag SIL SF6 I oS GEG = = G-OF I — G-6€ aa G G-8¢ = I GLE I if “€-9§ I I G-Gé = G GE i G G-¢ i aa GE € == G-1E I € G-0€ G € G-66 G G G86 € 7 G16 i” € G-9G L 9 GGG €1 9 G-¥G &P LG G&G PE 6€ GGG 6G 1g GIG OL 08 G06 9 SL G-61 66 Gl G81 86 Sia | GLI Iél PLT G91 G9 8é1 GGT LT SP GFL 6 9T G-é1 G G GGL = a GIT = = G-OL ‘ony “Ane ‘eq [OOdaeAT]T avon a 019249 uoyysg “MONT . TU uy, Po aqyno eoT0g LZ 10¥ 1982 GZS FOES 61 2z8 F06E — — — — — z = — G-LZ — — = = = a = — G9 : f= — —- 6 — I -— — G-GZ a = 7 I z as = oe = FG a — = = z a = = — G-8% 5 = = z I a € = al GZS 3 = = € ¢ an I a = G-1Z is —- — T F — ¢ = — G-0Z zi — — I 91 — = — — G-61 C — — L ial — G = — G-8T co) —. — &Z cE = G = j G-LT S = I 08 19 = or = T G91 © I = L181 1g — 61 — ¢ G-GT a z i SLE GZ = GI ¢ G G-FT ie Z g IGF 19 = SI II 12 G-€I i) € SI OLE III 66 htt GS II G-Z1 o 63 IP GOES LL Ee 81 99 Ne GTI fe 67 IL £9 9G 6g Il GI +6 G-O1 a Ee oF Z8 rae FOE €1 +P ‘7a G-6 ig 1g 9 9¢ FF 8F9 8g 69 GL8 G-8 iB LE 09 9¢ SF 798 FI 9LI S61 GL Z 9¢ LY 101 og PoE 3 Gg St9 G9 A GZ oF OL 1g S01 = L9 Z9E GG fB i G 8 02 ial = == 8s G-F < alee bal ees %; | : *Iequieseq | “loquloAON, *19Q 0400 “Youle “Gorey “Areniq a7 “AIENUBE “Arenue pe a } we ‘jeuueyyO ‘jouueyyD ‘jouueYyO, : 1a. Rosa ‘jouueyO ‘jouueyy *‘jouueyy ‘jeuueyO | N Os1OFL yoory yooy aoe nee os1OPL yooy osIOF] yooy ‘Ysoul [MBA Your-jyey ‘Aaengsq Aosaoyy SEA-FISHERIES LABORATORY. 259 Red Wharf, Beaumaris, Conway and Colwyn Bays. May. see lt | | | 14 10 BD DD DD DS DD ND ke et tt et TUB WISH SO WAID MH WIS Or Ot Ot Ot Ot Ot Ot Ot Ot Or Or Ot Ot Ot Or Or MI et te otha! Ittcrteos 60 June, PIPL LTT IPE LT) 1] el eee ron omen 340 8.8. “‘ James Fletcher.” July. PPT IEP LIP LPT TTL 1 Peel croc | amo am aeane! | | | | 116 Aug. LI TTT LT TT Lee | reer cam itm 08 1084 Sept. | Oct. Nov. Dec 1 == — — 2 1 — — 1 6 = — 3 48 3 — 12 323 28 2 18 936 65 7 22 1065 75 31 25 751 43 82 19 478 32 80 12 334 21 92 15 272 14 59 8 200 15 69 6 113 6 58 8 92 9 34 7 74 2 27 3 65 1 28 7 AQ 3 14 2 44 2 13 3 30 3 7 1 18 3 11 1 12 2 6 1 15 — 6 = wi —- 5 — 5 — 6 1 7 — 1 ll 3 = — 1 7) 3 —_— 2 — 4 es 1 ame ae — 1 — 2 ae 3 mae whe ) = = = Ea 1 EER = = — 1 = = — 1 -- ~- = 1 178 4955 330 650 | 260 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Menai Straits. Jan. Feb. Mar. April Aug. Nov. Dec. 14:5 15-5 16-5 17-5 18-5 19-5. 20:5 21-5 22-5 23:5 24-5 25:5 26:5 27-5 28-5 29-5 30:5 31-5 32:5 33:5 34:5 35:5 36-5 37°5 38-5 39°5 40-5 41-5 42-5 43-5 44-5 45-5 46-5 47-5 48-5 49-5 50:5 PET PP PEEP Pel Pet Led et rome | rrr Somon! | | PET TP eP PEPE ETT ET TT TPE Terre coe im me 00 e929 | ST a We) etescarsisiics) FI elt leminmmearmeacie | — | | ro | on | ames | sreumes | AHA Pemadanwanacn | | ret a ec te tl coll I Pause: (or) rs HPs ~J bo GO [Se bo le) GO. ho (Se) rs — GO nee Police cutter ‘“ Eric,’ Carnarvon Station. SEA-FISHERIES LABORATORY. Carnarvon Bay. April. May. | June. | July. Aug. Sept. 261 10-5 11:5 12-5 13-5 14:5 15:5 16:5 17-5 18-5 19-5 20-5 21-5 22-5 23-5 24:5 25:5 26:5 27:5 28-5 29-5 30-5 31-5 32:5 33°5 34:5 35:5 36-5 37:5 38-5 39:5 40-5 41-5 LA ded deere I a ab ay nS I Da ee esd enol IP TP a J Lo A De er trees al eel Pease Ft I) — ee) LJ J LJ el | ccm momar | | | | | | HweumaScocoml! ||| | | | Ltd stbetheatolh tt) bi bo bo 36 | 135 61 Police cutter ‘‘ Eric,’ Carnarvon Station. * S.S. ‘‘ James Fletcher.” 262 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Tremadoc Bay. Mar, | April.| June. | July. | Aug. | 12-5 13-5 14-5 15-5 16-5 17-5 18-5 19-5 20-5 21-5 22-5 23°5 24-5 25-5 26:5 27-5 28:5 29-5 30:5 31-5 32:5 33°5 34:5 35:5 36-5 37-5 38:5 39-5 40-5 41-5 42-5 43-5 44-5 45-5 46-5 47-5 48-5 — bo WNWAWDODPOONUWWHAH® PUI dd esletiscmol PETTITT — is 4 | 297 12 Police cutter, Pwllheli Station. Near New Quay. Sept. | Oct. | Nov. | Feb.* |July.* = = — 1 a = a 1 1 — |{|—] = 1 3 = 2 == pees 4 — }|—] — 3 9 — | — |] — 2 7 SS | = 5 | 16 = | = 1 2 9 = | = 1 ASS © iil — 2 | -— 6 dems _ 34) — S| D0 4 |. |e 5 A haats = 4 | — 6 ae 2 1 1 12 gene =) =|) = 8 ies 3 | — | = OsmaTS =) =) = 6. alate =| = | = 5 7 = | =| = 4 2 = | = |) = 6 2 cae = = 3 i = |= | — 1 1 ates — 1 2 1 io) = = = = 3 aes as = = 1 = = | =} = if = as —_ a= 1 = aes = ae il = 11 10 3 | 106 | 232 * SS. ‘“‘ James Fletcher.” 2638 SEA-FISHERIES LABORATORY. te leeeleweleeelevelon wee leewleeelene ee leeeleeeleneleneles tele welewelaeeleseleesleeslension OOOO IOC Oi Iciniod Ieicicn (cicied (rire isin walter lee nleeeleenleeelesslone Ce eleeeleweleseleselene TSN ODO OD = wale weleaelewelenelensleeclons seeleeeleoele eee leeeleseleerleceles eeleeelene ereleweleeelene ol vol [resfeve|eecfese|ers|oeefoee|eeeloes|ece]onelowsfees|eee| a leds calfe |podkaod fos 1 aalae mabe say [evefere|ore|eeefteefesefece|eoeloee|ocelers|eselers|eests wig ecefesejeee ters L [trclescfeecleecfeeelecelees|ees|eesfas Fala 1 60 [58] fo00)fpoal baal pae| [bool Roalbsoal heel laoclfs ® |b por enoleed bed bee Bee bee os ee ene bee ed Fs be Be L [eslere|teelers|ere|teelere|eer|teelece|euefeen|ors]. | vifevely [eeefesefees ele lee ah iF cooly fever] le feesfeesfeecfeee[ers|ereferelerefersters zt sol [eve[eeclees 17 {f229|0e|p0d food boc roti. [evefevefeee Tete Ecc leealraa eaclat Tee Z [ere[resltvelece|ere|ecs|enelsneleen| votle |eoeferefere @ peele feelers: lecsyereerelese Tee peers eee Lp eel: , te] lees|ers|ece ae ee reaper li (po porlbad bax z [eeeecefens vosle | [eee leee vey vo0ig) |essloesfee ley (eeelees polos (ke bootear LIT bebe F3poa|pod ioc 5 |balpoo z le con) fporteacfpeo lets 7 leoe| Bile lreclteeltes @ [erferfee [pooper fc z |ere|ees 2 {ka [pse|pedocofice [ond fooo)flfaoeoodfaao vesloqiecltes lee: ore gu lereleae Olt eelerles: Tee Fy Ifo con Dae ele retlg [eecfeerle fp [oeefeeel lt leqieclestee: omit fle: Brereleerlg leecleee ter: Fyilpoe popes Sy bed pod ee Fy pes pec 116 kolelg |g fel fede fq freslee: orig [ecle: Fy [peaocrlbool=y |paclfaca| poe Bp ele [pod poaes BS, Npoctr litle belle |g ig i ieee LG ka |paapoa|poal oss fonfa z le bole 19 [eels Gig ferelg te lel p le colt UT feelers ¢ |e [ele & [erelere|ese T tess Liz bole Te ele LIt bolero Peletele Ig vel ip [eeelees BIg (eels: & leeelers|enel- mbes poms peeled 1 vafeeefesefeeely vefeolg Posnenelta) eee leeelene L oa O00 Ke) eerleee oll] eelewele Ce Oe Or re i) an | AF Riles oA{fe. |e2}h0d Aca] oq oe pec] 368 pact bad fsea oq ad |>ee kea|poclbo4 sce| bod poo pooled bad sha fsaah ope] op poe 1 nelant vag [resfenefees|eeeletsfone|seefieclieelece|ereone[enclevefecs|ereleneloes VE (2 |L |F \€ |e |L |F |e |e |L |F fe [o |L IP |e [a |L |F S [o II | Ie |e |x IF Ie oI IF Ie |e It IF fe) sg 6 £ 6 £ }$ £ 6 “SI6T “1940900 “ZIGT toquioydog ‘SI6T “snony ‘I6T Aine “I6I ‘ounr ‘CIG6L ‘Av ‘Sh6) ‘punory poso[g [oodyoviq ‘Kong uosjeN avon :sdnoryg of y ‘TOW GNY XS ‘HLONAI— II I it [kee ad face steele Neale a Poor af pele dlsetee|asalh le le le [eeleeelees vl [reefs ly Flay leer eae “lg cle |p leclely | oe) 00 Cn ale OU T le (ere ecst: Ig We PAP dF ba bax Alt € | |L |F € io fo) P = 1D UD 1D 1D 19D 1D 1D 19 19) 19-19 19 19) 14) 19) 1H 19 19.19 ASHOOCRAOOnAHHMOOr NAS NNANANAA A A OD OS OD OD 6D OS OD OD OD CO SH GIG TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 264 eeotee ee ecee eeeeee eeccce omeece weecee weeepe ovecee eeccee eeeeee DW 10 HSH OY OO ecceee eee eee eeecee eeecece eee eee eecees eeeeee ee ceee eeeeee eccece |e weeee eeccee eeecee G I eee eee a eeeee eee eee weer el tee eens sees eee ceslesceee ee cc ee lee cess eeceee sec eee see eee Il ee eeee ee eeee ee eeee a eeeee eer ecclone Pewee lee ces(ececee DOgOnos OC ieiCiil igic i iii? DOs ci iciinl Icio icin Rein iin niin) eee ceelecsseelecesce Tote eet eee see ceeleseeesleeecce GOs tn icninl Iginicinry eee c es lececee Sees circa) ee eeee eee eee eee eee ee eeee eeceee eeceee ee ceee eee eee see eee wee eee mst OD OD LD et et SH eeaeee eeesee eee eee eee eee neces sa eeee sence ee eeee lor) eee eee GA OD rt CO 10 NH eee ene ences ences Dogo’ (Onieiciriy se ecee eee eee NAO ONICD OD | Bee eel tee eee eee) scenes eens eee eee sees eee eee scenes I eeeeee teeces Onn eeecee ences eee cee Sion ee aeee ee eeee ee cece Oo) se eeee ee eeee ee eeee ee ceee sec eee eee eee ee eeee eee eee see eee weceee ewes etc eee eee cee LT ea is ie OS Ba ances sees se eeee cece es cceee eae eee ee eeee 0 G I 0 F F F F NNN N NAN AN OI OD OD OD OD OD UD UD UD UD WD UD A] UD WD ACD 1D AWD UD UD ID WD 1D 1 1D 1D 1D 1 1} 19 19 1D 19 19 1D 19 3) ‘3 6 2 “GIGI Ge AON “GIGI “290 “GIGI “1940990 “GI6L ‘Ane 216) ‘Auenjsq Aosaoy SEA-FISHERIES LABORATORY. 965 joo BU ee eer a | | B Sve Ceres eee oes oe ee eee : G8 | (or) Or sos ss tS OD Om AN SAN 6 AS | = [Se es ee oe S a8 8 8 4 [eee eee Non eee She = [|S 8S Be 8 OS Sea a a mie Oyo oersynce Geea: to feos 5 | Pee ee ee: 3g ® ¥ z= SIS o 21s PMI SIesOI=IegnensnC GED IS Gions Gon aie = | (a) Senses chet seca eens = Bo Ce Rue ©. Roe ADR ie to ri ee Rea BERS EERE tee ee ee ie mee [P38 ese See eam iae en no eer 3.8 818) SIS WeM) eI Ge) Sto 88 8 8 bos 8 Bo 88 BIR 8 3 GASES Cl COON Tin Naar p Rone aaron mG monica el Jel plas Sieem cee ous Meyx ce: liom fetvitemt ol celtisli se” «elites hey piel weman enh us Wo ROM oP «Mee Weisel ay «figs meme ell e/a ken el le prea is oft helMit olga (ue Sem hen ely cent @lMnenmeu Terence Seep eee ee oe ee eNIGImIOIGG fe 6 8 Nov., 1912. of 2) CaCO Geis 65 es =a ee CIE SSG) SP Pe SG ee PE ee nee l Mee emis eae Grn ceca Sele Soaps wee te gees oi [ e238 Dem MRE ei COLOMCNICOI IG ch Sth OT seecupagae cae a compet ce: : cs er eorne Re end Cine oer aon Tale S oe Sen IROOM SSeS Foe fe eae esq oe = | : So a re = . . . . . . . . . . . . . . . . . . . . . . . 2 EELUEEEDEC Le Sor ee = SoS 8 8g) 6 gBNe So) SNS NeGICO—IOIGON Otic Raeeauin cane 2 : ey | SSS SSO SSoponess |: sins a: 2: 2: a 2] 3| 4) 1| 2| 3| 1) 2| 3] 4) a) 2 3] 4) 1] 2} 3} a! aj 9) 3} aj al 3 4} 1) al al 4 SUR e eis © loan oll“ leanlonr(s Sale a Isreltst ery Shred ive) Geen an oan ean ee petal Gels smn eh Sipe eaters cgi siopetes feu “ieiisy) (a ‘aie 9:78 . ‘ele op wet tie) \kes efi tel vue: el [fe eur sje vege) Ae 3 ee le Tm COICO: Caicoreichareatl ems cr aires bcs tera Bevin nuns 5 . Loma! ° oe . . 8 oe . 66 . June, 1912. | O By 0) Qa "on OOo SS io 8 iSh ono! 08 OlLD lon Oglomo. JON ceso— ol Wollno S 1g 16 UD 1D 1D UD 1D WD UD 1D 1D 1D 1D 1 1D 1D 1D 19 19 19 19 19 19 19 19 SHAMHOSRDASHAMHDOSORDASCHAMHOOLDAS SIN NNN NAN NAAN 0) OO OD OD OD OD OD OD OD OD SH Date. Sex. a = i>) = La > Gs} jaa) i=} Pp ES = (e) cS) > o [2a] a) : : ; iS 5S : ; ce 8 : Wel SSI =o : f= i or | | Ts OES OD NO NOD ae : : oT = | Se Ppaepeseee pp:::i:pr:s : ae .S) S Santee tees : : rae ets oes aN EE SED ie eraeri ay e g g 3 gl : : es | = BECEECCCS CoS eee pQ wD po i EI a Pe CUCM CONS] C= COrCO| uN unm Vici et tyes SRD sqne gos m (“] 2S eNO eee eo ee 5 Rte SoS Oe ee ee SF SY cep Se 6 SS =I $s $8 8 8 8 Bassists Bee 88 bs ees eee 8 8 = aie fs er fara] - | Gor GO eee Rae ee 2 8 : TREC ese: u & | Ns a: Se ee ee et ae ka ey: > =) a : a | Tr: = ; ae ; : : ; : : : ma [Skee See ere eee cp 8 Sele eghem g s °3 (Eee ee es ta oe ees a e a oe oS 8 6g BOICUCICI ICING) ayo OlGn nee Eco MOmENS (coe D =) se 22 een Pe eee open ene er ae il So O90 Oe Ol! OL the Centoe TOL yoles DEeNG < a 5 | So 88 8 8 eB Se Bees flees Rigi See Seen ee 619 Bie ua) 5 [co soe ee ee TOO OCDINO AS cs: :::s::i:t:ii 2 |e ie Se ee Nee oe es 44 Oe Oh athe NOs et Ae TC aOR SC ED BMD MEG es “sae Sok eas 2: 8) StU e 8 aap 5 8 19 3 oo 8B 8 1b 8 8 : [Ol Bee Spee eee TSI] G Ge Se Uae ee Se See ee iM SSO ON oc a [=| 22s 8 fs be Fe ee ee Pe ees eueee buses pupeers. es eS a] Sel Sy Ss & TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 266 5 } P ¢-OF G-6§ G-8§ GLE G-9§ Ges GPE eeelesclecslocs sleee Sood ieieied eitied iniiel nie) tle eelee ela waleweleenleesleesleceleselecelenclscalen G-ge eeeleecleeelece slows Peele seleweleceloveleaeloveleeslerslocelecs|seelece sleeeleecleovloe G-ZE ee eleenleeclene elece tee lecaleceleceleralevcleoeleneleeelees|seslecslece sleweleesleeelseclecelee DOO Oo iio Ionic ciriel (einen inter ecclece oa eeeloee G-Tg pool ceclece oleee eel eee leeeleccleceloreleeelencleee|ens|seclessles eleceleesleos|occlecs|ee we eleeeleesleceleeclensle ajooctiooclke I eeclecs C-0E werleesiecclene eleee seeleesleceleeele tieeeleceleealeselecelece slows lecelerelecclecelee seelee epaono eeelee I Sealpoolh 4 € weeloee C-6Z DO OOo iene nities ieinel nine ier DIS OC Oil ioc leidil isiriel isc irri icicles (iris ecelece|ecalace see se eleeeleasleeelen Ego} oncHlonaIs00Kkg on ee G-8g OO Sided anil ieigy (ore iene cries T erelecelecclcoeloe T looo|ooo,00 se efeeeleesleccleeclevele eeelee srles Fé ecclecclocsiece T T oe “1 eeelee CLG OO Sigg eine! sical (onic ieiciel aici I weelecelece(on er anlee|eale 5/000) joo se lenaleceleceleceleeeleeuleeelonslecelevsisusleeclees 200|s00Ifo00|/o001 6 eee C-0% CSUR | ecclece 2907 eeelece seelocclece silleies|ieceleee|seclese|ee oT [ee ele eel eeeleweleseleneleaeles IT eeclee COO 7 t eee G-GZ OOS (tie inicio ino! iecirt se eleccleceles ayes aell ies | cool oe Spal coscalh seeleeelensloe eal eeclecs eeelecelee opo|fe € eee G-FZ eeelee I ecelece “NT T e002 o|[Pec||poaliaoallr eeelee ‘IT POo|GRE FE ele iel|isie I . s00l@ Nie DoH Odio Inieiol Isiciel isiniol Iseicl inc IT ¢g cal Zz z eee G-8z eeele aC eesleee eal % weeleeeleeele 16, TI ee eleee elect eee sleeelae aaa |Z wee leee IT Pocike . Peele e ele erlecclsesiccclon € € oP e 9 eee G-ZZ oe Tle eeclene coolke Zz S984 on molrg seelee gor see ‘le € 2007 I oe I if sale weeleeelewelee . reir eee BDb son}o00| 3 iF eee C-1Z eeelee G Bod ond T 9 200i I Z Bua Po a orf fess “Je1@ oe lp oe ra Pani bd BOG IED E Ob | sess seelee 1G seelee wag oe C-0% coelee I Zz eee ole I stele I I IZ seeleeelece weelace . c oe sl oe eT . 1Z IZ Baa}ooolke pono . . 1Z ae oop esike eee C-6T we eleesleeeleveloes . lz eerlece € @ Z Z eesloee ‘l-loqle VeTly Boal epa|iocolh 2 DIS Cio Ion inno igri Ieiriel Iiriry weeleccleceleccle 13 * G-8T DO! Sigg edie! (oaiol iaicig| (oir icie peers ci) staal cst e ol eorloee ai ore) ¢ 219 a I eeele enol? I eeelecelecsleecloceloes eecleeslensles He eee G-LT DO) Stil nite! isda! ect einen nici a oli eeelevelee coolke eorleee 2901 Poolooolke c eee 1Z 200\/o00}/900||oo0|ono}}oq5 1500 eeeleeele 2 [Psa fess eles c-OT OO ein iene ioral Isniol iin ici se epeeeleeelenslenele woelecclecelove efor elerelecsleeclecelenuelone assesses eoele erlocclee woes eeslecele illu ae G.CT OOO nicl iris (ori Irn OS Sod onil initio nicl iniriey inries etry eleeeleeelecslenelecelas sesh ee . zl S600) Iolo! Inigo Isieiol ein! Isreal icici . ee elecsleeelencleveles CFI DOG ood! intial enn! (aici aici ier eoele seeleeelen . eal eee | Sogo odio! lone Isinion cic! iar s(t melee eleeel ene eeeleneleeeleaslenalecels 9a0|/o00{o09|[o00}}000)/000 00 G-ET OOD tial inno ioral (aii incline) weal welensleeeleeslncsleveleeslaueles | slew eleeeleweleceleeeleneleveleeele spteele weeleccloceloesioe eeelecslece eles eee @-ZI OO Sno! ioniol ein ors! Isreal nr Ooo eiiel ieicio icieiel ior} tele eleeelsesloeslereieecies slecele sees ecclecelee sales | . on woslecelecel|eceioe . C-IT DOD) tial ieniol aici! sec iret nr Belew eleeelenelensleccleceles ae ies OOOO ongiol lninicl Ieiies Icicicl inieiea inirien Inia Iniry ee se levsleaele sin ellleies|ies eae eaaeal esl Ss C-OT | | | ¥ \€ |¢ II IF |€ (2 € |é |I |€ |e | |e fo [0 IP |e @ IT € |G jC |€ | |I |€ |@ jE \€ | IL \€ |e IT eg \2 IT € |6 |G |F (€ |@ IT ‘ {e) ¥ fc) e GIGI “90°ed ‘sqteaqg reuoy GI6I “AON “‘SPIBIAG TeUOT, “GIGI ‘Ae “‘STRIYG TeUsT 3 £ S| O41 Ss. } 2 “CIGT “Aqne ‘Avg UOAIeUIR,) GIGI “oune | “Ber ‘AEN ‘Avg woAreuIed ‘Avg uoareuled SIGT “AME “Keng MON IeON ‘ley ‘skeq uoAaeureg pue uesipaeg SEA-FISHERIES LABORATORY. 267 Sex and age of 4,054 Plaice captured during the months October to March, 1909-1912; Anglesey to Cumberland. Sex Male. Female. Age Group I. 1, Il. IY He Il. Til. IW Mean | length. 9-5 2 — = f= — = — — 10:5 1 — = — 5 — — — 11-5 3 = — = 7 — — — 12:5 13 = —- | — 6 _ — — 13-5 11 — — | =— 12 — _ — 14-5 26 2 — — 18 1 — — 15:5 69 16 — — 64 15 — — 16-5 149 57 — — 142 43 — — 17-5 178 133 — — 142 81 _ — 18-5 161 147 2 — 127 144 1 — 19:5 99 125 a — 72 146 12 — 20-5 56 125 6 = 51 117 Il — 21-5 28 115 10 — 21 126 11 — 22-5 9 88 _4 — 17 109 14 — 23-5 9 75 10 — 15 81 7 — 24-5 5 50 10 — 8 64 14 — 25-5 1 4] 16 1 3 50 7 — 26-5 — 36 11 1 1 29 12 — 27-5 — 39 14 — 2 17 14 — 28:5 — 13 13 2 1 12 13 — 29-5 = 9 9 5 4 10 18 1 30:5 — 2 13 5 3 7 9 — 31-5 = 3 5 2 1 7 11 2 32:5 — 3 8 1 — 2 11 — 33:5 = = 3 — — 1 3 2 34-5 — 2 2 4 — — 6 4 35-5 — — 2 4 — = — 3 36-5 — = = — — = 2 1 37-5 = = = 1 = = 1 — 38-5 — — 1 1 — = 2 1 39-6 = = = — — — — 1 40-5 — = = — = = — — 41:5 = = = — = = — 2 | ee | 820 1,081 | 146 27 722 1,062 | 179 17 268 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY, Lengths and Ages of 4,348 Plaice, irrespective of sex, captured during the months October to March, 1909-1912, Anglesey to Cumberland. Age Group 0 If, | Il. TIT. TVE Mean length. INO?) |) No: No. No. No. 5:5 9 = = = == 6-5 47 — = = = 7:5 60 — = = = 8-5 44 1 = — = 9-5 6 22 = = — 10-5 2 14 == = = 11-5 = 26 = == = - 12-5 = 35 = —= = 13-5 = 37 = = = 14-5 == 61 3 = = 15-5 = 158 31 = = 16-5 — 300 100 — — 17-5 = 320 214 = — 18-5 = 288 291 3 = 19-5 = 171 271 19 —_ 20-5 = 107 242 17 — 21-5 = 49 241 21 — 22-5 = | 26 197 18 — 23-5 = 24 156 il7/ — 24-5 = 13 114 24 = 25:5 = dee le © 101 23 1 26-5 = Te © 4) 165 23 1 27-5 = 2 56 28 — 28-5 = 1 25 26 2 29-5 = 4 19 27 6 30-5 = 3 9 22 5 31-5 = 1 10 16 4 32:5 — = 5 19 1 33:5 = == 1 6 2 34-5 | — = 2 8 8 35:5 = = = 2 7 36-5 = == = 2 1 37-5 = i | le. 1 1 38-5 a = = 3 2 39-5 = = — = IL 40-5 = = == = = 41-5 = = | = = 2 168 1,668 2,143 325 44 SEA-FISHERIES LABORATORY. 269 Il]. Average Values of the Co-efficient A during the years 1911 and 1912. S oe 3g | Eee cultse ese me ga-| ent] Fishing SSeeeco 2 Spc = a 23 | ae Ground S32.) Bos | eee = Fa | 2A AS |@ = BS | 8a = = nee wm aay ® o | rs) Ss | Jan. | 0-964 = = — 0-971 — = Heb | — =) — —_ — Whee) == —_ 0-834 5 — — — = April | — c= == = oo a May — — — — = = = 1911 June — — — — — — —_ uly. a? 0-974 | 1-15 0-918 = — — IN|) es 0-991 | 1-14 0-996 — — — Sept. 1-06 1-06 1-04 = = — Oct. | 1-04 -= == No Denil =< a = Nov ees — | ine _ = — Dec. = = 1-01 = = — Jan. _ = = = = = — Feb. = -- — — = — = Mar. = = | = | = = = —_ April — — = | = — — — May = 0-981 = | 1-45 1-06 — 1912 June | — 1-03 = 0-992 = 0-991 = July a 1-03 0-995 1-03 = 1-00 0-987 Aug. — 1-05 — 1-03 = = Sept. — 0-997 — | 1:00 — — = Oct. — 1-06 0-812 | 1-03 = — — Nov. — — — | 0-958 0-921 — —_— Dec su ey == 7) 0:994 | 0:s00"| == = | 270 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. EXPERIMENTS WITH MARKED PLAICH DURING 1912. By Jas. Jounstone, B.Sc. Three experiments were made in 1912. The first one dealt with 212 plaice, which were caught in the neigh- bourhood of Nelson Buoy on Sth June, and were berated on the same date. At the end of the year 26 of these fishes had been returned. The second experiment was made on 38rd October, when 153 plaice were caught and liberated, also in the neighbourhood of Nelson Buoy. At the end of the year 26 of these plaice had also been returned. The third experiment was made in Luce Bay on X2nd October. At the end of a day’s trawling for spawning plaice for Piel and Port Erin Hatcheries about 45 of the smaller plaice caught were marked and liberated. At the end of the year only one of these fish had been returned. It is, of course, too soon to attempt to summarise the results of these experiments, since the fish marked will continue to be returned for another year. The migrations made are, however, charted on pp. 308-5, and are there discussed in relation to the movements of plaice in general which accompany changes of sea- temperature. Tables showing the details of the recaptures for the year 1912 are given here. 271 SEA-FISHERIES LABORATORY. LT LT Le LT LT Nh LT LT LT LT LT LG LG LT oangd ep jo Pod J ee Ee ee ‘SULO UT yysuey ur osvorouy GPG *SUI0 UL poangdeooyy|ommgd eoory uoy A. qysuoT 6LL'8 GL'9'86 GL 9'G6 G19 G6 GL 9'G6 GL 9 VG GL 9 el 619 GI 6L9'6 jo o4eq “ SLOP OT “G sureog drysyysry avg yo sop OT Ronee: suOygeE TT ‘Aong, WOSToNT WOT *AA*N SoprUt ¢ BRORnARe eo eeeeaer ‘ers KONG UOSTON WOIT “\ANE opr 3 “ suroygey BT ‘drysqusiy avg joodaoary woaz *\\°N popes Hreeeerereresesurouqez FG] ‘oodyourg woay “Ay societal sees diysqysiry Avg oqureoosoy Jo “A soprur g srereeees SUTOUGRT QT “ae? JOOd toaAL]T WO, “NY SOPIUU FT nostetaaeanicte aeacbaogasoadesn: - sumoygey LT ‘Avg oquieoor0qy sss vassessarsassenecessaserse*esees 1OOCMOGTE JO “A\ SOI OG tee eeseee Peete eee eee e weet sete enenes poodsportg jo “M SOLU 0% RSOCSICOSIO MO OCCCIgC CO Cicer icicle) poodspoerg yo “M SOpLUL 0Z Peete treet eee erst eee etesseesees ee eeeee Aong UOSTON OpIsNg eee eee e cece es eeeeee SULOY RY 6 “Aon UOSTON ULOdT “AACN Pere terre eee w eerste eee sasene SULOY} RT alt ‘AC oq ULROOLOTA[ ‘opnyzisuory pue opnyyeT omngdrooy JO oe] q ‘GIGI ‘IT GNUWIUGaxy ‘SULO UT poyeroqiry UoYAL yysuay 986 VI OLZ WI G83 WI 696 VT 096 VI PLE WT 893 WI OST WI PPS WI 991 WI 68s VI 663 WT 086 WI TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 272 “M&F Ls 8 LS ST T'SI "N /81 ofS ‘M8 oP Is g GLG errr "N JST ofS "M {SS of bl F GE ZLSI'6 "N G3 0&6 "MS oP LS G GZ SS |) INGE BS "M ,2G of Thi G F& SLIT 0G | “N,ZG o&¢ "M ,ZS of Toll t¢ LG GL'O1'8 | “N,18 o& r “MM ,0E of ILL {Z &Z G16 GS "N 93 o&S z "M ,9E of LI fg GZ G16 FI "N /ZP ofS is “MA LG oo Jal §¢ G-1¢ ZT6 11 "NSE 08S “M 166 of Lt € GS CL 6'F “"N PP ofS "MM 83 of LI I GS Z1'8'61 "N /8S o&¢ "MA PE of ail ¢ FZ Z1'8'S1 "N , IG o&S : “AN 61 6S LT £% G-8S ZS'SL "N USP 08S f “AA ,0G of LI $1 CLG Z1'8'6 ND GS) ogo “SuULO ul -gingdeo “Sulo UL poangdeooyy ‘omydeoary “opngiouory jo yysuory ur Uo jo Oye pure poyyseyn OSBI1OUT qyouey Opngyyey “ore suLOUqEy BT “AryswYysry wueyeg “G'g'g sept OT Soe ie ii diysyysry RULey eg yo aS SOpTUr G Ce ny SULOY ZV eT ‘peop § SULIO ears) TO “+ SULOYyRy GT ‘prop S.owug year Yo "nN Aq “A\'N treseseeeeeeeseeseressesseeseeeeteesesees DBE § OULIC) JBOD “MTT ‘sucoygey g ‘diygsqusry reg Joodaoary pure drysqysry “\\‘N [oodasoary. woomyqog: Teeeeeeserssereses STULOUZRT GT ‘AON oqeIsuoH ysoA\ FO COS i iii i iri iri) poodyporrg jo “M SOyTUL 0Z tereresseeeeees SuTOUqey FL ‘AISI SvYT eq “A\*N seyrur g SULOY} CF GI “YW sulmoq iMoy, joodyortg ‘Avg joodaoary vseeres Cryspysry Avg oqurwoorxoy, ULOAZ “oP NY SOTTUU P popenErGoABooDUSAo IIE jyj9 (OMAN EH 91 oodsperg JO Jsvolqy teeteeeesresteseerreesresseers surouger g ‘Kong WOSToN, CASH sop g Surteoq digs 4) swmoyqey op “duysqysiry aeg “g'g'q, sopur z 1G 1G IG 9G ‘omngdvooy JO ov] q "sULO UL poyeroqry uoyA\ yyouey panuyuoj—ZI6l ‘J INDWINaaxT 686 -V'T OFG Vl 8c WI 966 VI 896 VT She VI 86 VT 1g¢ VI Gh VI 96 VI IL6 VI GLE VI C6L VI 661 WTI “Pq JOON 273 SEA-FISHERIES LABORATORY. ‘oangdey jo pouyn ‘suo UL yysuory ut osRvoLOUy "SULO UL poimmgdvooyq|oingdeooyy uoy A yjouey GUILT LE i EC CL IL &é GL IL €% GUILT 06 CLIT 06 CULL 06 CU IL 61 cL Il él 3) es GL OL 96 GL OL Te CL OL6 él Ol 6 GL OLS GL Og jo 09eq "NL ofG “mM mat of "N GP o€G “M (8G of “N /GG o€G "ML of "N OF o€9 “M. 7¥G of "N /69 o€¢ “M /00 oG "NPP o&% “M9 of ‘N LLY 0&9 "M 166 of "N67 o€G “M /OL of "N LPP 0&9 "M 78 of "N /9P 0&9 ‘opngisuorTy pue opnqyey soacboo00000 oguoconsacDdbosaGooudc00 qaodyynog ‘yueg ostopy o0g0p “* gou-oyeqs ‘Arengsy o[qqry Yo ‘syueq osrozy poosasbooe resseenceerteeceearerevssosesvereeonere aay WOISTEL) 06000900000000000000 es gou puey,, UL oroys SoseTTe AA 500000000000 teres (Cy Surtvoq PURTSI) puRS, UNG YO sodo0cd000d00000 ve CQ Surrvoq purst) pursy ung YO tteteseneeeseeeseeeecesseessesovereeerevssoes TOMB) WOISIOAT 000000 Heeteeeteeeeetoereeosons Qrgaiay FoUURYO PlOFUl “MAN snudry guiog “ay Aq “HG SuLeOq prof s,ouIQ yeoID “MT “totq ytodyynog WOIF “NY opt | “qaodyynog ‘epoxy Sog ,, SurproTyz ,, eae eeeeeees seer e reer seer ose eesens SUOY YF 6 ‘Keg aq WeRdOLOT BODDOODOOOOOOOOOOUOOOOOOOOO Pp000% Gays wmeyyAry MOTO oT LUt & seceee eee er eee eer esesns punois pesoyo joodsporrg jo apis ze eee meee eee ee sess eee eesesseesessees SULOYYR 8 ‘joodyorlgq m6) eee “ sunoyqey g ‘Aong WOsTONT WOT, “GN SoptU Z SULOYZET 9 ‘oodyorrq pue Aong uospoyy uooagjoq AvM FLEET ‘amgdeooy JO o0R[q ‘ZIG ‘II INGWIuGaxy GG “suo UL poye1oq iT uUsY AL qysueT 96€ VI foe VI 8lé VT 8ePr VI Ee VI 69 VT SLE VI €lé VT. Igé WI GoF VT Ilé VT 866 VT Ivé V'I 8éé VI 69 VI Osh VI eats JO "ON, aoe 0 G06 GL IL FI = srepeeeseceeeeesce DUULTAqUINY “UPOT[LY “ssoumquryg FO | F-0Z 60S VI *SULO UT "suo UT ‘gmnydeg | ‘suto ut |peanqdeooy|omydeooy | ‘opngisuoT poeyedoqry | = “yoqey jo yysuey ur} uefa fo 07eq pue -ainqdeooy JO 90Rq woyA JO ‘ON pouweyw | oseotouy yysuery epnyyey] yysuey GIGI ‘IIT INGWIiNaaxy TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 274 M iV os . —— 0 G-9% ZLSL0Z NI 9 ofS Sir were reece tec esece weeceee Sr yrpAeg ICON G-9Z Z8E VI "M {ST of eee g 0Z ZLZLOL "Ni 8S ofS BSOOOIOOOOOOOOOIOOIOIOIUI eee ABA\joU “1OOF.194R AA ‘uUeuUy IvON C-6T ltr VI AN AGL oi? Ls 0 OH CUCLOL | NEL ofG POU peay] ppoysneyy Worz -g soprur ¢ &% LES WT "MM 6S of SULOYI] ST “A'S LI ¢ GG ZUZL9T | “N,9Z o€¢ | PUL “ANSE Usoeagoq SuLveg FYST ‘purysy UyNG FO cS L&E VI fe “M ,8G of Ls § LZ CUZI'S ANE OS Aas [Poorerere SULOYILT OZ ‘PVOH S,oWIG 94} JO *N Solu OT | 8-9 OFF VI M {6S o£ Is t 83 Alcala "NES of [oT Re souIGQ yeers) wHOIZ “NY AQ “MN STIG | G-2S e0F WT UMN gl wi? LI g C-FZ ZL IL OE OR OVS Law |PreccecnconccpsiooccappponooON | istyaKaRE (aMeHY CT ‘purysy ugnugd vO ¥Z Che WI NN Ae oP LI g FG CLILO€ 'N fixe ARE) Smee e eee mee eee eeeeeeseeeesseeserees SULOYy RT FI ‘pueys] ugjng G-&S 908 V1 Lg 0 cS ZL IL6Z — rrreseeesereeee suoyqey Og ‘Avg ueSipreg jo y1ed yyION, GZ 918 WI "M SP 002 NS ates i at ZL IL 6Z Ni “fh ofS ee cceee wee ewer cee testes eseese qou-ox24s ul ‘spueg-9]-Wo9jog IZ O&F V1 ms) 0.0 09) Ur | “sumo ul ‘amqdeg | ‘sto ur |poainqdeoay|omnqdeooy | ‘apnyzisuoT poyeroqry ‘oqery jo yjsuey] Ut woy At jo 93eq pue ‘aingdeooy JO coe q uo At JO ‘ON poussW esevolouy yysuey epnyyneyTy yysuey panuyUuojo—ZI6L ‘Il INAWIAad xX SEA-FISHERIES LABORATORY. 275 HYDROGRAPHIC INVESTIGATIONS AND THE FISHERIES OF THE IRISH SEA. By Jas. JoHnstone, B.Sc. (WirH CHARTS.) The variations of the salinity of the water of the Irish Sea, during the year 1912, are discussed by Dr. Bassett in another paper in this Report; and the relation of these salinity variations to the general circula- tion of water in this area, and to the weather of the year are also considered. The present paper deals with the temperature observations only, and an attempt is made to correlate these data with the fluctuations in the winter plaice fishery off the coast of North Wales. This attempt has not proved to be a very successful one; never- theless, it seems to be useful to attempt to discover what results may be obtained from the data available. I. The Temperature Observations. These are :— (1). Semi-diurnal sea-temperatures, at the surface, at various Irish Sea Light Vessels. These observations are made for the Meteorological Office, and copies have kindly been supphed to us. The temperatures of the sea at 4 p.m. are abstracted, 10-daily and monthly means being calculated. The monthly means are given in Table I. (2). Hourly temperature observations made by the officers of the S.S. James Fletcher, when at sea doing scientific work and police duty. These observations are carefully made, and are very numerous, Neverthe- less, the cruises of the ship are necessarily restricted to certain lines and areas, and the variable nature of the 276 TRANSACTIONS LIVERPOOL BIOLOGICAT, SOCIETY. police duty does not permit of all the Coastal Stations being regularly visited. Gaps in the various series of data, therefore, occur, but in spite of these the figures are of very considerable value. They have been abstracted from the vessel’s temperature log-book, and monthly means have been calculated. These are given in Tables Il. and III. The first column under each Station gives the number of observations made during each month; the second gives the range of dates on which the observations were made; and the third is the mean temperature. In plotting the latter data, the points graphed should, obviously, not be the middles of the monthly periods, but the median dates of the ranges shown in Col. 2. The thermometers used for these observations are “‘ Kiel ”’ instruments, graduated in fifths of a degree C. They are regularly compared with a Richter thermometer, which again had been compared with a standard hydrogen thermometer at the Charlottenburg Institute. Table IV shows the mean monthly sea-temperatures at Nelson Buoy, Liverpool Bar, Great Orme’s Head, Red Wharf Bay, and Point Lynus, for the whole period 1909- 1912; and these data are also graphed in ‘Text-fig. ile Some points of interest in these data may be noticed at once. The range of variation of sea temperature is variable; it is greatest (about 12° C.) at the Lancashire Stations, Liverpool Bar, Nelson Buoy, and Piel Gas Buoy, and it is least (about 9° C. to 10° C.) at the North Wales Stations (Great Orme’s Head, Red Wharf Bay, and Point Lynus). The dates of maximum and minimum temperature also vary: at the Lancashire Stations the minimum occurs about the third week in F ebruary, while it occurs about the second week in Mazch at the North Wales Stations. The maximum also varies, occurring about the first week in August in the case of the SEA-FISHERIES LABORATORY. 277 Lancashire Stations, and about a fortnight later at the North Wales ones. There are two periods in the year at which the various graphs cross or approach each other closely: about the middle of April and about the beginning of October. At these times the temperature of the sea along the coast of Lancashire and North Wales is very nearly uniform. (3). The data of the periodic hydrographic cruises. These are given in Dr. Bassett’s report, but they are also plotted in Charts I to LV, where isothermal lines are Hi 16 Aun W fo~w dany Feby. Mar Gpril May June July Aug. Sept. Oct Nov. Dec. Text-Fic. 1. Variations of Sea-temperature at various Coastal Stations in 1912. 1, Red Wharf Bay; 2, Off Pt. Lynus; 3, Gt. Ormes Had. ; 4, Piel Gas Buoy; 5, L’pool Bar; 6, Nelson Buoy. drawn. On the hydrographic cruises surface tempera- tures are observed, as a very general rule, at points about midway between the regular stations, and also at various coastal stations. The sea-temperature at the surface 278 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. during the periodic cruises is determined by a Richter thermometer. The deep temperatures are observed by a Nansen deep-sea thermometer, used in the small Nansen- Pettersson insulating water-bottle. In the cruises after September of this year an Ekman water-bottle and Richter reversing thermometer were used, the other instrument being undef repair. It will be shown later that the sea-temperatures at Hydrographic Stations 5, 6, and 7, are probably of con- siderable importance, and it is advisable to discuss them in some detail, endeavouring to ascertain how far the individual temperatures observed on each cruise express relatively stable conditions, or are only “‘ accidental ”’ variations. It is necessary to consider (1) the effect of the variability in date of the periodic cruises; (2) the variation in surface temperature along the line of stations between Holyhead and Calf of Man; and (3) the varia- tion of the sea-temperature with the depth. (1) It is clearly impossible so to arrange matters that the periodic cruises are always made at the same dates in each year. The February cruise has been made as early as 27th January, and as late as 25th February, and the dates of the other quarterly cruises have also been inconstant (Table V.). Strictly speaking, it is impossible to compare the results of different years without making allowance for this variability, since the difference of temperature which might have taken place between (say) the 27th of January and the 25th of February, might be greater, or nearly as great as the differences between the temperatures of successive years. It is necessary, then, to ‘‘ correct’’ these data: to reduce them to the data which would have been obtained if the cruises had been made on the same days in each year. This might be done by interpolating from an SEA-FISHERIES LABORATORY. 279 harmonic sine and cosine formula, but the labour of this would be very great, and the results not at all reliable when only a few cruises in the year are made. It is, however, possible to deduce a ‘‘ factor’? by means of which the temperatures may be corrected in a simpler manner. Daily temperature readings are made at the Carnarvon Bay Light Vessel, which is not far away from Stations 5, 6, and 7, and is situated practically in the fairway of the Channel. From the known variability in sea-temperature at this point during the small periods in question, the corresponding variability at the three hydrographic stations may be deduced by supposing the changes to be parallel ones at both places. There is every reason for supposing that this is the case. If the daily temperatures obtained from the hght- ship be plotted, it will be.seen that those observed during a period of(say) 25 days may be regarded, without significant error from our point of view, as an ‘‘ element ’”’ of the curve. That is, they may be regarded as lying about a straight line, and since the inclination of this is, of course, the same at all points, the rate of variability of the temperature function may be calculated. Let the straight line be a + bz, we have to determine the con- stant a and the coefficient 6, the latter representing the rate of variation of temperature. The mean temperatures for every two or three days during each period of time covered by the quarterly cruises have, therefore, been ealculated, and ‘‘ moments of inertia’’ have then been obtained (see Elderton “‘ Frequency Curves and Correla- tion, 1906) by Pearson’s method. In the notation of the work cited m,, which i simply the sum of the mean 1 temperatures, is equal to / (ab + x)dx, while m,, which Lg Ly; is the “first moment” is equal to i x(ab+ax)dx. We thus Lz 230 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. get two equations, and by solving these simultaneously a and b can be determined; a being = and 6 being o 1 being the half range. All this is very simple and involves very little arithmetical work. What we really do 0 1 is to approximate to : , t? being the temperature and ¢ the time. Only by taking moments about the means of the periods in question can it be seen whether the tempera- ture is decreasing, increasing, or is stationary, since the “‘ accidental’ variations from day to day obscure the trend of the curve. The daily increment of temperature thus calculated is shown in Table VI. It is of practical importance only in the months of May and November, when the sea-temperature is changing rapidly. It need hardly be apphed in the months of February and November. (2). The variation in temperature between various points on the Holyhead to Calf of Man line of stations, must also be considered. The stations are ten miles apart, and Station 5 is about 10 miles distant from Calf of Man, while Station 6 is about the same distance from Holyhead. The difference of temperature in a distance of thirty miles on some of the Lancashire lines of Stations may be considerable, but it is quite small on the line including Stations 5, 6, and 7. The mean temperature of each station, at each cruise during the years 1907-1912, has been calculated, and the differences are shown in Table VII. The temperature of Station 6 is regarded, in each case, as T° C., and the difference between this and the mean temperature of the adjacent stations is shown. The greatest positive difference is 0°63° in August; and the greatest negative difference 0°33° C. in February. As a rule the sea-temperatures at SEA-FISHERIES LABORATORY. 281 points midway between these stations have been observed in the cruises of the last three or four years, and it has been noticed that the variation is fairly regular, and can usually be predicted. (3). With very few exceptions hydrographic soundings have been made on the periodic cruises at Stations 5, 6, and 7. The object of this practice has not been to investigate temperature or salinity stratification ; for it was apparent, when these investigations had been in progress for a short time, that the Irish Sea, North of Holyhead, was an homothermic and homosaline water mass; and that the differences in temperature and salinity between surface and deep layers was only significant in the shallow water near the coast of Lancashire. It was seen that these differences were relatively large only in calm weather in the summer, when relatively warm and hght water was carried by the tide from the heated sand- banks along the land, and overlay water which was colder and denser. Soundings are, therefore, made on the Holyhead to Calf of Man line, in order to provide a check against any ‘* accidental ’’ conditions, or undetected errors in the observations. The mean temperatures at the sur- face at each station, for each sample month throughout the period 1907-1912 have, however, been calculated (Table VIII), and also the mean differences between this temperature and that of the bottom water. The difference is, of course, negative in all cases, and is maximal at Station 5 in August, when the mean bottom temperature is 0°4° C. lower than that at the surface. The difference between the temperature at the surface at these stations is, therefore, very small, and indicates nothing more than the small effect (on this line) due to the greater proximity to the land of the Stations 5 and 7. The differences between surface and 282, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. bottom are also very small, and are almost always in the same direction. Even if there were a vertical circulation in this region (and there is no evidence whatever that this is the case), the temperature of the surface water would only be affected to a very small extent by this factor. : The water along this line extending from Calf of Man to Holyhead probably possesses a more “‘ oceanic ”’ character than does any other part of the Irish Sea, North of Anglesea. It will be seen from Table IX that the annual range of temperature here (5°4° C.) is less than it is at any other point investigated, and approximates closely to the yearly temperature indicated in the Atlantic Ocean to the West of Ireland. Everything indicates that the flow of water through the Irish Sea from South to North runs transverse to this line, that is, between Isle of Man and Anglesey. The drift-bottle experiments themselves provide actual evidence; which is again sup- ported by a study of the direction of the isohalines and isotherms, since the flow of water obviously must generally take place in a direction normal to these curves at each point. It is also probable on @ prior: grounds that the flow is in this direction since the prevalent direction of strong winds is S.W. to N.W.; while Ferrel’s Law shows that whatever tidal streams and currents there are in the sea here must be deflected to the East. It may be premised, therefore, that the water between Anglesey and Calf of Man represents, in its physical properties, the water further south in St. George’s Channel, and even outside the mouth of the latter in the open Atlantic Ocean, and that variations of temperature and salinity at Lancashire Hydrographic Stations 5, 6 and 7 are probably parallel to those occurring outside the Channel. SEA-FISHERIES LABORATORY. 283 For these reasons, considerable importance is attached to the physical investigation of the sea at these points, and the results of the hydrographic cruises of the years 1907-1912 are given in Table X. The figures are the means of the three stations, and only the surface temperatures are considered. The ‘‘ corrected tempera- tures’’ are deduced by the method already described. The figures in brackets (May and August of 1911) do not represent the results of the hydrographic investigations since no cruises were made in 1911 except those of February and November. The mean difference between / 79 re Text-Hic. 2. Mean Sea-temperatures at Hydrographic Stations 5, 6 and 7 during the months February, May, August and November of the years 1906-1913. The figures plotted are the ‘corrected’? ones of Table X. the mean temperature of the sea at Carnarvon Bay Light Vessel, during the middle ten days of May and August, in the years 1907-1912 (except 1911), and that of Hydro- graphic Stations 5, 6, and 7 at the same times, have been calculated; and the values in brackets represent the temperatures at the lightship, minus this difference. It is probable that any error so involved is insignificant: the year 1911 was obviously a year of high range of tem- perature, as shown by all the other results. Fig. 2 represents these mean temperatures at 984 TRANSACTIONS PETROL BIOLOGICAL SOCIETY. Stations 5, 6, and 7 for the years 1907-1912. The difference between the various years with respect to the annual temperature range is considerable: thus the range in 1909 is only 4:76°, while that of 1911 is 791°, or 8°29° if we compare August of 1911 with February of 1912. This difference is much greater than any that can be accounted for by “‘accidental’’ variations of surface temperature, or interchange of water between surface and bottom, or errors due to observation, or variation in the dates of the quarterly cruises. There seems to be no doubt that it must be traced to events occurring outside the Irish Sea, that is, to variations from year to year in the temperature of the water entering this sea area. This variability in annual temperature range is, at present, all that can safely be deduced from the data: the form of the curve does indeed suggest a periodicity in these variations, a periodicity which is exhibited best perhaps in the amplitude of the annual temperature wave, and in the value of the figures for the ‘‘mean’’ months—May and November. But, obviously, the period of years throughout which the observations have been carried on is too small to allow of the deduction of conclusions of this kind. II.—Temperature Differences in the Eastern Side of the Irish Sea. Even in this very limited sea-area these differences are fairly considerable, and this is because there are two main series of conditions: (1) The effect of the very extensive sand-banks fringing the coasts of Lancashire and Cheshire, and tending to produce great temperature differences; and (2) the effect of the relatively strong inflow of water round Anglesey from the open Channel: this tends to reduce temperature differences, in the regions SEA-FISHERIES LABORATORY. 285 influenced, to a minimum. Table IX shows the mean temperatures for the four sample months, February, May, August, and November, at a number of stations, coastal and off-shore ones. The means have been calculated for the four years 1909-1912 only, since these are the only years for which temperature records for the coastal stations are available. It will be seen that there is an area of sea extending from about Morecambe Bay to the Mersey Hstuary—bounded roughly by the parallels of latitude 54° 00’ N. and 53° 30’ N., and by the meridians 3° 00’ W. and 3° 30’ W.—where the annual temperature range is relatively great; and where the minima are low and the maxima high. Thus at the Stations, Morecambe Bay and Liverpool North-West Light Vessels, at Nelson Buoy, and at Liverpool Bar the range varies from about 10° C. to 12°5° C., the minima from about 4° to 6°, and the maxima from about 15°5° to about 16°5°. This part of the sea is influenced by the strong tidal streams which oscillate between the sand- banks in the bays and estuaries, and the open sea off- shore. The great extent of sand laid bare by the ebb- tide cools the water flowing over it in the winter months, and warms it to a corresponding extent in the summer. This area includes most of the summer fishing grounds for soles and plaice. The mean temperatures for the two principal series of hydrographic stations are also given in the Table. Stations 1 to 4 he along the 54th parallel of latitude, Station 1 being about 10 miles from the land, and it and the others are 10 miles apart. The temperatures at these stations do not differ very much in the months May and November, but in February, the month of the minimum, the temperature falls as we pass out from the land, while in August, the month of the maximum, the 286 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. reverse condition holds good: the annual range of tem- perature therefore decreases with the distance of the station from the land. The second line of Stations 5 to 7 le on a line between Calf of Man and Holyhead, and are nearly equidistant on either side from the land and from each other. There is much more uniformity at these points. Station 7 is about ten miles distant from Holyhead, and is probably affected shghtly by the tidal stream which enters Carnarvon Bay as an indraught, and sweeps out again; but Stations 5 and 6 are probably not at all affected in this way, and their annual range of temperature is only about 5°5°, a value which is not much greater than of the water in the Atlantic Ocean west from Ireland. Midway between Isle of Man and Ireland, and in an area including these three stations the physical - condition of the sea is probably more uniform than in any other place north of Anglesey: it is here that critical and really quantitative experiments would probably indicate a high degree of uniformity in the distribution of pelagic life. Nearer the land, on either side, the physical conditions become much more complex, as the sea becomes more shallow, and the influence of the tidal streams becomes apparent. The annual range of tem- perature at Port Erin is very much the same as that off the coast of Anglesey between Carmel Head and Point Lynus. There is hardly any trawling in this part of the Irish Sea, nor round the south end of the Isle of Man on the one hand, nor off the coast of Anglesey between Point Lynus and South Stack on the other. The sea between Point Lynus and the Liverpool North-West Light Vessel, south from about parallel 53° 30! N. is intermediate in physical conditions between the two areas mentioned. There are few large sand- banks along the coast of North Wales, and those of SEA-FISHERIES LABORATORY. 287 Liverpool Bay are too far away to exert any appreciable influence; hence the temperature of the water here is not influenced by the land to the same extent as it is off the coasts of Lancashire and Cheshire. The main drift of water is from St. George’s Channel round the coast of Anglesey into Red Wharf and Beaumaris Bays; and since this water is colder in the summer, and warmer in the winter than that normally present in the sea off Liverpool Bay and the coasts of North Wales, so the temperature in this area is more uniform than it would be in the absence of this inflow. Still the land does exert an influence, and so the temperature range in these areas is greater than it is in the fairway of the Channel. The very important winter plaice fishing grounds in Red Wharf Bay, off Point Lynus, in Beaumaris Bay and off Great Orme’s Head, and in Channel Course (that is, in the track of vessels approaching Liverpool Bar from Point Lynus) are situated in this area. These temperature differences are best shown by the isothermal lines plotted on Charts I to IV. The chart drawn for February is for 1913, since the only hydro- graphic stations visited during February, 1912, were those on lines | and 2, and these points are insufficient to define the isotherms exactly. It should be noted that these charts represent the differences of temperature in a_ broad manner only, and that much more numerous observations would certainly show that the isothermal lines run more irregularly than represented, although their general direction might still be the same. It is very probable that they are quite sufficient for the investigation of any relationship between temperature and fishery periods or productivity that may possibly exist. Chart I represents the distribution of temperature during May—one of the ‘‘mean’”’ months. The prin- 288 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. CHaRrtT I. ree Sarg, Serpe Isotherms in the Eastern part of the Irish Sea during May, 1912. SEA-FISHERIES LABORATORY. 289 cipal feature is the approximate uniformity of tempera- ture over the entire area. There is a large, irregular patch of water in the middle of the Irish Sea, where the temperature is about 9°: the narrow tongue which is seen to pass to the west of Anglesey terminates a little way to the south, as the observations made by the Irish Fishery vessel ‘‘ Helga ’’ during this month show. Near the coast of Lancashire are the highest temperatures observed, 10° to about 11°. Everywhere in the area covered by the isotherms the gradients are slight, that between Nelson Buoy and Red Wharf Bay being about 15°, while between the former point and the Bahama Bank, the gradient is less still. Along the line of Stations between Piel Gas Buoy and Bahama Bank the isotherms run rather irregularly, a condition which is to be traced to the rapid tidal streams which oscillate in this direction between Morecambe Bay and the sea off- shore, and also to the fact that the sea-temperature is rising rapidly at this time of year: the daily increment at Carnarvon Bay Light Vessel is about + 0°08. At this time of year the highest temperature gradients are those at right angles to the coast line of Lancashire, the isotherms running nearly parallel to this, and being closest to one another here. Chart II represents the distribution of temperature 6 during November, the other ‘“mean’’ month. ‘There are notable differences, however, in the course of the isotherms at this time of year. The sea-temperature is rising rapidly in May, but falling less rapidly in November, the daily increment during this month at Carnarvon Light Vessel being -0°038 in degrees Centi- grade. The water off-shore 1s warmer than that in-shore in November, but colder in May. There is a tendency for the isothermal lines to bend in towards the coast of 290 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Cuart II. Ordre army Southampen Isotherms in the Kastern part of the Irish Sea during November, 1912. SEA-FISHERIES LABORATORY. 291 North Wales in November, but to bend upwards towards the east side of the Isle of Man in May. The direction of the general drift of water is indicated by straight lines drawn normal to the isothermal curves; hence the main drift of water in November (and in February) appears to be round the coast of Anglesey into the sea off the coasts of North Wales and Liverpool Bay; while in May (and in August) it rather appears to be towards the sea between Isle of Man and Cumberland. At any rate, these appear to be the general directions along which temperature changes are occurring. The temperature gradients during this month are steeper than they are in May. That along the line of Hydrographic Stations 1 to 4 is nearly 3°; between Nelson Buoy and Bahama Bank it is about 1°5°; and between Nelson Buoy and the Red Wharf Bay fishing area it is very much the same. A further important condition may be noted: there are two areas of relatively warm water, (1) just South of Bahama and King William Banks, and (2) just North from Red Wharf Bay and Great Orme’s Head. Chart III represents the conditions in February, 1913 (the other Charts relate to 1912). The course of the isotherms cannot be very precisely indicated for this month since the data for the hight vessels and the various coastal stations have not been obtained at the time of writing. It is, however, added here in order to amplify the general argument of the paper. It shows that the conditions represented by the temperature distribution — of November still exist, and that the differences and gradients shown in the chart for that month are accentuated in February, when the process of cooling on the one hand, and the progress of the drift from the Channel round into Liverpool Bay are attaining a 292, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. maximum. There are still two areas of relatively warm water situated in relatively shallow sea areas, (1) the Bahama, King-William Bank areas, where the tempera- ture is about 7°, and (2) the Red Wharf area, where the CuHart III. te Le b+ temperature is about the same. The shape of the isotherms show that at this time both areas are about equally affected by the inflowing warm water from the South-West. The gradients are now much steeper: that SEA-FISHERIES LABORATORY. 298 along the line of Stations 1 to 4 is about 5° to 8°; that from Nelson Buoy to BahamaBank is about 4° to 7°; while that from Nelson Buoy to Red Wharf Bay is about the same. Off the Hstuaries of the Ribble, Dee, and Mersey, the gradient is steeper still: this is the coldest part of the whole Irish Sea in winter, with the exception of the upper reaches of the Solway Firth. Centrally the gradients are small, and the temperature is very uniform over a wide area. So much can be deduced from the incomplete observations of February, and the general trend of the isotherms, while subject, no doubt, to slight alterations, will probably remain the same when all the observations are obtained. The period of maximum temperature is represented by Chart IV, which represents the conditions on 15th August, 1912. The highest temperatures, about 16° to 17°, are now found close in-shore, and the lowest in the central sea-area south from Isle of Man. The gradients are fairly steep, and lines drawn normal to the isotherms would run approximately at right angles to the general trend of the coast line, since the isotherms run roughly parallel to the latter. So far as the latter indicate the direction of inflowing water, this appears to be more towards the sea between Isle of Man and North Lancashire, than round Anglesey into Liverpool Bay. IiI.—Temperature Conditions and Fish Migrations. The general conditions existing in the Irish Sea during the summer of 1912, and the winter of 1912-13 are represented in the Tables and Charts which have been discussed. Summarising them, it may be stated that the differences in temperature in different parts of this area are relatively considerable at two periods of the year, (1) the months December to February, when the sea is | 294 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. CHart IY. SEA-FISHERIES LABORATORY. 295 cooling down towards the minimum; and (2) in the months June to August, when the sea 1s warming up towards the maximum. Although the whole area under consideration is quite small, yet the different parts present differences which seem to be of significance, if it is assumed that physical changes may be factors which influence the migrations of fishes. The whole sea does not, in fact, heat up and cool down at the same rate in its different parts, and it is probable that these differences, with the temperature gradients which they set up, may be the factors of fish migration to be investigated. The assumption that temperature changes are factors of this kind is probably justified by all that is known of the life history of fishes. The rate of development of the egg, and the length of the periods between fertilisa- tion and hatching and metamorphosis are certainly affected by the temperature, and it is very probable that an empirical formula might be obtained from sufficient data, that would enable these periods to be calculated, the temperature being known. The rate of growth of adult fishes is also probably affected by temperature, and so also with the relation of length to weight: fishes of the same length are heavier in summer than they are in winter. During the colder winter months plaice either do not feed at all, or, as a rule, contain little in their alimentary canals. The rate of metabolism of fishes is certainly affected by changes of temperature: the frequency of the respiratory movements of the mouth and gills, for instance, which varies with the temperature. Generally speaking, all these things are particular cases of van’t Hoff’s law, that is, the rate of a chemical reaction is a function of the temperature at which it is carried on: the vital processes which have been mentioned above are all cases of directed chemical reactions. 296 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. There can be little doubt that there are optimal con- ditions of temperature for plaice of different ages; that is, growth occurs most rapidly when the temperature is at a certain value, and this must be the case even when food is abundant, for digestion and assimilation must pro- ceed most rapidly at such an optimal temperature. The scarcity and abundance of food is, perhaps, a factor of less importance than might at first be supposed: on such a coast as that of Lancashire, Cheshire, and North Wales the crustacea and shell-fish on which plaice of different ages feed are generally very abundant somewhere or other on the fishing grounds. Local scarcity of food may, indeed, lead to migrations, but these are merely the local ones, occurring indiscriminately in many. directions, which are indicated by the marked fish experiments. There are instances of great abundance of plaice on various restricted parts of the sea bottom where food is abundant: such, for instance, was the case near West Hoyle Bank, at the entrance to the Estuary of the Dee in the year 1910; or the local abundance of plaice in Rock Channel, off the Estuary of the Mersey, a phenomenon observed many times; or the local abundance of small plaice at the entrance to Walney Channel in Morecambe Bay. In all these cases food of some kind was particu- larly abundant on the areas mentioned: Mactra and Scrobicularia, in the case of the West Hoyle Bank shoals; Cardium and Pectinaria in Rock Channel; and small Mytilus in Walney Channel. So also with many more similar instances which might be observed, if particular attention were paid to the question of the association of fish shoaling with changes in the bottom fauna. But all such migrations and segregations are apparently aperiodic; they do not recur, or if they do, the recurrence cannot be predicted. In a certain sense they are SEA-FISHERIES LABORATORY. 297 “accidental ’’; that is, they are due to the operation of a multitude of small causes. It is hardly possible to attempt to correlate changes in the nature and abundance of the plankton with the aperiodic migrations or segregations of plaice, or still less with the larger migrations which experience shows are repeated with a certain regularity from year to year. It would, indeed, be possible to trace a possible connection between the abundance of vegetable plankton and the local abundance of small shell-fish on particular parts of the sea bottom, but it seems clear that the demonstration of this relationship is impossible by existing methods of investigation. It is not yet certain what is the kind of food on which these small shell-fish subsist, whether it is organised food in the shape of phyto- plankton, whether it is dissolved organic matter in the sea water, or organic detritus in the sea-bottom deposits. Until this question has been fully investigated, it seems impossible to expect that the food of the plaice and other bottom-living fishes feeding on benthic animals can be traced back to the phyto-plankton; and changes in the habitat of food, and fishes eating it, related to changes in the plankton contents of the sea. It is probable that salinity changes may be factors of significance in determining the nature and times of the migrations made by such fishes as plaice. But this question is not discussed in the present paper. The salinity changes that occur from time to time, and from place to place are, indeed, fairly large in the Irish Sea, though they are less in value, and far less easily observed than the corresponding temperature changes. It is, nevertheless, far more difficult to suggest a hypothetical relationship between salinity changes and changes in the metabolism of fishes, than it is in the case of the tem- 298 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. perature. It is, of course, possible that some internal change is produced when a fish moves from water of relatively low to relatively high salinity, or vice versa: the nature of the processes controlling diffusion through the epithelia of the gills, or other surfaces, must undergo change in such an occurrence. It is also possible that there is an optimal salinity for the fish as well as an optimal temperature and an optimal pressure of water, but the investigations so far made do not suggest what these optimal salinities are. The question of the salinity is one of very great difficulty, and its investigation would involve salinity determinations of the water at very numerous stations, and very often throughout the year, since the changes in-shore are probably relatively com- plex. No attempt is, therefore, made to investigate this possible relationship. It is almost certain that there are optimal tempera- ture conditions for plaice of different ages, but it is impossible, in the meantime, to say what these are. They are susceptible of investigation, and might be determined with a fair degree of accuracy. It was with this object that samples of plaice were obtained, and the length- weight coefficient k evaluated for different fishing grounds and seasons. The method is certainly quite a sound one, for the value of k, that is the ‘‘ condition ’’ of the fish as regards nutrition, must be an index of its rate of meta- bolism. No data of this kind are, however, yet available, since it has been found impossible, after four years of investigation, to obtain the complete series of plaice samples, with the temperature records of the fishing erounds when they were caught, which would allow the estimates to be made. The hypothesis may, however, be made that there are such optimal conditions of temperature, and that SEA-FISHERIES LABORATORY. 299 changes in these conditions, that is, rise or fall of tem- perature, as the case may be, are the proximate causes of the migrations of plaice which are to be mentioned. It may safely be assumed that these periodic migrations are really adaptations. The fish is living under conditions of a certain kind, and its functioning is of a certain nature. When the conditions change the fish responds, not by a change of structure, or functioning, in the special sense, but by a migration into another area where the conditions are similar to those of the area in which it was previously living. In general, it will be the case that the adaptation brought about by such a migration will be incomplete, that is, the fish will not be able to remain within optimal conditions by making a migration, but the object of the latter movement is, no doubt, one of this kind. This is probably, to some extent at least, the meaning of many kinds of fish migration; that of the Mackerel, Bass, Garfish, and some other species into the Irish Sea. In these cases the fish, experiencing a rise of tempera- ture in the seas to the South and West, in the mouth of the Channel, endeavours to correct this by migrating to the North. But it may also be the case that the meaning of such migrations is also the effort of the fish to enlarge its area of distribution: as the temperature rises In adjacent areas it moves into those regions. This may be the nature of the migrations of the Cod and Whiting into the Irish Sea during the early months of the year. These fishes, living in colder waters to the North, migrate to the South as the temperature there falls and approximates to that of the sea-area in which they find their optimal conditions. If this hypothesis is sound, it ought to be possible to predict the time of maxi- mum appearance of Cod in the northern part of the Irish 300 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Sea by studying the temperature gradient during the last months of the year in the sea further to the North. This explanation of the migrations of plaice in the Irish Sea was suggested by me in 1911, and I reproduce here a chart which was then made for another purpose. Chart V was based on the plaice-marking experiments carried out in 1906-10, and shows the main results of the latter; distinguishing between such adaptive migrations as have been considered above, and real spawning migra- tions—movements which, however, might be regarded as having very much the same meaning. It is impossible to present here the detailed evidence on which the above chart was constructed, since the hydrographic investigations of the years in question were not complete enough to allow of the construction of charts showing the isothermal lnes. In 1912, however, the marked-plaice experiments were begun again, on, it was hoped, a larger scale, and according to methods utilising the experience attained in the earlier investigations. These extended experiments have, unfortunately, not been made, but two fairly large lots of plaice were marked by me (1) in June, 1912, on the summer plaice fishing grounds near Nelson Buoy, and (2) in October on the same grounds. The summer experiment was made in order to investigate the movements of the fish about the time when the marked segregation on this ground, which is always observed from year to year, had fairly been established. In October, or thereabout, the plaice begin to desert this ground. ‘‘ Practical’’ men say that they have been fished out, but this is certainly not the case, and the disappearance of the fish is due to their migra- tion into other fishing grounds. The experiment in October was made in order to show the nature of these migrations. In each case about 200 plaice of lengths 301. SEA-FISHERIES LABORATORY. CHART V. this > SOLWAY FIRTH & Ga chy t SPAWN ry, General scheme of plaice-migrations in the winter months based on the results of the marking experiments. 302. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. varying from about 19 to 35 centimetres were marked and liberated. In neither case was the condition of the fish very satisfactory since they had been rather roughly handled in the course of the trawling by which they had been caught, but quite enough were liberated in a condi- tion sound enough for the purpose designed. The summer migration may be considered first since this is not shown in the chart on p. 301. Highteen fish are recorded : these were they returned during the months of June, July, and August. The months of recapture are indicated by the lines representing the hypothetical paths pursued by the fishes caught. Continuous lines represent the June-caught fish, broken lines those caught in July, and lines and dots those re-captured in August. The heavy lines are isotherms for the middle of the whole period—August 15th. Chart VI shows these migrations. The number of fishes recaptured is, it is true, few, but the nature of the migrations made are almost precisely similar to those observed in the recaptures of previous years in two experiments made on this ground at about the same time. It is, therefore, quite justifiable to conclude that these migration paths are not ‘““accidental’’ nor unusual ones, but really represent those followed by plaice living on this fishing ground at this time of year. There were a few other fishes returned during the same months, but the place of recapture of these was uncertain, and they are not included in the chart. . The latter shows clearly that the migration paths are, in the main, perpendicular to the direction of the isothermal lines; they cross the latter, very generally by the shortest routes. It is true that the paths are not exactly transverse to the isotherms, but the latter have been drawn for the middle of August. It is quite likely SEA-FISHERIES LABORATORY. 303 that had a great number of fish recaught in June, after liberation during the same month, been available, and had there been isotherms available for that month, the CHart VI. correspondence with the hypothesis would have been more exact. So also with the other two months: there is 304 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. no doubt that there will be a significant variation in the shape of the isothermal lines during these three months. It is also to be noted that the straight lines on the chart do not necessarily represent the general direction of the tracks followed by the migrants. They are the only lines that may be drawn for this purpose, and it is quite possible that the fish in many cases may have travelled along a curved track, thus crossing the isotherms more transversely than is indicated in the chart. The absence of any recaptures in the in-shore waters of the bays and estuaries during these months is very striking, also the absence in the fishing grounds off the coasts of North Wales and the Isle of Man. There can be no doubt that plaice of the range of lengths represented by the experiment are moving out from the shallow water in-shore towards the deeper water off-shore during the time of increasing and maximal sea-temperature. But it is also clear that the migration is not necessarily from shallow to deep water, that is, it 1s not increasing pressure that the fish is attempting to attain, but rather a lower temperature. It is moving from warm water into cold water, at the tume when temperature of the latter at vts point of departure is rising. Chart VII represents the results of the experiment made in October; and also those recaptures of fish, liberated in the June experiments, which were made in the months of October, November, and December. The thick lines are again the isotherms for November 15th, 1912. The months of recapture are indicated by the nature of the lines representing the tracks of the fishes: the broken lines represent recaptures in October; continuous lines those in November, and lines with dots those of December. It will be seen that a number of plaice (10) have migrated into Morecambe SEA-FISHERIES LABORATORY. 305 Bay, the Estuary of the Ribble, and that of the Mersey. i Such along-shore migrations have always been observed in previous experiments. They represent the capricious, or aperiodic migratory movements already referred to. CHart VII. mince Survey Sims thampeea VO" But it will also be noted, not only from this, but also from previous experiments that they occur mainly during the winter months. 306 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The conspicuous off-shore Westerly migrations of the summer experiments are almost quite absent. Instead of these the migration paths fall into two groups, (1) towards the fishing grounds off the coast of North Wales into the Red Wharf winter plaice grounds; and (2) towards the winter plaice grounds to the South and East from Bahama Bank. Twelve fishes have taken the former course, and three fishes the latter: not a very great number, but since these results, again, are entirely con- firmatory of those of the similar experiments of former years, we are thoroughly justified in regarding them as typical and truly representative of a much larger number of migrations. Five other recaptures are represented on the chart as having been made on the Bahama area: these are shown by the arrow-heads without lines con- necting them with the place of liberation. They were plaice recaptured in January and February of 1913, and they are not treated like the rest since it 1s uncertain how - they have migrated: they may, for instance, have travelled North from the Red Wharf Bay area. It is, however, fairly probable that they are fish which took part in the migration that is indicated by the lines and dots, and that they have remained on the Bahama Bank area for a month or so longer without being recaught. With the exception of the ten fishes which have made the along-shore migrations, all the others move in such a manner as to support the hypothesis indicated above. Those plaice which have migrated into Red Wharf Bay have moved out of water at a temperature of about 9° into water at a temperature of about 11°. So also in the case of the plaice migrating into the Bahama, King-Wilham Banks area; the rise of temperature accompanying this migration is also about 2° C. The adaptation brought about in these winter movements is the same as that SEA-FISHERIES LABORATORY. 307 achieved in the summer ones: the fish, experiencing a change of temperature moves in such a manner as to make this change minimal. In the summer it moves out of water rising in temperature into colder water; and in the winter it moves out of water falling in temperature into warmer water. The majority of the migrations studied by the marking experiments are not spawning ones. ‘The greater number of the plaice liberated are quite immature: practically all the females are, and only a small proportion of the males are sexually mature. The plaice fisheries in Lancashire waters are essentially fisheries for immature fish, and it is only in the late summer and autumn months that a few larger mature plaice appear in the shallow waters. The question of migration as an adaptation to temperature change is not therefore complicated by the simultaneous occurrence of spawning migrations, at least not to such an extent as seriously to affect the conclusions made here. Migra- tions of sexually mature plaice, or plaice about to become sexually mature, do indeed occur: thus, rela- tively large plaice move from Luce Bay (on the South coast of Scotland) to the shallow water banks off Ramsey, in the Isle of Man. Some, also, of the plaice inhabiting the in-shore waters off the Lancashire and Cumberland coasts may migrate towards this area. There is no doubt that the most important (perhaps the only) spawning area in the northern part of the Irish Sea is this area off the North-East coast of the Isle of Man. It is a fishing-ground which would well repay investigation, in view of the results of the marked-fish experiments of this and former years; but, unfortunately, the few observations made on it are of no value at all for the purposes of this discussion. 308 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. There is more information with regard to the winter plaice fishery in the Red Wharf Bay area, but this has been derived almost entirely from the measurements of plaice made there by the S.S. ‘‘ James Fletcher,’ and from the samples of fish sent by the officers of that vessel to the Laboratory. Unfortunately little or nothing is known as to what proportion of the larger fish caught in this area during the latter part of the year are sexually mature, or whether or not they actually spawn there. It is, however, unlikely that they do, so that in this case the migrations appear to be governed by the temperature-adaptation factor. . It is assumed here, as a working hypothesis, that changes in the productivity of the fisheries from year to year are due entirely to differences in the periodic migratory movements made by the fishes themselves. It can hardly be believed that the cause of a bad plaice fishery in the Irish Sea (say) during a certain winter is that the fish are actually less abundant over the entire area than they were during the previous winter, when the fishery was a good one. It may be the case that the actual quantity of fish inhabiting the whole area is decreasing slowly from year to year, although there is no indubitable statistical evidence in favour of this statement. But the actual difference between the total catch of plaice, in a certain fishing area, in two successive years, may be far too great to admit of the conclusion that the whole area had become depleted to such an extent. What does actually occur is that there are differences from year to year in the degree of segregation of the fish on definite fishing grounds. These differences of segregation are, in turn, due to differences in the migration paths taken by the fish as the result of eg SEA-FISHERIES LABORATORY. 309 adaptation to change of temperature, or of salinity, or of both. The total quantity of plaice in such an area as the Irish Sea, with St. George’s Channel, probably remains much the same from year to year: if fish are scarce on one particular fishing ground they are more than usually abundant on others; admitting, of course, that a progressive slow change may occur, a change which is nevertheless too gradual to produce a very notable effect in the productivity of two successive seasons. If this is the case, the relation between changes of physical conditions and changes in the productivity of the fisheries ought to become apparent by following up the line of investigation suggested in the previous pages. In order that it may be successful this method requires a knowledge of accurately collected fishery statistics. Fortunately, the system of collection adopted by the Board of Agriculture and Fisheries some years ago provides at least the machinery for the collection of these data. The “‘D2’’ forms now in use by the Board’s Collectors of Statistics contain information with regard to the quantity of each kind of fish landed by all first- class fishing vessels (steamers and smacks) ; the duration of the ‘“‘ voyage ’’; and the locality of the ground fished over. These ‘‘D2’’ forms for the years 1906-1912, and for all landings of fish at the Port of Bangor, in North Wales, have been sent to me by Dr. J. T. Jenkins, and they have been examined and abstracts of the quantities of plaice landed day by day, during this period, from the fishing grounds off the coast of North Wales, have been made. The grounds in question include Red Wharf Bay itself, and the deeper water off-shore from it and Point Lynus down to about 20 fathoms; the fishing grounds in 310 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Beaumaris and Conway Bays, and off Great Orme’s Head, in Carnarvonshire; and the grounds in ‘‘ Channel Course,’’ that is, the tract of sea between Point Lynus: and the Liverpool North-West Light Vessel. The area is rather large, and perhaps better results might have been obtained by considering only the fishery in Red Wharf Bay, but it is often the case that a vessel is returned as having fished both in Red Wharf Bay and in Channel Course, or in Red Wharf Bay and off Great Orme’s Head, or in Red Wharf Bay and in Conway Bay. There seems to be no alternative to combining these various grounds in one, rather heterogeneous, area. The immediate results of this study of the statistics are given in Table XIII. The entries are means for each week of the period, a week meaning the days from Sunday to Saturday (both included). The first column under each year gives the total number of days’ fishing recorded in the forms filled up for the week; the second column the total quantity of plaice, in cwts., caught during the week; and the third the mean catch, in ewts., per day’s trawling. Only first-class sailing vessels (smacks) fame these returns, and the results represent the effect of the fishery of a fleet of vessels varying in number from about a dozen to thirty. Steam trawlers also fish on this ground, outside the territorial limits, and a certain (small) number of third-class fishing boats may also trawl at times. Neither the steam trawlers nor the third- class vessels furnish returns to the Collector of Statistics at Bangor, and the conclusions which may be drawn from the summary are valid only if it is assumed that the results of the fishing operations of the small fleet of smacks represent the relative abundance of plaice on the grounds. It is probable that this conclusion is a correct one. SEA-FISHERIES LABORATORY. 311 In the original statistics themselves the plaice small,’ 9d 66 99 66 caught are recorded as “‘ large, medium, or ‘‘ size not distinguished.’’ No attention has, however, been paid to this classification, and the plaice are indeed almost all returned as ‘“‘ large’’; only very occasionally ‘““medium.’’ It is certain that an are they said to be ordinary catch of plaice from these grounds cannot properly be described as consisting of ‘‘large’’ fish. The lengths of the fish caught will be seen by referring to the tables of plaice measurements made in this area during the years 1909-1912 by Captain Wignall, of the Lancashire fishery steamer ‘‘ James Fletcher.’’ These tables are published in previous reports. What is found in this area is a plaice population of a high range of lengths, 10 to 50 centimetres, a range which is only exceeded in the Irish Sea area by that of the plaice caught in Luce Bay, where fish of 62 cms. in length have been taken. The distribution of age and sex is also tabulated in the Reports, but these figures have been obtained only by the examination of monthly samples of about 100 fish each during the various seasons. Unfortunately very few observations at sea have been made, and the figures of the sample catches do not give a reliable estimate of the proportions of sexually mature plaice on the grounds. The progress of the fishery is well shown in the tables given in this paper. Table XIII shows the mean daily catch for each week for the period 1907-1912, and Table XII the mean daily catches for each month for each of the years, and the mean daily catch for each month for the whole period. Fig. 5 represents the “mean monthly catches for each of the years 1909-1912, and the mean monthly catch for the whole period 1907- 1912 as the dotted line superposed upon the curve for the year 1909. The latter curve gives a general picture 312 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 4 yn / Si / ' / ol \ \ fl AL 1909 O es z — o 5 2 7 19/0 5 ieee L 6) 2 / 19/1 , i LAY \ Ba 19/2 Op Feb |MarlApr'!MayVunl/u/ Aug\Sep Oct|Nov|DecVan. |Feb.|Mar Trxt-Fic. 3. Mean quantities of Plaice (in cwts.) caught per day’s fishing in the North Welsh Winter Plaice fishing area during the years 1909-1912. Figures on the vertical axis represent cwts. The dotted line superposed on the curve for 1909 represents the mean catch for the whole period, SEA-FISHERIES LABORATORY. 313 of the yearly progress of the fishery which is probably not far from the truth. Practically no fish are caught during the months of April and May; the catch then rises at first rapidly and then more slowly till November, when it rises rapidly to its maximum about the end of December. The mean catch then falls very rapidly towards the minimum, in March. The drop at the end of December is generally very striking, but this is due, to some extent at least, to the fact that most of the boats cease fishing during the Christmas week. The different years show fluctuations which appear to have a real existence. The year 1909 was exceptional in that the fishery did not rather suddenly cease about the end of December, but continued on into the January and February of the following year, attaining its maximum in January. The fishery was again exceptional in 1910, not only in that a certain noticeable quantity of fish was caught throughout the entire year, but in that the quantity caught during December was greatly above the mean. In 1911, the fishery during November and December was below the mean, and in 1912 the lowest catches during the four years were made. In all the years the fishery appears to begin during June. But the time of the maximum varies from year to year: it was in January in the winter of 1909-10, in December in 1910, about the end of November in 1911, and about the end of October in 1912. Assuming that these statistics really represent the progress and productivity of the fishery—there are no means apparent of checking their accuracy, and we must make this assumption—some relation between the fluctuations in productivity and the date of the maximum may be sought. The only hypothesis which seems to be suggested by the study of the experimental and hydro- 3814 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. graphic investigations carried out in the Irish Sea is that the plaice fishery in Red Wharf Bay and the adjacent grounds is the result of an extensive immigra- tion of fish into this area from somewhere else. The rapid falling-off in the productivity of the fishery during the latter weeks of the year must also be due to the emigration of plaice from out of the North Welsh fishing grounds into some other area—that is, unless it is the case that the vessels simply cease to fish for some other reason than the scarcity of plaice. If the fishery ceased because the grounds were becoming depleted by the intense fishing of the few last weeks of the year, the curve of catches would fall more slowly than it does. It also appears to be really the case that the plaice have actually disappeared from out of Red Wharf Bay by the beginning of the year, for the trawling experiments made by the ‘‘ James Fletcher ’’—such as they are: there is a regrettable lack of these during January and February—show that fish are then very scarce. It must therefore be concluded that the fish do actually migrate out from the Bay. The marking experiments support both of these assumptions: it is the case that relatively large numbers of marked plaice migrate into this area from the fishing grounds further north and _ east, it is also the case that a fair proportion of plaice marked in Red Wharf Bay during the progress of the winter fishery have been recaptured in other fishing grounds, principally in Cardigan Bay and off the South-West coast of Ireland, though some have also been taken on the Bahama Bank grounds. If the aperiodic fluctuations in the values of the mean catches made are due to differences in the quantities of plaice migrating into or emigrating out from this area, or if these migrations are adaptations ee Se ee é SEA-FISHERIES LABORATORY. 315 on the part of the fish to temperature changes, then it ought to be possible to correlate the differential tempera- ture changes with the fishery statistics. The greater the drop of temperature in the Nelson Buoy area, for instance, in comparison with the fall of temperature in Red Wharf Bay, the greater should be the migration from the former area to the latter. It was with the object of testing this supposition that the temperature tables in this paper were calculated. Fig. 4, for Hawn odoos rt Rata 9 ” BD (QT TF DOL 1909 3 1910 49/1 19/2 Text-Fie, 4. The mean fall of temperatures at the stations Liverpool Bay and Nelson Buoy (high range curve), compared with the fall at the stations Red Wharf Bay and Great Orme’s Head (low range curye). Figures on the vertical axis are degrees centigrade, on the horizontal axis months. instance, is an attempt to represent the temperature differences at the two fishing grounds. The low-range curve is that for the mean of the two stations Nelson Buoy and Liverpool Bar; and the high-range curve is that for the mean of the three stations Great Orme’s Head, Red Wharf Bay, and Point Lynus. There are certainly differences between the various years, for the 316 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. point at which the two curves cross is rather different in each, and the difference between the temperatures read off from the curves for any date is not always the same. But no certain relationship between these temperature fluctuations and the fishery fluctuations can be deduced. There owght to be some relationship, and the fact that it cannot be seen is not to be explained in any other way than by supposing that the hypothesis of temperature-adaptation by migration is not true, or that the temperature data, and the fishery statistics, are too inaccurate to exhibit it. ! The years 1909 and 1910 were years of low range of temperature at. Nelson Buoy: the latter was 12°5° in 1909 and 121° in 1910. These also were years in which the plaice fishery in Red Wharf Bay was relatively good. The years 1911 and 1912 were years in which the range of temperature was high: it was 14°25° in the former and 130° in the latter, and they were also years in which the fishery in Red Wharf Bay was relatively poor. In fig. 5 the fluctuations of temperature at hydro- graphic Stations 5, 6 and 7, in the month of November, are compared with the mean daily catch of plaice, in cwts., in the Red Wharf Bay area during the last two months of the year. Here there does seem-to be a relationship, The years of low temperature are good fishery years, and vice versa, and the correspondence is quite good—indeed, it is all that could be desired— except for the year 1912. In that year the catch of plaice ought to have been better than that of 1911, since the temperature had fallen, yet the opposite is the case. If, however, we suppose—what, indeed, is very probably the case—that the exceptionally bad weather of the latter part of 1912 affected the fishing by preventing the smacks from going to sea, then the relationship would hold good. 7 SEA-FISHERIES LABORATORY. 317 There can be no doubt that the experimental work does indicate with a fair degree of certainty that fluctuations in the abundance of fish on a ground are the result of fluctuations in the regular migrations on to that ground; and also that these migrations are affected by temperature-fluctuations, with regard to the number of fish taking part in them and the dates at which the 907 , 1908 . 1909 . 19/0 . 19/1 . 19/2 "Catch of Plaice 0 /00 ene (efe) Sea-Jemperature in November Text-Fic. 5. Variations in the catch of plaice per day’s fishing, and in the sea-temperature in November at hydrographic stations 5, 6 and 7. The mean in each case is 100, the other figures represent the deviation above and below these means. migrations begin and end. The fact that the physical and statistical data available fail to show this relation- ship in a satisfactory manner is, no doubt, due only to the inaccuracies, or insufficiency, of both these series of data. The methods in use, both with regard to the physical observations and the collection of the fishery statistics, are quite satisfactory: the planning of the 318 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. work is, perhaps, nearly all that can be desired. But it is quite clear that this work is not carried out with the thoroughness that is the of the relationships sought, apart altogether from the possibility of the prediction of the productivity of a fishery. This is the main result of a study of the physical and statistical data obtained in a relatively small sea-area, where the observations are probably more numerous than almost anywhere else in the British Seas. It has not, so far, been realised that fishery investigations of this kind ought to be conducted with all the thoroughness and attention to detail, and the desire to avoid all possible sources of error, that characterise a laboratery investigation in chemical and Of course the great scale on which a fishery investigation must be carried on makes this necessary for complete demonstration physical science. accuracy difficult of attainment, yet it is quite certain, from a study of the data considered above, that without it much of the labour expended must be futile. I.—Sea-temperatures at the Light-Vessels, 1942. Monthly Means. Carnarvon | Liverpool |Morecambe| Bahama Bay, N’rth-west, Bay, Bank, Solway, 53° 6’ N. | 58° 31’ N. | 53° 54’ N. | 54° 20’ N. | 54° 48’ N. 4° 45’ W.| 3°31’ W.| 3°31’ W.| 4° 13’ W.| 3° 327 W. January ......... 8-94 7:49 6-16 7:33 5:40 Kebruary ...... 8-21 5:93 4-93 6-11 4-86 Manchieeeeeeeeeees 8:21 6:83 6:72 7-49 7-11 Morin aseccessstias 9-04 8-83 8-61 8-66 9-49 Mave Sy eeeacacelies 10-91 11-17 11-99 11-01 11-72 JUMEM wee yetienens 12-16 13-49 13-60 12-94 13-89 Sully) Poss es hes. 14-44 15-26 15-94 14-65 16-43 August ......... 14-82 15-05 14-77 14-60 14:38 September ...... 14-15 13-77 13-49 13-49 13-06 October ......... 12-94 11-93 10-96 12-04 10-23 November ...... 11-38 9-44 8:50 10-06 7-72 December ...... 10-29 8:27 7:33 8:38 6-21 319 LABORATORY. 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S ° S ° S| 6 g . S| n n n nm na nm = é é F é 3 ; “qquoyy es "M GZ oP SM )LP of "M J&P oF "M JSE oF "M {96 oF "M LT oP a "NST 0cG "N LP ofS ‘NST 0&9 ‘N PZ 08S "N /LZ 0&9 "N93 0&9 fam) “peo Aen’) MoN Ieayy ) “purysy Aospaeg “yorqg yynog ‘peop jeulaeg “OSNO, APPUAL ‘snudry yuIog SVE) FFG) Ul SUOT}eIg [VISVOD SNOJTeA ye soanjeseduie3-veg uve “TIT a. SEA-FISHERIES LABORATORY. 321 1¥Y.—Mean Monthly Sea-temperatures at various Coastal Stations in 1909-1912. Red Great Liver- Piel Point | Wharf | Orme’s | pool | Nelson Gas Lynus. | Bay. Head Bar Buoy. | Buoy. JATUBIEY cacéoncen0ce 6:5 7:5 6:3 5:6 4-8 5-1 February ......... 6-1 6:3 54 | 44 3:8 4-4 WMemrchtenc-csstss.- 12-5 12-5 12-3 12-5 12-1 12-7 November ......... 9-3 8-8 8-2 7-6 7-6 8-9 December =...-..-- 8-4 8-2 74 6-6 6-4 6:5 1VYa.—Mean Sea-temperatures at Red Wharf Bay Fishing Grounds. the Nelson Buoy and Aug. Sept. Oct. | Nov. Dec. | Jan. Nelson Buoy—Liverpool Bar. TIGI®) oe eegongesoueodee 16-0 13-9 13-2 | 7-5 3-9 5:2 IQ conceoodssoaubees 15-8 14-9 12-7) 6:9 6-7 5-1 I@I ces ceencooeccoaces 18-5 16-8 WAG || ee) 6-8 == III cogecuecneaeeneea 14-9 12°5 OHS |) 6-4 = Point Lynus—Red Wharf Bay—Gt. Orme’s Head. GX) .docasbeseesoneeEE 155 | 14:3 13-6 9-2 | 7-7 6-9 iC)... on MS ie ion |e ries 84 | 8 6-3 NOE reat eescie ees | Gas || eee 12:3 se 6-4 Weare aisles eric olna)0 92 145 | 13-2 11-9 92 | 8-5 = | | Y.—Dates. on which hydrographic stations 5, 6 and 7 were investigated, 1906 to 1912. Cruise. 1906 | 1907 | 1908 | 1909 | 1910 | 1911 | 1912 Feb. Se esiile 7) 25-1;- | 27-1. | QENT lath 4) ei May =< PVN | 1S: | SV | 7-V Soe | 208 VI | 27 VIN | 27-VIL| 9-VlIL| ~— | 30-Vir Mees 142X0| 5-X1 | 27-X ANT ||, 252 XQ 25 5X 8-XI | | : V as 322 TRANSACTIONS LIVEREOOL BIOLOGICAL SOCIETY. VI.—Rate of variation per day of Sea-temperature at Carnarvon Bay Light-Vessel during the range of dates of the hydrographic cruises in 1906 to 1912. fe) TNBLNCUBVEY — cnadcasccosonosocooccoqa0n6 is = 0-0102, decreasing t Malye = sacinascesaccousaesecenecensesescs » = 0-081, increasing JNTNSAIISIG | gboadéoo000q00 bbDEcqKbb00d00 » = 0-0033, increasing November ..22sc.scsccecsetine macctetus » = 0-038, decreasing VII.—Mean differences of Sea-temperature at the hydrographic stations 5, 6 and 7, 1907—1912. Mean Temp. at | Mean Temp. at | Mean Temp. at Station 5. Station 6. Station 7. February ............ Ol is AW = 3333 IMENSY Vedosbsocco0dsobo00 T° — -09 are T° + -05 August ...........068. T° + -08 | aN T° + -63 November...........- T° — -29 AS T° + -03 YIII.—Mean differences between the Sea-temperature at surface and bottom at hydrographic stations 5, 6, and 7, 1907—1912. Station 5 Station 6 Station 7 Temp. at | Temp. at | Temp. at | Temp. at | Temp. at | Temp. at Surface. | Bottom. | Surface. | Bottom. | Surface. | Bottom. February | T° |@—0-12| T° |e Sos Er tee May ......... 7° D2 — 0-18 T° 0229 ne TT? — 0-16 August ......| 71° T° — 0-40 ae T° — 0-20 T° T° — 0-30 November ... ane T° — 0-11 pe. it? — 0-15 file i 9:04 9 IX.—Average temperatures at various stations during | the years 1909—1912. | Mean Feb. May. Aug. Nov. | Annual Range Hydrographic Station 1...) 4-9 9-3 15:3 11-5 10-4 < Bee asi 5-4 8-9 14:3 11-6 8-9 93 Seon 6-2 8-6 13-8 11-8 7:6 5 oye ee 6:7 8-6 13-4 12-0 6-7 i 5 Oe ee Sar 8-5 12-9 12-1 54. i ca tGhr like t766 8-4 13-1 12:3 5-5 aie et 8-4 13-8 12-3 6-5 Piel Gas Buoy ............... 4-4 9-3 = 8-9 = Nelson Buoy .................. 3:8 12-0 16-4 7-6 12-6 Liverpool Bar ............... 4-4 11-8 16-3 7-6 11-9 Great Orme’s Head ......... 5:4 11-2 15-9 8-2 10-5 Red Wharf Bay ............ 6-3 10-3 15-6 8-8 9-3 Point Lynus .................. 6-1 8-8 14-9 9-3 8-8 Mcrecambe Bay Lightship 4-8 10-8 16-0 9-0 11-2 Liverpool N.W. Lightship 5-6 10-4 15-3 9-3 9-7 SEA-FISHERIES LABORATORY. 323 X.—Mean Sea-temperatures at hydrographic stations 5, 6 and 7. | | - 15 February. | 15 May. | 15 August. | 15 November. | | Mean (|Correct’d| Mean |Correct’d) Mean (Correct? d| Mean |Correct’d Temp. | Temp. | Temp. | Temp. | Temp. | Temp. | Temp. | Temp. 1906...... = = | = = = | = | iile7@® | Miewe WE fcosoce TOY |) ell 7-95 | 8-59 | 12-43 | 12:49 | 12-52 12-14 1908...... 7-14 7:25 8-28 | 8-33 | 12-99 13:05 | 13:13 | 12-45 WOOO Peer. 8-25 8:07 8:58 8-34 L2H e228 eEN-93) 9) Moe 1910...... 6:85 | 6-73 7-69 | 8-66 | 13-50 | 13°52 | 12-10 | 11-34 Tbe s55ee 757 | 7-46 = (3D) (15-37) | 13-11 } 12:35 MOND eet: 7-08 | 7-08 9-24 9-88 | 13-49 | 13-54 | 12:06 | 11-79 | { . | | The numbers in brackets are calculated as explained in the text. XI.—- Average catch of plaice (in cwts.) per day’s fishing during the period 1907—1912. Red Wharf Bay and Channel Course. Average Average Average Average Week. | Catch. | Week. | Catch. | Week. | Catch. | Week. | Catch. 1 1-50 14 0-01 27 0-31 40 1:36 | 2 1-26 15 0:04 28 0-45 41 1-47 | 3 0-80 16 0-19 29 0-53 42 1-54 4 0-26 17 0-15 30 0-46 43 1-27 | 5 0 18 0-15 31 0-68 44 1:10 6 0-20 19 0-11 32 0-36 45 1-20 7 0-13 20 0 33 0-96 46 2-53 8 0-43 21 0-07 34 0-79 47 2°31 9 0 | 0-08 35 0-67 48 3-05 10 0-10 23 0-01 36 1-09 49 3-57 11 0-05 24 0-06 37 0-72 50 5:24 12 0-09 25 0-12 38 0-88 51 5:29 13 0-06 26 0:05 39 | «60:87 52 1-57 | | a XII.—Average catch of plaice (in cwts.) per day’s fishing during each of the years 1907—1912. Red Wharf Bay and Channel Course. 4 | | | Weekly ) Mean Periods.| 1907 1908 1909 1910 1911 | 1912 | 1907-12 1 0 0-03 0-13 3-68 0-58 | 0 0-88 2 0 0-06 0-07 0-79 0:02 | O 0-18 3 0 0 0 0-23 0-01 0-06 0-06 4 0-20 0 0-04 0-12 0-02 0 0-08 | 5 0-14 0 0-02 0-25 0 | 0 0-08 | 6 0-19 0 0-03 0-15 0-02 | O 0-08 7 0-35 0-02 0-04 0-26 0:20 | 0-44 0-26 8 0-38 0-03 0-75 0-75 0-72 0-20 0-57» 9 0-43 0-26 0-92 0-71 0-55 | 1-28 0-83 10 0-42 1-26 1-28 0-53 0:29 | 1-00 0-96 11 0-82 0-18 1-99 0-94 0:99 | 1-81 1-35 12 0-82 0-89 1-96 2-78 3-20 1-72 2-27 a | 2:37 1-66 3-07 7-01 2-42 0-91 3-55 y-Channel Course -1912. the. Red Wharf Ba ice on ts.) of Pla In cW Winter Fishing Grounds, per week during the years 1907 Average daily catches ( XIII. 324 TRANSACLIONS LIVERPOOL BIOLOGICAL SOCIETY. Week. } 2 < | “kep god e8e190Y | sgo5g0 !|ooce seco |ooce coco a : | & NOM Ul | SSeS |ooee |eaice tec “surysy . | | ds) @ 1 | skep jo ‘on | CSSS EIQ | GOs Ch OR | Mao 2S & @ = ES | ‘Kep god os8etoay | W555 |oodo |code S52 S222 = ew fed 10 reas} = ° 5 ° . a 2 qysneo Yysiy tmot | oonS |oone |osoe |ooce “surysy D | (or) skep Joon | PERS | OSRao lone mMAtS | otra ses2)| 2s" Sees eee — sep dod o8eioay | aia los oa lod 56 | S065 eoeco Oo we Yen) Ven) wD = ‘auSneo USI nN LS m9 = 12 10 a 4Y, UMW | mama !loaan |lontrwal!laoHoS |] amoo = oo cf = ‘surysy © . oO Ee 10 — I~ N 0 sa? N Ne) sXep JO “ON Noa) eics OD = Sea es | 2 2) Same ‘kep aad eBetaay | cso 50 |odg00 |] coco |oSod |oodo S Ye) S “yusneo USL ge a & +y, WH | oomoe |losxneS |oooo |osgon |oono “Surysy . = (oo) oowo sXep Jo ON | “R20 | aR Sears a Lol Aep dod e8eraay | oS S56 | ogoo w a a & ‘gysneo Ys SNOSo!lOonmoOO “surysy NG) 1D ON | IS Sig!| S'S AGI WAT | a5 |laoaoo S & ‘yq8ne WM | sooo |oooo “Surysy ° m4 oD E~ Of CO =H =H CO sXep Jo “on Eis | ANS eNO 1D <> = © Table XII1I—Continued SEA-FISHERIES LABORATORY CD YSIS Qa Ss SIS —— fl = ~~ . eitutellaseh xe whee GNU . 5 . Aep sod odvi0ay SSeSae |SoooSs |oogSe HOO 1|oona ai . el Re — . . . . . a qysnes YsMy Sooo |NOoNMmM !AHoSo lIsS Sm ooor — | [| Loe | bes ee Sooo lAtrHt |NHOSO | mat |] onno sABp jo “ON — a ao 2 895 | S255 | 28s) Ze . = —_ Aep dad odvi0ay Seeae | SaoSo | ©oen | coos | ooSeS = e816 Ee | 2. = . By statears a. 6 a a ee qysneo ys Sn OO 1[SOOHMINMOAM | CHNE | OMNOS “SUIYSY skep Jo ‘oN DSSS | HADAR | Maram | oomn |loaon ee Bo BSO0/NSHS | SERS - gS . . . . . . ry . ° ry . . . MuppdeaseioN We tarry eioiiey WSIS NSS bees : 10 10 So 1019 «210 19 AQ 19 29 = e 5 . . . . 5 ez qwsne UM | Saoa SO! OOM |! Oaan | aoneo = N =< “Surysy : I~ OD on 019 sXep JO ‘ON 2 Saoekas can ascot” |e cas, aie Mapewoe Es ORs =|S558|es8es |sasz Aep sed e8¥100V | -5 55 15056515555] 5 4545 | anon S Ql alis 2 | oo a a 9 > qwsnee us | S35 SSOSCOINMDAS | HOMS | Morn [—] ANDINA Ala Ast Burysy | : 10 OO or) OND | DOOR |] OOD sXep jo ON one ol SIS Seine oO foal _ los ey | sae. eee : F} ra a aS ou ; : Kep sod odvi0ay Gece l|oooeo 1leoooo |] ace0e |] aHON ea ae Ries S : s : 3 = WEN WM | sooo HSOSOS |ONOSO |] FHS OM |] HOAHS os tesa “Surlysy i INE | HNN sXep jo ON a Se PSN yee, NX Om NN N Him © a ie) &S) Nolivol maron “ep Jod oseioA Ns vt 610 rs + 19 S219 Tues 2 Y Vid606 166656 |]HECce|Se0d65/1SS655 XK 19 10 S . is) as aN vs) lS us) & qysneo Ysiy +n or Sqn oto oO 1S 6 WD ex CO 1D “SuIysy b Jo) skep jo ON YS GY ISS Of NCO 1 (Gat as Oo or =] os a4 | | lox Bac) 1 © b= CO aoa An Of HIG CO | me oor an) e | TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 326 Et O19 +4 OO BS SPH) 1G re rt aN ANAS | Onan 1D OO > S & SH oo0 18 “‘Aep ied oser0ay | ‘qyoneo YShy “C161 = = —— —= || BIL |) eee G GL: | GL:S I = = = =p] == = €S P 0! oO 0 OLE G8 &¢G 96:0 | GGL 8G GFT 0:L9 L¥ ILI 9€| 16 GG GV GG G:99 0€ 66:61 | G:-166) GL 9E-P | G-OLE 69 66:6 G-1Gé| 98 1é-P GEE) LL 1g 79 | 09:1 |SFFOL] 99 | SECT |] G-L19) OG 6G-9 | G-LOT 96 | SFT O:1E1] 06 |G0O-€ | SZ-60€} 86 0S 06 0S-¢ G-9FS| 66 GEG G-GES| OOT | FFT G6 G9 L8:0 0:8L 06 €F-G | GGGi vail 6P Ch | 06°€ |G6:F2c| LG 0-9 G-€0F| S9 06-0 6 OL Gé-0 O-L 0G I8-T | G:éSI} 8 SP 69 OL T LY 8G LLY L-18 OP F6:G | G96 6 G6:0 GLP 0S 80-1 | SL-SL €L LY 9¢ OF-F TE] O€ CTs 18 €€ 0S:6 | GLP 61 IL-1 G:€9 LS GF-0 | SL-61 FP OP OF 08-6 G-9G 06 IL-0 G L OST 9G SI L¥-0 | G-61 If 0 0 8 GP 89 SEL | GL:SP €§ 0ST GGG GI CF-0 I GG 1€:0 G-9 1G CF 1 06 iat ia GI 89-0 9G 8& 06:0 G:F G C€é-6 | S-CLI 6P | 0 (0) €T FS:0 | GG-Ge LP $P OL OL 1 6 8 09-0 6 cI LG:G | S-9FT LG 0 0 9T GG-0 1G tke GP € 18-0 G-9 8 GL-0 FG GE 19-G 98 €§ GPO 0-€1 Ié 9L:0 | SL-9T GG IP = > > =a E o oe ue o = ene o = =a © i =i © > eo Bo 3 5 Bo o 5 Bo 3 ie So 3 - Bo a a Bo ga Fe | ae & Gre | as S GI | Ga S Cre | ae © ETFO | ta iS Roe ulleaes i = | ie fa Slee ba coalesce ds Sal ce i S Se LG seer ele a eo Se ee pe Sie. a. : of E a , a ‘ ey, | ARYA ® © = & =| = a S < a | \ ‘TI6I ‘OI6T ‘606T ‘S061 “LOGT LMOCHEEIY OD) UD: ¢ eel, SEA-FISHERIES LABORATORY. oot REPORT ON HYDROGRAPHIC OBSERVATIONS MADE IN THE IRISH SEA DURING 1912. By Henry Bassett, Jun., D.Sc., Professor of Chemistry, University College, Reading. It is pleasant to be able to report that, thanks to a grant from the Development Commissioners, the hydrographic investigations which the Lancashire and Western Sea Fisheries Committee have been carrying out for the past seven years have now been put on a much firmer basis. It has become possible to make observations monthly instead of only quarterly, and the 8.8. ‘‘ James Fletcher,’’ under Captain Wignall’s able guidance, now makes the necessary cruises as part of the regular routine. The monthly cruises under the new régime began in May, 1912, since which date Mr. W. Riddell has taken over the actual collection of the water samples and all necessary observations on the steamer. The samples are forwarded to Reading for analysis. The number of Stations at which observations are made has been increased to 24, with the object of making a more detailed study of the area than has hitherto been possible. The positions of the Stations are shown on the accompanying chart. Surface observations are made at all these Stations on the February, May, August and November, or “* quarterly,” and intermediate samples are only collected from the three deep Stations V, VI and VII, since such samples from the shallow Stations are of relatively little value, owing to the fact that there the water either has ihe same salinity from top to bottom or else shows erratic cruises. Bottom ae os 3 Ses RS SE y Ds } { wr) \ z } \ NN ae aA A AS ee fet ee Fi \ stg oO % a Cong \ . : E Sec Om se SY = ae C) S SS U aw ay ae \ ii ms i RS we : y / oN SS 5) x u 2 2 S ‘ op) q S) > i i} S f tant “3 oOo O ST = na ce i “ey BE 8 . 0 Pr. LX = ¢. s ra ° i =) 3 a) tt eee S ® e a I \ \ es C ee We \ LS 38 dy 2 ; :O . a x \ XS SS =. G QO co) a, SH Y aay \ SS \N 2 “ % \ E<| “| = QOS SS WY x ’ ®& 2°} (eee c OX’ Sh e \ Si! 1 ee =| ¥ 2 Om : Q : ‘, AWS \S ~o 6) 3 M a bs H \ = Ne a O ~ ae Fa ve L INS ae O N (Gea ed 4 ~ | 2) ‘ i y Shr | © ae | = ASX = x N | S) US : ) Cle) issues ia as 3 | ies . I. 54°N.; 3°30’ W. | 10.40a.m.) 9-6 | 18-42 33-28 | 25-71 Il. 54°N.; 3°47’ W. | 11.40 a.m] 8-95/ 18-54 33-49 | 25.96 II. 54°N.; 4°4’W. | 12.40 p.m 9-1 | 18-77 33-91 | 26-27 IV. 54°N.; 4°20’W. | 1.40p.m] 9-1 | 19-04 34-40 | 26-65 Station V. 53° 53’ N.; 4° 46’ W. 7/5/12 (3.30 p.m.), Depth (metres) T° CI°/,, 8°/.. oe 0 9:27 19-09 34-49 26-69 28 90 19-09 34-49 26-73 57 90 19-09 34-49 26-73 Station VI., 53° 43’ N.; 4° 44’ W. 7/5/12 (4.50 p.m.) Depth (metres) ay, Cl, Svan ot 0 9-35 19-12 34-54 26-73 30 9-0 19-13 34-56 26-79 70 8:9 19-14 34-58 26-83 Station VII., 53° 33’N.; 4°41’ W. 7/5/12 (6 p.m.) Depth (metres) Ae (Eso. ) egiele2 5.0 14:7 18-64 33-68 25-04 54°20'N. 5 4°13°W. | 3.7.12 5.50 | 14-5 18-80 33-96 25-30 54°15 'N. 5 38°57°W. | 3.7.12 6.50 | 14-9 18-67 33-73 25-03 54°10'N. ; 3°42’W. | 31.7.12 7.50 | 14-7 18-55 33-51 24-91 54°S’N. : 3°27’ W. 31.7.12 8.50 | 15-4 18-28 33:03 24-41 _ SEA-FISHERIES LABORATORY. 339 September 10-11, 1912. Stations I to IV., 10/9/12. Surface observations only. Station. Time. AVS OIG si fete) Ot I. 54°N.; 3°30’W. 2.45 p.m. | 13-4 | 18-34 | 33-13 | 24-89 ITE DA°N.; 3°47°W. | 4.30 p.m. | 13-6 | 18-43 | 33-30 | 24-97 WW O5ATN.; 4°4°W. 5.30 p.m. | 13-6 | 18-76 | 33-89 | 25-43 IV. 54°N.; 4°20’W. 6.30 p.m. | 13-4 | 18-86 | 34-07 | 25-62 Station V., 53° 53’ N.; 4°46’ W. 11/9/12 (8.20 a.m.) | Depth (metres) le Clr Swee Ct 0 13-25 19-00 34-33 25-84 30 13-0 19-00 34°33 25-89 75 13-25 19-00 34:33 25-84 Station VI., 53° 43’ N.; 4°44’ W. 11/9/12 (9.30 a.m.) Depth (metres), A ele /en Sivas Ct 0 nest 5 | 19-05 34-42 25-85 30 i Beil 19-04 34-40 25-92 73 13-4 | 19-04 34-40 25-86 Station VII., 53° 33’ N.; 4°41’ W. 11/9/12 (10.40 a.m.) | Depth (metres) ap CV) 50 Sian ot 0 13-9 19-04 34-40 25-76 30 13-6 19-03 34:38 25-81 56 13-65 19-03 34:38 25-80 aL HAN. ; 3°30°W. 340 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. October 7-8, 1912. Stations I to IV., 7/10/12. Surface observations only. Station. Time. iT TI. 54°N.; 3°47’W. THT. 54°N.; 4°4’W. TV. 54°N.; 4°20’W. 12.40 p.m.| 12-0 1.40 p.m.| 12-3 3.29 p.m.| 12-9 4.35 p.m.| 12-2 Cla Dies 18-29 18-60 18-87 18-94 33°04 33°60 34-09 Of 25-09 25-47 25-73 25-96 Station V., 53°53’ N.; 4°46’ W. 8/10/12 (8.25 a.m.) Depth (metres) ly Clo/= Sve Ot 0) 12-4 19-03 34:38 26-05 30 12-3 19-02 34-36 26-05 90 12-35 19-01 | 34-34 26-03 Depth (metres) Re Ci 0) | 12-83 19-05 30 12-7 19-05 66 | 7138 19-05 | Station Wiles 3o SSN Ace E 8/10/12 (10.45 a.m.) Depth (metres) Ave i) 13-25 30 13-05 57 13-2 CEs 19-08 19-06 19-06 {e) 8/00 34-47 34-43 34-43 SEA-FISHERIES LABORATORY. 341 November 4-8, 1912. Stations I to IV., 4/11/12. Surface observations only. (fe) Ot Station. Mie, | m2 |ciey,,| Se) ie DAGNEsca7o0°Wh 1.0 p.m. | 10-6 | 18-24) 32-95 | 25-28 10g HACN. 3 3°47’ W. 2.0 p.m. | 10-5 | 18-45 | 33-33 | 25-58 HE 54 SN7 4 C2W.. 3.0) p.m. | Il-l | 18-81 | 33-98 | 25-99 Nee 4 SNE 4°20 W. 4.0 p.m. | 11-2 | 18-92) 34-18 | 26-12 Station V., 53°53’ N,; 4°46’ W. 5/11/12 (10.5 a.m.) Depth (metres) aS Ola Sh Ct 0 11-8 18-99 34:31 26-11 30 IES 18-99 34-31 26-09 88 11-8 19-03 _ 34:38 26-17 Station VI., 53° 43’ N.; 4°44' W. 5/11/12 (11.15 a.m.) Depth (metres) ais Cle Sivas Ct 0 12-2 19-06 34°43 26-14 30 12-0 19-05 34-42 26-15 44 12-1 19-06 34:43 26-15 Station VII., 53°33'N.;- 4°41’ W. 5/11/12 (12.20) p.m. Depth (metres) ate (Oe Si/es ot 0 11-9 18-92 34-18 26-00 30 11-85 18-92 34-18 26-01 56 11-85 18-91 34-16 25-99 342, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Stations VIII to XXIV. Surface observations only. Station. Date and Time. | T° Claes Swies Ct a.m. Vill 58°27N. ; 4°5’W. 6.11.12 11.5 11-7 18-91 34:16 26-01 p.m. IX. 53°31/N. ; 3°31/W. | 6.11.12 1.20 | 10-4 18-25 32-97 25:32 X. 53°37N. ; 3°45°W. 11.12 2.20 | 11-2 18-72 33°82 25°85 XI. 53°43/N. ; 3°58’W. 11.12 3.20 | 11-4 18-94 34-22 26-11 XII. 53°48'N. ; 4°12’W. 11.12 4.15 | 11-7 19-02 34:36 26-17 XITI 53°54/N. ; 4°27 W. 11.12 5.10 | 11-4 19-00 34-33 26-19 a.m. ; XIV. 54°32'N. ; 4°37'W. 11.12 9.10 | 11-6 18-97 34:27 26-14 XV. 54°37'N. ; 4°45°W. 11.12 = =10.0 11-2 18-86 34-07 26-04 XVI. 54°35N. ; 4°27°W. AL12 «11.0 10-8 18-64 33-68 25-80 XVII. 54°34/N. ; 4°12’W. L112 12nn} 10:8 18-73 33°84 25-93 p.m. XVIII. 54°32’N. ; 3°55’ W. 11.12 1.0 10-8 18-66 33-71 25:83 XIX. 54°29/N. ; 3°43’W. 11.12 2.0 10-2 18-28 33-03 25-40 XX. 54°24N. ; 3°57 W. 11.12 3.5 10-5 18-44 33°31 25:57 XXII. 54°20’N. : 4°13’°W. 11.12 4.10 | 10:8 18-82 34-00 26-05 a.m. XXII. 54°15’N. ; 3°57°W. | 8.11.12 6.30 | 11-0 18-84 34-04 26-05 XXIII. 54°10’N. ; 3°42’W. | 8.11.12 7.30 11-0 18-65 33-69 25-78 XXIV. 54°5'N. ; 3°27 W. 8.11.12 8.25 | 10-2 18-26 32-99 25:37 December 3-4, 1912. Stations I to IV., 3/12/12. Surface observations only. — Station. Time. RO | lo | @: I. 54°N. ; 3°30’W. 8.20 a.m.) 7-4 | 18-08 | 32-66 | 25-54 MM b4INa3 3 AW 9.20 a.m.) 8-3 | 18-46 | 33-35 | 25-96 Til. 54°N.; 4°4’°W. 11.15a.m.) 8-6 | 18-63 | 33-66 | 26-15 IV. 54°N.; 4°20’W. , | 12.30 p.m.| 9-1 -| 18-91 | 34-16 | 26-46 | { Station V., 53° 53’ N.; 4°46’ W. 4/12/12 (8.45 a.m.) Depth (metres) RS Claas Sie Ct 0 10-2 18-96 34-25 26-35 30 10-2 18-95 34-23 26-34 60 10-1 18-95 34-23 26-36 SEA-FISHERIES Station VI., 53° 43'N. ; Depth (metres) te 0 10-1 30 10-1 50 10-1 LABORATORY. 343 4°44’ W. 4/19/12 (9.55 a.m.) CW) 50 Sie ot 18-98 34-29 26:40 18-97 34-27 26-39 18-97 34-27 26-39 Station VIL, 53° 33'N.; 4°41'W. 4/12/12 (11.5 a.m.) Depth (metres) i 0 10-5 30 10-4 90 10-35 CN"o0 19-04 19-04 19-04 Bcc 34-40 34-40 34-40 Ot 26-42 26-44 26-44 344 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. THE PLANKTON ON THE WEST COAST OF SCOTLAND IN RELATION TO THAT OF THE IRISH SEA.—Parrt III.* By W. A. Herpman, F.R.S., anp Wm. Rippetit, M.A. In continuation of our attempt to trace the planktonic conditions in the sea lying to the West of Scotland and North of Ireland in relation to those in the Irish Sea, a series of further observations were taken from the S.Y. “‘ Runa” during August, 1912. It will be remembered that in several previous summers we obtained at certain localities considerable hauls of phyto-plankton such as are not to be found in the Irish Sea at that time of year, and the suggestion was made that the vernal phyto-plankton, which ceases in our more southern seas some time about May, persists to a later period in the more northern waters—especially in the more land-locked fjords and between the islands, where possibly it 1s not brought into competition with invasions of oceanic organisms. A further point of interest which seemed to call for investigation was the distribution of the oceanic plankton, and its connection with the physical conditions in a wide sense. During the first few summers (1907-10) we had worked among the inner islands and sea-lochs, from the Clyde Sea-Area to Skye; while last year (1911) we extended the observations as far North as was possible in the time—to Lerwick in the Shetlands. This year (1912) our object was to work still further to the West, along the line of the Outer Hebrides, and to sample the open Atlantic water to the South of Barra * Parts I and II were printed in the Fisheries Laboratory Reports for 1910 and 1911. SEA-FISHERIES LABORATORY. 345 Head. We had hoped possibly to get observations from as far out as St. Kilda, but that was found to be impracticable in the series of gales we encountered during that exceptionally unsettled summer. The same types of nets and instruments were used as on the previous cruises—the Nansen net (with No. 20 silk) used on the Lucas Sounding Machine for vertical hauls, various open tow-nets for horizontal surface work, and the large shear-net for occasional hauls in the inter- mediate waters; the salinity readings were taken with Gel aréometers, since tested by titration and corrected, and the temperatures with the standardised Kiel thermometers. The physical observations on this cruise were all taken by George Herdman, and a list of these in detail will be found at the end of this paper. The itinerary was as follows:—We left Port Erin in the Isle of Man at 11-0 p.m. on July 30th, and reached Lowlandman’s Bay, in Jura, on the evening of July 31st, and Oban on August Ist. For the next two days we were taking observations in the Firth of Lorn round Kerrera and Lismore islands, and reached Tobermory Bay, in Mull, on the night of August 3rd. On the morning of the 5th we took some vertical hauls in the deep water at the north end of the Sound of Mull, and then crossed the Sea-of-the-Hebrides by Hyskeir, in bad weather, to Castle Bay, Barra. For the next two days we worked round the south end of the Outer Hebrides, trawling and taking tow-net samples and physical observations; and then, on the morning of August 8th, started northwards through the Sea-of-the-Hebrides past Barra, Hriskay, the Uists, and the Long Island, taking three days to reach Stornoway, in Lewis. JDuring this traverse, besides taking plankton hauls in the open sea, we entered some of the lochs on the eastern side of the islands and 346 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. sampled these less open western waters. After a day at Stornoway, we crossed the Minch on August 12th, by the East Shiant Bank, to Loch Ewe in Ross-shire, where we were detained for a day by a heavy gale. On the 14th we commenced to work southwards inside Skye, taking observations in Gair Loch, Loch Torridon, Sound of Raasay, Loch-na-Beiste, the Narrows of Skye, Loch Alsh, Sound of Sleat and Loch Nevis, which occupied the time until August 19th. On that day we ran from Loch Nevis, by Eigg and Muick Islands and round the west of Mull, to the Sound of Iona where we remained over the 20th, and put in that evening to Ulva Channel in Loch-na-Keal, after a visit to Inchkenneth. A gale on the 21st kept us still sheltering behind the island of Ulva, and on the morning of the 22nd we worked round Gometra and the Treshnish group, and along the north coast of Mull. On the 23rd we took observations round Ardnamurchan and to the south of Muick, and reached Tobermory Bay that night. On the 24th we worked down the Sound of Mull to Oban, and remained over the 25th in Dunstafinage Bay, at the entrance to Loch Ktive. During the 26th we made a traverse south along the Firth of Lorn to the Isles of the Sea, and up north again to Oban Bay. On the 27th we started southwards for home, taking observations in Kerrera Sound, off the Isles of the Sea, off Colonsay and Oronsay, and through the Sound of Islay to Lowlandman’s Bay in Jura. The following day we crossed the sound of Jura to Loch Swen, and worked up to Tayvallich. On the 29th we started from Loch Swen, in bad weather, down the Sound of Jura, and ran for shelter at night behind Gigha. On the 30th, still pursued by the gale, we came round the Mull of Cantyre, and got into Larne Lough in the North of Ireland at night. The following day, leaving Larne SEA-FISHERIES LABORATORY. 347 at 7-0 a.m., we took a series of hourly observations across the northern part of the Irish Sea, and arrived in Port Erin Bay at 2-0 p.m. on August 3lst—having traversed about eleven hundred and twenty sea-miles.* We had taken in all, on the 382 days of the cruise, 90 temperature observations and 89 readings of the ardéometer, and 48 hauls of the tow-nets, besides those of the dredges and trawls which are not under consideration in this paper.t The temperatures ranged during the month from 11°36°C. to 138°52°C., while in the unusually warm summer of 1911 the range in much the same waters was from 112°C. to 178°C. The greatest salinity record in 1912 was 272 (= 346 °/,,, corrected), “* off the island of Hriskay, two miles east of Binch buoy, Sound of Barra open,’’ and “four to eight miles east of Ushinish hghthouse,’’ on the east coast of South Uist, both on August 8th; and also in the Minch between East Shiant Bank and Ru Rea on August 12th; and four records of 271 occur on the eastern side of the Outer Hebrides; while in the Shetland cruise of 1911 we got readings up to 276 in the open sea to the east of the Shetlands on August 12th, and several of 27°2 to 27°4 between the Orkneys and the Shetland Isles, but nothing higher than 27 in Hebridean or Scottish waters. (For further particulars of the physical observations see the lst on p. 370). Of the sixteen deep, vertical hauls with the Nansen net, seven were from 100 fathoms or over, the two deepest being 145 fathoms on August 7th, “* Barra Head lght- * A olance at the Chart reproduced as fig.1 on p. 369 will give some idea of the distribution of Jand and water in this most diversified region. Notice especially the great extent of the chain of the Outer Hebrides. For some of the results of the bottom work see ‘‘ Spolia Runiana,” Journ. Linnean Soc., Zool., 1913. 348 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. house W. by N., Hesker Island N.W., outer edge of Muldoanich N.E. by N.4N’’; and 113 fathoms on August 2nd, N.W. of Bhaic Island, in the Firth of Lorn. As our main object in this paper is to discuss the nature of the plankton, we shall now consider the various tow-net hauls in some detail. The lst is as follows :— “Runa,” 1912—Plankton Hauls. The following are used in the right-hand columns : — Z = Zoo-plankton, P = Phyto-plankton. N = Neritic, O = Oceanic. Z + p =A small amount of phyto-plankton with the zoo-pl. O + n = A few Neritic forms with an Oceanic gathering. Date. Locality. Depth. Quantity. Nature. Former years. Aug 2 N.W. of Bhaic Island ......... 113 faths. Small Z+p,O0+n P.N (Z.1911) a 5 Off Ardmore, N. of Mull ... 109 faths. Medium Z, O P.N (Z.1911) * 6 Castle Bay, Barfa............... Surface Sm. Z+p,N+o Same *5 miles EK. of Muldoanich ... 107 faths. Med.+ Z+p, O — *5 miles EK. of Muldoanich ... Surface Sm. Z+P, O = ah 7 *Off Barra Head, Bernera ... Surface Sm. Z+p, O+n — *Off Barra Head, Bernera ... 145 faths. Med. Z, O — es “OT IDSA? Sonsosooanc0cccea900C 102 faths. Med. Z, O — 5 *4 miles E. of Loch Eport ... 94 faths. Med. Z, O = » 10 *Upper Loch Seaforth ...... Surface Med. P, N = *Mouth of Loch Seaforth...... 42 faths. Med. Pp, N _ *Mouth of Loch Seaforth...... Surface Med. P, N — »5 WS BEng (Slavierous WBA socoscoccose Surface Sm. Z, O — Onit Iw Uisllayael — socccncsos00002 Surface Large Z+p,0+N — ,» 15 Outer Loch Torridon ......... 50 faths. Sm. Z+p, O Same Outer Loch Torridon ......... Surface Sm. Z+p, O Same “Abereln Save eye socosossosssccosse 35 faths. Sm. Z+p, O a *Loch Shieldag, nearer Kyle.. 70faths. Med. Z+p, O = Upper Loch Torridon ......... Surface Med. P+z, O+N Same Date. Aug. 17 = - 18 a Lo = _ 2B a ws me 25 26 29 27 no 2S SEA-FISHERIES LABORATORY. Locality. Middle Loch Nevis ...........- Middle Loch Nevis ............ Tarbet, Loch Nevis (night) ... EO fe Vinekesisland! | eesees.ccse. Between Lunga and Staffa ... Si), [Biarel Git (SieRIE) Gooesceoeceson Wiesol GOmebra«-s.-ec- 54255957 SING Gea In i eaeaeesenecescesscas SIN GSE Wi Aasarnceeeesceedarioce Off Ardmore Point ............ Off Ardmore Point ............ *$.E. of Muick Island ......... *S.H. of Muick Island ......... S. of Ardnamurchan............ S. of Ardnamurchan............ *Off Ardtornish Point ........ *Off Ardtornish Point ........ *Off Ardtornish Point ........ *Dunstafinage Bay ............ = Oislesvoh Sea ceceescesesee-- “(Orit Colloiseyy ccsssononsconeacee BSmOnebavvallichter sacsa-ceasc SING ote Denvavallichim ts )ceeecees =No of Vayvallich ......°..... “Tayvallich Bay .....5.......- Depth. 79 faths. Surtace Surface 105 faths. 70 faths. Surface Surface Shear Surface 78 faths. 100 faths. Shear Surface Shear Surface Shear Surface 72 faths. Surface Surface Surface Shear Shear Surface Surface Quantity. Med. Sm. Sm. Med. Med. _ Med. + Sm. La. Med. + Med. + Med. + La. Med. + Vy.ta. La. Nature. Z, O Z, O Z, O Z, O Z+p, O Z, O Z, O Z, O Z, O Z, O Z, O Z, O Lb, © Z, O LL, © Z, N+o P, O+n P, N+o Z, O Z+p, O+n P+z, N+o Z, O+n Z, O+n 12 IN P, N 349 Former years. Same Same Same Same Same Same, Same, 1911 1911 1911 1911 *Those marked with an asterisk are new localities not visited on our previous plankton cruises. Some of these hauls were at localities visited in previous years at about the same time of year, and are thus comparable with the former ones. The rest are from new localities not reached in the previous cruises. We have grouped them as far as possible in natural districts, some at least of which correspond with those discussed in the former reports. 350 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Firtu or Lorn. August 2nd, N.W. of Bhaic Island, 113 fathoms. This is practically the same spot as “‘ between Kerrera and Mull,” July 21st, 1909, 80 fathoms, and July 24th, 1911, 110 fathoms. The present gathering agrees with that of 1911 in being mainly a fine zoo-plankton. There is, however, a small mixture of phyto-plankton, formed by ‘some neritic Diatoms, notably Hucampia zodiacus, Lauderia borealis and a couple of species of Rhizosolema. In 1909 the gathering, though still a mixture, was rather more phyto-planktonic than on the other two more recent occasions. On each occasion again there has been some admixture of oceanic and neritic types. In 1909 the neritic predominated, and on the present occasion the majority of the species are oceanic in the proportion of about two to one. Although the Firth of Lorn is open to the Atlantic to the south of Mull, the plankton does not seem to be so thoroughly oceanic in its nature as that which comes in north of that great island in the region round Ardnamurchan. Possibly the North Atlantic drift sweeps northwards from outside Islay towards the Outer Hebrides without approaching the inner islands and channels until it reaches the Sea-of-the-Hebrides between Barra Head and Tiree, and then sends a branch inwards towards the north of Mull. Such a distribution might account for some of this year’s observations. A surface gathering on August 25th in Dunstaffnage Bay, off the Firth of Lorn, North of Oban, shows an oceanic zoo-plankton with very few Diatoms and a few neritic animals. Most of our hauls about this neighbourhood* in former years had more phyto- than * Not, however, at quite the same locality, but further south off Kerrera, Bernera and Lismore in the Firth of Lorn. SEA-FISHERIES LABORATORY. 351 z00-plankton, and the Diatoms present were chiefly neritic forms. But these former hauls in 1909 and 1910 were fully a month earlier, about July 21st; so it is possible that on the present occasion the neritic Diatoms had disappeared and been replaced by Copepoda and a few other animals. In 1911, however, the hauls in the Firth of Lorn on July 24th to 26th were zoo-planktonic im character. Dunstaffnage Bay is close to the entrance of Loch Ktive, where, in 1896, the late Mr. George Murray found the neritic diatom Skeletonema costatum in great abundance in August—in marked contrast to the mainly oceanic zoo-plankton that prevailed in that neighbour- hood this year. We cannot, however, say that the plankton in Dunstaffnage Bay is necessarily any guide to what was present at the same time in Loch Etive, so much may these fjord-like inlets on the West Coast of Scotland differ from one another in their characteristic organisms. We have two surface hauls taken further south in the Firth of Lorn, or the open water outside ;—on August 26th off the Isles of the Sea, and on August 27th off the island of Colonsay. Both show an admixture of zoo- and phyto-plankton, and of oceanic with neritic forms; and, contrary to what one might have expected, the gathering which was taken further out in the open sea off Colonsay is the more neritic of the two, and also contains by far the larger numbers of Diatoms, at least ten species being well represented, and most of them, moreover, were neritic. So that the Colonsay gathering might well be described as a phyto-plankton with an admixture of some animals, and also as being neritic in character with a few oceanic forms added, chiefly Copepoda. It must be remembered that even if some oceanic 362 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. plankton is carried up this channel, the proximity of numerous small islands and rocks, and of the long coast lines of Mull, Islay and Jura, is bound to supply some neritic forms, and these may be carried unusually far out to sea by the strong tidal currents that prevail here in the neighbourhood of the Coryvrechan whirlpool. Nortu Enp or MULL. This year we have had three vertical hauls from practically the same spot, off Ardmore at the north end of the Sound of Mull, one on August oth from 109 fathoms, and two on August 22nd from 78 and 100 fathoms. All three were of very much the same type, in each case mainly zoo-plankton added to a certain amount of phyto-plankton, from four to six species of Diatoms, represented by numbers of some hundred to about forty thousand individuals each, and the general nature of the majority of the species in each case is oceanic. All] this agrees very closely with the haul taken on July 11th, 1911, from 105 fathoms, but differs markedly from the phyto-planktonic and mainly neritic hauls obtained at that same spot in July, 1909 and 1910. The evidence seems to point to the conclusion that earlier in the season the water in that region may be occupied by a neritic phyto-plankton, which becomes replaced later on by an invasion of zoo-plankton from outside. If that explanation is correct, then it would appear that the phyto-plankton lingered on to a later date in 1909 and 1910, or that the oceanic invasion was greater in 1911 and 1912. As distinctly oceanic forms which made their appearance in the Ardmore vertical hauls this year we may note the Copepod Jfetridia lucens (in every haul) and the Siphonophore Cupulita sarsi (see below). SEA-FISHERIES LABORATORY. 353 Three surface hauls taken this year rather further out, off “‘ The Cailliach’’ at the N.W. corner of Mull and between the north of Mull and Ardnamurchan, showed an oceanic zoo-plankton. Shear-net hauls obtained on the same days (August 22nd and 28rd) off the north coast of Mull, off Ardnamurchan and to the S.E. of the Island of Muick, also showed an oceanic zoo-plankton containing many specimens of the pelagic Tunicate, Doliolum tritonis, a notably North Atlantic organism. ‘The vertical haul taken on August 19th this year off Muick Island was likewise of the same nature, almost wholly zoo-planktonic of an oceanic type, and containing some specimens of Doliolum tritonis. A small surface gathering taken on August 23rd to the S.E. of Muick was composed wholly of oceanic organisms, with the exception of a few individuals of the Cladoceran, Evadne nordmanni. We have had no gatherings in previous cruises in quite this same region off Ardnamurchan and between the north of Mull and the southernmost of the small isles, with which the above hauls can be compared. Further north, however, round Higg and Canna, some phyto-planktonic samples were obtained in 1910. This year, at any rate, the Atlantic water carried oceanic organisms as far in as the channel between Mull and Ardnamurchan. OutER HEBRIDES. Most of the localities in this region were new oe untouched in our former cruises. A vertical haul on August 7th, S.E. of Barra Head Lighthouse on the Island of Bernera, the southernmost of the Outer Hebrides, is the deepest (145 fathoms) in x 354 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the whole series, and is also the one that was taken through water that is most nearly the open Atlantic. The catch is, as would naturally be expected, an oceanic zoo-plankton. Comparatively few Diatoms are represented, and only one of these, HRhizosolenia shrubsoler, is regarded as neritic. The only neritic animals, apart from a few larvae, are the wuniver- sally present (“‘ panthalassic’’) Tintinnidae. Amongst characteristically oceanic organisms we have Huchaeta norvegica and Cupulita sarsi. We add the full list as a record of our deepest haul. S.E. of Barra Head, Bernera. August 7th,1912. 145 fathoms. Calanus finmarchicus! Bas.teeasaccsescastcees stems ceeeen Cone eeenenes 3,000 Pseudocalannusleloneatusimmesses-ssnee eee ecee neste eee eee eee er eee 1,300 ID UIC MA SHEY TWOIAYSEER) onoononsbnsc0nancHsonenoaconncbnecaaDaDODEDHaCRCRC" 1 ACartia. ClauUsi. | Lsssnssnentapeneeat soaneienesegeeeeueebueaee eeceeeetoe 150 Orthona similis. sec ccasecen oes oesooeahiocccelameee hee ee eee eee EEE 2,000 Nappi sid. hike Ue not dactsels detainee ae oneiecke at ne ORR eee REE REE 10,000 Mecapod larvae yy eececsns ce seee cones ciscals wesc: «reece see ece ee epee eee 2 Sasitta bipunetatay cccs.scn cece oseesnee a eeces cee ete eee cee seen eee eee 25 PGE Lys ass ceictapats sists sites weatelsjo steoteots ails Siac este lees Pk more Se ee Ree 450 Cupullitarsarsh secceosets conwsmeietisiteejseseeeasacetc aceeee ee eeeeCeenee 1 Medtsoids) .5.jz..is-lscigeuaave nsectctntesnusmesecicvemeicisuk ones econ Cena ene 15 Pinatinmidae: _ sh sre sees wscmeneecsesitelae ice we alee se Sees ee eee eee 800 Peridini WM SPs ii osc os kosepeie senses cack ceeeberee nee eee eee eReRee 1,700 Coratiiim: LUSUS: .5. cise Jsdestgate onc stneeesiaeieasieeicnecte shee ee eer ene 150 Biddulphia resia) i. juaetceweonsereseces aes ieee -vese Geen oe Ree eee 150 Corethronveriophilumeereeseeeeeeeeee ence eee e ee pence eee EEE EEE Eee 150 Coscimodiscuspraciia tus reste seer erste reece cee ee eee Eee EE ee EEEEEEEe 450 IMATPAC SO) ETAT, TEIANSFONIN, — cogcaaconcnsocnsoceccsunvoanBoooncooKconsescS 41,600 ee Shrulbsol@ticjsecstscoeenaseececetna Ooo ck ee ene eee 92,500 The nearest approach to this locality in our former series of observations was the haul taken on July 14th, 1911, from 80 fathoms, at ten miles south of Castle Bay, Barra, and that gave, as on the present occasion, a coarse oceanic zoo-plankton. We have also in the present year a surface gathering taken off Barra Head, Bernera, on the same occasion (August 7th), which gave, however, only a small haul in which both zoo- and phyto-plankton, both oceanic and neritic forms, are represented. SEA-FISHERIES LABORATORY. 355 A pair of hauls, one vertical and the other surface, from some ten miles further north, off the Island of Muldoanich, on August 6th, gave much the same evidence. The vertical haul, from 107 fathoms, is mainly oceanic zoo-plankton, although Tintinnidae and the neritic Diatom, Rhizosolenia shrubsolet, are repre- sented. The haul contains, however, the characteristic oceanic forms, Metridia lucens and Cupulita sarsi, and abundance of Calanus finmarchicus. The surface gathering on the same day, five miles east of Muldoanich, does not show either Metridia lucens or Cupulita sarsi, and has very few Calanus finmarchicus. Like the corresponding haul the following day, off Bernera, it represents both phyto- and zoo-plankton, mainly oceanic in type. We may expect that even in water that is oceanic, when it approaches a coast there will, no doubt, be a certain admixture of neritic organisms derived from the animals and plants of the shore. August 6th, Castle Bay, Barra. This gathering agrees fairly well with that taken on July 12th, 1910, in Vatersay Sound, which is simply the channel through to the Atlantic at the mouth of Castle Bay. In each case there is a mixture of zoo- and phyto-plankton and of oceanic and neritic types. In the present year the neritic diatoms were perhaps rather more in evidence than on the former occasion. The difference in date, nearly a month later this year, must be borne in mind. Continuing up the line of the Outer Hebrides, in waters that had not been examined on any of our previous cruises, we had a vertical haul on August 8th, from 102 fathoms, two miles off the Binch Buoy to the east of the Island of Eriskay. This gathering was mainly zoo-plankton, and was certainly oceanic in type. 356 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Like some of the previous hauls, it contained Cupulita sarst and a large number of Calanus finmarchicus. There was also one specimen of Nyctiphanes couchu. The araiometer record here was 272, and the pure Atlantic water no doubt comes in here from the west through the wide Sound of Barra. The next vertical haul further north was on August 9th, from 94 fathoms, at a spot five miles east of the mouth of Loch Eport in North Uist, and this again showed an oceanic zoo-plankton containing a large number of Calanus finmarchicus and other oceanic Copepods, amongst which we found one hundred specimens of Metridia lucens. The neritic Evadne nordmanni also occurs in this gathering. We have next two hauls, one vertical and the other surface, taken at the same time in the outer part of Loch Seaforth, between Harris and Lewis, on August 10th. The vertical haul was from 43 fathoms, and was a large gathering of a phyto-planktonic character, and mainly neritic. As it was the most abundant haul that we obtained in the Outer Hebrides, we insert the details here, as follows :— Outer Loch Seaforth. August 10th, 1912. 42 fathoms. Chilaramg 1raTTNAVRE OTC 4555000000002 0c000000000000b0000D5oSHoa000Rs8 50 Pseudocalanus elongatus ................sseeseeeceeeeenenenees 39,000 Acartiay ClAUsl s)he vesincessemcneiiccitecieaecter cece tee Ce eRe PERE 570 Oithomna similis i565 oe weissie Hee o aie oe ap noe oles aaneneeeeee eer eee 2,300 Metridia TUCems' 3 .i.. iiejisa cine ciecciosine oeigels nlince cides eee ee eR eEeRe 1 IN auld eisierseristee cictaeisateitela ie diasisleelseisis dalsieseeieeeesesee ees eee Re RE eee 10,200 PI UIbED caiseieiaisinsnnine aiisinis emisloaatcteite sclepaeis neue oe se tence ee eee 1,150 amellibranchtlanvacer-e--eac-nesceeeeee reer e eee eee eee EEE 2,300 Medusoids) siis.iss<. 55 ceuele semutesee erst ne aciieiclas deals eee eRe ee ee eee 12 iPleurobrachiay pile ussyeeee eee renee eee eee cece eee eee ee eeene 1 PntinniGAe). A..:-mestvosck een ds eben sees seae see ec eae eee eee 24,000 Oikopleura: Gioia sei 45 5. sates sewseis sleep deseiee ce etisac ee eee eR EEee 1,150 POTIGIMiWTD ISP putes he instosierleltes vens-lee ae aaeteee eeeesse hee eee RE REe 3,000 Dino ph ysis acuta: (.¢ssiscosteeceesivssecinertestdecnseiacaeceemceeecers 570 Asterionella bleakleyi ...0.......0.2.cc0cce-ceeseescssonsonorseo ss 570 Bs JAPONICA). Pascnsitaaetbiece deen seeiisse Geo ee eRe ne 570 SEA-FISHERIES LABORATORY. 357 WO NACLOCELASDOLEAIE) ease acccucaesaecanaedauceeracedeessoeteceseces 27,300 a DROW westasctie ceca cece sin diseases eireisteareseine sis oe vs 1,603,000 - GOMSOTI Ch UI ecee- n colcsiestes letcatenacrorcinmemcnctnets 355,700 me Ce lem merene ase tos setiosie nse siigaemoavintietweumenecteawene 60,000 a GIEGT OES, ssoqvodbovodconbesodouosHsoabonoosoanossGaaNC 410,400 5 HEIRESS S54 cac0d5soonccudgnodHopeHduseunsdocsodraoSdsesdGeo 86,600 3 SPO POsmarcterete setsistete eteielte oieete seselovisleleeie a eieta isteioisieiisie leieltalstes 4,286,400 Corethronkcriophilumiy sseeseseseteceesceeceeecaceseeeese ees eceee 2,300 Coscinodiscusiradiatusie ee csccseesecscs-teoeeeseesceenececesceee 1,150 BN CAMP ARZOCI ACU Seer erian-stscteaatacaen ace sec sane celoecle siecle 11,500 GCimardiaghacci d ames ssscececeseecee asicwaces sence cemecescncens 5,700 Wari eri arp OOLCALS) s-ice sis emseraaince stots seaediss otis ene sieiisias/cesseles 627,000 Nit zschiaeserlatapetrcncacccencce seaec sect wel tees sek sie stusaaeeemmar es 96,000 biZOSOleniay SEMIS PIMA) ee pecodeecesee ce sescece sees wae ew esses 148,500 3 ST uMSOle woe cence sescesecte Terese esse ese tee oowen 131,100 5 StOlbertOuMiibmeeceeeetceeasccencee eos as omunese 20,000 MA MASSIOSIRAPOTAVAIGD, oS elenciccnciesenvels vecesonantieessiosiitescates 22,800 a MOLGENSKiOl ALG Wee sees ee ees ee ee seroetee sees 46,200 It will be noticed that the Copepoda are mostly oceanic (including Metridia lucens), whereas the Diatoms, amounting in some cases to millions and in others to hundreds of thousands, are almost wholly neritic. The surface gathering was of the same type, in its main character a neritic phyto-plankton, but having a few Copepoda and other animals that are regarded as oceanic. | Another surface haul was taken on the same day in Upper Loch Seaforth, above the island, some miles further inland than the position of the two last hauls. It is a well-marked phyto-plankton of neritic type, containing large quantities of Diatoms (common species of Lauderia, Chaetoceras and Rhizosolenia). This haul is very much of the same nature as the surface haul in the outer part of the loch, but is, if anything, as might be expected, even more markedly neritic. The last of these Outer Hebridean samples was a surface gathering taken on August 12th in the middle of the Kast Shiant Bank when re-crossing the Minch towards Ru Rea. It is again an oceanic zoo-plankton, with no further features worthy of notice. 3858 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Locus on MAInLAND NORTH OF SKYE. We have five gatherings from Loch Torridon, all taken on August 15th :—A vertical haul from 50 fathoms and a surface haul in the Outer Loch; two vertical hauls (35 and 70 fathoms) from the branch known as Loch Shieldag; and a surface gathering from Upper Loch Torridon, beyond the Narrows or “ Kyle.’’ The last of these is mainly a phyto-plankton, but not a very large or marked one. Its main Diatom constituent is the oceanic Rhizosolenia semispina, but it also contains the neritic Lhizosolenia shrubsoler. This gathering then is not so striking as the one taken on July 19th, 1911, in Upper Loch Torridon, when the Diatoms very markedly predominated, and we had over three hundred million individuals of Wétzschia delicatissuma in each of two nets hauled simultaneously. The other four hauls taken this year in the Torridon district were all of much the same character, oceanic zoo-plankton with a comparatively small amount of oceanic phyto-plankton. Practically the only neritic organisms present in all these hauls are some Tintinnidae. We print the details of the vertical haul from 70 fathoms in Loch Shieldag as a specimen. L. Shieldag (Loch Torridon). August 15th, 1912. 35 fathoms. CalanusiiminarchiGusmepepseer tere seeree reece cece eee nee CeEEEEe 300 Psendocalanus elongatusyeyeeer ee oe seeer- eee eee 3,450 Oithoma similas: caigseceecenceseeee soos ces meee eee eee 2,900 Metrictias Iticens sent fsiwseciges enoaste seeeleneeeden ee yee cee R ECR Eee 20 Na pli © asccsccsamcuntevies oc saeeeeeeate seve ne siteoasia sie Rep ee eee enere 3,100 Dhysanoessamaschits teres eee eer eee tee ee eee eee eee ee ee 4 Sagitta ibipunctata ypssns-e eee eeeeeeecee cece eee eeemene 10 Tintinnidaes - 2.2 - (60:8, 2 9250 eee VORD Sc) | OSsO Tee Gh. Oe eel We have before us also the statistics for Oban, which occupies a central position on the West of Scotland, and for Stornoway, which may be taken as representative of the Outer Hebrides, and find that they show the same contrast, except in the matter of rainfall, which seems to have been unusually heavy at Oban during August, 1911—although the hours of bright SEA-FISHERIES LABORATORY. 367 sunshine also give a high record for the same month, as the following table shows :— August. Temp. Sun. Rain. Oban S’way Oban S’way Oban S’way eee OO Ome 199) 166 4:61) 3:92 Qe en, OO tal le 70 Be) Bel HEY) If, then, temperature and the amount of sunshine during the month have any effect upon the amount and distribution of the plankton, here is a case where one would expect the effect to be well-marked. The right columns of the list on p. 348 show that (after removing all those localities that were sampled for the first time in 1912) most of the remainder showed the same type of haul in 1912 that we recorded in 1911. A few, however, in the Firth of Lorn and on the north coast of Mull have lost their phyto-planktonic and neritic character, and must now be classed as oceanic z00- plankton. But, on the other hand, the hauls taken off Colonsay, off Ardtornish in the Sound of Mull, and at the mouth of Loch Seaforth, along with some of the gatherings taken far up the lochs, such as those in Loch Swen, in Loch Seaforth and in Upper Loch Torridon, show phyto-plankton mainly of a neritic character. It is possible that the effect, if any, of the great heat and unusual amount of sunshine in August, 1911, was not shown by the plankton until later. We showed last year* that in the Irish Sea a marked increase in the plankton in September and October, amounting to about nine times as much as in the same period of the previous year, seemed to correspond with the larger amount of sunshine in August, 1911 (194 hours recorded at Port Erin, as * Tancashire Sea Fisheries Report for 191i, p. 153. 368 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY, against 80 hours in 1910). Unfortunately, there are no data available from the Hebridean waters later than August. There is a great want, as we have pointed out before, of a series of periodic observations on the West of Scotland, such as we now have year after year from Port Erin in the Irish Sea. It seems unfortunate that the International Council for the Investigation of the Sea has not included the West Coast of Scotland in its scheme of work. It is the only part of our outer coastal waters that has not been systematically investigated. The West of Ireland and the North of Scotland are included in the periodic observations, and it is to be regretted that such an interesting connecting link as the Hebridean Seas should have been omitted from the official programme. We see no reason to modify our view that the spring phyto-plankton seems to remain longer in northern Scottish waters than it does in the Irish Sea. It probably disappears more slowly some years than others, and it certainly seems to be replaced more on some occasions than on others by invasions of oceanic zoo-plankton. This summer there seems to have been a well-marked invasion of this character to the north of Mull, carrying even such an Atlantic organism as Doliolum almost into the Sound of Mull (see fig. 1). It seems not unlikely that there is a definite connection between oceanic water containing Calanus in quantity and shoals of herrings in the Hebrides. We have noticed on several occasions that we obtained large hauls of Calanus at spots where either the night before or the night after good catches of herrings were reported. This is one of several matters upon which we hope on some future occasion to try to obtain more convincing evidence. SEA-FISHERIES LABORATORY. Chart of West Coast of Scotland from Mull of Cantyre to Hic. 1. Butt of Lewis. 370 rae a a Oe MW lecs We eec 14... 15... 16... 17... 18... MW) occ 20... TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. “Runa,” 1912. Physical Observations. Thermo- Time. Locality. meter. 9.0 a.m. 2 miles N. of Maidens .................060 11-88°C. 10.0 a.m. E. of Garron Point, 5 miles off ............ 11-83 11.10 a.m. S. end of Rathlin Island bearing N.W.... 11-81 12.0 noon Mull Lighthouse bearing E.N.E., 2miles 11-97 1.0 p.m. Machrihanish bearing E...................... 12-30 3.45 p.m. Sound of Jura, off N. end of Gigha ...... 12-41 8.0 a.m. Lowlandman’s Bay, Jura ................+. 11-90 10.30 a.m. Off Ruadh Rock (Sound of Jura) ......... 11-97 12.45 p.m. ‘Off Wasdale Island ................0..0-0sc0e 11-80 9:0 “a.m: Qban Bay, Sescesecccnss0sonnseeneene sasceeeeeee 12-00 10.45 a.m. Between Oban and Lismore ............... 12-07 2.50 p.m. Between Mull and Bhaic Island ......... 12-00 8.0 p.m. Sd. of Mull, betw. Salen and Tobermory. 12-10 9.30 a.m. Tobermory Bay (high tide).................. 12-31 25pm: Wobermonyp Baye. sn cccssess s+ cecseeeesceaeeee 12-44 6!50)pnms, Lobermony Bayecnn-sscsssecce-eeeseeaeeee sees 12-36 9.30 p.m. Tobermory Bay (after rain) ............... 12-13 OYA Dame i OtheArdmores Mall eereeeeeeeeeeeeeceeeeeeeee 12-40 5.0 p.m. Minch, between Hyskeir and Barra 12-46 9:30%asm) (Castle Bay, Barrage. sssssecceseceecaeeee eee 12-40 4:0) pam. 5 miles Hof Muldoanich =.2--...s.sse-eere 13-20 11.15 a.m. Pabbay bearing N.W. _ ............-.0ee0 12-52 12.0 noon 4 miles S.E. of Barra Head, Bernera ... 12-92 11.0 am. Off Eriskay, 2 miles KE. of BinchBuoy... 11-94 2.30 p.m. 4 to 8 miles EK. of Ushinish Lighthouse... 12-21 10.0 a.m. Off Ushinish Lighthouse ..............,... 12-03 4.30 p.m. 7 miles E.S.E. of Loch Maddy ............ 11-86 11.30 a.m. E. of Sound of Harris ....................200- 12-26 2.30 p.m. Upper Loch Seaforth, above Island ...... 12-36 6.0 p.m. Off Ru Hurnaway, 8. of Stornoway 12-50 5.0 p.m. At Stornoway (some fresh water) ...... 13-38 9.0 p.m. At Stornoway | fromriver jf ...... 12-25 9.45 a.m. 1 mile 8. of Stornoway ...................+. 12-38 10.30 a.m. 8 miles from Stornoway ...............2.060- 11-74 11.45 a.m. On East Shiant Bank ........................ 12-38 1.30 p.m. Between E. Shiant Bank and Ru Rea... 12-42 PN) Torin, Oe TRinL 148) oconosonsocnsbonscHoancadscce0D0008 12-62 A:0) pans Oi Hwesisland rsp cesesscsse ss seneeeeeceereer 12-95 1ZOraims (SSobiRubReay) .... 5. .ce.csceeceeeceereennree 11-54 2.0 p.m. Head of Gair Loch (much rain) ......... 12-62 11.15 a.m. Mouth of Gair Loch ..................-.0606 12-0 12.15 p.m. Entrance of Loch Torridon.................. 11-66 Iara, lore Slarielebyee — ccopocansqsconacososunvocenoces 11-36 2.30 p.m. Upper Loch Torridon ......................+ 12-55 4-305p:m.., [Of Croulinbeg Waren-eree ss. -cs-t eee ee eee 12-46 eM) form, — Osir IARI, Socpconcocososoonsavescabdonacooe 12-01 930 jasms) WWoch-na-Beistelce ssescssedeassecensersseeee eee 12-21 1045ia.m. LochJAlshwen....-sscscenssessesscace eee en eeene 11-90 2.30 p.m. Sound of Sleat, below Glenelg ............ 12-56 ? Middle of Loch Nevis ....................200 12-19 Pell joni, Aver ceye, ILO a INES) scosacsaoaeconcbcacacosoaee 12-43 ONS jaums | Outer muochBNevasms-e-esseseececaeeseeeeeeeee 12-54 12.15 p.m. Off Muick Island ..................0...0-eceees 12-40 1.45 p.m. Off Cailliach Point, Mull .................. 12-59 8:30) pim) ySoundtollonaenss-cesseeseeseeeeeeeeesetee eee 12-74 CHD Geren, ~ Ta) Toya, (S@MWAC! cooconococqonseecanecanscHcoeseC 12-60 JEL Sypsmses inplonam Sound ieee sscseseee seececeeee esr eeeee 12-60 Ariao- meter. 26-5 26°5 26-6 26:5 26-6 26:6 26-4 26:3 26:3 25:8 25-5 25:7 26:0 26-0 25:7 25:7 25:0 SEA-FISHERIES LABORATORY. 371 . Thermo- Ario- ; Date. Time. Locality. meter. meter. Aug. 21... 12.0 noon In Ulva Channel ................:0.seeeseeeeee 12-50 26-7 eo Onna Ola eno GOMECLEA Rs ncsccesecerecceceencccces 12-33 26-9 310) jon. Oui ING @rf IWIN eeponesecsebsooancnbouscoscddooan 12-57 26-9 Obsp mss) Of Ardmoreye Ont) .crecsssccsaecaecr=--ssaces 12-41 26-9 » 238... 10.30a.m. Off Ardmamurchan ...............ccccseeeeeee 12-10 27-0 NAD jor, (S, WE MICK “Geooassnnosogoosoconsoacsoono0550c6 12-15 27-0 4,30 p.m. Between Muick and Ardnamurchan ...... 12-60 26-8 » 24... 2.0 p.m. Betw. Ardtornish Point and Avon Rock 12:8 26-0 » 25... 3.0 p.m. In Dunstaffinage Bay ...............:....000 13:02 abt. 23 » 26... 9.0 am. Off Dunstafinage Point ..................... 12-41 25:3 11.0 am. Between Oban and Lismore Lighthouse 12-76 25-2 2.30 p.m. N. of Isles of the Sea ................cceeeees 12-46 26-5 ; Ban aids 8.30 a.m. §. end of Kerrera Sound..................... 12-02 26-4 9.30 a.m. Between Sheep Island and Isles ofthe Sea 12-30 26-5 J 10.30 a.m. Between Isles of Sea and Colonsay...... 12-40 26-5 . ile sOramemeO it Hot Colonsay. iene-cssccescecce-aieessse: 12-55 26-5 i 4.30 p.m. Between Colonsay and Sd. of Islay ...... 12-75 26-6 6.0 p.m: E. end Sd. of Islay ..................ceceeeeee 12-20 26-6 7.0 p.m. Sd. of Jura, off Lowlandman’s B. ...... 12-20 26-7 > 28... 9.0 a.m. Off entrance Lowlandman’s B. ............ 12-25 26-6 9.45 a.m. Off Mor Island, Sd. of Jura ............... 12-03 26-7 11.0 a.m. Loch Swen, off Tayvallich ............... 12-90 26:3 SO spe Doe N-sofs bayvallicht \ .cs:asececsmaccnss 12-99 26-4 » 29... 3.0 p.m. Mouth of Loch Swen ...........,.........00 12-24 26-6 _ 4.30p.m. Sound of Jura, N. of Gigha ............... 12-43 26-7 >» ol... 7.30 a.m. Entrance Larne Harbour .................. 12-40 25-4 8.30 a.m. Off Belfast Lough ...............00.eceeeeeee 12-58 26-8 9.30 a.m. On Course (S. by E. 44H.) .................- 12-59 26-7 10.30 a.m. TD Yo) = MopensenncononcencHoncer re snaeecencnecee 12-70 26-7 11.30 a.m. Do. (Bradda Hd.,8.E.byS.) ... 12:78 26-8 12-30 p.m. Do. (Bradda Hd., S.E. by S., Contrary Hd., E. byS.) ... 13-19 26-8 1.30 p.m. WD OSH foros hase ceucacescwcusaeceseuntacsscine 13-52 26-7 2.0 p.m. Port Hrin Bay .............2..s.ceseseceenseees 13-40 26°7 Note.—The Thermometer used has been checked ’ against a standard instrument; the necessary correction is) Oi 15>. The Aréometer has been checked by titration, and the following correction must be applied :—Correct in the usual way for temperature (A in Knudsen’s tables), then add 0°20 to the corrected reading to get pj;.;. For example, on August 7th, at noon, the corrected temperature would be 13°07 and the ardometer reading corrected for temperature becomes 26°23 and, with the final correction pi;; = 2643 and S = 3460 °,.. The readings on the 8th when corrected give slightly lower results, but that on the 12th at 1.30 p.m. gives S = 3461°/,,, and this is the highest of the series, 372 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. AN INTENSIVE STUDY OF THE MARINE PLANKTON AROUND THE SOUTH END OF THE ISLE OF MAN.—PART VI. By W. A. Herpman, F.R.S., AnpREW ScorT, A.L.S., and H. Masext Lewis, B.A. (With a plate and other illustrations.) METHODS. This work has been continued during 1912 on the same general plan as in preceding years. ‘This completes the sixth year of this collection and detailed analysis of the plankton week by week, and we consider it desirable that, if possible, ten years of continuous observations should be accumulated before any change is made in the scheme of work. That, it is hoped, may enable us to draw conclusions which are not vitiated by the data of some exceptional year. The work at sea in April, 1912, during the time of the vernal phytoplankton, was carried on from the steam- yacht ‘* Runa,’’ with the capable assistance of Mr. W. Riddell and his successor, Mr. H. G. Jackson; while in Port Erin Bay Mr. Chadwick and Mr. T. N. Cregeen, of the Biological Station, collected six samples a week throughout the year—two with a fine net (No. 20 silk), two with a coarse one (No. 9 silk), and two vertical hauls from 5 fathoms. The authors have divided the rest of the work between them on the same general lines as in previous years. As in the case of the last report, we shall give here only a comparatively brief statement of results, selecting for discussion any points which seem new or which we- SEA-FISHERIES LABORATORY. 373 have not dealt with before. Consequently, we must refer readers for fuller information in regard to the details of our methods and some of the results to the preceding five parts of this work (see Reports for 1907-1911). MATERIAL AVAILABLE. | The collections made this year have amounted to nearly 400—all taken within the limited sea-area off the Isle of Man to which this ‘* Intensive Study ’’ is confined. The series of samples, including those of former years, is now as follows : — At Sea, from Yacht. In Bay Year. ann throughout Totals. Spring. Autumn. Year. 1907 218 ~ 279 138 635 1908 156 242 157 559 1909 329 147 231+ 49 756 1910 107 249 296 652 1911 120 84 314 518 1912 87 0 299 386 Totals ... 1,017 1,001 1,484 3,502 In addition to these plankton samples from the neighbourhood of Port EHrin, the Fishery steamer “James Fletcher’’ has taken a large number of both vertical and horizontal plankton hauls in other parts of the Irish Sea during the past year, and other samples were taken from the ‘“‘Runa’’ during the summer further North, along the West Coast of Scotland, all of which have been worked up in our laboratory and are available for comparison. No change has been made during 1912 in the nets employed or the method of using them (see last Report, p- 128).. 874 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. PLANKTON OF PORT ERIN BAY IN 1912. As before, the plan of work is to take two horizontal hauls (coarse and fine nets) and one vertical haul on two occasions each week throughout the year—that is, six hauls per week, about 24 per month, and 312 in the year. The twelve months of 1912 are represented by their hauls as follows :— Months ...| I | IT | IL} IV} V | VI | VIL) VITL | 1X} X | XI} XI Sauetitienlk 24 24 24 | 27 37 21 | 27} 27 | 334) 19} 25} 21 The work has thus been carried out for us with great regularity, and the average per month is about 25 hauls. The lowest monthly record is 19 for October, and the highest 33 for September. The high number in the latter month is due to some extra hauls having been taken in addition to the usual programme. The upper whole-line curve in fig. 1 shows the total plankton caught in the horizontal tow-nets (coarse and fine added together) in Port Erin Bay during the months of 1912; while the lower broken line shows the corresponding curve for the hauls of the vertical net, multiplied by two for the sake of distinctness. Consequently, the scale on the left-hand margin applies only to the upper curve. The positions of the vernal and autumnal maxima are distinctly seen, and also the summer minimum in July and August. Neglecting the vertical hauls at the mouth of the Bay, which give much the same result on a smaller scale as the horizontal nets (see fig. 1) but are not directly comparable with them, and treating the coarse and fine nets together as before, we get the following averages for the total plankton, and the number of individuals of the SEA-FISHERIES LABORATORY. 375 chief planktonic groups, per haul of the standard net for the twelve months : — Double Average Diatoms. Dinoflag- Copepoda. Copepod Copepod 1912. hauls. catch. ellates. Juv. nauplii. January ...... 8 2-7 48,409 4,697 6,227 0 4,605 February 8 2°8 60,409 1,611 3,346 0 5,940 March ......... 8 15-4 4,099,737 19,235 2,801 400 23,967 ANvorail” 28edo560 9 25-5 21,267,907 2,233 3,213 0 13,204 IW | caseebaas 9 36:3 27,891,917 1,299,576 53,742 4,456 191,089 UMC senesons 7 37:5 46,824,314 24,014 74,129 O 122,643 duly, ssoeenueas 9 13-6 40,966 2,684 32,620 389 39,789 August ...... 9 13-1 683,874 306 31,996 271 32,196 September... 9 23-4 = 8,172,122 2,681 46,207 0 27,904 October ...... 7 9-6 242,486 679 75,577 0 35,463 November ... 8 3-2 41,642 5,409 14,078 0 6,470 December <2. - 7 6-4 11,659 1,423 6,044 0 1,803 This table may be compared with the similar ones in the last three Reports (Part III, p. 212, Part IV, p. 199 and Part V, p. 130). Compared with that for 1911, it shows a lower actual maximum in total catch (375 c.c. in June, 1912, as against 46 c.c. in May, 1911), but the general level of the catches from March to June is higher aocc 30 Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dee Fig. 1.—Total Plankton Curves (horizontal and vertical nets) in the Bay. 376 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. this year, and the vernal maximum seems to be spread over a great length of time. In 1912 the smaller but quite decided autumnal maximum is in September, and is greater than in 1911 (234 c.c. as against 15°3 c¢.c.). The Diatom maximum is a month later and nearly twice the bulk of that in 1911, but this is wholly due to the enormous quantities of Rhizosolenia taken in June; nearly 41 millions of the 47 millions in the table being due to Rhizosolema. The well-marked Dinoflagellate maximum is in May (June in 1911), and is unusually high. The Copepoda reach their maximum at an unusually early date, at least a month before that of 1911, when the highest numbers were in July and August, while this year they are in May and June. The table above and the remarks following it apply to the double hauls of the horizontal tow-nets; while the diagram below (fig. 2) represents the curves for total plankton, Diatoms, Dinoflagellates and Copepoda as captured in the vertical net at the mouth of the Bay. On the left-hand margin the volume in c.c. of the total plankton, and the separate scales for Diatoms, Dino- flagellates and Copepoda, respectively, are indicated. The general correspondence with the results obtained from the much larger catches of the horizontal nets will be noticed. DIATOMS. Compared with the previous year, the appearance of Diatoms in quantities in the spring of 1912 was earlier. Nearly 2 millions was reached in the double haul as early as March llth, and nearly 25 millions on March 2\lst, and these high numbers were sustained until the middle of June, the actual maximum being 202,993,600 on May 30th; whereas in 1911 millions were not reached SEA-FISHERIES LABORATORY. 377 until May 10th, and the numbers had dropped again by June 12th, and the maximum haul was only 69,982,500 on May 16th. So that, whereas last year we were able to show the rise and fall of the Diatom vernal maximum in a table (p. 133 in the last Report) giving the numbers throughout May and the first week of June, this year we should need to give them for the four months March to 500000 Diat- 2000 Dino: 1,000Copep: Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Fic. 2.—Curves for chief groups and total plankton of vertical net in Bay. June in order to cover the period of the Diatom visitation. On analysing the vernal maximum into its constituent factors, it is found that species of Chaetoceras and Lhizosolenia are enormously more abundant than any other forms, and that the former is present in greatest quantity in March and April and the latter in 378 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. May and June. From the middle of May to the middle of June the bulk of the catch is composed of Rhizoso- lenia, but Guinardia is also represented by numbers of from 14 millions to nearly 23 millions, and these two genera (along with a few tens of thousands of Chaetoceras and a few Hucampia) are the only Diatoms found in our nets in June. The autumnal maximum was a few weeks earlier in 1912, and was higher; as in previous years, it consisted mainly of a few species of Chaetoceras. Tue More Important GENERA OF DIATOMS. We shall again pick out the more salient features in the distribution throughout the year of the same seven genera of Diatoms dealt with in previous reports. Biddulphia.—This genus is represented, by a few thousands and tens of thousands only, from January to the middle of May, and again from the middle of September to the end of the year. The highest record is 88,240 on March 11th, and in autumn the highest is 69,960 on November 14th. These numbers are consider- ably lower than those for 1911. [See note (p. 380) on the species or “‘ forms’ of Biddulphia present. | Chaetoceras.—The maximum this year is at the end of April with 94,733,000 on the 29th, 26 millions more than the maximum of 1911 (on May 16th). The autumnal maximum also is greater, with 293 millions on September 26th, as against 104 millions on October and, 1911. Coscinodiscus.—The numbers are rather higher this year than in 1911, the highest record being 462,750 on March 21st, and the highest monthly average 100,619 for April. On May 9th there was a large haul of 119,600, SEA-FISHERIES LABORATORY. 379 but after that date the numbers dropped suddenly, and in June the genus was entirely absent. It appeared again in the middle of September, and rose to a second maximum of 35,000 on October 7th. Rhizosolenia.—This genus was present in enormous quantities from the middle of May to the middle of June, and was much more abundant than we have ever known it before. The two highest records are 184 millions on May 30th and 173 millions on June 3rd—per standard haul in every case quoted. After dying down in the middle of July, Rhizosolenia was again present from September 13th for about a month, the highest haul being 647,000 on September 30th. Thalassiosira.—There was one large haul of over 6 millions on April 29th, but the next highest was only 289,300. In 1911 the maximum was not until the end of May, by which time this year the genus had entirely disappeared. Its appearance in autumn was also earlier this year, but the numbers only reached 28,000 (September 30th), as against 287,000 on October 5th, 1911. Guinardia.—This genus is unusually abundant this year, very high numbers being met with throughout May and June, and the maximum being 22,800,000 on June 3rd; 70,000 on September 30th is the highest record for the autumn. Lauderia.—This form is more abundant than in 1911, but not so abundant as in 1910. The maximum is 124 millions on April 29th, but only on that occasion did the numbers reach the millions. We give here the monthly averages of these seven genera of Diatoms, as follows :— 380 1912. Biddul- Chaeto- Coscino- Rhizoso- Thalassi- Guinardia.Lauderia. phia. ceras. discus. lenia. osira. a . Jan. ... 24,920 7,342 9,877 22 0 257 189 Feb. ... 36,885 10,301 10,034 12 0 105 "0 Mar. ... 21,176 3,977,292 95,446 525 25 162 337 April ... 21,869 18,365,750 100,619 36,464 721,338 3,158 1,622,478 May 1,072 2,844,861 14,586 22,008,744 41,033 2,789,433 170,878 June 0 67,543 0 40,833,771 0 5,919,429 0 July 0 39,527 56 1,228 0 158 0 Aug. : 11 694,961 0 13 0 0) 0 Sept. ... 4,131 7,702,658 1,677 117,122 3,978 10,967 8,944 Oct. ... 5,827 214,421 11,914 820 57 2,176 29 Nov. ... 25,714 9,476 5,436 0 0 “21 0 Dec. . 8,059 1,106 1,573 0 0 141 0 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The above table shows very clearly how the different genera reach their maxima at different times, and how Chaetoceras in spring gives place to Rhizosolema and Guinardia in early summer. Notr on THE ForMS or BIDDULPHIA PRESENT. Under the genus Biddulphia above we have, as in previous years, recognised and recorded two “‘ species,”’ B. mobiliensis and B. sinensis (see a and 6b, fig. 3), but some variations in these forms have been noticed of late upon which we wish to make some observations. In the photo-micrograph (fig. 3), @ points to what has been regarded hitherto as B. mobiliensis in our district, and b to a typical example of B. sinensis. Our B. mobiliensis undoubtedly approaches the form ‘‘vegia,’’? regarded as a distinct though allied species by Ostenfeld (Medd. Kom. Havunders., Plankton, Bd. I. 6, 1908). Gran, in the Diatomacea of the Nordisches Plankton, unites these two forms as B. mobiliensis, and we in recognition of the facts, as we conceive them, consider that they should be known respectively as Biddulphia mobiliensis, forma regia, Schultze, and B. mobiliensis, forma sinensis. SEA-FISHERIES LABORATORY. 381 Fie. 3.—Photo-micrograph of a plankton haul showing (a) Biddulphia mobiliensis, forma regia ; and (b) B. mob., f. sinensis. In the XVIIIth Annual Report (for 1909, p. 222 we recorded the discovery of Biddulphia sinensis in Port Erin Bay for the first time on November 9th, 1909. We also showed that it increased in numbers from 400 specimens on November 9th in the coarse net to 1,600 specimens in a haul with the same net on November 13th, and for the rest of the year the numbers varied from 1,000 to 800 for the coarse net. We then stated: ‘“The view is definitely held by Ostenfeld that this is a ‘“ease of an exotic species which was introduced ‘accidentally (e.g. by a ship from the East) into ‘* European waters near the mouth of the Elbe, probably ‘*in September, 1903; and the rate of dispersal from that “point is used as an indication of the presence and rate ‘of flow of currents. If Ostenfeld is right in his 382 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. “interpretation of the facts, then our record shows that ‘the species had extended to the centre of the Irish Sea ‘“in 1909, and that here, as elsewhere, it reached a ‘‘maximum in November. It is, however, possible that — ““we have in all these records the unusual increase of a — ‘rare species which had previously escaped observation.’ The specimens of Biddulphia sinensis noticed during - the first year of its occurrence in our: area were single cells, as shown in figs. 1 and 2 on Pl. I..- There was not the slightest indication of increase in numbers by cell division. On p. 207 of the XIXth Annual Report (1910) . we state: “The Indo-Pacific Diatom, Biddulphia ‘* sinensis, which has appeared recently in our N.W. ‘“Huropean seas, is again present at Port Erin in ‘* November in quantity. ‘“It seems now, from its appearance in the gather- “ings, to be in much more vigorous condition than when ‘“it first occurred in the Irish Sea. The cells are seen ‘to be in active division, and chains of two and four ‘‘ cells adhering together are quite frequently seen.” The general appearance of the dividing Biddulphia sinensis in 1910 is shown by fig. 3 on the Plate. It agrees fairly well with the text-figure given by Ostenfeld on p. 363 of the “‘ Internationale Revue d. Hydrobiologie und Hydrographie,’ Bd. II, 1909. Up to this time all appeared to be well with Biddulphia sinensis in our district, and it was acting just as a sound species ought. It again made its appearance in the autumn of 1911, and for a time continued in a normal condition. Towards the end of that year, however, odd specimens were noticed which showed a departure from the true sinensvs form, and appeared to be adopting some of the characters of Biddulphia mobiliensis. We state on p. 138 of the SEA-FISHERIES LABORATORY. 383 XXth Annual Report (1911): “In our district ** B. sinensis is of more elongated form than is shown in ‘““Ostenfeld’s figures. Most of our specimens of ‘““ B. sinensis are very distinct and easily distinguishable ‘from the mobiliensis-regia group by the shape and the ‘“‘ position of the spines, but we have found one or two ““specimens during this last year where one end of the ‘*“ cell bore the characters of sinensis, while the other had ““the appearance of mobiliensis. Until, however, we get ‘further specimens we do not propose to base any “opinion as to the species upon this possibly abnormal ‘“form. We are watching the fresh material of ““B. sinensis carefully in the present year (1912), and ‘“may return to the subject in our next report.’’ We are now carrying out that intention. The change in the stability of Biddulphia sinensis. became more marked in the Bay gatherings taken in the early spring of 1912, and again in the Bay gatherings taken in December. The appearance of the abnormal forms is shown by figs. 5, 7, 8, 9, 10, 12, 14 and 15 on the Plate. All these figures show clearly that one end of the cell is a Biddulphia sinensis, while the other end shows a decided approach to the appearance of Biddulphia mobiliensis. The spines have migrated away from the base of the continuation processes of the shell to nearer the centre. The concavity between the spines which is distinctly visible at the semensis end has become almost obliterated at the mobiliensis end by the migration of the spines. The continuation processes have also suffered to some extent. They have disappeared entirely in figs. 7 and 9, and only one is left in figs. 8, 10, 12, 14 and 15. Most of the figures show the cell in the process of division. In some cases one of the daughter cells will become a typical 384 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Biddulphia sinensis, as in figs. 6, 7 and 9. The other daughter cell in figs. 6 and 8 will apparently give rise to a cell very like the parent, and the ends will again be unlike. On the other hand, figs. 8, 10, 14 and 15 show that while one of the daughter cells may give rise to a sinensis-mobiliensis form, the other will produce a form closely approaching that of a true mobiliensis. Fig. 4 shows very distinctly two daughter cells of which the external ends are clearly of the sinensis type, but the internal ends where division is taking place are assuming a characteristic mobiliens’s appearance. When division is completed we would arrive at the first stage of the transition of Biddulphia sinensis into simensis- mobiliensis, then later at the next division probably we should have two apparently distinct Diatoms, Biddulphia simensis and B. mobiliensis. We have noticed that when Biddulphia made its appearance in the autumn collections from Port Erin Bay during the last two years B. sinensis was at first the prevailing form. 2B. mobiliensis then becomes more plentiful. later in the winter and in the following spring, when B. sinensis diminishes in numbers. Gran, who reports on the pelagic plant life in ‘““Depths of the Ocean,” by Sir John Murray and Dr. Johan Hjort, refers to the known case of the Diatom Rlizosolenia hebetata occurring in two perfectly distinct forms. On p. 320 he describes the differences in the cell-walls and setae of Chaetoceras decipiens in spring and summer, and the variation in size and shape between specimens of Biddulphia aurita from along the Arctic coasts and off the south of Norway. He says: ‘‘ We find “a variation of a different nature in the case of Rhizoso- “lena hebetata. It occurs in two perfectly distinct ‘forms, that were formerly regarded as good species. SEA-FISHERIES LABORATORY. 385 ‘“The first, which belongs to Arctic waters, is thick- ‘walled and gross, and is the true Rh. hebetata. The ‘“second, R. semispina, has thinner walls and is pro- ‘““portionately longer, and it is furnished with a long ‘hair-like point at each end. Its distribution extends “over practically the whole Atlantic, though it is chiefly ‘““to be found in the neighbourhood of the cold currents. ‘“These two ‘species’ can originate from one another “‘ reciprocally as the result of one cell-division. During ‘““the course of transition a cell may be hebetata at one ‘end and semispina at the other.’’ This is just what we find is happening with our Biddulphia sinensis. Biddulphia mobiliensis (Bailey), as figured by Ostenfeld in the volume of the “‘ Internationale Revue ”’ referred to above, is not nearly so common in the Irish Sea as the larger form he names B. regia (Schultze), and which we have all along recorded as biddulphia mobiliensis (see figs. 16-19). We now regard it as probable that these three so-called species are all forms of the same Diatom in various stages of transition or modi- fication. Bailey’s name, mobiliensis, appears to be the older one, and ought to be adopted in preference to the others. For the sake of uniformity with the records in our previous reports, we continue to use the names sinensis and mobiliensis for the two forms shown in text-fig. 3 (p. 381), although we are not now inclined to regard them as being distinct species. They are, we consider, two forms (B. mobiliensis, forma sinensis, and B. mobiliensis, forma regia) of the original species B. mobiliensis, Bailey. On the other hand, however, we are informed by Dr. H. J. Allen that he and Mr. Nelson succeeded at Plymouth in growing pure cultures of the forms Biddulphia sinensis, B. mobiliensis and B. regia, and Z 386 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. that these retained their distinctive characters for over a year. It may well be, however, that in the constant environment of a laboratory experiment a marked variation or ‘‘form,’’ arising as a mutation, may continue to preserve its distinctive characters through many generations and appear to be stable; while under the varying conditions of a natural life in the open sea such marked variations may arise in some individuals, persist for a time, and then die out or be replaced more or less completely by one of the other forms. When examining a gathering such as we show in fig. 3 (p. 381), the forms a and b certainly seem very distinct; but on the other hand, the figures we give on Pl. I, lke the cases quoted from Gran (in Murray and Hjort), do not seem explicable on the view that we are dealing with independent species. They may be regarded as mutations which under some circumstances breed true, but sometimes throw back to the original form of the species. . EXPLANATION OF PLATE. Fig. 1. Biddulphia mob., f. sinensis, as it first appeared in the Irish Sea in 1909. Fig. 2. Ditto, a slightly elongated form. Fig. 8. Ditto, normal division as it appeared in 1910. Fig. 4. Ditto, transition form in process of development. Fig. 5. Ditto, transition form after division and elongation. Fig. 6. Ditto, normal but rather slender form dividing. Fig. 7. Ditto, one end without continuation processes. Fig. 8. Ditto, the form ‘‘ sinensis-mobiliensis”’ dividing. Fig. 9. Ditto, one end without continuation processes. Fig. 10. Ditto, mobshensis dividing. Fig, 11. Ditto, slender but nearly normal form. Fig. 12. Ditto, abnormal form. Fig. 18. Ditto, probably a dead cell, showing divisions unusually near the end. Fig. 14. Ditto, mobiliensis dividing. Fig. 15. Ditto, mobiliensis dividing. Fig. 16. Biddulphia mobiliensis, ‘‘regia’’ form of long shape. Fig. 17. Ditto, ‘‘ regia’’ form of short shape (turned sideways). Fig. 18. Ditto, ‘‘ regia’’ form dividing. Fig. 19. Ditto, ‘‘regia’’ form dividing. Fig. 20. Ditto, ‘‘ regia ” form approaching Ostenfeld’s “* mobiliensis.”’ Note the unusual number of spines in figs. 10, 12, 14 and 15. The figures are all photographs of equal magnification. Prate I. Photo. by A, Scott. V ARIATION JON LED IDIQUIPAIEIT AT. SEA-FISHERIES LABORATORY. 387 DINOFLAGELLATA. The monthly averages for Ceratium and Peridinium throughout 1912 were as follows : — 1912. Ceratium |Peridinium 1912. Ceratium | Peridinium tripos. spp. tripos. spp. January ...... 3,977 AB || Uwky “scscocded 1,318 1,367 February ... 1,211 62 | August ...... 98 208 Wikylay adsecocee 11,510 0 | September... 2,669 0 AN ae, Basseeoee 929 1,027 | October ... 646 33 WARY cecesceoe 13,342 1,283,389 | November... 5S 15S7/ 229 Minee weten. c= 1,014 23,000 | December ... 1,096 176 The maximum in both cases is in May, a month earlier than in 1911. The numbers for Ceratium tripos were a little higher that year, but in 1912 Peridiniwm reached far higher numbers. In 1911 the maximum was only 38,000 (June 3rd), while in 1912 it was 8,650,000 (May 9th)—the greatest number of Peridinium we have ever recorded during these series of investigations. Peridinium is to be regarded as an oceanic form, and this exceptional abundance in 1912 agrees with other evidence that that year our western coasts showed an unusually large invasion of Atlantic organisms.* NoctTiLuca. We have remarked before (Part IV, p. 213) on the exceptional occurrence of Noctiluca miliaris in abundance off the Isle of Man in the late summer of 1910, and (Part V, p. 141) on its persistence in reduced numbers in Manx waters during practically the whole (10 months) of 1911. In 1912, again, this organism was well represented throughout the year, the only month * See also Herdman and Riddell on the Plankton of the West Coast of Scotland, elsewhere in this Report. 388 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. when we have no records of its presence in Port Erin Bay being April. The numbers usually vary from a few hundreds to a few thousands. On the whole, Noctiluca seems to be least plentiful in spring and early summer (February, March, April and May), and to become more abundant in autumn. Our largest haul is 16,400 on October 7th, and the next is 4,600 on November 16th, after which the numbers diminish to the end of the year. CoPEPODA. We have again taken out the records of the nine commonest species of Copepoda, and have obtained the following results : — Calanus finmarchicus.*—This species is again present throughout the year, and in rather larger numbers than in 1911. One very high record is 50,720 on May 17th, and several hauls from one to over six thousand were taken from April to July. In October there is one large haul, namely, 2,120 on October 7th. Pseudocalanus elongatus.—The highest record this year is 91,960 on October 21st; this is nearly twice as large as the highest in 1911. There is another, smaller, maximum in May to June, with 65,200 on May 20th and 44,500 on June 17th. Last year the maximum was in July, and there was no marked autumnal increase. Oithona similis.—This is again the commonest species in our nets. The highest monthly average is 36,444 in June, but the two actually largest hauls are in autumn, 87,530 on September 26th and 75,400 on * We have sometimes in the past followed G. O. Sars in calling this species C. helgolandicus, but we are now inclined to agree with Wolfenden, Hsterly, and others in thinking that the characters used in the attempt to separate ‘‘ finmarchicus ” and ‘‘ helgolandicus”’ as Species are too shght and inconstant—and so we return to the older name. SEA-FISHERIES LABORATORY. 389 October 7th; these numbers were only exceeded in 1911 by the one enormous haul of 225,450 on July 18th. Temora longicornis.—The distribution of this species again forms a simple normal curve, rising from an average of 4 in January and February to 17,000 in May, and sinking to zero in December. At the time of the maximum, which is earlier, the numbers are higher than in 1911. We find 50,400 on May 17th, followed by 835,400 on the 20th. Paracalanus parvus.—The distribution of Para- calanus follows the same general lines as in previous years, having its maximum in September (49,390 on September 7th; 44,060 on October 24th) and its minimum im spring and early summer, during which time it is sometimes absent for periods of a few weeks. Acartia claust.—High numbers occur from May to October, some of the highest being 52,200 (May 20th), 41,950 (June 17th), and 59,490 (June 27th). The maximum appears to be earlier than in previous years. Anomalocera pattersoni.—This species was again very rare, being present in only 14 of the Bay gatherings throughout the year. The greatest number were caught in April (180 on the 10th); and Anomalocera is entirely absent in six out of the twelve months. Centropages hamatus.—This form appears first in March, increases to a maximum of 2,600 on May 17th, and dies down again by November. Microcalanus pusillusx—The only records for this species this year are as follows:—Apri! 9th, off Port St. Mary, coarse and fine nets together, 50; May 2nd, Bay, usual double haul, 30; August 7th, Bay, vertical net, 15; and December 30th, coarse net, 30—which is very remarkable considering that for the last few years the maximum of this irregularly 390 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. distributed species has been in winter. The species is obviously a scarce one, which varies much in its occurrence from year to year. The winter form, Huterpina acutifrons, was obtained in our nets from January (4,640 on the 4th) on, with decreasing frequency, to May 2nd, and it appeared again at the end of December. Jsias clavipes occurred from May to November, with a maximum of 300 on August 15th. These records agree in general with those of previous years. The monthly average hauls in Port Erin Bay for the eight more important species of Copepoda are as follows :— Z ‘ 4 E 2s Z : § : g aS) a 5 3 xe) gs iS) s ee = 3 q = S) a g = S Ss) = 2 3 a a g s3 mM =) o S oO OX 3 S oe eS iS) 4 > eo payuatyps Sa46aq Le | Be ST KU >I | Et SALASVSSSAPAPASGESSINVG D < 400 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. UTILITY OF PLANKTON INVESTIGATION. 1. The Modern Problem.—Many of the older naturalists worked at marine plankton qualitatively, and even connected the prevalence of certain organisms with the prosperity of sea fisheries; but modern instruments and methods of precision, such as might be expected to prove quantitatively the influence of variations in the type and amount of plankton, at different seasons and depths, upon the movements and abundance of fishes, have only been employed of recent years, and it is still too early to expect much in the way of demonstrated result. Some data have been obtained which are full of promise for the future; but marine biologists investi- gating the plankton in recent years have rightly felt that their immediate duty lay in making detailed experiments at different localities and seasons, and under various conditions, in order to test and standardise their instru- ments so as to determine the causes and understand the meaning of the variations in their catches. There is still much to be done in the way of obtaining agreement as to the nets to be used and the methods of investigation of the catches to be adopted before the results from different localities can be compared. 2. Plankton as Food of Fishes. fishes feed upon plankton during at least some portion of their hfe. The Loch Fyne herrings are frequently, at the time of a fishery, found to have their stomachs filled with NVyctiphanes, Euchaeta or Calanus. In some parts of the Hebridean seas the herrings have their stomachs filled with the Pteropod Limacina retroversa, and other oceanic organisms which may be carried in swarms into our coastal waters. Many other similar cases could be Many commercial SEA-FISHERIES LABORATORY. 401 quoted, and are known to biologists (see especially the works of Heincke, Moebius, Nordgaard, Pouchet, Murray and Hjort). Then as to demersal fish—young plaice, after their metamorphosis, feed chiefly on Copepoda, while in younger stages the larval plaice feeds upon Diatoms. We have found at Port Erin the post-larval plaice with its stomach shining through of a golden-brown colour from the Diatoms with which it was filled, and one of us has watched in a shallow pond the metamorphosed small plaice darting backwards and forwards pursuing, catching and devouring the individual Copepoda. Then again it has been shown that these Copepoda in their turn feed on Diatoms, Dinoflagellates and Protozoa. So practically all the main constituents of the plankton are concerned in the nourishment of either young or adult fishes. On the Lancashire coast we find the young plaice which are just appearing in the inshore nurseries have their stomachs filled with pelagic larval annelids. The Pollan (Coregonus pollan) of Lough Neagh, in Treland, has been shown to be on some occasions filled up with Mysis relicta, and at other times to be feeding solely on Cladocera; and there is reason to believe that the movements of the fish, which are extensive and periodic, can be definitely related to the presence and nature of the plankton. Dr. Hjort has shown a correspondence between the distribution of the plankton-feeding whales (such as the Greenland whale) and the most abundant swarms of plankton at particular seasons. Prof. G. O. Sars and others, in tracing shoals of herring and cod in the North and West of Norway, have distinguished between the AA 402 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. ‘“‘feeding’’ migrations and the spawning migrations, and the feeding migrations depend upon the plankton. 3. Bearing of Putter’s Views. and arguments of Professor Piitter in regard to the nutrition of fishes and other aquatic animals need not lead to any change of opinion as to The experiments the economic importance of the plankton. If, as seems likely in the hght of the recent experiments of Henze and B. Moore, Piitter’s figures require consider- able modification, then the argument as to the insufficiency of the plankton as a food material falls to the ground. But even if Piitter’s figures are correct, or partly correct, that consideration must if anything lead to an enhanced estimate of the importance of the plankton from the fisheries point of view; as, 1f Pitter has shown anything new and true, it is that such an animal as a fish could not be nourished by the amount of plankton in the water if the material were merely strained out of the average water of the sea area in which the fish was living. In order to get an adequate quantity of planktonic food the fish must seek out and capture the Copepoda, for example, just as fish on occasions can be seen to do. In other words, the fish must go where the plankton is abundant, and must in its movements follow the movements of shoals of plankton. It is the very poverty of the plankton in some sea areas, insisted on by Pitter, Lohmann and others, which makes it necessary for plankton-eating fish to move about in search of more abundant supplies. 4. Association of Fish with Plankton.—This association of shoals of fish with abundance of plankton is in agreement with many observations that have been made by naturalists in the past. I+ is well known that in coastal waters favourite line-fishing localities are where strong tides run through narrow channels or over SEA-FISHERIES LABORATORY. 403 rocks and banks, and these are just the places where of recent years it has been found that plankton is also most abundant. Any naturalist cruising on the West of Scotland (and no doubt in any other region where there are strong tides) could scarcely fail to notice the way in which the gulls and other sea-birds congregate where the currents run most strongly and where there are swirls in the water, indicating rocks or an uneven bottom, and resulting vertical movements of the water. These sea- birds are found to be feeding upon young fish, and the fish are there because the plankton is unusually abundant. A definite connection seems to have been established on the coast of Cornwall, by Allen and Bullen, between the results of the mackerel fishery and the occurrence of Calanus in the plankton. There is some evidence that on the West coast of Scotland there is a_ similar connection between herring shoals and abundance of Calanus. The matter is well worthy of further investi- gation. 5. Plankton and Movements of Fishes.—Many groups of the plankton, and especially the zooplankton, it is now known quite definitely, are distributed in swarms, notwithstanding various assertions to the contrary. In our coastal seas at least, where the fisheries we are interested in take place, the plankton is not uniformly distributed. Various localities and depths are characterised at different seasons by particular -assemblages of plankton, and it is reasonable to believe, in view of the facts given above as to the association of fish and plankton, that these variations in the distribu- tion must have a marked effect upon the presence and abundance of at least such fish as herring and mackerel, and also of the shoals of post-larval young of many valuable demersal fishes. 404 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. There is a method about the detailed distribution of the plankton that convinces one it must depend upon laws or factors which can probably be ascertained, and thus lead to the possibility of correlation and prediction within limits. That different currents or bodies of water in the sea differ very notably in their plankton is well known to biologists who have tested the matter. For example, in crossing the Atlantic to Canada one can tell to a nicety, even by means of a small silk net attached to a bath tap on a passenger steamer, when the ship has entered the Labrador current. The catch of plankton is suddenly increased enormously, and consists of an entirely different assemblage of organisms; and this abundant plankton is probably definitely related to the great fisheries on the Newfoundland Banks. Observations in the Irish Sea and on the West of Scotland have shown that the plankton at a locality may fluctuate, both in amount and essential nature, from year to year; and although a definite relation between these fluctuations and the variations in the distribution and catches of fish has not yet been established, it is reasonably probable that a fuller and more detailed knowledge of both will enable a correlation to be demonstrated. Artificial hatching, rearing and transplanting, if shown to be beneficial to the fisheries, must depend for success, in part, upon a knowledge of the plankton, for the young fish must obviously be set free where they can obtain their natural food. 6. Relation of Plankton to Hydrography and Fisheries.—It is clear then that there are definite relations between fishes and plankton organisms, and that it seems possible with fuller data to correlate some SS ee SEA-FISHERIES LABORATORY. 405 of the movements of fish with the distribution of plankton. There is thus a reasonable probability that an increased knowledge of the minute life of the sea may be directly useful in connection with the regulation of fishing industries. The plankton in many cases seems to be the link between the hydrographic changes and the fisheries; but it must not be supposed that the plankton is in all cases definitely related to the hydrographic data, and that, therefore, a knowledge of the hydrography would suffice. Kofoid showed in 1903 (Plankton of Illinois River) that there are variations in the quantity of plankton which are independent of hydrographic and meteorological conditions. He says: “‘ Somewhat regular alternations ‘““of growth and rest, of fission and spore formation, or ‘““of parthenogenesis and sexual reproduction, are ‘““fundamentally the basis of cyclic movement in “ [plankton] production. The amplitudes, and to some ‘““extent the location and duration of the pulses, are “plainly affected by the various factors of the environ- “ment . . . by light, temperature, vegetation, tributary ““water, various hydrographic factors, and by food ‘supply, and possibly, also, by chemical conditions not ‘“ directly concerned in nutrition, but the available data ‘“fail completely to afford any satisfactory environ- ‘‘mental factor or group of factors which stands in ‘correlation, even remotely obvious with this cyclic ‘“movement in production. JI therefore class this ‘‘neriodic growth, these sexual cycles which cause ‘“volumetric pulses, under the head of internal factors. ‘“The element of periodicity in itself does not seem to be ‘* consequent upon any known external factor.”’ EK. L. Michael (in his work on the Chaetognatha of San Diego, 1911) supports Kofoid’s view as applying to 406 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. both fresh-water and marine plankton,* and most planktologists will probably agree that there are such “internal factors’’ affecting the occurrence and quantity of the plankton independent of environmental or hydrographic factors. The investigation of the plankton is a very special study requiring exploring vessels at sea, laboratories on shore and carefully trained biologists. Unlike the case of hydrography, no information in regard to this subject of investigation can be obtained from any other source. But, on the other hand, it can, and ought to be, closely associated with hydrographic observations and also with the statistics of commercial catches. Hydrographic observations and plankton samples and information in regard to the fishing in the locality ought all, so far as may be possible, to be obtained simultaneously. 7. The International Work.—The plankton portion of the original programme devised by the International Council entailed the quarterly collection (in February, May, August and November) of plankton at a number of fixed stations, by means of horizontal (at various depths) and vertical hauls with nets of various mesh. [The justness of the criticism then made that the quarterly intervals were too long, and the fixed stations too far apart, is now generally admitted. | In August, 1909, the International Council resolved : — (i) ‘‘ That plankton samples should be collected by means of vertical hauls at certain definite places as often as possible (weekly or fortnightly), and that if research steamers were not available, observations should be made from lightships and inspection ships.”’ (ii) ‘‘ That quantitative methods should be employed to a greater extent than formerly, that samples should * See also, Herdman in Internationale Revue, Bd. II, p. 124, 1909. SEA-FISHERIES LABORATORY. 407 be measured volumetrically, and the larger organisms (Metazoa) counted.’’ | It was also decided that the nets to be used for this purpose should be : — (1) Medium Apstein, gauze No. 20 [180 meshes per inch | diameter of opening 16 cm. (2) Nansen, gauze No. 3 [55 meshes per inch] diameter of opening 50 cm. [ All this was a distinct improvement on the original programme, but must be regarded as a minimum. Horizontal hauls should be added. | In April, 1912, the International Council resolved : “That in addition to ‘ ordinary purposes ’— (1) “‘the principal aim and object of the plankton investigations with nets shall be to determine the entire life-history of a selection of the plankton animals which are most important as fish food, e.g., Copepoda [16 species named |; (11) “‘ with a view to determining the relation of plankton and fishes, simultaneous examination should be made of the stomach contents of pelagic fish and the plankton in the surrounding waters; (111) “‘it is extremely desirable that quantitative investigation should be made of the micro-plankton by Gran’s method (samples collected by means of a water- bottle and preserved with strong Flemming solution) ; (iv) ‘“that (1) and (111) should be begun in the May eruise, 1912.” [The determination of the life-histories of important organisms such as the 16 Copepoda named should no doubt be carried out, but it is said to involve over 200 separate forms, and so is a very large piece of work. It is quite a question whether it is the work that is most urgently required. No. (11) is excellent; but why (see iv) should it not be undertaken with the rest? ] 408 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. SomE CONCLUSIONS. It is obvious that in correlating fish movements with plankton we must take into account both the volume and the composition or nutritive value of the latter; further work is required on this point. It is desirable that some general agreement as to methods of estimating volumes, and also of determining nutritive values, should be arrived at without delay, so that comparable data may be provided for the approximate estimation of fish food at different localities and seasons. The methods of enumeration hitherto in use need not, however, be dropped. They may eventually prove to give results of value, and for the sake of continuity of observation it would be unfortunate if any gaps in the series of records were left. In connection with the zonal distribution of plankton and the vertical oscillations, it is necessary to make horizontal hauls at various depths so as to determine the plankton contents of the different strata of water. In addition to the minimum of observations required from our seas under the International organisation, it is most desirable that the observations carried out on our different coasts should be standardised under a national scheme of plankton research. Penne ee SEA-FISHERIES LABORATORY. 409 ON THE PELAGIC FISH EGGS COLLECTED OFF THE SOUTH-WEST OF THE ISLE OF MAN. By AnpREew Scott, A.L.S. The following is a summary of the results of the investigation of the pelagic fish eggs that were found in the plankton from the area off the south-west of the Isle of Man between the beginning of 1907 and the end of 1912. There can be little doubt that many of the egos collected had been spawned more or less continuously in the area between the limits recorded for each year. Their apparent spasmodic occurrence is probably due to a large extent to the drift of the water after the eggs had come to the surface. Sometimes they may be carried well inshore, even inside the breakwater where the bi-weekly collections are made throughout the year. At other times the eggs may be drifted out of the area altogether, and very few will be found in the plankton. Tt is also fairly certain that the eggs of some species of fish, which may not occur in the local fauna, will drift into the area from outside sources. It will be seen from the records that many of the fish may have a longer spawning period than was formerly suspected. This is fairly well shown in the case of the rockling and the dragonet. We have found dragonet eggs as early as January 23rd and as late as the beginning of August in hauls from places wide apart in the Irish Sea. This represents a general spawning period of about seven months for the dragonet, instead of from four to six months. Very few of the pelagic eggs have any marked character, apart from their size or the presence of an oil globule, by which they may be easily identified. The variation in the size of the eggs spawned by a single 410 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. female fish is sometimes very great, and the extremes often overlap with those of other species of fish, therefore the identification of preserved material can only be approximate. The eggs of some species of fish, which are not recorded at all from the area although the adults are known to occur, may, from overlapping in size, be recorded along with the eggs of other species. The number of eggs present in a single surface sample is usually very small, and there is greater difficulty in separating out the various kinds than when large numbers can be dealt with. The identification of preserved specimens of young fish in their larval and post-larval condition is often almost impossible owing to the mutilation that takes place when they are captured, and any colour that may be present generally disappears in the preservative. After the post-larval stage is reached identification becomes more simple, but the young fish sink deeper down in the water and are not often captured by the ordinary surface nets. Young fishes, with the - exception of rockling (or mackerel midges) and sprats, are seldom taken at the surface. The arrangement of the fishes followed here is that adopted by G. A. Boulenger in the Cambridge Natural History, Volume VII. Clupea sprattus, Linn.—Sprat. The spawning period of the sprat, according to the records made during the six years’ intensive study of the plankton collected at the south-west of the Isle of Man, extends from the beginning of April to well into September. In 1907 and 1908 the egg was only observed in one collection in each of these years, viz., April 2nd, 1907, and April 27th, 1908. Its first appearance in 1909 was on May 3rd. It occurred frequently throughout that SEA-FISHERIES LABORATORY. 411 month, but was not observed after June 19th. The records obtained during the years 1910 and 1911 are almost identical with each other. It was first noted on June 3rd, 1910, and disappeared after September 17th. The eggs occurred on June 5th in 1911, and were not observed after September 19th. They were present in every collection taken with the surface nets between the dates mentioned in each of the two years, i.e., a period of well over three months. The egg of the sprat did not make its appearance in 1912 until July 8th, and was not observed after the end of that month. The pelagic larvae were not often met with in the plankton, but when present were usually more abundant at the end of April than at any other time covered by the spawning period. It appears rather strange that the larvae were more common in the plankton of the area in 1908, one of the years containing a single record of the egg, than in 1910 and 1911. A surface collection taken on April 22nd, 1908, contained 130 larvae, and another, taken on April 28rd, contained 329 larvae. Only four larval sprats were obtained in 1910, and these were from a collection made on September 16th. No larvae were observed during the whole of 1911. The larvae were not taken in the area after the end of September in any of the six years, although we have found post-larval sprats 18 to 25 millimetres in length in the plankton collected off the North Wales coast as late as the first week in December. Gadus callarias, Linn.—Cod. The pelagic eggs of this valuable food fish occur in the plankton of the area between the end of February and beginning of May. In 1907 the eggs were not observed until March 29th, and the last date on which 412 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. they were present was April 27th. They appeared nearly a month earlier, March 4th, and disappeared after April 29th in 1908. The eggs were slightly later in making their appearance in 1909, and lasted a few days longer than in 1908. The first record was obtained on March 12th, and the last one on May 3rd. The year 1910 presented us with the earliest and latest records during the whole of the six years since the intensive study was initiated. The eggs were first noticed in plankton collected with the surface net on February 25th. They occurred frequently throughout March and April, and finally disappeared from the plankton on May 12th. The eggs of the cod were not observed in the plankton of 1911 until April 12th, and none were noted after the end of that month. In 1912 the eggs occurred in the plankton collected on March 4th. They were present throughout the month and during the whole of April. The last record was obtained on May 9th. Gadus aeglefinus, Linn.—Haddock. The pelagic eggs of the haddock were only observed in the plankton collected during the first four years of the intensive study investigations. None have been obtained since 1910. This is due to the almost entire disappearance of the fish from the centre of the Irish Sea which took place about that time. The Fisheries steamer was able to collect mature haddock from the fishing grounds between Lancashire and the Isle of Man for dissection in the fishermen’s classes for some years after their establishment at Piel, but the fish has been unobtainable for three years, and whiting have to be used instead. From the limited data available, we find that the spawning period extends from the beginning of — March to about the middle of May. The eggs were first SEA-FISHERIES LABORATORY. 413 obtained in 1907 from plankton collected on March 29th. They occurred in most of the surface samples taken in April, but none were observed that year after April 26th. No haddock eggs were observed until April 7th in 1908, which is the latest first occurrence during the four years. They were present in most of the surface samples from that date onward to May 20th, but after that none were observed. Their presence in the plankton of 1909 was limited to a period of about three weeks. They were first noted on March 27th, and disappeared after April 14th. The year 1910 presented us with the largest number of records and also the longest period of occurrence in the plankton of the area. The eggs were observed as early as March llth. They were present for fully seven weeks, and finally disappeared from the plankton on May 22nd. Gadus merlangus, Linn.—Whiting. The pelagic eggs of the whiting occur in the plankton off the south-west of the Isle of Man between the end of February and latter part of May. The appearance of the eggs during the last week of February is probably exceptional, as they were only observed in that month once in the six years. The normal time is evidently about the end of the first week in March. The eggs were found in the plankton as early as February 26th in 1907. Very few were observed in the March collections, but they were fairly prevalent during the month of April. The last record for the year was April 27th. In 1908 the eggs were first obtained from plankton collected on March 13th. They were present during the remainder of the month and throughout the whole of April. Whiting eggs continued one of the constituents of the plankton until May 12th. The eggs were much later in making their appearance in 1909 than 414 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. in any of the other years during the intensive investiga- tions. They also remained longer. Whiting eggs were not observed before March 26th. They were present in the plankton throughout April, and did not finally disappear until May 24th. In 1910, they were noted for the first time on March 11th, and continued in the area till the end of April. The occurrence and duration of the eggs in 1911 and 1912 were identical. Whiting eggs were first observed on March 4th, and were one of the constituents of the plankton till the end of April in each of these two years. Gadus pollachius, Linn.—Pollack. Gadus virens, Linn.—Green Cod, Coal Fish. Gadus minutus, Linn.—Poor Cod. Gadus luscus, Will.—Bib. The pelagic eggs of the pollack, green cod, poor cod and bib are certainly represented in the plankton collected in the area from the end of January to the end of May. The difference in the size of the eggs of these four species of Gadoids is so very small that it is quite impossible to separate the four kinds when preserved. In fact one cannot be quite certain even in differentiating whiting eggs correctly from the eggs of the four species mentioned above. It is well known that all the eggs spawned by a female fish are not exactly the same size. There may be a difference of at least one-tenth of a millimetre between the largest and smallest eggs of a single fish. This difference may be increased to three- tenths of a millimetre when the eggs of a number of the same species of fish are investigated. The range in size of the eggs of one species of fish may easily overlap the measurements of the extremes in the case of another species. We find that the largest egg of the poor cod is slightly larger than the smallest egg of the whiting. SEA-FISHERIES LABORATORY. 415 A. EH. Hefford, in his report on the teleostean ova and larvae observed at Plymouth,* shows very clearly, from comparisons of the egg measurements of four species of Gadoids, the uncertainty in correctly identifying some of the pelagic fish eggs. The following table gives the variation in size of the eggs of four common members of the Gadoids and the size of the green cod egg, another Do? member of the same family, for comparison. Poor cod eggs ... ... 095—1 07 mm. Bib eggs sah .. 105—1'15 mm. Pollack eggs... .. L13s—114mm. Whiting eggs ... ... 1069—1°352 mm. Green cod eggs cco LUG aM, The larval stages of the economic Gadoids found in the Irish Sea occur in the area covered by the intensive study investigations as early as the end of February. The post-larval forms are found up to the end of May, after which they probably sink below the surface and are not captured by the surface nets. Preserved specimens of the very young stages of Gadoids have a considerable resemblance to each other. They are easily mutilated in capture, and cannot often be identified with certainty. Molva vulgaris, Fleming.—Ling. The characteristic pelagic egg of the ling, which has a large smoky oil globule measuring 04 mm. in diameter, was only found once in the plankton collected at the south-west of the Isle of Man during the Six years’ investigations. It occurred in a surface collection taken on April 27th, 1908. The egg is comparatively small, measuring about 1:08 mm. in diameter, and the oil globule occupies fully one-third of the interior. * Journal Marine Biological Association, N.S., Vol. [X, No. 1. 416 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Onos spp., Risso.—The Rocklings. Two species of rockling are known to occur in the Irish Sea, Onos mustela, five-bearded rockling, and Onos tricirratus, three-bearded rockling. The former is the species most frequently met with, and is probably the one generally represented by eggs and young stages in the plankton of the area. The third species, Onos cumbrius, four-bearded rockling, may also _ occur, although it has not been recorded by any observer from the central area of the Irish Sea. The summary of the results of the six years’ investigation of the plankton from the south-west of the Isle of Man shows that the eggs belonging to one or other of the two species first mentioned may be present in the plankton throughout almost the whole year. The spawning period of the five-bearded rockling, according to McIntosh and Masterman,* lasts from April to August, and the three- bearded rockling from November to January. The size of the egg of the five-bearded rockling, according to these authors, is 0'72 mm., and the oil globule 0:°0825 mm. The egg of the three-bearded rockling measures 0°74 mm. and its oil globule 0218mm. The only difference, therefore, between the eggs of the two rocklings is in the size of the oil globules. In 1907 rockling eggs were present in the plankton from February dth to September 19th, with the exception of July, when none were observed. ‘The eggs occurred from January 4th in 1908 to August 7th without any interruption. In 1909 they were present almost continually from January 2nd to September 21st. The distribution during 1910 was much the same as in 1909, except that they persisted for nearly three weeks longer. The eggs were first noted on * British Marine Food Fishes. london, 1897. SEA-FISHERIES LABORATORY. AL] January 3rd, and were present every month till October 10th. In 1911 the eggs occurred from January 9th to September 10th. They disappeared after that date, but were again present on December 29th. Although rockling eggs were obtained on December 29th, 1911, they were not observed in 1912 earlier than January 26th. - After that date they occurred throughout each month till September 7th. The only month in the whole period of the six years’ investigation in which no rockling eggs were observed was November. Young rockling or mackerel midges from 10 to 20 mm. in length are frequently captured in the surface nets in various parts of the Irish Sea between the beginning of July and the end of August. Ctenolabrus rupestris, Linn.—Jago’s Goldsinny. A very small egg (08mm. to 09mm.) with transparent yolk and no oil globule has been identified as belonging to Jago’s goldsinny. It generally occurs in the plankton of the area in small numbers between the beginning of June and the end of September. In 1907 the eges were found in the collections taken between August 13th and the end of September. It is the only year during the period of intensive investigations in which the records show it to have been not uncommon. It was only observed on June 6th and August 6th in 1908. No records at all were obtained for 1909. It was present in the surface collections taken on August 10th and 12th in 1910, but apparently not at any other time. 1911 was also a blank year, and not a single specimen of the egg was obtained. It occurred once in 1912 in a surface collection taken on August 9th, BB PSS 418 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Scomber scomber, Linn.—Mackerel. The only record of the occurrence of the pelagic egg of the mackerel in the area was obtained from a surface collection taken on June 3rd, 1912. This is rather surprising, as the fish is very abundant some years in the whole of the Irish Sea. They are sometimes so plentiful that they can be captured inside Port Erin Bay and in Barrow Channel off Piel Island. Many samples of mackerel caught in the Irish Sea off Walney early in July have been examined in the laboratory during the last dozen years, but in no instance have we found mature reproductive organs. ‘They are nearly always in a spent condition. The eggs are not uncommon in Cardigan Bay plankton collected at the beginning of July, and it is possible that the majority of the fish that arrive in the central area spawn on the way up from the south. If this be so, then the larvae would have hatched before the eggs could reach the south-west area off the Isle of Man, unless there should happen to be an exceptionally strong drift of the surface waters from the south due to long-continued southerly winds. Drepanopsetta platessoides, Fabr.—Long Rough Dab. The characteristic pelagic eggs of the long rough dab are only occasionally met with in the south-west area off the Isle of Man. The egg can be readily identified by the marked space between the yolk and the shell, which gives it an appearance resembling a double egg, a small one inside a larger one. Mature fish are captured nearly every spring between February and April on the off-shore fishing grounds to the north of Morecambe Bay light-vessel by the Fisheries steamer when fishing for material for investigation in the SEA-FISHERIES LABORATORY. 419 fishermen’s classes. The spawning period probably extends from the middle of March to the end of April. The egg occurred twice in the plankton collected during 1907; first on March 29th, and again on April 10th. In 1908 only one record was obtained, and that was from a surface collection taken on April 14th. The eggs were present in the plankton of 1909 from March 27th to April 24th. They were observed in surface collections taken on March 27th, April 6th, 10th, 15th, 19th and 24th. The eggs were not captured in any of the collections made during 1910, 1911 and 1912. Psetta laevis, Rondel.—Brill. Small and half-grown brill are not uncommon in various parts of the Irish Sea, but full-grown mature specimens are not often met with. The pelagic eggs of the fish appear to be very rare in the area off the south- west of the Isle of Man, as it only occurred once in the plankton collected: during the whole six years. The single record was obtained from plankton collected on April Ist, 1907. On that date it was found to be present both in Port Erin Bay and also in the cpen sea. A single specimen of a recently hatched larva identified as a larval Rhomboid was captured in the surface net on May 2nd, 1910. The eggs are occasionally found in plankton collected in Carnarvon and Cardigan Bays in the early part of July. Zeugopterus punctatus, Bl.—Muller’s Top-knot. The pelagic eggs of one of the top-knots, which is probably the above species, are occasionally met with in the plankton from the south-west area off the Isle of Man between April Ist and July Ist. Mauller’s top-knot is the one generally captured when trawling is being 490 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. carried on in the central area of the Irish Sea. Adult specimens of the Norwegian top-knot are very rare, but the small size of the fish may prevent its capture by ordinary trawling methods. Top-knot eggs were present in Port Erin Bay and in the open sea surface plankton from April Ist to 27th in 1907. The records obtained from the plankton collected in 1908 showed that the eggs were present for nearly three months. The first eggs were observed on April 2nd, and they did not finally disappear until June 27th. The majority of the surface collections taken during that period contained at least one or two top-knot eggs. The occurrences were more limited in 1909. The eggs made their appearance on April 6th, and were not seen after the 14th of that month. No top-knot eggs were observed in the plankton of the area in 1910 and 1911.. They were only present once in 1912, and were represented in a surface collection taken on July Ist. The only larval top-knot that was observed during the whole of the six years’ investigations was captured in the surface net on July 4th, 1912. Lepidorhombus megastoma, Donov.—Megrim. The pelagic eggs of the megrim or sail-fluke are frequently captured by the surface nets in the area off the south-west of the Isle of Man from March to the end of May. The adult fish are fairly plentiful on the west and south-west of the island in the deep water, where the bottom consists of very soft mud. Spawning females have been trawled there occasionally by the Fisheries steamer when carrying on special investigations for the purpose of locating the spawning grounds in the Irish Sea, in the early days of our scientific work. In 1907 the eggs were present in the plankton collected on March 29th and onwards until April 27th. The distribu- a SEA-FISHERIES LABORATORY. 421 tion in 1908 appeared to be rather limited. The eggs were not observed before April Ll5th, and none were present in the plankton after April 29th. In 1909, they first appeared on March 27th, and were frequently captured throughout April. The eggs remained one of the constituents of the plankton up to May 24th. The first eggs obtained in 1910 were found in a surface collection taken on April 8th, and were represented in the plankton from that date onwards until May 3lst. This is the latest record in the whole of the six years’ intensive study investigations. The distribution of the eggs during 1911 was restricted to about a month. None were observed in the plankton before April 12th, and they finally disappeared on May 15th. We obtained the earliest record of the occurrence of the eggs during the six years’ plankton investigations in 1912. The first eggs were captured on March 4th. They were present almost continuously from that date onwards until May 9th. Over 400 eges were obtained from seven hauls with the shear-net in the open sea at Stations [I and III between April 12th and 27th. No larval or post-larval stages that could be identified as young megrims were observed during the investigations. Pleuronectes platessa, Linn.—Plaice. The pelagic eggs of the plaice, which can be readily recognised by their large size, corrugated shell and absence of oil-globule, occur in the plankton of the area investigated during the intensive study from February 9th to April 23rd. The first eggs observed in 1907 weré found in a surface collection taken in Port Erin Bay on February 22nd. They were noted again on March 6th, and in the plankton of the open sea on April Ist, 4th and oth. The eggs appeared to be generally distributed 422 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. in the Bay and open sea from March 13th to April 23rd in 1908. This was the latest date on which plaice eggs were found during the six years. The larvae were well advanced and nearly hatching. In 1909 the first eggs were observed on February 18th in the Bay plankton. They were generally distributed in the Bay and open sea throughout April and on to May 8th. The occurrences in 1910 were spread over a period of about two months. The eggs were present in seven collections taken in the Bay and in the open sea between February 28th and April 22nd. The plankton of 1911 gave us the earliest record of plaice eggs in the area during the six years. The eggs were taken in the surface plankton collected on February 9th and again on the 13th. They were only observed once in March, on the 7th. The plankton collected from April 4th to the end of that month showed that the plaice eggs were generally distributed in the Bay and in the open sea. The surface plankton collected on March 4th contained the first eggs observed in 1912. They were present from that date onward to April Ldth. Larval and post-larval pleuronectids were frequently captured in the surface plankton between March 11th and the end of April during the six years’ investigations, but they were generally too much mutilated to identify correctly. One post-larval plaice, 8°8 mm. in length, was taken in the surface net on April Ist, 1907. The stomach contained a single copepod nauplius. We have found eggs of plaice in the plankton collected in Cardigan Bay near the Patches Buoy off Aberystwyth in December and January. Pieuronectes timanda, Linn.—Dab. The eggs of the dab, which are about the smallest that are met with in the plankton collected during the SEA-FISHERIES LABORATORY. 423 spring months, appear in the area off the south-west of the Isle of Man from the middle of February to the beginning of June. ‘They occurred in Port Erin Bay on February 22nd, 1907. None were met with again until they appeared in the open sea plankton on March 29th. The eggs were generally distributed in the Bay and open sea throughout April up to the end of the month. Eggs of the dab were observed for the first time in 1908 in the plankton collected on March 11th. They occurred in most of the collections taken in April and May, and were present up to as late as June 6th. The eggs made their appearance in the plankton of 1909 on March 12th. They were fairly uniformly distributed in the Bay and in the open sea from that date onwards until May 17th. Very few records of dab eggs were obtained from the plankton collected in 1910. They did not occur before May 2nd, and none were seen after the 9th of that month. 1911 presented us with the earliest record of the appearance of the dab egg in the plankton of the area collected during the six years’ investigations. The first egos of the fish were found in a Bay collection on February 17th. None were observed again until March 4th. After that date dab eggs continued to be represented up to the end of April. The eggs occurred in the plankton collected during 1912 for a period of six weeks. They were noted for the first time on March 4th, and were generally distributed in the Bay and open sea from that date onwards to the middle of April. Solea lutea, Risso.—Solenette. Small pelagic eggs, measuring 0°76 to 0°38 mm. in diameter with many oil globules, which were identified as those of the solenette, were occasionally observed in the spring and early summer plankton of 4924 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 1907 and 1908. They were present in the open sea plankton collected on March 4th, 1907, and again between April 15th and 25th. A few more were found later on in the plankton taken between July 12th and 31st. Only one record was obtained in 1908, and that was from a collection made on March 11th. None were noticed in any of the next four years’ catches. The oil globule in the egg of the rockling sometimes splits up into a number of smaller ones when the egg is just spawned, but these small globules again fuse into one soon afterwards. It is just possible, therefore, that the eggs we identified as those of the solenette were really the newly spawned eggs of rockling. The characteristic egg of the sole was not noticed in any of the plankton collections taken in the area during the whole of the six years, but we have found them occasionally in the surface plankton from other parts of the Irish Sea. Trigla gurnardus, Linn.—Grey Gurnard. Trigla cuculus, Linn.—Red Gurnard. Trigla lucerna, Linn.—Yellow Gurnard. The pelagic eggs of the above three species are almost certainly present in the plankton from the south-west area off the Isle of Man from the end of March to about the latter end of August. There is considerable overlapping in the diameter of the egg and the oil globule of the three species, and it is almost impossible to state definitely which one may be represented at any particular time. The following table, which has been summarised from A. EK. Hefford’s report in the Marine Biological Association Journal already referred to, shows the amount of variation in the size of the eggs and oil globule of the three gurnards mentioned. SEA-FISHERIES LABORATORY. 425 Grey Gurnard egg 1:163—1:55 mm., oil glob. 0°25—0°33 mm. Red Gurnard egg 1°45—1:61 mm., oil glob. 0°28—0°33 mm. Yellow Gurnard egg 1:1—1°7 mm., oil glob. 0°22—0°29 mm. Gurnard eggs were observed in the plankton collected between April Ist and 27th in 1907. Only one record was obtained in 1908, and that was from a tow- netting taken on April 23rd. The eggs were noticed as early as March 29th in 1909, and from April 7th to 24th. Gurnard eggs were more plentiful in the plankton collected in 1910 than in any of the other years since the intensive investigations commenced. They were generally distributed from May 23rd to the 31st. A few were found on June 3rd and 7th, and again on July 14th. Surface collections taken on August 8th, 13th, 22nd and 28rd also contained pelagic eggs which were identified as 7rzgla sp. In 1911 the eggs occurred on April 27th, May 8th, June 4th and August 14th. The eggs found on August 14th measured 1°45 mm. in diameter, and the oil globule 032mm. These were probably the eggs of the Red Gurnard. Only one record was obtained in 1912, and that was from plankton collected on June 20th. Some doubt was felt from time -to time that possibly the summer eggs identified as gurnard might be those of the mackerel, but the colour of the oil globules was quite distinct. The oil globule in gurnard eggs is usually red or somewhat smoky looking, and the oil globule in the mackerel egg is greenish-yellow. The mackerel egg measures 1°22 mm. in diameter and the oil globule 0:32mm., which quite corresponds with the sizes given above for gurnard eggs. Callionymus lyra, Linn.—Dragonet. The very easily recognised egg of the dragonet appears to be generally distributed in the south-west 4926 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIFTY. area off the Isle of Man from about the end of February to the first week in August. It probably occurs even earlier than the end of February, as we have found it in plankton collected in Ramsey Bay on the north-east end of the Island on January 23rd. The eggs occurred in Port Erin Bay on February 26th in 1907, which is the earliest record obtained during the six years’ investiga- tions. It was noted in the open sea on March 7th. The eggs were generally distributed in the Bay and in the open sea during the whole of April. It was observed for the first time in 1908 on April 2nd, and was present throughout the month. It only appeared once in May, and that was on the 26th, when forty specimens were found. The eggs were generally distributed in the Bay in June. It was captured on July 14th, and again on August 7th. The first record for 1909 was obtained from plankton collected in the Bay on March 5th. ‘The egg was very rarely absent from that date onwards to June 25th. It appeared on March 15th in 1910, and was generally distributed to the end of April. The eggs only occurred once in May, on the 26th, but they were noted in the collections taken on June 3rd, 11th and 24th, and on July 8th, 14th and 26th. Dragonet eggs were first obtained on March 2nd in 1911. They did not occur again until April 10th, and were present during the remainder of the month. None were taken after May Ist. The eggs were more uniformly distributed in 1912 than in 1911. They were present in the plankton of the Bay and open sea from March 4th right on to June 3rd. Four hauls made with the shear-net at Station III on April 12th, 18th, 19th and 22nd contained 141 eggs. The haul on the 12th April captured 73 of this total. Although the dragonet eggs may disappear from the plankton collected off the south-west of the : { 4 é ' SEA-FISHERIES LABORATORY. 427 Isle of Man at any particular time in the year, it does not necessarily follow that they will also be absent from the general Irish sea plankton after they cease to occur in that area. The last recorded eggs from the area in 1912 were taken on June ord, but they were present in the plankton collected in Carnarvon Bay on the 2nd and 3rd of July. McIntosh and Masterman state that the dragonet appears to spawn from May to August. Ehrenbaum, in “ Nordisches Plankton,’ says that it spawns continually from April to August. In the English Channel it spawns from January to June. From the records above, we can safely state that the dragonet is spawning in some part of the Irish Sea from the middle of January to the beginning of August. The following lists give a summary of the results of several hauls with the shear-net at Stations I and III in the south-west area off the Isle of Man in April, 1912. Station I. 3 hauls, April 13, Station III. 4 hauls, April 12, 15 and 17 18, 19 and 22 Hees— Nos. Nos. Codie. 000 eae -.- 756 423 Whiting See Se Sol 797 Green Cod ... as boo, OP) 206 IBiby=-- fue wee sco OY! 461 Rockling... ee c06 IIE) 140 Plaice See BoE oS 1 Sail THB, “oP oy | as CHD 167 Dragonet ... on -.. 42 141 LaryaL FisHEs— Nos. Length. Nos. Length. Post Larval Gadoids .. dd 2—9'-5 mm. 87 3—8°5 mm. 5 », Pleuronectids... 1 75 mm. 8 5—8 mm. uy » Butter fish 31 6—15 mm. 46 6°5—21 (Pholis) a », Cottus sp. coco GS 4-5—7 mm. 4 5:5—6°5 i538 » Wparissp. ... — 1 75 Larval Gadoids aoe eee rk oo 55 Pleuronectids Se 428 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY- Priacic FIsH-EGGS AND LARVAE FounpD ELSEWHERE IN THE TRISH SEA. The wider investigation of the pelagic eggs and larvae of the Irish Sea, which forms part of the scheme of operations now conducted with the aid of the grant from the Development Commissioners, was commenced in July, 1912. It took some time to secure the various surface nets after the notification of the grant had been received, and the season was then too far advanced to make much progress. Hverything is in readiness for the work in 1913. The following tables give the results of surface hauls in Cardigan and Carnarvon Bays in July, 1912, which were the only places where eggs and larvae were fairly plentiful. Cardigan Bay, 7 hauls, Carnarvon Bay, 3 hauls, July 8 and 4. July 2, 3 and 5. EKees— Nos. Nos. Sprat 00 506 2 10 Anchovy ... ase 3 os Rockling ... 500 3 2 Goldsinny ies 27 — Mackerel ... 506 93 5 Sole 206 ss 4 Topknot ... oe 38 — Brill 506 ae 1 ] Dragonet ... acl — 2 Post Larval FisH—Es— Nos. Length. Nos. Length, Sprat 82 5—25 mm. 25 ~ 6—12 mm. Garfish 8 9—14 mm. 2 9 mm. Rockling ... — 82 5—16 mm. Lemon Sole 2 5°5—8°5 mm. 2 8—10 mm. Sole —. 2 7 mm. Topknot — 1 4mm. Brill 7 45 mm — Gurnard 6 5—l1]1 mm 2 5°5 mm. Dragonet 4 6—85mm 2 7—10 mm. Pipe Fish 3 20 mm — Labrus sp. 30 5—9 mm _— Gadoids — 15 5—13 mm. Whiting ... 1 30'5 mm — SEA-FISHERIES LABORATORY. 429 The occurrence of the pelagic eggs of the anchovy in July, 1912, is the third time we have found them in Cardigan Bay. The two previous records were obtained from plankton collected in 1906. The first was from a collection taken on June 14th, and the other on July 23rd. The late R. L. Ascroft found them in plankton collected off Lytham in 1896.* * Reports Lancashire Sea Fisheries Laboratory, No. XV, for 1906 (1907), p. 92. ih 430 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. DECAPOD LARVAE IN THE IRISH SEA. By H. G. Jackson, M.Sc. I. Martertan EXAMINED. This paper is a preliminary statement of the work carried out on Decapod larvae in the L.M.B.C. district. The material which has been investigated so far has been obtained in the tow-nettings which were taken by Prof. Herdman from his yacht ‘* Ladybird’’ during 1907, along with those collected in Port Hrin Bay during those months of the year in which the yacht was not in use. The similar nettings of years since 1907 have been examined for supplementary evidence of the distribution and occurrence of the larvae. Such larvae are rarely present, in any but very small quantities, in the surface tow-nets, so the deeper hauls of the shear-net have been principally relied on for furnishing a reasonable indica- tion of the young stages of Decapod larvae met with in this portion of the Irish Sea. In consequence of this, the records of the Bay hauls are unreliable and fragmentary, and complete data are only obtainable for the spring and autumn months—the periods in which the yacht was at work. The gaps in these records are only partially filled by the similar work carried on from the Lancashire Sea Fisheries steamer, ‘‘ James Fletcher,” owing to the fact that these latter investigations are conducted in very different areas from those worked by Prof. Herdman, so that, although use has been made of this material, the data has not been included in the table that follows : — Larva of Portunus depurator Do. P. holsatus Do. P. puber Do. Hyas araneus Pilumnus hirtellus (?) Do. Pinnotheres sp. (probably ; veterum) Munida rugosa _ Galathea sp. Do. Do. _ HLupagurus bernhardus Do. | #. prideauxta Do. _ * Glaucothoe.” Spiropagurus sp. ? Porcellana longicornis Do. Crangon vulgaris Do. | Nephrops norvegicus —Pandalus brevirostris Do. —P. montage Hippolyte varians * Lobsterlings ” Euphausids (Thysanoessa or Meganyctiphanes) Unidentified Macrurans— [M1] [M2] (Pandalid ?) [M3] [M4] [M5] (Hippolytid ?)- SEA-FISHERTES LABORATORY, If. Date of Appearance. (1907) April 23 Aug. 13, 21 April 8 and 9 Aug. 21 April 8 and 26 Aug. 13 Sept. 20 April ; April 18 and 26 Aug. and Sept. Aug. 13 April April 10-26 Aug. Sept. April Aug. April 8 Aug., Sept. Aug. Aug. Aug. Sept. April Aug. April April 23-26 Sept. April 23 April 24 Aug., Sept. April April 23, 26 Sept. 20 April 23, 26 Aug. 13 Aug., Sept. 20 April 8, 9, 23 List oF LarvarE Founp. Stage. 431 Distribution. Ist, 2nd Ist Ist, 2nd 5th 2nd 5th Ist, 2nd, 3rd lst, 2nd, 3rd Ist, 4th Ist, 3rd, 4th All stages Ist All stages Ist ? All stages All stages Ist, 2nd 4th 4th, 6th 3rd (4th) Calyopsis Several stages do. W. Calf P. Erin Bay 10 m. N.W. P. Erin P. Erin Bay 10m. &5m.N.W. P. Erin P. Erin Bay Off P. Erin Calf and 5 m. off P. Erin Off P. Erin Niarby! Point Off P. Off P. Off P. Off P. Off P. Off P. 10 m. Off P. Off P. Off P. Off P. Off P. Off P. Off P. Erin Erin Erin Erin Erin Erin N.W. Erin Brin Erin Erin Erin Erin Krin P. Erin W. Calf and Bay W. Calf Bay Off P. Erin Off P. Erin Calf Is., P. Erin Bay Off P. Erin Calf Is., P. Erin Bay Off P. Krin Niarbyl Pt. and Bay 10 m. & 3 m. off P. Erin ) > £ ‘3 @ 2 o ee) Abund- ance 432 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. IIIT. GENERAL CONSIDERATIONS. The above list of zoeas and other larval stages of Decapods is more notable for its relatively small BRIE than for any great abundance of forms. Perhaps the most striking omissions (not of an artificial nature, due to the removal during previous examination of some of the larger forms, such as Megalopa) which will be noticed in the lists are the young stages of two common crabs in the Irish Sea, Cancer pagurus and Carcinas moenas. Not a single representa- tive of the latter species, the common shore crab, was found in the tow-nettings, and the former was only doubt- fully present in the Ist zoea stage on the 13th of August. This absence is probably due to the fact that both these common species spawn in the late spring or summer, and that they both spawn close in-shore. For it must be remembered that the greater part of the most prolific material was taken in early spring or late autumn in localities several miles away from the coast. The most common Decapod zoeas were those of Portunus puber and P. depurator and Hyas araneus, and the three species seen to occur all through the spawning period of the year. A zoea which probably belongs to Pilumnus hirtellus was common in the autumn months, and present in less abundance during the spring. There is little doubt that this zoea is a Pilumnus, and the fact that only P. hirtellus has been recorded from the Irish Sea makes it highly probable that it is the young of that species. Another record of interest is the zoea of a species of Pinnotheres, which appeared very scantily in August. During the past autumn it has been taken in comparative abundance by Mr. Riddell in Cardigan Bay from the ‘James Fletcher,’ and a description of it will SEA-FISHERIES LABORATORY. 433 shortly be published. The species to which the zoea belongs is probably P. veterum. In the later parts of the year several kinds of ‘‘ Megalopa’’ stages were collected. The greater number of these were the young of Portunus or Hyas, but several are still unidentified, and at present there is no clue to their parents. The zoeas and young stages of Anomurans are very common indeed. Galathea larvae were present all through the spawning months, but the species to which they belong is not certain. There is possibly a difference in the species of Galathea larvae which occur at different times of the year, as has been noted below in the case of Hupagurus. The genus is exceedingly abundant in many stages. A curious regularity in the distribution of Hupagurus was seen in the material examined, but I am not yet prepared to state that this condition of affairs is the rule. During the spring 2. bernhardus was exceedingly common in every stage, and in all but one haul FE. prideauaii* was unrepresented; during the autumn EF. prideauxti was in its turn as common as its companion species had previously been, and E. bernhardus was now absent in all but one haul. The nettings taken from the “‘ James Fletcher 39) in Cardigan Bay in the autumn of last year do not, however, support these results, as, although FL. prideauaw is exceedingly common, L. bernhardus is almost equally so. The lengthy spawning period of EF. bernhardus, already referred to in another publication,t is borne out by the occurrence of a Ist zoea stage in Morecambe Bay as early as February of this year. ‘‘ Glaucothoe”’ * I hope shortly to publish a description of the zoea stages of E. prideauxiv. . | L.M.B.C. Memoir X XI, Eupagurus. cc 434 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. stages (of which the species is indeterminate) occur during the autumn sparsely. One specimen was found in August which seemed to belong to Spiropagurus, but that adult has not yet been recorded from this district. Porcellana longicornis (among the specimens described under this name there are probably included some of P. platycheles) is very common in the later months. In the printed lists of plankton records by the L.M.B.C., the greater number of Macruran larvae seem to be entered under the head of ‘‘ Mysis stage of Crangon.’’ As a matter of fact, the zoea and other young stages of Crangon and other allied shrimps are by no means abundant in Prof. Herdman’s plankton collections, far the most common Macruran being Pandalus. This genus is represented by two species, P. brevirostris and P. montagui, the former of which is much more common than the latter. Mr. Riddell has found in addition P. bonnieri in the hauls from Cardigan Bay, but this species does not appear to occur as far north as Port Erin. P. brevirostris is present in both spring and autumn hauls, but P. montagui was not found except in the early part of the year. Crangon sp. occurred fairly commonly in spring and less so in autumn in all its larval stages. Hippolyte varians was present in the spring, and at the same time other larvae closely resembling Hippolyte were found which I could not identify. Nephrops norvegicus was common in what Sars calls the first and last stages during April. No larvae of Homarus vulgaris were found in the zoea stages, but advanced “‘lobsterlings’’ (4th stage ?) occurred in August and September. There are several common zoea and mysis stages of Macrurans, which do not admit of identification at present, occurring at various periods of the year. These SEA-FISHERIES LABORATORY. 435 have been temporarily distinguished by the letter M and a distinctive numeral in my note-books, and a description or identification of them will appear in due course. During April, some Euphausid larvae (probably of Thysanoessa sp., and perhaps of Meganyctiphanes sp.) are exceedingly abundant, both in ‘‘ Calyopsis’’ and early “‘ Furcilia ”’ at Port Erin. stages in many of the plankton hauls ili 436 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. REPORT -ON SOME MUSSEL BEDS IN LANCASHIRE AND NORTH WALES AS “REGARDS THEIR LIABILITY TO SEWAGE ~ CONTAMINATION. | With Charts. By JAs. JOHNSTONE, B.Sc. CONTENTS. PAGE 1. Introduction ... ae S60 ose .. 486 2. Bacillus coli and its significance se nae aoe .- 438 3. Methods of Analysis ... 445 4. Epidemiological Hvidence and Standards of Impurity... 455 5. Description of the Mussel Beds and Sewer Outfalls ... 461 6. Bacteriological Analyses ... -. 476 7. Conclusions... 600 $00 see ake ave w. 483 INTRODUCTION. At the November meeting of the Scientific Sub- Committee I was asked to prepare a report on the principal mussel beds in Lancashire and Wales. This I now present with regard to some of these beds only: it has been impossible in the time to make a complete investigation of all the mussel areas, and indeed this report could not have been ready had not Dr. Jenkins, Mr. Scott and I already examined many of these mussel- bearing grounds. In June last we visited the Conishead Priory Scar; in July Mr. Scott and I visited Morecambe and Heysham; in the same month Dr. Jenkins and I inspected the Lune mussel beds; in November I visited the Estuary of the Wyre, where I met Mr. T. R. Bailey, Port Sanitary Inspector of Fleetwood, and saw the mussel beds at that port, and at Wardleys. In November Dr. Jenkins and I again visited Morecambe and saw much of the conditions there. Also, in June, Mr. Scott inspected the Roosebeck mussel bed and took samples, : SEA-FISHERIES LABORATORY. 437 and again in November. On most of these occasions I made bacteriological analyses of mussels and sea-water collected from the beds. The question of the contamination of the local mussel beds has become an important one again, for these reasons:—(1) The action of the Market Authorities and Health Authorities in certain towns in excluding, or attempting to exclude, mussels from certain localities. In one case, that of Blackburn, this action has been taken in virtue of special powers conferred on the local authority by a local Act of Parliament. In other cases the local authorities have apparently acted on the assumption that sewage-contaminated shell-fish are to be regarded as articles of food unfit for human consumption, an assumption which, in my opinion, would be very difficult to prove. (2) The action of the Fishmongers’ Company in causing analyses of the shell-fish from various local sources. (3) The Report of the late Dr. Bulstrode, in which reference is made to all the shell-fish beds in the Lancashire and Western Sea-Fisheries District. All these mussel beds to which reference is here made have already been investigated—some of them very fully. The question of their contamination, which has, apparently, only recently been before the public health authorities, is one with which the Committee has long been familiar, and which they have vainly attempted to bring before the notice of the Legislature during successive Governments, so that it is necessary to explain here why it is again brought before their notice. Also, I wish to take the opportunity of discussing here the present position of affairs as regards the significance of the contamination of shell-fish by sewage matters: I mean the general scientific question.;, It is now almost ten 438 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. years since the late Mr. R. A. Dawson and Professor Herdman appeared before the Royal Commission on Sewage Disposal, and gave evidence with regard to local conditions and the need for legislation. During these ten years this question has continually been before the attention of the Committee, and the responsibilities of the latter have been fully realised. I find, however, from a study of the literature, that these ten years have been almost fruitless of result as regards the activity of the public health authorities of this country. Nothing that matters in the least has been accomplished. Even with regard to the scientific questions involved—questions that really belong to public health science, and not to that of the sea-fisheries—we are now in the same position as we were ten years ago. With the exception of a few brilliant researches carried out by private investigators ,* nothing has been done, and almost every question raised in 1903 before the Royal Commission on Sewage Disposal still presses for settlement. I discuss, first of all, certain of these general questions relative to the contamination of shell-fish, and the methods of investigation employed, and then proceed to the consideration of the various shell-fish beds examined during the last two years. BacitLtLtus CoLi AND ITs SIGNIFICANCE. Why is sewage-contaminated sea or estuarine water to be suspected? Not because the sewage is in atself dangerous to the public health, but the sewage- contaminated water contains ‘‘ coli-like’’? microbes, which again are only to be suspected because among them may be the true Bacillus coli communis. This organism is * I refer to the papers by MacConkey and Clemensha, SEA-FISHERIES LABORATORY. 439 not, however, one which is pathogenic—at least it has not even been attempted to be shown that it may convey disease via sea-water and shell-fish; it is suspect because it may come from the human intestine, and there it may be accompanied by the pathogenic Bacillus typhosus. If we find ‘‘ coli-like’’ microbes in shell-fish, then we ~ condemn the latter because these microbes may indicate the presence of B. coli, and the latter may, in its turn, indicate the presence of B. typhosus. This indirect connection should be clearly understood. But. the true B. coli communis is not restricted to the human intestine. I+ occurs also in the faecal matter of horses, cattle, pigs, goats and geese (at least). It may also occur in human sputum, in the water draining off cultivated land, in rain water, in dust, even in such substances as crushed oats. Its presence in shell-fish is not therefore a proof that the latter are contaminated with human faecal matter. But we may argue, indeed the “* epidemiologist ’’? has argued, that B. coli is not less to be condemned even if it does proceed from the intestine of the domestic animals. Now the covert assumption made in this argument is that enteric fever may attack these animals, that disease-producing organisms may he voided by them, and that these organisms may transmit enteric disease to man; for the only epidemic disease which is to be considered when we speak about sewage- contaminated shell-fish is enteric fever. These several assumptions cannot be proved to have any basis of fact. Let us assume, however, that both ‘‘coli-like ’’ bacteria and the true B. coli have the significance that the public health official attaches to them. We have then to consider what is this organism, or category of organisms. It is quite evident on reading the literature relating to sewage contaminated shell-fish that there is 440 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. no agreement as to what is to be understood by the organism B. coli. It is a biological species, and therefore all that applies to the identification of species of animals and plants in general also applies to this bacillus—at least we must assume this until the bacteriologists prove otherwise. Now the recognition of an animal, a. disease- producing worm for instance, a malarial parasite, anything of that kind in short, is a matter of no difficulty for the expert. He can say at a glance (after experience, of course) whether or not the thing he is looking at is his animal. This is not the case, however, with a bacillus, for mere inspection fails to identify it. It must be cultivated in a number of nutrient substances, and the changes taking place in those substances must be observed before the organism can be identified with certainty. This is a laborious process, and no matter how great the experience of the bacteriologist may be, it must always be carried out in each analysis. The point here is that the public health officials in this country have not agreed upon a series of tests which are sufficient to identify ‘‘ coli-like’’ microbes. In the case of animals producing disease in cattle or in man there is agreement among biologists. There is also agreement among chemists as to the series of tests defining a poisonous substance, or a food adulterant. But it is quite evident that no such agreement with regard to the characters of ‘‘ coli-like’’ bacteria is to be found in public health practice. Let us see what are the common tests employed. In the following table are the tests which have been suggested, and against them are the names of bacteriologists who have worked at shell- fish contamination. The crosses indicate what tests are regarded. by each analyst as sufficient to pee the microbes. ‘JeIQUSSe-UOU oIe WIIG} o41s0ddo 8489} 04} 44} JepIsuod 99941UMWMOD YsI[suq oy} 9eY9 oZvoIpUT CG sjoquIAs oN], ‘oyeqod oy} uo spuadep uoMover sty} yey 0498 90941MIUIOD YsT[sum OUT, | qunOd0e OUT Udyey oq JOU poou AWYIGeIIVA SIYy} 99}4TUIUTOD UOTZeSIpIBpUeyg Yssuq 94} 07 Surpaoooe pue ‘pazueursey oq somMouros Kew osoreyoorg y. an =H H on ae ao x og ues see ain ve [see QUIQRTAS OSOONIS JO UOTVVQUOITIOT "FZ eee ose aoe x eee eae eee oe eee Beem ewes cena rece eensseseseesseeneee oulyejes | oyejod Jy Uo YIMOIS yuepUNqY ‘gz p00 S00 600 dao 060 000 000 O G00 --- Loqgeqgod ® uo yyaior3 UMOIG-MOTIA "ZS ‘ueyong hq peyrpour eee sae vee 000 Ao x 500 eee 990 aoooagLoccoobnou9codgLMOGENOOCOLD FELD NOCE) EE IS og WECM) MOD EL -10} O8OONIS UL *OH Jo %BT seonpolg ‘1% ° emuorojorg ejdnguimgy x eee sae see oe 000 eee ose Oo ORO“ pooanoosqn90A0}donDGebAOIR0R0000% Tp (OMNI NED! a BUCO SMOT SMS . -I9J osoonts ut *QO jo %ogG soonpoig °0Z (o) gee ace eee eee x aoe gio eee eee eee e eet eeesene eIpoul Jouoyd ul JMO1y) ‘6I S a oad 600 900 600 x 599 || G00 non 000 S0d000000000000 oulyeyes JO uoTzeUrA0F sex) ‘ST as 3 x x x e2 x ape x sect x r@) “ts |***4-cA0Iq pod-[e1jnou Jo soUDDSeION]T “LT Q eee 100 OO O0U eee eee x eee eee se eos x < eee eee eeseeeesesee sny[toeq oyy jo AMON ‘OT = 5c6 lela O06 550 600 60 600 FigD O00 O06 60 x O00 “++ DoyQoUL 8 WRI hq Surureys-wo NT “GT A : : ae ta a ne x a x x x x X [rrttetesess ouIgejas Jo uoTZoRjonby-uON “FT a . o. eee . eee . ose . sine tae eee eee x Koya SnUI}T] UT proe %9z JouoneUIO “ET a oe eee eve eee eee eee eee eee eee x eos O eee eee eeeeeeeeseseeeeese 07e141U jo TOTJON pey ‘OL Fe : x x x x a x ms s x x O Xe ble ** gfopul jo uoeMIOg “TT cI 900 eee eee eee aoe see eee eee one eee eee eee * 80900000990900009090000060000000 (oatyeSou) Ks | uoTJOvOL JONVysoOIg pue sossOA OUT, ‘OT Fe O eee 600 eee O00 cee eee 000 00 ees | aiels) O00 x o00000 yjo01q, 4ISOUT 6c 6 < . eee eee eee eee oe eee eee eee eee eee eee x ea qyo1q qiuope 66 , °g a . eee eee eee oes eee oe eee eee eee eee eee x eooeee qqo1q ulnut i ON), wes see eee x see eee x tee tae tee eee re) x 4 H}01q, reSns ouro JO UOeyUOUMIEJ ON 9 eu G00 OO 000 oe 000 x x x be x x eee wees eeeeseee yyprar snUurqt] 66 Say 'G eee eee eee eee eee eos eee eee eee eee eee eee x woeessoee yyorq que ud GG ‘h +. oes oes aoe eee pod eee eee see eee bee eee x treeeseerees TAOIG Qlo[Np «c ‘e x Sx >< x x x Se eee x eee x x x eeeeecore q301q 980908] 6é ‘ V6 x x x x x x vee x OR OP x xX | YJorq esoonys ATVs oTIq JO UOTFeIQUCTMIET = *T bin | BO | eo | Pe ee PB g why A | Of Ceo ee) ge | se | se |lsae| a #'| 28 | @ fe S week ae ek ey Bee eds ates soo Ey fees) es Ieeeel oe ‘sqai8ojormojovg, oy} Aq post i % © % s e 3 3 a gee is a & | oo snyuong 30 UOT}TUSO9e1 OY} IO $489], 3 3 = EF ie i 442 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Now we see at once that there is no agreement as to the series of reactions which are to be regarded as proving the presence of Bacillus coli. Some few tests, the fermentation of glucose and lactose (these are really all that everyone agrees upon), are common to all the series, but for the rest their adoption appears to be a matter of the amount of time that may be spent upon the identification. Generally speaking, public health bacteriologists in this country adopt Houston’s *‘ Flaginac”’ test. The mussel, or other shell-fish, is cut up and (after other operations to which J return later) is inoculated in MacConkey’s bile-salt broth. The organisms growing in this liquid are then separated from each other by ‘“plating-out’’ in gelatine, or some other medium. Colonies of the microbes growing on this medium are then selected for further study. As a rule, the analyst endeavours to select colonies which he regards as those formed by B. colz, but this procedure is, as Houston (1904, p. 178) says, ‘‘a speculative venture even to the expert.’’ Real B. coli colonies may, then, be neglected. After isolation, the organism is identified by growth on a number of media, and it has been shown (Houston, 1904, p. 105) that it “‘ cannot be said with certainty which tests should be employed, and how many of them.”’ Nowadays, however, most public health bacteriolo- gists probably employ Houston’s four tests (1) fermenta- tion of lactose broth, (2) fluorescence in neutral-red broth, (8) formation of indole, (4) fermentation and clotting of milk. This is the series of reactions which Houston employed in his work for the Sewage Commission, but it does not appear that he regards it as always essential for the definition of B. colz. Thus ‘‘a coli-like microbe, to be considered typical, must SEA-FISHERIES LABORATORY. 443 react positively to at least three out of the four tests employed’’ (Houston, 1904, p. 236). Thus even the meagre array of proof originally suggested by this bacteriologist appears to be too much in actual public health practice. This will be seen by considering Houston’s ‘““Quintuple Preferential Bacillus Coli Test,’’* a title which at once suggests some really well-planned method of analysis. Let us suppose we use Houston’s four tests to identify a bacillus—if all are positive the identifica- tion is made. But it may be that one or more of the tests fail; each of them is then given a preferential value, thus fermentation of glucose = 2, fermentation of lactose = 1, production of indole = 3, production of fluorescence = 4, and a negative result with cane- sugar = 4. The total value of the five tests is therefore 32, and the more nearly the value of the tests approaches to 37 “the stronger would be the evidence derived from its presence in favour of recent pollution by matter of excremental origin.”’ At first sight it sounds quite reasonable, but on looking into the matter it is not difficult to detect the confusion of thought involved in the suggestion. The’ covert suggestion is that of a comparison with the results of a chemical analysis: a solution of prussic acid is always prussic acid, whether it contains 5 per cent., or 0°5 per cent., or 0°00005 per cent. Let us regard the characters of a microbe then as all of the same order, so to speak, and give each a percentage value; the more of these characters the greater the percentage. Thus we * IT have been unable to procure a copy of the publication in which this test was described (Minutes of the Metropolitan Water Board for the year 1907). I therefore describe it as used by Buchan, Journal of Hygiene, Vol. X, p. 476, 1910. | 444 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. obtain an 100 per cent., a 96 per cent., a 90 per cent., and a 77 per cent. “‘coli-like’’ microbe! But is there really anything sound in the assumption? Clearly not, for if we regard a bacillus as an organism defined by certain characters, we expect that it will exhibit all those characters. It is true that a species of animal or plant may apparently lose a character (as in Mendelian inheritance), also a character may be variable in magnitude: thus the number of fin rays in the dorsal fin of a plaice may vary, yet the fish is undoubtedly a plaice. But the inability of a bacillus to ferment and clot milk, for instance, is an absolute disappearance of a character, and not a decrease in its magnitude. Besides, the laws of variation and heredity in higher organisms are sufficiently well known to allow us to appraise the modifications of character, but this is certainly not the case with bacteria. Variability in these organisms is only just beginning to be studied, and the results so far attained have not, in the very least, affected public health practice. Let us remember what is the object of these analyses. It is to detect, in shell-fish, &c., microbes (B. colz) which ’ have inhabited the human intestine and have then found their way into a new habitat. We detect these microbes by finding that they produce changes in various chemical substances, and that is all we know about them that is of value in recognising them. We find bacilli, which produce all or some of the chemical changes induced by the human B. coli, in many other situations. Now let us assume that a colon bacillus may undergo “loss of attribute ’’ and still remain the same biological species. Why should we say that it is only, say, 77 per cent. a Bacillus colu? The ‘‘ Quintuple Preferential ’’ method, then, works SEA-FISHERIES LABORATORY. 445 out in actual practice as follows: All the micro- organisms isolated from shell-fish in the usual methods of analysis (the use of MacConkey’s bile-salt broth) ferment glucose, and most of them ferment lactose, while a large proportion form indole, and clot milk, and fluoresce neutral-red. Suppose that the colony we isolate from the primary culture is of value 100, then all the bacilli found were B. coli. Suppose it has the value 90 per cent., then 90 per cent. were B. colz, and so on. By using this method we are always sure of getting some B. coli as the result of the primary cultures. ” says Dr. Houston in a passage “* Bacteriologists, of great literary merit, ‘‘ever pressing forward to the unattainable goal of absolute knowledge, are apt to leave in their wake a track of nebulous knowledge which to the uninstructed observer may suggest superficial, and not, as ought to be the case, merely incomplete knowledge.’’ This is really an excess of humility when we remember that it is just this incomplete or superficial knowledge (for both categories of knowledge are identical) that is applied by those who have to do with the public health and the livelihood of fishermen and others. Metuops or ANALYSIS. The method almost universally applied now is that devised by Dr. Houston. Ten oysters (or mussels) are taken from their shells and cut up into small pieces, and put into a vessel of water containing 1,000 cubic centimetres. Various volumes of this liquid are then taken: 100c.c. is equal to 1 oyster, 10c.c. to 1/10th oyster, and le.c. to 1/100th oyster. We then take 10 c.c. of the liquid and mix it with 90c.c. of sterile water, 1 c.c. of this diluted liquid now contains 1/1000th 446 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. oyster; repeating the’ same dilution from the last mixture, we get another one in which | c.c. contains 1/10,000th oyster, and so on. Somewhere we obtain a dilution where there are no bacilli, at least we find none. We then say that (for instance) 1/1000th oyster contains B. coli, but 1/10,000th contains none. ' Jf we only make one such trial this conclusion seems quite valid. ha But the flask containing the dilution, value 1/1,000th oyster in 1 c.c., contained very few bacilli: theoretically it must contain not more than 10. Suppose it contained 5 organisms, and suppose the volume of liquid in the flask is 100c.c. If we take l1c.c., the probability that it contains one bacillus is 1 in 20, the probability that it contains none is 20 to 1. We do not find a positive result then, let us say, and we assume that B. coli is absent in 1/10,000th oyster; but the chances may really be 20 to 1 that it is present. meee Suppose now that the flask containing the dilution (1/1,000th oyster = 1c.c.) gives a positive result. But it may be that this flask really contained very few bacilli and that we just happened to get one, in spite of the chances against it. But another trial may prove to be negative. We must then state our conclusions in this manner: B. coli was present in 1/1,000th oyster, but it may have been absent; or it was absent in 1/1,000th oyster, but it may have been present. All that we must say is that B. coli was present in 1/100th oyster and absent in 1/10,000th oyster, for the statistical error clearly involves three dilutions. If we wish to be more precise we must make a number of cultures from each flask and then calculate the probabilities.* _ * All this is obvious enough and similar, or analogous, precautions against error would be taken in chemical or biological research. But I can find nothing in bacteriological literature to show that these consider- ations affect public health bacteriological practice. SEA-FISHERIES LABORATORY. - 447 Or we must adopt a better method of analysis. Clearly, if we only cut up a mussel or oyster into small pieces, some of the bacilli present in the animal’s body may adhere to the pieces. We must, in order that the method may be reasonably accurate, grind up the pieces of oyster along with the water in a mortar, so as to make a real emulsion. After practising this I am now convinced that the grinding up must be done with sand, so as really to break down the tissues of the shell-fish. We need not fear grinding up and destroying the bacilli. In nearly all the analyses mentioned in this paper five mussels were taken. The soft bodies of the animals were detached by cutting through the muscles attached to the shell, and left in one of the valves. The flesh was then cut up as finely as possible by means of sharp scissors, and the mass was dropped into a mortar and rubbed down with the pestle. Small Wedgwood mortars must be used; glass ones break on sterilisation. In this way an emulsion of 5 mussels is obtained: it is put into a wide-mouthed flask and water added to make the volume of emulsion 250c.c. I1c.c. should then contain 0°02 mussel. Obviously, all the precautions to secure sterility of apparatus and hands are taken. It is quite unnecessary to do more than wash the hands very thoroughly in hot tap water: blank experiments will show this. Neutral-red, bile-salt, lactose agar has previously been melted, and the tubes are contained in a large dish of water at 45°C. Petri dishes are ready, and 1 c.c. of the emulsion is taken from the flask and put into each Petri dish. The 1 c,c. pipettes should be selected for wide apertures, as the capillary orifices used by chemists may block up. If the drop of fluid remaining after the pipette drains be blown out, a bulb containing sterile 448 TRANSACTIONS LIVERPOOL BIOLOGICAL. SOCIETY. cotton-wool must be fitted to the pipette, and this bulb must be blown into, otherwise the breathoof the operator may infect the Petri dish. The medium is then poured. 7 Dilutions may be made. If so, it. will seldom be found that. the mean numbers of colonies in a 1/10th dilution are approximately 1/10th of the higher dilution: It is this that convinces me that exceptional care should be taken in preparing the emulsion. Five such plates are, as a rule, made, and a mean number of colonies is obtained. Just whether an emulsion of 5 mussels in 250 c.c., or one of 10 in 250 c.c. ; or whether a dilution of the 5 in 250 emulsion should be made, ought to be apparent from the natural conditions of the bed from which the sample was collected. Obviously, the analyst himself ought to collect the samples. . The red colonies growing on the plates are then counted, and some of them are isolated in pure subculture. How many should be so isolated will depend on the number on the plate. I think 10 colonies are usually enough. All this is simple, but the identification of the organisms isolated presents formidable difficulties. The large majority of the large, rapidly-growing colonies on such a plate will give positive results with Houston’s “* flaginac ”’ series of tests. But if we push the analysis a little further, the investigation becomes much more difficult. In my) own experience* only a small proportion of these (about 10 per cent. if the non- fermentation of cane-sugar be regarded as an essential character) are really Bacillus coli. One may then find a mean number, per mussel, of ‘‘coli-like,’’ or ‘“intestinal’’ organisms, and then by subculturing and identifying a small number of these, find what proportion * See Journal of Hygiene, Vol. 1X, 1910, p. 430. SEA-FISHERIES LABORATORY. 449 of them were B. colt. The statistical errors of such an estimation must be reckoned with: obviously, the probable error of the mean count per plate must be calculated, and this may be done by making a trial series of plates, say 10 to 20, and then finding a probable error This is calculated in the following example :— Ten plates, each inoculated with 1 c.c. of an emulsion of 5 mussels in 250 c.c. of sterile water. The plates contained 210, 258, 274, 277, 302, 305, 352, 375, 453 and 730 colonies. The mean number of colonies is 303. The frequency distribution is as follows :— x f wl | fel | fant? Between 200 and 300 colonies... 4 =i —4 +4 » 300and 400 ,, 4 0 0 0 , 400and500_,, 1 Aji 7] S51 », 800and600_,, 0 +2 0 0 ;, 600 and 700 x5 0 a3 0 0) » 700andso0o ,, 1 +4 we ane tt G 10 +1 21 ihe meania S20-¢ 100 = 360. 10 The standard deviation is Oi 100 x i 114u5 & and the probable error of the mean is 145 x 06745 = 98. This means that we may divide the range of values into two parts: (1) a part lying between the mean —98, and the mean +98, that is, between 252 and 448; and (2) a part between the lower limit of the range and 2982, and between the upper limit of the range and 448. Suppose that any single count from a plate is now made, it is just as likely that its value will lie between 252 DD 450 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. and 448 as that it will be greater than 210 and less than 252 or greater than 448 and less than 730. It is conventional to regard it as probable that it will lie within the range, mean + the probable error. That is to say, the mean of our estimation is any number greater than 252 and less than 448, and in making a comparison of this analysis with a ‘‘ standard’’ we must bear this in mind, for any number within the range is equally probable. One might possibly use such an estimate for all analyses made by the same methods. Obviously, in comparing the results of two analyses, the probable error of the difference of the averages must be calculated and taken account of. I can find no indications of these statistical precautions in the literature relating to shell-fish bacteriology. One must insist that they are not fanciful precautions, but the application of plain common sense. These considerations would apply if we were quite certain that we could isolate an organism, call 1t Bacillus coli, and be quite sure that it was an indication of the transmission of organisms, only temporarily* altered in character, from the human intestine to the body of 2 shell-fish. But there is no convincing evidence that we are able to do this. We do not know how many distinct strains of B. coli inhabit the human intestine; nor whether or not there are strains differing so little as to be indistinguishable by the methods in use from those of the human intestine, but with an entirely different * Consider the recent work on ‘‘ pure lines’ in heredity. A Bacillus we may assume is subject to variability. Letthis variability be represented, occasionally anyhow, by small mutations. Then even in the limited time that a bacillus might take to reach a shell-fish from a water-closet, there would probably be time enough for the formation of ‘‘ pure lines,”’ that is, permanently altered strains of organisms. Let us suppose a bacillus will divide every four hours, in three days there will be 18 generations and 9" individuals. The environment during these three days will have been represented by many different series of conditions. SEA-FISHERIES LABORATORY. 451 distribution and significance. It ought to be clearly understood that public health practice, at the present time, does not enable us to state with confidence that any bacillus found in shell-fish or in sea-water or mud can be identified with those living in the human intestine and nowhere else, and must therefore have proceeded from the human intestine. let it be granted that the B. coli of the domestic animals: is indistinguishable from that of man: then it must be shown that this (bovine, say) bacillus has the same significance as the human one. That is, since enteric fever is practically the only disease which the epidemiologist has to consider in relation to shell-fish, it must be shown that there is bovine enteric, and that it may be communicated vza pathogenic bacteria, drains, sewers, estuarine water and shell-fish, to man. An examination of the literature will show that, since the Report of the Sewage Commission in 1904, no serious contribution to the bacteriology of sewage and shell-fish and the normal human intestine—that is to say, no contribution helpful to the fishery administrator or epidemiologist—has been published by the public health researchers, with one or two exceptions. I refer to the papers of MacConkey and Clemensha in the Journal of Hygiene, and to the book—“‘ Bacteriology of Surface Water in the Tropics ’—of the latter investigator. In these papers a really adequate attempt to investigate the bacteriology of sewage organisms has been made, but there is no indication that their results have affected public health practice. Indeed the modicum of bacteriological evidence regarded as necessary in 1904 for the identification of B. colt 1s now apparently too great. The general method of analysis adopted in the Hh) 452 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. reports made to the Lancashire and Western Sea- Fisheries Committee has been, then, to isolate sewage organisms from a sample of shell-fish and to estimate the approximate mean number of these contained in a single mollusc. A number of the organisms so isolated are then sub-cultured, and their cultural characters are determined. If, say, one-fifth of these organisms give the reactions of Bacillus coli, we may then say that one-fifth of all the sewage organisms isolated in the primary cultures were B. coli, paying due attention, of course, to the statistical errors involved. What we do find in such a method of analysis is several categories of organisms. I have given the reactions of 225 such organisms in a former paper (Journal of Hygiene, Vol. IX., No. 4, 1910), making use of MacConkey’s tables for the identification of intestinal bacteria (Thompson-Yates Laboratories Reports, Vol. IV., Part I., 1901; and Journal of Hygiene, Vol. VI., 1906), and refer the reader to this paper. If, however, a report on the liability of a natural shell-fish producing area to sewage pollution consists not only of a bacteriological analysis of the shell-fish them- selves and the water in which they are living, but also includes a detailed survey of all the natural conditions —positions of sewer outfalls, direction and strength of — tidal streams and currents, wind drifts, rise and fall of tide, &c., and also a critical consideration of the epidemiological evidence available—then it may be possible to dispense with the detailed examination of the colonies of organisms isolated in the primary cultures. If, for instance, a quantity of an emulsion corresponding to one-tenth mussel fails to produce any change in bile- salt glucose broth (see p. 481), we may accept this reaction, without any reserve, as indicating that B. coli SEA-FISHERIES LABORATORY. 453 is so scarce in the shell-fish sampled as to be safely neglected from the point of view of dangerous contamina- tion. If, on the other hand, a quantity of emulsion corresponding to 1/50th part of a mussel contains from 100 to 1,000 organisms* growing on neutral-red, bile- salt, lactose agar, as red colonies, we may be pretty sure that the bacteriological contamination is too great to be neglected; for among these 100 organisms there would certainly be from 10 to 20 which we should be able to identify, on detailed examination, as B. coli. Negative results with either of these primary media are of the utmost value; and the investigator will usually be able to find a parallelism between the numbers of ‘* sewage bacteria’ isolated and the results of a survey of the natural conditions of the locality from which the shell- fish samples were collected. It is, nevertheless, quite certain that the identifica- tion of the organisms isolated in primary culture is of the highest importance. So long as public health bacteriologists rest content with describing a B. coli as an organism fermenting glucose and lactose, forming indole, and fluorescing neutral-red, they must confuse together, not only the various species of intestinal bacteria inhabiting man and the domestic animals, and possibly also sea-birds and fishes, but also perhaps bacteria normally occurring in the soil and in estuarine waters, and perhaps devoid of any significance from the point of view of public health. To class all these forms as “‘typical”’ or “‘ atypical ’’ B. coli seems to be a quite unwarrantable proceeding. It always was so, on purely theoretical grounds, and it is now plainly erroneous in view of Clemensha’s recent work. * The lower limit is represented in some of the analyses of River Lune mussels (p. 478). The upper limit may be represented in exceptional cases, or in mussels purchased from fish-shops. 454 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. There can be no justification for the wholesale con- demnation of a shell-fish area on the results of a bacteriological analysis carried on by Houston’s ‘“‘flaginac’’ methods, unless this analysis has been accompanied by a rigorous survey of the area from which the samples were taken, under all possible conditions, and by a critical consideration of the epidemiological evidence available. Yet, the experience of the Com- mittee is now that several important shell-fish beds have been condemned by public health authorities merely as the result of the bacteriological analyses of samples of mussels obtained from fish-shops or from market stalls. It may be that these analyses were adequate ones, but, so far as I know, the details of the methods employed have not been communicated to the Committee. It -is not even certain that the samples in every case were really obtained from the areas implicated. So far as I know, the mere statement of the vendors that they were supphed with mussels from such and such localities is accepted without seeking for further proof. In one such case that has come within my own experience the sample condemned was said to have been obtained from a locality in North Wales. Yet at the time when this sample was analysed the mussel fishery had ceased in the locality in question because of the statutory close season. It might be urged that these mussels were fished illegally during the close season, and while trippers, or casual shell-fish gatherers, may occasionally take mussels from the foreshore at this time, it is clearly impossible (at least it will seem so to those who know the local conditions of the fishery) that mussels should be sent away by railway during this period. In such cases the Local Authority acts, no doubt, in perfect good faith; still, one must demand legal proof of the collection of SEA-FISHERIES LABORATORY. 455 the sample from a definite fishing ground, if that fishing ground is to be condemned as the result of the analysis. In the present Report the main evidence considered is that founded on repeated surveys of the shell-fish beds. It might be urged that (as in Dr. Bulstrode’s last enquiry) this evidence is, in itself, sufficient. Never- theless, bacteriological analyses have been made, but it must be pointed out that these are only provisional ones, and that the detailed investigation of the bacteriology of the -mussels from local sources is still proceeding, and will be reported upon in due course. EPIDEMIOLOGICAL EVIDENCE AND STANDARDS OF IMPURITY. We must be under no illusions as to what is meant by ‘‘ epidemiological evidence.’’ This is a department of public health work into which the layman is rather diffident about entering—perhaps even the epidemiologist fears to tread there. But, after all, the conclusions are only such as require the balancing of very ordinary evidence; and it is not, apparently, a field only explored by the medical officers of health, since one finds that ‘trained investigators,’’ or inspectors, are responsible for many of the results. It is all founded, so far as shell-fish epidemics go, on a very few notable investigations: that made by the late Dr. H. T. Bulstrode, in the cases of the famous enteric explosive outbreaks at the Mayoral banquets at Winchester and Southampton in 1902, for instance; and that made by Dr. Hamer in the case of an enteric outbreak in the East End of London in 1911. It cannot be maintained that either the care with which these outbreaks were investigated, or the success attending the enquiries, have been paralleled in other similar investigations. a 456 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. I quote a few such instances of epidemiological evidence with regard to the transmission of enteric fever by means of shell-fish. It should be noticed that there is more illness of another kind associated with the consumption of mussels. It more frequently happens that a person eating mussels becomes suddenly ill, with all the symptoms of gastro-intestinal poisoning due to ptomiaines; or perhaps with symptoms of the peculiar affection called ‘‘musselling.’’ These illnesses do not concern us, since they are due to obviously decomposed shell-fish, or to personal idiosyncracy. Case—ate steamed mussels on 1/9/’07 and frequently from thence to 29/11/’07. Then he ate one mussel raw and remarked to his wife that he would have no more, as they were not good. He took ill on 4/12/07. His blood gave a + reaction on 27/12/’07. He died on 4/1/08. Case—ate cooked mussels on 17/12/’07. He com- menced to be ill seven days later. Huis blood gave a + reaction on 29/12/’07. He died on 3/1/’08. He had influenza prior to 24/11/’07. All the family ate mussels on 17/12/’07, but no other one was ill. Case—ate raw and cooked mussels several times, beginning December, ’07. Others in the house also ate cooked, but not raw, mussels. He became ill on 11-12/12/’07. His blood gave a + reaction on 31/12/’07. He died on 27/1/708. Case—ate steamed mussels and oysters at a shop on 21/12/’07, with three companions. He became ill on 3/1/’08. His blood gave a positive reaction on 10/1/’08. He died on 16/1/’08. His three companions remained well. Case—ate cooked mussels on 21/12/’07, and so did a friend who was with him. He was ill on 28/12/707. SEA-FISHERIES LABORATORY. 457 His blood gave a + reaction. He died on 24/1/’08. His friend did not become ill. Case—called at shop—and ate Id. worth of steamed mussels. Her friend ate whelks. Two days later she was ill with stomach pains and diarrhea. On 3/12/’08 the doctor suspected enteric and the patient was removed to hospital. Her blood gave a — reaction. The case was regarded as enteric. “The West Cheshire Coroner investigated the circumstances of the death of a boy of seven, Walter Grace, who had died after eating two pocketfuls of mussels gathered off the shore at Seacombe, and also some banana and orange peel out of the gutter. Blame was laid by the Jury on the mussels, the Coroner remarking that that was not the first death in the district from mussels taken in the Mersey Estuary.”’ (One might suggest that the jury contained greengrocers, but not fish salesmen.) Some cases are, of course, very convincing. Three men, W., D. and B., called at a shop—at various dates between 2/11/’07 and 20/11/’07, and all ate steamed mussels. B. had been drinking hard. W. became 111 on 17/11/’07, D. on 18-21/11/’07, and B. on 22/11/’07. They all had enteric. D.’s wife ate steamed mussels from the same shop on 2/11/’07. She became ill on 13/11/’07. W., B. and D. did not live together, and there was no enteric at the place where they lodged. These are some of the best of the cases. Many are not nearly so good, and the evidence may reduce down to this—that A. ate mussels at a date antecedent to the onset of illness from enteric fever consistent with the interpretation that the mussels were the cause of disease. Now we must admit that there is some considerable 458 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. amount of enteric fever which can be traced with reasonable certainty to mussels, or other shell-fish; but it will hardly be possible to accept all the cases in which this cause is alleged—at least not without more evidence than is often adduced. We must reckon with “ typhoid carriers,’ with infected articles other than food, with food-wrapping materials infected in various ways and transmitting the disease, with fly carriers, generally with dirty and unsanitary surroundings. We must always remember the possibility of other articles of food acting as carriers—vegetables, fruits, milk. We must regard personal contact of convalescents with articles of food used by others as a possible cause of distribution. Jt 1s far from being certain that all these causes are excluded in those cases where the infection is ‘‘traced’’ to mussels. Again, one is perhaps not entirely unjustified in suggesting a not unnatural disposition on the part of Medical Officers of Health and Sanitary Inspectors to push the blame of epidemic disease cropping up in their own areas, on to other areas with which they have nothing to do. Mussels are such a convenient scapegoat. One may urge, in the case of a thickly-populated and dirty part of a big town, that the public health officers should set their own house in order. But no doubt they do their best. One may also urge that the zeal which has been directed to excluding mussels from the public markets, under the Food and Drugs Acts, because they were sewage-contaminated, might also be applied to the destruction of moribund mussels exposed for sale in low-class fish shops; and to seeing that this kind of food is stored in sanitary conditions. It cannot be urged by the Medical Officers of Health, unless because of inexcusable ignorance, that the Lancashire and Western Sea Fisheries Committee have SEA-FISHERIES LABORATORY. 459 not done their utmost, with the object of minimising the danger to the public health, to improve the condition of the mussel-bearing areas, and to try and obtain power to deal with this question. I think this activity, and the expense to which this Committee has been put in exercising it, has not been recognised as it ought to have been. It is therefore natural to reply to the public health people with a tw quoque in this matter. At any rate, the remarks on ‘‘epidemiological’’ evidence should be borne in mind in considering the conclusions of the last Section of this Report. STANDARDS. The same vagueness and ‘‘ nebulosity ”’ that has been noted in regard to the question of the identification of B. coli may be observed also in the utterances of some public health bacteriologists. | Houston (1904, p. 107) thus attempts a classification of bacteriological impurities in estuarine waters with respect to shell-fish contamination. He divides such waters into various classes : — (1) No evidence of objectionable contamination— m@ J, Golb, inn IO) C6, (2) Appreciable, though slight evidence—no B. cola in 10 c.c., B. coli in 100 c.c. | (3) Definite signs of pollution. | Suspicious—no B. coli in 1 c.c., B. cola in 10 c.c. (4) Obvious signs of pollution. To be condemned— noes col mm vl c.c., 4 colo im llekc: Here, then, we have a standard. JB. coli must not be present in 1/10th c.c.; if so, the water is objectionably polluted. But, this is only bacteriological condemna- tion, not “‘necessarily administrative practical or legislative condemnation.” 460 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Dr. Houston says that the ‘‘ provisional bacterio- logical and topographical conclusions’’ must be ‘“‘confirmed by epidemiological and administrative considerations.’? For instance, ‘‘ whether the con- taminating material is likely to have a high or low enteric morbific value: past epidemiological experience in circumstances broadly parallel, &c.’’ But, again, Dr. Houston tells us that ‘* neither the chemist, nor even the bacteriologist, can place a ‘ disease-value’ on any given pollution’’ (1904, p. 103). The “standards,” then, do not help us materially. There remains, there- fore, epidemiological evidence, but it is clear that this kind of evidence is not always convincing, and further, it is clear that outbreaks of disease would not, in some cases at least, have ever been traced to definite mussel layings if it had not been previously known that these layings were bacteriologically contaminated. I would refer in this connection to the case of the Conway Estuary. I can find no suggestion of “‘ epidemiological evidence’’ in relation to these mussels prior to the publication of my report of 1906, when the Estuary was first shown to be seriously polluted by sewage. Analyses in themselves then do not help us greatly in founding a standard, since we are warned to accept the conclusions of the bacteriologist only qua bacteriologist, and not necessarily as anything leading to immediate helpful practical recommendations. It is true that this remark does not apply to the work of the Fishmongers’ Com- pany. We find there that all bacteriological results are interpreted into practical administrative ones, that is the mussels are either passed or rejected, as a rule, on the results of the analyses. Nevertheless, little or no information is given as to the precise degree of bacterio- logical impurity on which these conclusions are founded. SEA-FISHERIES LABORATORY. 461 DESCRIPTION OF THE MussEL BEDS AND SEWER OUTFALLS. (1) The Roosebeck, Piel and Conishead Priory Mussel Beds. (Chart I). These beds have acquired considerable importance during the present season on account of a flourishing fishery on the Roosebeck Scar. This began about the end of September and reached a maximum during November, when 95 tons of mussels were despatched from Piel Station alone. Approximately a similar quantity must have been taken to other centres, such as Baicliff, and sent away from there. The fishery on this bed is a very infrequent one, and except for a few mussels taken occasionally, it is many years since such a quantity of shell-fish have been removed from the Scar. Chart I shows the position of the bed, with its surroundings. All the cross-hatched area bears shell-fish, but those to the south-west end of the Scar are at present small, though of good quality. In Dr. Bulstrode’s Report a considerable area of mussel-bearing ground is shown to extend along the western side of Ulverston Channel, but at the present time there are practically no mussels there. The area fished during November is surrounded by a continuous line: it is, roughly speaking, about half a mile in diameter. During this month it began to dry at about low water of a 14 feet tide (Liverpool tables). It goes down to extreme low water of full spring tides. There are various other mussel beds in Barrow Channel. There are two small beds, one on each side of the ferry slip at Roa Island, one directly opposite on the beach at Piel Island, and a larger bed further up the channel, at the place locally known as Head Scar. In 462. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. addition to these, there is a scar at the extreme northern end of Barrow Channel, at the place known as Scarth Hole. This bed is not shown in the chart. The Conishead Priory mussel bed, which is not shown on the chart, is situated about seven miles to the north of the Roosebeck Sear. -A shallow-water channel, Ulverston Channel, extends from Roosebeck right up to Ulverston, and this never dries. It varies in width at low water from about 50 to 70 feet. The Conishead Priory bed is situated on the foreshore locally known as Cope Scar, on the western side of the channel, and about one mile below Ulverston. It is a bed of very little economic importance and is not fished at the present time. None of the Barrow Channel beds is regularly fished. At very rare times mussels have been taken from the foreshore near Piel, and from the bed in Scarth Hole. Such occasional fishing may occur, during periods of unemployment, by persons who are not fishermen: for instance, during the winter of 1908-9, when there was much unemployment in Barrow. There is always, of course, the possibility of these mussels being taken by trippers, or by local people, for other purposes than marketing. But so far as the public food supply is concerned, the only one of this group of mussel beds that matters is that at Roosebeck, and a proper fishery only occurs here rather infrequently. The Sewer Outfalls. All the sewage of Ulverston, representing a population of about 10,000, enters the sea, practically untreated, by an outfall situated at the head of a little creek. This creek opens into Ulverston Channel about a quarter of a mile south of the sewer outfall, and about SEA-FISHERIES LABORATORY. 463 three-quarters of a mile north from the Conishead Priory mussel bed. Two other small sewers enter the Channel; one (conveying domestic sewage) from Conishead Priory (an hotel), and the other (conveying a manufacturing effluent) comes from a chemical works. All this sewage must flow down the channel during the time of low water, when the volume of water in the channel is least, and must pass directly over the mussel bed on Cope Scar. The Barrow Channel outfalls are shown in the chart. The principal one is the main Barrow sewer (1 on the chart), a pipe passing out over the sands and discharging at some distance above low water into a shallow gutter, which runs down towards the channel, and an open sewer near this pipe. These sewers carry untreated sewage and serve the populations of Barrow and Dalton—about 72,000 people, at times. The sands in the vicinity of the outfall are very foul, and at certain states of the tide, and with certain winds, the smell of this foreshore saturated with decomposing sewage matter is very obvious. Barrow Channel from the south-east extremity of Walney Island up to Barrow Docks is very narrow at low water of ordinary tides, and all this sewage becomes concen- trated there. It is true that even then the sewage must be very greatly diluted, nevertheless we will see that the pollution of the channel water, on the last of the ebb tide, near Roa Island is considerable. In addition to this sewer, a small one (No. 2), serving a population of about 150 people on Roa Island, discharges on the fore- shore to the west of the Ferry Shp. There are several small mussel beds near Roa and Piel Islands, and since these come adry at low water of most tides, they must be exposed to very serious risks of pollution. Three other sewers (Nos. 3, 4 and 5) discharge on —_ 464 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the foreshore to the east side of the Piel railway embankment. These serve the population of Rampside (about 150 altogether). They discharge well up the beach. I do not think that any of these sewers can affect, to a significant extent, the Roosebeck mussel bed. Piel Embankment and Roa Island form a barrier from the mainland down to practically low water in the channel; and there is a training wall, a rubble structure, the top of which is just awash at high water of spring tides, extending from Piel Embankment out to Foulney Island, while beyond Foulney towards the S.S.E. the foreshore is very high and stoney and continues the barrier still further. The ebb tide running out from Barrow Channel runs closely to Piel and Walney Islands, so that the channel just at Walney Point is relatively very deep. The ebbing tide from the more northern part of More- cambe Bay runs down Ulverston Channel to the east of the mussel bed, but unless the tide is greater than a 14 feet (Liverpool) tide the bed does not come adry. It is for the most part, then, covered with water on the ebb tide, so that the sewage reaching 1t—that from Ulverston (7 miles away) and from Rampside—is enormously diluted. When the bed does come adry the ebb tide water, containing the Ulverston sewage in a state of greatest concentration, then flows down Ulverston Channel to the east of the bed and about half to three- quarters of a mile distant. Now when the tide turns it sets up Barrow Channel on the one hand, and to the east of the mussel bed, over Mort Bank, on the other hand. | This flood continues for over half an hour while the tide is still ebbing from the foreshore between the mussel bed and the mainland. When the flood tide does begin to stream over the mussels it will indeed contain SEA-FISHERIES LABORATORY. 465 a possible admixture of the diluted sewage which had previously ebbed down Barrow Channel. But by this time the sewage must have become so enormously diluted that its effect on the pollution of the shell-fish must have become quite negligible. We see, then, that the chance of sewage from Barrow Channel, the most important source of con- tamination, 1s very remote. On the other hand, the chance of pollution from Ulverston is very remote on account of the distance of the sewer outfall. There remain the three sewers from Rampside: now the volume of sewage discharged from these outfalls is very small, and this liquid, with some land water draining from various “‘ becks,’’ runs down a fairly large and deep gutter not far from the training wall, and some distance from the mussel bed. This empties into the sea to the south-east of Foulney Island. The consideration of this mussel bed is rather important, not only because it may be the source of an important public food supply, but also because the sources of contamination are such as can easily be reckoned with. We see that it is most unlikely that the shell-fish can be polluted to a significant extent. Yet it is quite certain that bacteriological analysis will indicate some degree of contamination, and the only possible conclusion is that this is such as may safely be neglected. (2) The Morecambe and Heysham Mussel Skears. (Chart II). In October, 1906, I reported on the results of some inspections and analyses made by Mr. A. Scott and myself with respect to the Morecambe and Heysham mussel beds; and came to the conclusion that the degree EE | i 466 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. of pollution at that time was not such as need cause alarm, particularly in view of the probability of the improvement of the sewerage scheme of the Borough. Since then, however, Dr. Bulstrode has visited the district in question, and has reported at some length on its condition. Further, there are important changes, both in the sewer outfalls, and in the situations of some of the mussel beds and sand-banks. It is therefore necessary to re-consider the whole question of the lability of these mussels to sewage contamination. The situations of the main mussel skears and sand- banks are shown on Chart II, but since it was impossible to make a detailed survey the positions of the various beds and banks are only shown approximately. It is hoped, however, that the sketch chart is sufficiently accurate to give a fair idea of the risks of contamination to which these shell-fish are exposed. The population of Morecambe is, of course, a very variable one. It may be taken as about 11,000 normally, but there is a very considerable influx of visitors during the holiday season, and it is obviously difficult to estimate this. When the sewerage scheme, now in operation, was designed, it was intended to cope with a population of about 60,000 people. Four sewers now discharge into Morecambe Channel and Ring-hole. One of these (No. 1) conveys treated sewage from the septic tank installation: this discharges into the sea at the point shown, not far from the Skear known as ‘‘Seldom Seen.’”’ The outfall No. 2 is that referred to in my former report as the ‘‘ Midland Culvert’’: it is very much now as it was in 1906. No. 3, the ‘‘ Queen Street Sewer,’ has been discontinued. and the sewage formerly discharged by it is now being diverted into the main system. No. 4, the “‘ Calton SEA-FISHERIES LABORATORY. 467 Terrace’’ sewer is also now discontinued, the area formerly served by it being now served by the main system. No. 5 is the ‘‘ Thornton Road’’ sewer referred to in my former report, it remains as it was in 1906. No. 6, the “‘ Bare Outfall,’’ is also unchanged. It discharges very near to low water at a position above all the mussel skears. In addition to these sources of pollution the men employed at the ship-breaking works in the Old Harbour must also be reckoned with. About 200 men may be employed at times, and these use closets which discharge directly on the foreshore. There are also two small sewers, serving a population of about 4,000 people at Heysham. The positions of these out- falls are not shown on the chart. They lie between the Morecambe West End Pier and Heysham. | There are also considerable changes in the positions, and in the productivity of the mussel skears themselves. Ring Hole, which in 1906 contained abundance of mussels, and which had been selected for the transplanta- tion of small shell-fish from Heysham Skears, is now sanded up, and there is no suitable ground here for the erowth of mussels. The two important skears shown on the 1906 chart, ‘“‘Seldom Seen’’ and ‘‘ Reap’’ Skears, are now also sanded up. ‘* Baiting Knot’”’ Skear, which lies on the other side of the channel, between the West End Pier and the Old Harbour, still exists. But there are, at the present time, very few mussels on it. The beds known as “‘ Little Skears ’’ are also sanded over, and do not bear mussels in sufficient quantity to count so far as the supply of the markets is concerned. “ Jacky John’’ Skear, that one at the extreme western end of the Heysham series, is also sanded over. All the other beds remain very much as they were in 1906. Mussel ground exists at “‘Bare Ayre,’’ that is the ll 468 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. shaded part of the foreshore between the Thornton Road and Bare outfalls. There is also good mussel ground at ‘“ Stone Skear,’? which lies towards the other side of the channel, between the Thornton Road outfall and the Central Pier. There are patches of mussel-bearing ground on the rising ground, or brow, between the Central Pier and the Old Harbour, and between the latter and the West End Pier; probably there are smaller patches of mussel ground elsewhere. These latter places, however, are not fished by the regular musselers, and are only exploited by reckless visitors, and some- times by the unemployed and shiftless elements of the Lancaster population. One or two other smaller mussel beds are not shown on the chart, “‘ Walmsley’ deep- water skear, for instance. This is shown in the 1906 chart. The most important mussel grounds are those on the skears below the main sewer outfall. These skears are: ‘“ Old Skear,’’ ‘“‘ Knott-End,’’ ‘‘ Cockup,”’ “‘ Little-out,”’ ‘“Great-out,’’ and ‘‘ Bankside.’’ There are channels, or ‘*Gunnells,’’ between some of these skears, and on the bottom of these gunnells mussels may be found. It has been suggested that small mussels, from the higher parts of the skears, might be transplanted into these gunnells, and the suggestion seems to me to be an admirable one. The position of the principal sandbanks and channels is, as I have said, only indicated roughly on the sketch chart. These banks and channels are not accurately represented in any chart published, and they ought, of course, to be properly surveyed, in the interests of such an enquiry as this. It was, however, quite out of the question that we could attempt this in the limited time at our disposal. It is a suggestion that I commend to the Local Authority or the Scientific Sub-Committee. SEA-FISHERIES LABORATORY. 469 One very notable change must be noted. In 1906 the Heysham Skears extended over towards Yeoman Wharf, and Grange Channel was then a comparatively narrow strip of water. But during the last few years extensive changes have taken place in the channels in the upper part of Morecambe Bay between Grange and Morecambe. The result has been that the spit forming the south-west extremity of Lancaster Sands has been eroded away, while material has accumulated on the Morecambe side, encroaching on the channel between Lancaster Sands and the mainland. Yeoman Wharf has also extended much further to the east, so that ‘‘ Low Skear’’ has become sanded over. The result of all these changes is that the ebb-tide stream setting down Grange Channel now runs further to the east than it did in 1906, and a much greater volume of water must flow over the Heysham Skears. The dilution of the sewage flowing down from Morecambe towards the Heysham Skears must therefore be greater than it was. (3) The Fleetwood and Hambleton Beds (Chart III). The natural conditions here are fairly simple and easily understood. There are three main mussel-bearing areas in the estuary of the river Wyre:—(1) Seaward from Knott-End Ferry, in the channel, and on the sides of the adjacent banks; (2) in the bed of the river itself between the Docks and the Fleetwood salt and ammonia works; and (3) in the bed of the river, and on the foreshore at Hambleton, and extending from about Wardley’s Hotel for about three-quarters of a mile seaward. The mussel beds (1) are of no economic importance; those at (2) are often fished, mussels are found on the banks, and also in the bottom of the river on ground which does not come adry. These shell-fish 470 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. are, as a rule, of rather poor quality. The mussels taken from the river at Hambleton are well-known and fetch a very good price. Those raked from the bed of the river are very fine shell-fish, but those on the foreshore are rather poor in quality. The Sewer Outfalls. Formerly all the sewage of Fleetwood, representing a population of about 15,000 people, was discharged into the Wyre between the Ferry and Docks, through various outfalls. At the present time it is diverted from these old outfalls and taken across the Fylde peninsula to a pumping station near Rossall. The outfalls 6 and 7 on the chart are near Rossall Landmark, much further seawards than is shown on the chart, and is thus com- pletely removed from any influence upon the shell-fish beds of the Wyre. There are, however, several other sources of pollution. There are several small drains on the Knott-End side of the Estuary, near to the Ferry, but these need not concern us here. On the Fleetwood side there are two sewers (1) a small drain from an ice factory, and (2) a storm overflow from the main system. Further down the estuary, near the Docks, are three drains conveying manufacturing effluents; (3) comes from a fish-oil works; (4) from a fish-curing house; and (5) from a ‘‘fish-meal’’ works. There are iron pipes terminating well above low water mark, on the beach, so that the effluent reaches the estuary by little brooks flowing right through the mussel beds—at this point, however, the shell-fish are very small and are rarely fished. The sewage from Hambleton appears to drain into the small becks entering the estuary here. That from Poulton-le-Fylde enters into a little brook called Peg’s Pool: this is the outfall marked (8) on the chart. SEA-FISHERIES LABORATORY. 471 The manufacturing effluents mentioned above are offensively smelling liquids containing organic matter and sulphuretted hydrogen in solution. I examined these liquids in February, 1911, and reported on the question of the contamination of the Wyre to the Scientific Sub-Committee Meeting of that month. It is, therefore, unnecessary to refer further to them here. Also the question of their discharge is not relevant to this enquiry. They certainly constitute technical ‘““nuisances,’’ and it appears that they may be regarded as detrimental to the mussels in the neighbourhood of their outfalls. The remedy is therefore clear. The discharge can be inhibited either by the Local Authority acting under the Public Health Acts, or by the Fisheries Committee itself in virtue of its bye-laws. The sewage entering the river at Poulton-le-Fylde is the only serious cause of pollution. This outfall is 39 situated about a mile distant from the Wardley’s mussel bed and at low water the diluted sewage must flow down a series of rather narrow channels and then over the shell-fish. Still the volume of water carried up the Estuary on the flood tide is very large, and this must dilute the sewage to an enormous extent. The mussels usually fished are also shell-fish that are raked from the bottom, so that they never come adry. (4) The Lune Mussel Beds (Chart IV). In February, 1904, Mr. A. Scott and I visited the Estuary of the Lune and saw the mussel beds there; and I collected samples of the shell-fish and reported on the analyses made. ‘This report was incorporated in a report to the Lancashire County Council by the Medical Officer of Health, and this also contained the results of analyses made by Professor Delépine, of Manchester University. 1 | 472. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Dr. Sergeant himself came to the conclusion that he found it difficult to express an opinion as to whether the County Council would be justified in asking the Local Government Board to hold an enquiry (with the object of considering whether the Rivers Pollution Prevention Act should be applied to the case of the Lune). He fully believed, however, that the present system of introducing large volumes of sewage into the river was objectionable and avoidable, and he thought this practice likely to render harmful the shell-fish caught in the estuarine waters. Professor Delépine found clear evidence of the pollution; by faecal matters, of the estuarine water and river banks, and he suggested that these shell-fish might at times become dangerous to health. Mr. Scott and I found distinct naked eye evidence of faecal pollution of the banks of the Estuary in the neighbourhood of Crook Skear; and I found that the mussels from both Crook Skear and Bazil Point Training Wall were polluted, though I then thought that the degree of pollution was not excessive. Ultimately the question of the pollution of the river was submitted to the Local Government Board, but the latter body concluded that there was not enough evidence to justify them in proceeding further with the proposal to declare the tidal waters of the Lune a ““ stream ’’ within the meaning of the Rivers Pollution Prevention Act of 1876. The whole question then remained in abeyance until early in 1911, when Dr. Bulstrode’s report was published. It then became advisable to re-examine the locality and this Dr. Jenkins and I did last July. Finally, the action of the Blackburn Local Health Authority, in excluding Lune mussels from sale within the borough, has brought the condition of the Lune prominently before the notice of the Fisheries Committee. SEA-FISHERIES LABORATORY. 473 The Mussel Beds. The only mussel beds in the Lune are those at the lower extremity between Glasson and Sunderland Point. One of these, situated on the eastern side of the Estuary, is called Crook Skear; the other “‘ bed’’ really consists of mussels growing on the stones forming the training wall, extending along the western side of the river from Bazil Point to near Sunderland Point. The shell-fish here are of finer quality than on Crook Skear. There are several smaller patches of mussel ground near the training wall, but the shell-fish here are of very little economic importance. South from Crook Skear, and in the bed of the Estuary, there are also mussels, but these never come adry. The Sewer Outfalls. The sewer outfalls marked on the chart are those which are referred to in Dr. Sergeant’s report to the County Council in 1904. Those lettered A to G discharge mostly domestic sewage, but some manufac- turers’ effluents are also carried by them. Sewers H,, H,, and H, discharge the domestic sewage and other effuents produced by Messrs. Willhamson’s mills. Sewer I carries untreated sewage from the Lancaster Infectious Diseases Hospital. All these serve a popula- tion of about 34,000 people. There is no other outfall until Stodday is reached, where a sewer (J), serving a population of about 9,000 people, discharges into the river some distance above low water mark. Two other sewers discharge further down: one (K) at Conder Green opens into a brook which then flows across the sands into the river; the other (L) at Glasson Dock opens into the river directly. The first serves a population of about 1,000 people, the latter about 400 people. Ha 474 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. We see, then, that the sources of pollution of the Lune are very numerous. We return later to the question of the effect of all this discharge on the shell- fish beds. (5) The Mussel Beds in the Estuary of the Conway. (Chart Y). The question of the pollution of the mussels taken from the Estuary of the River Conway is, of course, one which has now passed out of the hands of the Sea- Fisheries Committee. The Corporation of the Borough apphed last year (1911) for a Provisional Order under the Sea-Fisheries Act of 1868, which would enable them to improve, maintain and regulate the mussel fishery in a specified area. An enquiry was held at Conway in December, 1911, and in August of 1912 the Act of Parliament (Ch. CXLI., 2 & 3, Geo. V.) confirming this Order received the Royal Assent. The Order enables the Corporation to make regulations, to erect storage and cleansing ponds, and to impose a royalty not exceeding ls. 6d. per cwt. of mussels. Really the royalty payable by the fishermen is at present fixed at 3d. per bag of mussels exceeding three inches in length, and 2d. per bag of smaller mussels. The object of the Order is to give the Corporation power to arrange that the mussels, which are at present dangerously polluted by sewage bacteria, shall in future be relaid in pure sea water for such a time as will enable the shell-fish to cleanse themselves from the bacteria. Experiments made by Professor Klein, of Bartholomew’s Hospital, in London, and by myself in the Estuary of the Conway, have shown that if a grossly polluted mussel be relaid in uninfected sea water for a period of about four days, over 90 per cent. of the contained bacteria become eliminated— SEA-FISHERIES LABORATORY. 475 discharged by the shell-fish. This Order seems to me to be an admirable one, and if its provisions are enforced with care and intelligence it should put an end to all trouble with respect to the pollution of the Conway mussels, and should develop to a great extent this important local industry. It is to be hoped that the Corporation will administer it with sympathy and intelligence. Although the matter has now passed out of the hands of the Fisheries Committee, it is, nevertheless, useful to give an account of the condition of the Estuary of the Conway with respect to the contamination of the shell-fish contained therein. This area has now been investigated since 1904 and the conditions with respect to contamination are probably better known than in any other shell-fish area in the country. Bacteriological investigations have also been made from time to time, and a considerable amount of evidence with respect to the communication of disease by these shell-fish has accumulated. The case of the Conway may thus be regarded as a standard one, with which other similar cases may be compared. The Mussel Beds. The cross-hatched areas in the chart represent the positions and extent of the mussel-bearing grounds. These grounds extend from the Harbour at Deganwy to some distance out to sea, altogether outside the Estuary. Most of the bed of the river below low water mark contains mussels, and there is a considerable area of scar-ground, coming adry on low spring tides, which is also covered with mussels. Also there are mussels on the banks at the mouth of the Estuary, on both sides of the channel. Further up the Estuary, from near the 476 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. town of Conway to some distance above the bridges, there is mussel ground on the channel bottom. Mussels are raked all over the bed of the Estuary on the shaded part, and are picked by hand on the scars. The Sewer Outfalls. The sewer outfalls are also marked on the chart and the numbers adjoining them indicate the number of people in the area served by the sewers. Above the bridges there are two sewers, one serving a population of about 600 people, and opening on the western side of the river; and the other serving a population of about 1,250 people at Llandudno Junction, and opening into a little brook which flows down over the sands to open into the Estuary quite close to the tubular railway bridge. On the western side of the river is a further group of three sewers serving a population of about 2,600 people—that of the town of Conway. Further down, two small sewers serve a group of houses (about 690 people) at the place known as Morfa Parade. On the eastern side of the Estuary there are sewers at Deganwy and Tywyn, serving a population of about 1,600. Thus this part of the Estuary, only about 1; miles long, and, on the average, about one-third of a mile in width, receives the sewage of a population of about 6,750 persons. Also, above Conway, the sewage from a population of about 4,120 persons also drains into the river. | BACTERIOLOGICAL ANALYSES. I give here an account of recent analyses only ; many more have been made in the past, but all those to which I refer have been made by identical methods, so that all the results are comparative. I take Conway first, as this locality may be regarded as a standard one, with which the others may be compared. SEA-FISHERIES LABORATORY. ATi Conway Estuary. 26 June, 1909. A sample of mussels taken quite close to Deganwy Sewer outfall. Five mussels emulsified in sterile water and made up to a volume of 2650 c.c. 1 c.c. of the emulsion = (0-02 mussel) contained 25 intestinal* bacteria (also 55 colourless bacteria). 22 39 62 99 99 Mean No. of intestinal bacteria per mussel = 2150. 9 August, 1912. A sample of mussels from the bottom of the river near the north side of the bridge. Five mussels emulsified in 250 e.c. of sterile water. 1 c.c. of the emulsion = (0-02 mussel) contained 29 intestinal bacteria (No colourless bacteria). 39 9? 59 99 39 2” be) 39 29 33 399 9? 39 9° 99 29 55 9 99 29 29 Mean No. of intestinal bacteria per mussel = 2200. 9 August, 1912. A sample of mussels from the bight between Morfa Parade and the point of land to the north-west. (Locally, (Anglice) ‘* Stinking Pool.’’) Five mussels emulsified in 250 ¢.c. of sterile water. 1 c.c. of emulsion = (0-02 mussel) contained 28 intestinal bacteria (1 plate contained about 50 colourless bacteria). 29 9? 20 39 29 39 ” 2 ce) 40 29 2? cE) ”? 39 39 18 29 39 29 3? Mean No. of intestinal bacteria per mussel = 1300. Water Analyses.—The small figures placed in the chart on the Estuary at low water indicate the numbers * I call these bacteria isolated in Griinbaum’s neutral-red, bile-salt, lactose agar medium ‘‘ intestinal bacteria’ with all the reservations indica- ted in my general discussion of methods of analysis. 478 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. i of intestinal bacteria contained in 1 c.c. of surface water. | The samples were taken at various times, so that it is inadvisable to calculate a mean. They will, however, give a fair idea of the approximate degree of pollution of the water. Lune Estuary. 23 June, 1912. A sample of mussels from the training wall at Bazil Point. Five mussels emulsified in 250 c.c. of sterile water. 1 c.c. of emulsion = (0-02 mussel) contained 53 intestinal bacteria and 1 colourless bacteria. 99 97 99 39 99 29 99 29 99 48 29 99 29 5 93 93 29 2? 60 ” 9? 99 20 99 2 99 99 80 29 99 99 0 29 29 Mean No. of intestinal bacteria per mussel = 3700. 23 June, 1912. A sample of mussels from Crook Skear. Five mussels emulsified in 250 c.c. of sterile water. 1 c.c. of emulsion = (0:02 mussel) contained 157 intestinal bacteria and 7 colourless bacteria. 39 39 5 99 33 99 29 o> 39 3? 146 39 39 3° 3 99 29 39 92 117 39 39 9 1 33 ted 33 33 82 33 99 ” 2 99 39 Mean No. of intestinal bacteria per mussel = 6500. Water Analyses— 1 c.c. of surface water contained— At Bazil Point. At a Pool on Crook Skear. 77 76 86 111 90 120 88 56 70 46 Means are 83 82 intestinal bacteria per c.c. SEA-FISHERIES LABORATORY. 479 Morecambe Mussels. 2 July, 1912. A sample of mussels from Bare Ayre Point. Five mussels emulsified in 250 c.c. of sterile water. 1 c.c. of emulsion = (0-02 mussel) contained 27 intestinal bacteria (2 plates contained colour- less bacteria). 2”? : oy) 96 2” oy) ry) ” 2? ” 95 ” 9 oe) ” ” 2 53 2 ” 2” oe) 39 59 2? 99 29 39 Mean No. of intestinal bacteria per mussel = 3100. 3 July, 1912. A sample of mussels from Little-out Skear. Five mussels emulsified in 250 c.c. of sterile water. 1 c.c. of emulsion = (0:02 mussel) contained 17 intestinal bacteria (1 plate contained colourless colonies), th) 99 5 29 99 99 22 39 29 3 ” ate 29 ” 99 39 22 99 99 39 9 29 “ 99 13 , © oy) 2”? 29 Mean No. of intestinal bacteria per mussel = 600. 23 November, 1912. A sample of mussels from Stone Skear. Five mussels emulsified in 250 c.c. of sterile water. 1 c.c. of emulsion = (0:02 mussel) contained 4 intestinal bacteria (No colourless colonies). 39 29 99 99 39 99 2° 9 8 2 2” ” 9 29 5 99 99 92 Mean No. of intestinal bacteria per mussel = 300. Water Analyses— Numbers of intestinal bacteria in 1 ec.c. of water invoian 9— Bare Ayre Pt. (3 July, 1912), 61, 44, 36, 48, 28. Mean = 42, Little-out Skear (3 July, 1912), 0, 1, 0, 1,0. Mean = 0-4. Bare Ayre Pt. (28 November, 1912), 7, 11. Mean = 9. Channel, off Central Pier (23 November, 1912), 3, 8. Mean = 5:5. Channel, off Old Harbour (23 November, 1912), 6, 14. Mean = 10. Channel, half-way Old Harbour to West End Pier (28 November, 1912), 28, 40. Mean = 34. Near Main Sewer Outfall (23 November, 1912), 3, 2. Mean = 2:5, Off Reap Skear (23 November, 1912), 3, 5. _Mean = 4. | 480 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Estuary of the Wyre. 23 February, 1911. Sample of mussels from the Estuary near Wyre Dock. Five mussels emulsified in 250 c.c. sterile water. 1 c.c. of emulsion = ‘ (0:02 mussel) contained 2 intestinal bacteria. 39 99 29 29 392 29 99 39 Mean No. of intestinal bacteria per mussel = 66. 9 March, 1911. Sample of mussels taken from near Wardley’s. Five mussels emulsified in 250 c.c. sterile water. 1 c.c. of emulsion = (0:02 mussel) contained 3 intestinal bacteria. 9 9 29 99 9° 33 3 ? 99 4 39 29 99 99 Mean No. of intestinal bacteria per mussel = 125. 5 November, 1912. Sample of mussels from the Estuary near Wyre Dock. Five mussels emulsified in 250 e.c. sterile water. 1 c.c. of emulsion = (0-02 mussel) contained 48 intestinal bacteria. 99 3? 29 33 93 9 34 29 29 99 39 31 39 29 39 99 23 39 99 Mean No. of intestinal bacteria per mussel = 1650. 5 November, 1912. Sample of mussels from the channel near Wardley’s. Five mussels emulsified in 250 c.c. of sterile water. 1 c.e. of emulsion = (0:02 mussel) contained 7 intestinal bacteria. > 9 1 9 99 29 99 20 99 33 39 92 9 39 29 39 39 10 3? 9? Mean No. of intestinal bacteria per mussel = 600. SEA-FISHERIES LABORATORY. 481 Water Analyses— Number of intestinal bacteria per c.c. of surface water from :— Channel near Wyre Dock (23 February, 1911), 1, 0, 2,0. Mean = 0-75. Channel near Wardley's (10 March, 1911), 26, 24, 17, 24, 20. Mean = 22. Roosebeck and Barrow Channel Mussel Beds. 27 June, 1912. Sample of mussels from the Scar. Five mussels emulsified in 250 c.c. of sterile water. Intestinal bacteria absent in 1/10th mussel. | Nore.—In this analysis MacConkey’s bile-salt broth was used. All tubes containing 1/10th and lesser fractions of a single mussel were unchanged after 48 hours’ incubation. The “ enteritidis-reaction ”’ also failed with 1/50th part of a mussel. | 1 November, 1912. Sample of mussels taken from fisherman’s bag immediately after the shell-fish had been taken. Ten mussels emulsified in 250 c.c. of sterile water. 2 c.c. of emulsion = (0:08 mussel) contained 33 intestinal bacteria. > 39 99 39> 99 39> 21 29 2? 33 39 24 39 33 99 92 29 99 - 39 1 c.c. of emulsion = (0:04 mussel) contained 15 intestinal bacteria. 1 Mean No. of intestinal. bacteria “per mussel = 310. The ‘‘ enteritidis-reaction ’’ was obtained with 1/12 but not with 1/120th mussel. No recent analyses of mussels from the Barrow Channel beds have been made. These are hardty necessary since the conditions are such that serious pollution cannot be avoided. BE 482. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Water Analyses— A number of samples of water from Barrow Channel, from the end of the Ferry Slip, were made in May, 1908, at various states of the tide. The results are as follows: Nos. of intestinal bacteria in 2 c.c. of water— 5 hours before high water—Sterile. 3 39 99 1 29 ” =f. 64 hours before low water—0. 4t 2” oy) ==), 24 5 FA —200. i if > 1000. Conishead Priory Mussel Bed. 13 June, 1972. Sample of mussels taken direct from the bed. Five mussels emulsified in 250 c.c. of sterile water. 1 c.c. of emulsion = (0:02 mussel) contained 6 intestinal bacteria. 29 399 1 32 99 99 39 21 2? 39 99 99 24 99 99 3 Mean No. of intestinal bacteria per mussel = 770. Summary of results of recent mussel analyses Mean No. of Locality. Date. intestinal bacteria per mussel. Lune Estuary, Crook Skear ...... 23 June, 1912 6,500 as Bazil omntieeeene 23 June, 1912 3,700 Morecambe, Bare Ayre Point ...| 2 July, 1912 ; 3,100 Conway, near Bridges ............... ) Anes, III | 2,200 oy near Deganwy ............ 26 June, 1909 2,150 Wyre, near Fleetwood ............ 5 Nov., 1912 ; 1,650 Conway, near Morfa ............... 9 Aug., 1912 1,300 Conishead@Rrionyeeeeeeee eee eee 13 June, 1912 770 Heysham, “ Little-out” Skear .... 3 July, 1912 600 Wryres ab) Wardley.s\-ncnese-mels ssa 5 Nov., 1912 600 Roosebeck Scar © ....ccscacccceccesees 1 Nov., 1912 310 Morecambe, Stone Skear ......... 23 Nov., 1912 300 Wyre, at Wardley’s ..............000 9 Mar., 1911 125 Wyre, near Fleetwood ............ 23 Feb., 1911 66 Roosebeck: l EUPAGURUS. 49 although the genera cannot well be confused. The species of Anapagurus at present recorded from British seas may be thus distinguished.* ANAPAGURUS— 1. Internal antennae, three to four times the length of the eyestalks, which are short and thick. Ambulatory hmbs shghtly pubescent.—A. hyndmanni. 2. Internal antennae about twice as long as eye- stalks, longitudinal orange band on hand. Ambulatory limbs almost smooth; a few small spines on anterior borders. Right chelipede of male enormously developed. A. laevis. Row of small spines on wrist of left chela. 3. Internal antennae about three times the length of eyestalks, which are slender. Chelipedes pubescent. Right hand elongate, ovate and smooth, in length equalling the wrist. Left chela slender with nearly parallel sides. Ambulatory limbs smooth, © slightly pubescent. A. chirocanthus, Lilljeborg. (A. ferrug- ineus, Henderson). The key to the British Hupaguridae given below has for its justification the fact that it enables one to identify the living animal, when means of removing it from its shell are not readily available. KupaGurus— 1. Chelae naked. (a) Limbs tuberculate and spiny on upper border. Strong rostrum. Dactyl contorted. E.. bernhardus. (b) Limbs granulate. Weak rostrum. Dactyl straight. EL. prideauaie. * Henderson. Proc. R. Phys. Soc. Edin., vol. [X., 1885-8. 498 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 2. Chelae pubescent. (a) Left chela median dorsal carina on hand. (1) Three long carinae on right hand. Hand ovate. Fairly pubescent. EH. excavatus. (11) No carinae on right hand. R. chela wrist=length hand. Very pubescent. EL. pubescens. (b) Left chela without carina. (1) Hyestalk longer than A, peduncle and ttle shorter than A, peduncle. Chelipedes densely pubescent. H. cuanensis. (11) Eyestalk as long as A, peduncle, but shorter than A, peduncle. R. chela shghtly pubescent. Wrist spiny on inside. EL. forbesw. The genus Hupagurus is of world-wide distribution. E. bernhardus is found in Scandinavian and British seas, Bay of Biscay and Mediterranean. There are doubtful records from the Atlantic shores of North America (probably H. acadianus), Behring Strait to Kamtschatka. It seems to be vertically distributed from low-water mark to great depths. The Paguridea are almost unrepresented geological strata. Ortmann mentions one species, known by its chelae only, in Hungarian Kocene, but he is somewhat sceptical as to its authenticity. Loérenthey (Math. u. Nat. Ber. Ungarn, Bd. 24, 06) -has since recorded three species from Oligocene and Miocene. As in the previous case only the chelae have been found. Ee EUPAGURUS. 499 EXTERNAL CHARACTERS (PI. I). In the segmentation of the body the Hermit Crabs exhibit a wider divergence from what might be assumed to be a typical Higher Crustacean condition than any of their allied Decapods. There is no portion of the body from which a segment could be taken which has not lost its primitive design in its specialisation. In the Macrura and Brachyura the simplicity of the abdominal region is preserved, even if the cephalothorax is specialised, but in Eupagurus the condition of the abdomen is such that it is a matter of some difficulty to demonstrate any segmentation at all. An abdominal seoment of the Crayfish (Astacus) would be found to possess three kinds of protective plates:—The dorsal tergum, the ventral sternum, and the two lateral pleura. An appendage is attached on each side to the outer end of the sternum. The sternum is attached to its fellows in front and behind by means of a flexible arthrodial membrane, and to each flanking pleuron by a hard membrane—the epimeron. No such typically developed segment is to be found on the Hermit Crab. The only fully calcified portions of the abdominal region are the first and last segments, and neither of these is in any way normal. The peduncle never at any stage bears limbs and although a narrow sternum is present in the larva, it vanishes altogether in the adult animal, while the sternum and the pleura of the sixth segment are always in a more or less membranous condition. Cephalothorax.—The exoskeleton of the Decapoda has been described so frequently that it will be unnecessary to do more than refer briefly to points peculiar to the type under consideration. The first character which calls for mention in the cephalothorax 500 . TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. is the slight calcification of the fused terga and pleura. The only portion of the dorsal shield which is at all heavily calcified is the ‘‘cephalic’’ region bounded behind and at the sides by very deep grooves (Text-fig 1). The branchiostegite is almost membranous and the cardiac portion of the carapace is only lightly calcified in its anterior portion. On the anterior border there is a median pointed triangular rostrum of small size, and on either side of it, separated by long shallow excavations, are two supra-orbital prominences.* The front now becomes continuous laterally with deep grooves, which pass back to join the cervical groove. The branchio- stegite is hinged to the groove on both sides. It drops vertically downwards anteriorly, almost at right angles to the dorsal shield, but the angle becomes gradually less acute further back, till in the thoracic region the lateral walls form a smooth curve with the dorsal side. Were the body not so narrow, the appendages would present an obstacle to the animal retiring into its shell. As it is, they can be folded up beside the body in a very small space. The proximal joints are flattened considerably from side to side to reduce the size of the animal when it is in its shell. The lateral border of the cephalothorax is prolonged forwards to form a considerable lobe on either side, which projects on a level with the end of the rostrum. This lobe is supported dorsally by its folded and calcified edge. The hind border of the carapace is reflexed and attached to the eighth thoracic somite, the tergum of which is partially separate. Certain lines and areas are recognisable on the carapace. The most important of these is the groove corresponding to the cervical groove * The front between the supra-orbital lobes in #. prideauati is almost linear. Oy tl EUPAGURUS. 501 of other Decapods (Branchial groove, Bouvier). It is very deep and is the more clearly outlined by reason of the comparatively dense calcification of the region in front of it. The homologies of the terms by which writers have described the other grooves and lines of the carapace are not altogether clear, but the following aecount—principally based on Borradaile—summarises the accounts of the various writers. TExt-Fie. 1. Anterior to the cervical groove (c. Boas, c. Bouvier, and 2 and 2’ Borradaile) is a deep longitudinal groove extending forwards to the edge of the front. Bouvier calls this the linea anomurica, and Boas calls it line b. This longitudinal groove is continued as a faint crease to the back of the carapace, and this portion Boas calls the linea anomurica. Borradaile combines the naming of the two others, calling the whole line from end to end the linea anomurica. A small crease (/a’) passing vertically downwards from this line on a level with the cervical groove is also part of the linea anomurica according to Boas. Bouvier and Borradaile do not recognise it. A small longitudinal groove above the linea anomurica and parallel to it starts from the cervical groove and passes 502 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. forward for a short distance. It is called line d by Boas. It, with its continuation backwards past the cervical groove, is probably homologous with the linea thalassinica (line 3 of Borradaile). For the Text-figure Borradaile’s numbering has been adopted:(p. 501).* It is as follows :— 2. Boas’ line e.—Bouvier’s ‘‘ branchial groove ’’— commonly known as the cervical groove. 2’. Continuation of cervical groove at the sides of the carapace. 3. Boas’ line d. (front part only), also probably the linea thalassinica. 4. Linea anomurica. 5. Soft area at side of carapace. 6. 6’. Borradaile refers to as ‘‘ hard plates in this area.’’ In this species calcified bars are present which probably represent similar structures. 7. Rostrum. The Sterna of the cephalo-thoracic region do not require detailed description. Those situated posteriorly are mostly very narrow, that of the fourth thoracic somite being reduced to a mere bar in an antero-posterior direction. This sternal bar is in an _ interesting’ condition. It is always displaced slightly to the left— a modification due, no doubt, to the asymmetry of the chelipedes and the greater size of the right limb. All the sterna behind the fifth somite are separated by an arthrodial membrane, and the last two are again reduced to narrow bars—transversely placed—separated by long stretches of membrane. The free articulation of the two last segments on one another aids in conforming the animal to the shape of the shell. * Figure of Callianassa (Fig. 125, p. 691), Gardiner’s Fauna of Maldives and Laccadives, I1., 2. Marine Crustaceans, Pts. X and XI. EUPAGURUS. 503 The Thoracic epimera form the inner wall of the branchial chamber and support the gills. The whole constitutes a thin, slightly calcified plate, grooved between the segments by vertical sutures. The inturned edges of the epimera at these grooves form part of the endophragmal system. The Abdomen of the Hermit Crab is quite unique among the Malacostraca. It is a distended sac, which might perhaps be described as banana shaped, into which the gonads, digestive glands and renal bladder have been crammed. The first segment (or peduncle) is small and narrow and calcified. The last segment and its appen- dages is also calcified, but the remaining four segments are represented by an ungainly membranous bag, which shows practically no trace of division into somites. Traces of the terga can be distinguished above each pleopod on the left side, and in a corresponding position on the right (fig. A, Pl. I). They can barely be seen in young specimens and less in males than females. The position of these remnants shows that the fifth segment is greatly and the fourth rather elongated. Mention should be made of the prominent ‘‘ columellar’’ muscle on the third segment. It seems to have only a passive function in fitting the body more closely to the shell. APPENDAGES (PI. IT). The appendages of Hupagurus bernhardus bear very obvious marks of the asymmetry which affects the whole animal. There is always (in the present species) a striking inequality between the chelae, and of the abdominal appendages only one, the uropod, has survived on the left side. The walking legs, head appendages and maxillipedes remain symmetrical. 504 SOCIETY. TRANSACTIONS LIVERPOOL BIOLOGICAL A considerable degree of specialisation is shown by the limbs. Some are used for facilitating rapid egress and retreat into the shell, some for locomotory purposes, the telson and uropods for hanging on passively to the shell, and the pleopods for causing a flow of water in the shell, and (in the female) for carrying the developing eggs. The male and female differ only in the disposition and number of the pleopods. The appendages may be arranged as follows :— Cephalon. Somite I. Ist Antennae. ee Zand va IIT. Mandibles. IV. Ist Maxillae. V. 2nd Maxillae. Thorax, Somite VI. Ist Maxillipedes. VS vend a WalnIES tard a IX. Ist Pereiopods. X. 2nd Pe XI: 3rd ie XIT. 4th 5 XLTE.. 5 Sth: if Abdomen. FEMALE. Right. Left. Somite XIV. Absent. Absent. XVE i 1st Pleopod. XVI. is nid Gee XVII. a Burl ae SOWUUE a Ati, 2IDK: Uropod. EUPAGURUS. 505 Mate. Right. Left. Somite XIV. Absent. Absent. XV. a fo XVI. B Ist Pleopod. XVII. B PANG © op xeV I a SiR! ag XIX. Uropod. Uropod. The First Antenna (fig. 1) is attached almost immediately beneath the eye, but the joints turn inwards and upwards, and thus appear to be attached on the inner side of that organ. The ex- and end-opodite, the former of which is much the larger, bear multiarticulate flagella. That on the exopodite possesses a fringe of long setae. The endopodite is quite small and insignificant. In the proximal joint is lodged the auditory sac, which opens to the exterior by a narrow longitudinal slit on the upper side. The Second Antenna (fig. 2) is larger than the first, and considerably more prominent by reason of the very long flagellum. The protopodite is two-jointed and the flagellum—which represents the endopodite—is attached to it by two moveable segments. A narrow pointed sickle-shaped exopodite, the squame, is present. The Mandible (fig. 3) is a strongly calcified elongate structure. The portion immediately under the mouth is tooth-lhke and strongly grooved within. Into this groove the head of the palp fits. The palp is a little, jointed structure, probably used for cleaning the biting edge of the mandible and helping the food into the oesophagus. The outside portion of the mandible is a long bar (the apophysis), which serves as an attachment for the powerful muscles moving the appendage. 506 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. First Maxilla (fig. 4) —Only the endopodite of this appendage is present, and that is a slight structure, bearing a minute flagellum. The coxa and basis, which almost make up the appendage, are membranous in texture but edged with strong setae. Second Maxilla (fig. 5)—To this mouth-part is attached the Scaphognathite, which represents a modified exopodite. The endopod is a slender spike, partly hidden by the large basis and coxa, which again constitute the greater part of the appendage. Both are unequally bi-lobed. The First Maxillipede (fig. 6) resembles the Maxillae rather than the two following mouth-parts in its general structure. The coxa and basis are still on the inner side, but neither is divided. The rest of the appendage is thin and membranous. The exopod is minute and bears no flagellum; the endopod is more massive and has a fine setose flagellum. There is no epipodite. The Second Maxillipede (fig. 7).—This, and the following appendage, are more or less typical in struc- ture, possessing a seven-jointed endopod, and a flagellated exopod. The exopod in Mxp. II is com- paratively much larger than in Mxp. III. The Third Maxillipede (fig. 8).—The _basi-ischio- podite bears a row of powerful teeth, increasing in size proximally. The degree of approximation of the two Maxillipedes affords an important point in classification. These two hmbs take an active part in feeding. The First Pereiopod or Chela (figs. 9 and 10).—In the present type the inequality in point of size of the Chelae is very striking, the right member being half as long again as its fellow. An exopod is absent, two joints, the ischium and basis, are fused and the propos is prolonged forwards to form with the dactylos the crushing edges. ~- EUPAGURUS. 507 The Second and Third Pereiopods (fig. 11) are alike. They are similar in essential structure to the Chela, but they are not chelate and the dactylos is long, curved and grooved. It is characteristic of the present species that this joint is contorted. The Fourth Pereiopod (fig. 12) is remarkable for the possession of a moveable dactylos, which forms a sort of sub-chelate termination to the limb. File-lke surfaces of corneous granules are present on the propos and dactylos. The last three segments are bent at right angles to the rest of the limb in this and the following appendage. The Fifth Pereiopod (fig. 15) is similar to the previous limb, except in its termination. The last joint is flattened and provided with a stiff brush of setae and a surface of corneous granules. The crab continually passes this leg inside the branchial cavity with a scrubbing motion. The Pleopods (figs. 14 and 15) are essentially the same in structure in both sexes, consisting of a protopodite bearing two rami. They are present in the male on the left side only of the third, fourth and fifth segments, and in the female on the second segment as well. All the male and the fifth female appendages are slender and the internal rami are minute. The other female pleopods (the ovigerous legs) are comparatively massive, and the branches are sub-equal and bear long setae. Uropods (fig. 16).—The uropods are the only paired abdominal appendages in the adult, and they are the same in both sexes. The external ramus of the left one is large and sickle-shaped, and the whole appendage is much larger than the right one. Autotomy takes place as readily as in Crabs, and in the same manner. (See ‘‘ Cancer,’’ p. 56.) 508 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. E\NDOPHRAGMAL SKELETON (PI. III). The Endophragmal Skeleton (figs. 17 and 18) is a complicated system of calcified plates in the thorax, which serves chiefly as an attachment for muscles, but also as a supporting framework for the viscera. It is formed by the inturning of the edges of the epimera and sternum of each segment. Typically two vertical plates arise from the fore and hind border of every thoracic sternum, and a similar plate projects from both edges of the pleuron at the side. Thus each plate is double, as it is duplicated throughout by the neighbouring segments. The outgrowths from the sterna are known as the endosternites, those from the pleura (or epimeral plates) as the endopleurites. The endophragmal skeleton in HL. bernhardus is not well developed and differs in many respects from that typical of the Macrura. ‘The endosternites are only fully developed in the fifth and sixth thoracic somites. The endopleurites conform more nearly to those of such a type as the Crayfish. A sternal canal is never present. Median plates caused by the folding of the sterna sagitto- longitudinally are developed on the fifth and sixth thoracic segments. Preparations of the endophragmal skeleton, from which the form of the individual somites may be studied, can be best made in the following way. Remove all of the carapace behind the cervical groove, separating it carefully from the underlying epimera. Cut off the abdomen at the peduncle, and each limb a few joints from the proximal end. Clean out the gut and stomach, after cutting a window in the cephalic shield, and such portions of the overlying muscle, etc., as can be scraped away without injuring the skeleton, and boil gently for a short time in a 10 per cent. solution of EUPAGURUS. 509. caustic potash or soda till the skeleton is clean. It may then be washed and transferred to alcohol. INTEGUMENT. The structure of the integument of the Hermit Crab does not differ in any respect but degree of calcification from that usually found in the Crabs and Lobsters. Only the chelae and the first two walking legs are comparable with the calcified portions of a Crab in hardness. The rest of the body is covered by a mem- branous investment with shght deposits of lime in certain places. The essential structure of the integument is as follows :—* 1. A chitinous exoskeleton, which may be shown to consist of four layers. (a) The cuticle, a thin, structureless layer. (6) The pigmented layer, fine lamellae parallel to the surface, between which the pigment hes. j (c) The calcified layer makes up the greater part of the hard exoskeleton. It is laminated, but more coarsely than the previous layer. (d) A thin, non-calcified layer. 2. The epidermis, which secretes or forms the chitinous layer, and is a single layer of columnar cells. 3. A connective tissue or dermis, in which are imbedded numerous rosette glands, whose ducts pass through the outer layers to the exterior, blood vessels, muscle fibres and scattered cells. During ecdysis the Hermit Crab follows the same method as that of the Macrura, withdrawing the body first, then the limbs, and lastly the abdomen from the cast-off exoskeleton. * Vitzou. Récherches sur la structure des téguments. Arch. de Zool. expér. et gén., T. X. (1882), p. 451. 510 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. ATT MENTARYG CAINS (Rainey As usual in the Arthropoda, three regions of the alimentary canal may be recognised. The fore-gut or stomodaeum—comprising the oesophagus and stomach— which is lined with cuticle; the mid-gut or mesenteron, which is soft-walled and has no chitinous lining; and the hind-gut or proctodaeum—a term synonymous with rectum in this animal—which is also lined with a chitinous cuticle. Fore-Gut. The Mouth is a laterally ovate aperture lying behind the foot jaws. It is directly covered by the pair of mandibles. In front of the opening—which is directed downwards—is a broad tripartite fleshy lobe, the labrum, and behind it is a smaller lip, the metastoma. The mouth leads directly into the Oesophagus, a thick-walled tube whose lumen is greatly constricted by three massive infoldings of the wall (fig. 20). Bright red pigment is always contained in the walls of the oesophagus. Three bunches of stellate glands—two antero-lateral and one posterior—are present at its proximal end, and similar glands are scattered in the lips of the mouth. Each gland is globular, and the somewhat conical cells composing it arewradially placed round a small central cavity. From the cavity a narrow duct, which is almost certainly a single cell, leads to the surface. Similar glands occur in large masses in. the walls of the rectum. There seems no reason why these glands should have any other function than that of lubricating the walls of the passages in which they are found, in order to facilitate the ingress and expulsion of the food matter. It is difficult to conceive of any EUPAGURUS. 511 appreciable chemical action being exerted by the oesophageal and labial glands on the lumps of food soaked in sea-water which pass up the tube. The oesophagus terminates on the underside of the Stomach (figs. 21 and 19). Its opening is guarded by a pair of calcified flaps densely fringed with setae. The cardiac portion of the stomach (cardiac fore-gut of Pearson) is considerably larger than the pyloric portion. Tt is a large membranous bag with a flat roof. The ossicles present in this and the hinder part of the stomach do not diverge sufficiently from the typical form in the Decapod Crustacea to justify a detailed description.* The cardiac ossicle is far more slender than is usual, and is bow-shaped; the pterocardiac ossicles are also slender, and articulate with the long curved zygocardiac bars. The pterocardiac ossicle is almost vertical. Viewed from the side, the oesophageal plates are seen to join the post- pectineal ossicle. Infero-lateral cardiac teeth are present. When the stomach is cut open in sagitto-longitudinal section the general structure of the apparatus can best be seen (fig. 19). The lateral teeth are unusually massive and are prolonged backwards into strongly pectinated ridges. The summit of the cardiopyloric valve also bears a ridge of great blunt setae like a comb. A pectineal tooth is present. There are five valves opening into the intestine, a superior median valve excavated ventrally (fairly large in this species), a pair of dorso-lateral valves and a pair of smaller infero-lateral valves, both richly setose. On the roof of the pyloric region is a pair of semi-circular ridges of setae, and between them a median ridge bears a bunch of setae. * See Huxley’s ‘ Crayfish,’ Pearson’s ‘ Cancer,’ Bronn’s ‘ Thierreich,’ Bd. VY. 2, and many practical text-books, HH 512 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Mip-Gut. The pyloric valves project into the achitinous Mesenteron or Mid-Cut. This is by far the largest part of the intestine and measures on the average about 6 cm. in a well-grown specimen. This great stretch of achitinous gut is the more striking when one examines the allied Hupagurids. The American EF. longicarpus has chitin stretching into the anterior part of the abdomen, and in our own #. prideauaw it is found in about the fourth abdominal segment. In the present species the mid-gut does not cease till it joins the rectum in the fifth abdominal segment. At the base of the pyloric ampullae, at the origin of the mid-gut, the two ducts of the digestive gland originate, and immediately behind their point of origin, but on the dorsal surface, arise a pair of pyloric caeca (mid-gut caeca of Pearson). The caeca come off close together and run forward on the top of the stomach for a short distance, closely applied to its walls, and then dip down, passing slightly forwards, till they each end in an irregular coil underneath the stomach. The Digestive Gland (or liver) may conveniently be described now. It consists essentially of a pair of axial tubules stretching from their origin under the stomach to a considerable distance into the abdomen, and giving off numerous diverticula (fig. 25). The axial ducts are round and broad in section, and during their passage through the thorax are applied closely to the latero-ventral side of the alimentary canal. The caecal diverticula which arise from this part are few and short, but when the central ducts have passed the peduncle, they separate from the gut and run the remainder of their course on the surface of the flexor muscles of the abdomen, It is from EUPAGURUS. 513 this part of the tubes that the bulky mass of branching diverticula which fill the cavity of the abdomen arises. The gonads are usually imbedded in the liver, and the alimentary canal either passes between the two lobes or through the right portion. The tubules are not packed very closely together, and they therefore retain in section their circular outline. The digestive gland is copiously supplied with blood by the superior abdominal artery and its branches. The course of the mid-gut is uninterrupted till it joins the rectum. It is a thin-walled smooth tube, without convolutions, through which the faecal matter can be seen. Just before the rectum a long unpaired caecum (caec., fig. 25) arises from its dorsal surface, which passes backwards between the liver tubules to the dorsal surface of the mass, and terminates in a small coil in the third abdominal segment—a little beyond the testis in the male. The caecum seems to be usually longer in the male than in the female. It has been very badly named 5) the “‘ hind-gut caecum,’ seeing that it arises from the achitinous part of the alimentary canal. There is apparently considerable variation in the place of origin of this unpaired caecum among the EKupagurids, though it is always derived from the mid-gut. It appears to form some index to the extent of the chitinous lining of the hind-gut, as it always comes off at the junction of the two parts. M.T. Thompson describes it in £. longicarpus as passing from the thorax back into the abdomen—the reverse direction of EL. bernhardus— and in #. prideauaii it arises in the fourth abdominal segment more than half-way up the abdomen, and is comparatively short, 514 ‘TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. HinbD-GuUT. The Rectum is from two to three centimetres long in a full-grown animal. It is thick-walled and muscular, and packed with the rosette-shaped glands mentioned above. The walls are considerably folded internally and have a thick chitinous ning. They are richly supplied with blood from the plexus of vessels which covers them. The Anus opens on the under surface of the telson and is surrounded by a sphincter muscle. In the living animal the rectum exhibits vigorous peristaltic movement. HistToLocy oF ALIMENTARY CANAL. The walls of the oesophagus are formed of very long narrow cells, with a thick base of fibrous connective tissue and an outer layer of muscle fibres. The lumen is lined with cuticle. Mention has already been made of the glands on the oesophageal walls. The cuticular lning is continued through the stomach, and the gastric mill is formed by calcifications in its substance. No other histological feature of the stomach calls for notice. The lining of the mid-gut is very characteristic. The cells are columnar, with large nuclei and consider- able contents of fatty matter. They have a striated border which appears in sections as a dark lining to the cells. The muscle layers at the base are frequently thrown into small plications. The epithelium of the hind-gut (fig. 22) is more regular than that of the achitinous gut. The nuclei are smaller and there are very scanty cell contents. A thick chitinous layer lines the gut. Behind the basement membrane is a wide layer of muscle bundles and glands which are arranged in very definite clumps. A layer of connective tissue with blood vessels and nerves surrounds the whole. The structure of the paired and abdominal BHUPAGURUS. 515 caeca gives no clue to their function. The cells are long and columnar, with small oval nuclei situated near their base. They have a striated border similar to but narrower than that of the mid-gut. The cavity is occluded by the much folded walls. The histology of the digestive gland differs somewhat from that described by Pearson in Cancer. The so-called ‘“fat cells’? are never scattered round the lumen, but bulge out from one point only at a time (fig. 23). It seems doubtful whether the division into “‘ fat’’ and ““ferment’’ cells can be justified, and whether the fat cells are not to be considered only as ferment cells engaged in excretion. These cells have a very distinctly striated border (fig. 24). Small deeply-staining cells are found between the larger ones. They probably give rise to the ferment cells. ‘The nuclei of the ‘‘ ferment’’ cells are to be found two-thirds of the way from the periphery, those of the “‘fat”’ cells at their extreme base, nearly all the cell being filled by the huge oil globule. BLOOD VASCULAR SYSTEM (Pls. III and IV). With the exception of the portion of the blood system which relates to the abdomen, the course of the blood, both arterial and venous, is that of a normal Decapod Crustacean. As in the crayfish or the crab, the pure blood from the gills passes to the pericardium and is driven by the heart through definite blood-channels to the various parts of the body, whence it returns for aeration by means of irregular sinuses to the gills. The Heart (fig. 28) les in a space, the pericardium, situated directly under the cardiac part of the carapace. It appears pentagonal in shape from above and rectangular from the side, though not so markedly 516 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. as in the case of the Macruran and Brachyuran heart owing to the extension of the postero-inferior angle. Viewed from behind, it has a distinct sinistral inclina- tion. The walls are thick and strongly muscular, and the cavity in older specimens is almost filled by the strands of muscle which pass across it. The blood enters the heart by three pairs of ostia provided with flaps opening inwards—one pair placed antero-dorsally, one latero-ventrally, and one _ postero-laterally. Seven vessels leave the heart, three passing forwards, three downwards, and one backwards. The heart-beats are regular in any one individual, but there is some variation in different specimens. The contractions are very explosive, and each contraction draws in the anterior end of the heart, stretching the two lateral and median arteries at the same time. The Pericardium, whose walls have the same general outline as the organ they enclose, is a fairly spacious thin-walled cavity extending from the cervical groove anteriorly to the beginning of the eighth thoracic somite posteriorly. It rests ventrally on the mid-gut, and dorsally is applied closely to the carapace. On either side of the posterior part of the pericardium there is a shallow cavity. These possibly represent the ‘‘ poches pericardiales ’’ of Brachyura. The blood is brought to the pericardium from the gills, and passes through the ostia to the heart. The various spaces in the body which are filled with blood do not represent a true coelom. They are morphologically a part of the vascular system which has become greatly distended and which has been termed by Lankester a haemocoel. A portion of the renal organ and the gonadial sacs may possibly represent the true coelom of other animals. EUPAGURUS. 517 The Arteries* (figs. 25, 26 and 27) leaving the heart are for the most part easy to trace, but the dissection is greatly facilitated if about a cubic centimetre of strong borax-carmine or methyl-green solution in water be introduced into the heart of the living animal by a hypodermic syringe an hour before it is killed. It is advisable to stupefy it with a weak solution of alcohol before operating, and the hole in the carapace can be conveniently stopped by a drop of hot wax. The stain will be found to have attached itself to some extent to the walls of the vessels, which are thus rendered visible throughout their courses. Three main trunks run forwards from the heart, the median cephalic (or ophthalmic) artery, and the paired lateral (or antennary) arteries (fig. 25, Pl. II). The Ophthalmic artery (opth. a., fig. 25) lies close to the surface; it may be seen through the carapace in injected specimens. Passing over the top of the stomach without giving off any important branches, it plunges down and divides into two vessels, one on either side of the brain, which supply the region of the front of the cephalon. The vessel is dilated into a flask-shaped bulb just in front of the heart. The Lateral arteries (ant. a.) arise on either side of the cephalic artery. While the median vessel rises on leaving the heart in order to surmount the stomach, the lateral arteries turn sharply outwards and pursuing a level course on either side supply both that organ and the surrounding tissues with branches. At their anterior extremities the arteries bifurcate and give numerous branches to the excretory organ and muscles which lie laterally in the cephalon. * For a comparative study of Decapod arterial systems see :— Bouvier, Ann. des sci. nat., zool., Ser. 7, Vol. XI, 1891, p. 197. 518 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The Hepatic arteries (hep. a.) ate given off from the sides of the heart. They are small and have no longer the important function which is assigned to them in the Macrura and Brachyura, and their part in supplying blood to the liver has been entirely taken over by the superior abdominal vessel. They terminate in small twigs on the gut. The Sternal artery (d. st. a. and st. a., figs. 26 and 28) is the largest and most prominent vessel connected with the blood supply. It arises in the median line at the extreme postero-ventral corner of the heart just under- neath the superior abdominal vessel, but while the latter follows in the thorax the course of the gut, the former immediately swings to the left and plunges downwards. After passing the intestine, the sternal artery turns forward sharply and runs horizontally from the seventh to the fifth thoracic somites, when it again turns down and pierces the central ganglionic mass between the nerves of the second and third pairs of pereiopods. Under the nerve chain the vessel divides into anterior and posterior branches, running towards the head and tail respectively (fig. 26). This portion of the vessel may be con- veniently called the inferior thoracic portion of the sternal artery. The anterior portion of this ventral artery gives branches to the chelae and the mouth parts, and two median branches ascend through the central gang- honic mass to supply the lower part of the stomach, the caeca, and part of the renal organ. After the branches to the first maxillipedes have been given off, the vessel divides, the two branches pass to the front of the oesophagus and anastomose on its walls, without, how- ever, forming a ring. From each side branches to the maxillae and mandibles arise. The posterior portion of the sternal artery is typical EUPAGURUS. of Seed sea 519 up to a point, in that it gives segmental branches to the remaining thoracic limbs, but in the adult, and in all probability in the larva, it never passes into the abdomen. This artery, in fact, divides in the sixth thoracic somite into right and left branches, which supply the last pair of pereiopods. Small ascending arteries are given off with all the branches to the pereiopods. The blood supply to the abdomen is entirely carried by the Superior Abdominal artery (s. abd.), and the vessel has undergone remarkable adaptation for its extra duties. A large trunk leaves the heart just above the sternal artery and passes above the gut—only giving off small branches—as far as the first abdominal segment. Here it divides into two large vessels. One (seg. a.) passes directly downwards to the right, turns backwards, and runs on the top of the flexor muscles. It divides in the third segment into sub-muscular and _ supra- muscular branches. The former follows the course of the nerve cord and terminates near the last ganglion; the latter gives numerous branches to the liver and gonads and finally divides into branches supplying the uropods, telson and rectum. ‘The other vessel (s. abd.), veering slightly to the left, continues on the surface of the liver and supplies the gonads and pleopods. In the female we have the interesting condition that each ovary is partly supplied by one vessel and partly by the other (fig. 27); in the male the morphological left testis 1s supplied by the ventral (right) branch, while the right testis 1s supplied by the dorsal (left) branch. M. T. Thompson finds in the young animal that the fourth zoea and the glaucothoé stages have a superior abdominal vessel with segmental branches, but that on the metamorphosis into the adult all these branches are 520 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. lost except part of the right one in the second segment. A new artery arises from this branch; it assumes the function of an inferior vessel and develops into the prominent ventral division of the superior abdominal artery present in the adult. This modification may have been due primarily to the animal’s assumption of a shell, and secondarily to the fact that nearly all the organs of the body—which in other Decapod Crustacea are supplied by separate thoracic arteries—are to be found in their bulk extended into the abdomen. One may conjecture, in the first place, that the pressure of the shell on the under-surface of the body would constrict a ventral vessel, especially at the peduncle, in such a way as to make its output of blood inefficient. In the second place, a vessel so remotely connected with the heart as the inferior abdominal, under these disadvantageous conditions, would be of little value in maintaining an efficient flow of blood through the large number of slender ramifying vessels required by the abdominal organs. Its place would tend to be filled by one more directly in communi- cation with the means of maintaining the circulation. Thus the superior abdominal artery, whose size and proximity to the heart qualify it for the task of providing a large quantity of blood, has come to monopolise the supply to the abdomen. Blood Sinuses and Veins.—The whole of the space inside the body walls might be theoretically considered as one large sinus containing impure blood. ‘The presence of the viscera divide this space up into several smaller sinuses, which are, however, all connected with each other. Above and in front of the stomach there is a distinct blood space—the Dorsal sinus. The main sinus with EUPAGURUS. 521 which the outer afferent vessels of the gill lamellae communicate runs ventrally the length of the thorax. This Sternal sinus is continuous with the cavity of the abdomen, which constitutes one great Abdominal sinus. The sternal sinus does not communicate directly with the gills, but is connected to the Infra-branchial sinuses on each side of the body, into which the gill vessels open— by five distinct clefts on either side—the Branchial sinuses. Into the infra-branchial sinuses also open the haemal cavities from the thoracic limbs. The Afferent Branchial veins, mentioned above, run from the infra-branchial sinus up the outer side of each gill. The blood is conducted down the inner side of the gill lamellae by the Hfferent Branchial veins to the five Branchio-cardiace veins, which open by three slits on each side into the pericardium. The Blood is a slightly opalescent but almost trans- parent fluid in which corpuscles float. The presence of haemocyanin gives it a faint bluish colour, which becomes intensified if the blood be left exposed to air. It coagulates under such conditions to a grey-white solid. The setting is effected by clear amoeboid cells which float in the lymph. Several kinds of cells (or amoebocytes) are to be found in the blood, but, according to Cuénot,* they constitute a series of stages in the breaking down of one kind only. The principal amoebocytes are semi-transparent amoeboid cells with large nuclei and finely granular cytoplasm. These cells increase in size and become full of eosinophilous granules. The almost solid body of granules is a prominent object in the blood at this stage, and amoebocytes in this condition are known as eosinophilous amoebocytes. The * Archies de Biologie, T. XIII, 1895, p. 245. 522 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. cell now degenerates and it is eaten by the clear amoebocytes, which exercise a phagocytic function until the granules make their appearance in them. The granules from the degenerating cells appear to be dissolved by the lymph. RESPIRATORY SYSTEM. The branchial cavity is a part of the external world bounded on the inner side by the epimera, and above and on the outer side by a lateral flap of the carapace, which is called the branchiostegite. The gills lie on the epimera. The inflected portion of the carapace is in other higher Crustacea strongly calcified, but in the Pagurids it is always membranous and thin. Conse- quently the gills are far more exposed than is usually the case. Certain calcified bars serve as some support for this: membranous flap, which is quite free, so that water can enter the branchial chamber from all sides except the roof. The action of the scaphognathite keeps the water in circulation over the gills. The branchiae are phyllo-branchiate—that is to say, composed of numerous flat lamellae placed transversely to a central axis. On the inner side of each axis runs the efferent branchial vessel, and on its outer side the afferent branchial vessel. The gills are smaller in front than behind, and they are all pyramidal with their apices pointing upwards. All the gills are arthrobranchs but one on the twelfth segment, which is a pleurobranch. No podo- branchs are present. The gill formula is the same on both sides, viz. : — Segments ©-‘Vvi. vil. (vill. 1x. “x. 1. |) aieatere Arthrobranchs 0 0 2 a 4 2 2 Pleurobranchs 0 0 DW) oa) 0 1 0 EUPAGURUS. 523 In minute structure the gills are seen to be covered by a thin sheath of chitin, beneath which is a single layer of cells, the epidermis. The lamellae consist merely of this epidermal layer with its chitinous invest- ment on both sides, separated by irregular spaces. A distinct vessel—the outer lamellar sinus—runs round the outer edge of each lamella. It is in communication with the cavity of the lamella (the lamellar sinus). The central axis is dumbbell-shaped and besides connective tissue there are two other kinds of cellular structures to be found in it. These are the branchial excretory cells and the branchial glands first described by Allen in Palaemonetes.* There are two kinds of these latter structures, and Allen’s observation as to their different positions in the animal he studied holds good tor E. bernhardus. The reticulate glands are distinguished by the fact that the cytoplasm of their cells appears as a deeply staining network, the nuclei are spherical and lie near the base, and the ducts and the nuclei belonging to them are very distinct. The protoplasm at the apex of each cell stains deeper with Erlich’s haematoxylin and siurefuchsin than the remainder. This type of gland is almost exclusively found round the efferent vessels. The other type of gland is characterised by the absence of the network, the smaller size of the individual cells and the larger relative size and more central position of the nuclei. It is also much more difficult to follow their ducts and distinguish the nucleus of the duct. This type of gland stains very lightly, and is neither so abundant nor so prominent as the reticulate type. It is generally found round the afferent vessels of the gill axis. In general structure these branchial glands are precisely similar to the stellate cells which are present in the * Quart. Journ. M.S., Vol, XXXTY., p. 75, 1893. —— 524 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. alimentary canal, in the dermal layer of the body wall, and on the under side of the abdomen. Cuénot states that the branchial glands give a mucoid secretion. * EXCRETORY SYSTEM (Pl. IV). The Renal excretory system of the Hermit Crabs has attained a complexity which no other Crustacean exhibits. In addition to the complex arborisations which ramify between the viscera in the cephalo-thorax, there is (in the present species) a large unpaired abdominal sac. All this belongs to the antennary gland (‘‘ green gland ’’) system. Excretion is also performed by separate cells in various parts of the body—notably those in the gill axis, and an excretory function has been attributed to the ‘‘ferment’’ cells of the digestive gland. It is not possible to make a dissection of the excretory system without previous treatment of the animal. A spirit specimen rarely shows more than the abdominal vesicle and the antennary gland, and, at best, indistinct traces of the remainder of the system; so it is essential to make a complete study on living material by means of injections. The substances which are suitable, par excellence, for such injections are methyl-green and séiurefuchsin in solution in sea-water. A fairly strong solution, the exact strength is immaterial, should be made of the pure substance. One or two c.c. may be introduced into the animal by means of a hypodermic syringe inserted in the arthrodial membrane under the thoracic limbs. The crab may now be returned to its shell and allowed to live for about forty-eight hours, after which it may be-killed * Archives de Biologie. T. XIII., p. 250, 1895, a EUPAGURUS. 525 and dissected. The antennary gland will not take the coloration, but the rest of the system will be distinctly outlined. It will be found that the colour has also appeared in the excretory cells of the gill axis. In an injected specimen it will be found that there is an antennary gland situated in the front of the cephalon behind the second antenna, which communi- cates with a diffuse and complex spongy mass in the thorax leading to a thin-walled bladder, the nephrosac, in the abdomen, all of which represents the “‘ bladder ’”’ of other Decapod Crustacea (fig. 29). Except for the abdominal nephrosac and the median ventral thoracic mass, the system is paired. 1. The Antennary Gland (9.9.) consists of two parts, which communicate with each other, an inner—the end sac (‘‘ saccule’’) which is surrounded by an outer—the labyrinth. The whole is somewhat kidney-shaped and has a lobulated appearance. The connection with the bladder arises from the upper side, above the notch, and the artery supplying the gland passes in a little lower. The end sac is slightly exposed on the dorsal surface of the antennary gland. Its cavity is broken by blood lacunae and by the extensive ramifications of its walls. Sections show that few prolongations arise from its dorsal side. The walls are irregular, and are often more than one cell thick. The cells are large and squamous, the nucleus is spherical and at the base of the cells, and the protoplasmic contents are light staining and finely granular. The borders of these cells are irregular and protuberant, and oil globules are often present (fig. 32). The labyrinth is an intermediate duct between the bladder and the end sac, whose cavity has become excessively convoluted by ingrowths from its walls. The epithelium lining this portion is very distinct from. that 526 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. belonging to the end sac. The cells are still squamous but much smaller, so the nuclei appear to be side by side in straight rows. The border of the cells is regular and without the lobed appearance which characterises that of the end sac. The cytoplasm is scanty and striated; it stains more strongly than that of the end sac. The labyrinth communicates by a narrow passage with the rest of the system. 2. The Anterior Vesicular Mass (Marchal)* com- prises that portion of the system apart from - the antennary gland, which lies in the thorax and cephalon. The opening of the whole to the exterior is connected with this part of the system. The passage commences close to the connection with the antennary gland. It is at first wide, but rapidly becomes narrow, and passes downwards underneath the second antenna, where the external orifice is situated (fig. 30). The arrangement of the Anterior Vesicular Mass is as follows:—The canal from each gland expands into a mass of ramifying tubules in front of the stomach (epigastric lobe).. Although these two masses are close together in the mid-line, they do not communicate with one another. From each epigastric mass (eg. J.) a narrow branching canal runs backwards, closely applied to the muscles, to join another mass of arborescent tubules situated on either side of the stomach opposite to the depression between the cardiac and pyloric ossicle of the gastric mill. Branches from these two lateral para- gastric masses (pg. 1.) pass across the stomach in the above-mentioned depression to meet, but not to coalesce, in the mid-line (sg. l.). Underneath the stomach is a median unpaired * Archiv. de zool. expérim. et gén., Ser. 2, Vol. X, 1892, p. 57. EUPAGURUS. SBA portion (m.v.l.), which.is connected by anterior and posterior branches to the two lateral masses. The remainder of the system comes under Marchal’s head :— 3. The Posterior Vesicular Mass, which includes the unpaired bladder in the abdomen and its connecting tubes with the two paragastric masses. The connecting tubes are a pair of branching ducts which run on the top of the alimentary canal side by side | till they reach the abdomen, when they unite in a large thin-walled vesicle (bl.) of considerable extent—rather the shape of a centrifuge tube—which is about three- quarters the length of the abdomen. It is called the nephrosac. The walls are composed of squamous epithelium with striated cytoplasm at its base and a large spherical nucleus in the centre of each cell (fig. 31). There is a distinct dark border to the’ cells of the labyrinth and vesicular masses, which is probably due to a striated margin or ‘‘ Harchensaum.”’ The bladder is tucked between the lobes of the digestive gland—or between the ovaries in the female. As the excretory system hes wholly in the venous blood sinuses of the body, excretion is probably carried on by direct diffusion through the walls. In seetions of the vesicular masses cells may be seen with their inner portions projecting as a clear vesicle into the cavity of the organ. These vacuoles may be shed as small bladders into the lumen, or the entire cells in the end sac are nipped off and pass to the exterior. The excretory fluid is full of such bladders and single cells. 528 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. NERVOUS SYSTEM* (Pls. IV and V). The nervous system of Hupagurus shows little trace of the asymmetry which involves so many other parts of the animal. The variations in position and size which occur in the nerves supplying the opposite sides of the cephalo-thorax are exhibited in any higher Crustacean, but the twist of the abdomen necessarily causes a certain amount of alteration of the abdominal portion of the nerve-cord. There would be no reason to expect any further modification in a system which is not of large bulk, and whose functions are in no way altered by the ehange in symmetry. The degree of concentration of the thoracic ganglia is intermediate between that of the Macrura on the one hand, and of the Brachyura on the other. They are not disposed in a diffuse chain as are those of the Crayfish, nor are they indistinguishably fused as in the common Crab, but the concentration is carried to a stage in which the individuality of the ganglia has been lost, while a more general division into regions representing the fusion of two or more ganglia is preserved. Thus the central thoracic ganglion-mass can be differentiated into three (er perhaps four) main portions, which respectively supply the mouth parts and chelae, the first pair of walking legs, the second and third pairs of legs, and the fourth pair. The nervous system may be conveniently described in three portions: the brain and its connectives, the thoracic ganglon-mass, and the abdominal chain. The Brain or supra-oesophageal ganglion (fig. 37) is situated in the mid-line, under the anterior margin of the cephalo-thoracic shield, behind the eye-stalks and * For a comparative study of Decapod nervous systems see :— Bouvier, Ann. des sci. nat., zool., Series 7, Vol. VII, 1889, p. 73, aE EE —— EUPAGURUS. 529 above the epistoma. It is transversely ovate from above, and a bi-lobed appearance is given to it by a shallow median depression. The nerves supplying the principal sense organs and the circum-oesophageal connectives with their offshoots arise from the brain, and branches are also given to the surrounding tissues. Optic nerves (n. op.).—A pair of nerves arise in the front of the brain and pass, diverging slightly, into the eye-stalks. Immediately after passing the base of the peduncle the nerve swells to furm a small ganglion, from which fibres supplying the eye muscles arise, and ends in another enlargement under the retina. Oculo-motor nerve (n. m. o.).—The muscles of each eye and its adjacent parts are innervated by a much smaller nerve, which pursues a track parallel to and outside of each optic nerve. The Antennulary nerves (n. a.,) are really four in number, but owing to the fact that the nerve supplying the first antenna and that supplying the otocyst have coalesced on either side, a single pair only is visible. This pair arises from the under surface of the posterior half of the brain. Each nerve is broad and has but a short course, plunging downwards and forwards on leaving the brain into the peduncle of the limb, where it divides into auditory and tactile and muscular branches. The Tegumentary nerves (n. teg.) arise on either side of the brain, slightly above and behind those supplying the first Antenna. Each nerve is broad and prominent, and passes outwards and shghtly forwards, surrounded by the mass of excretory gland which envelops the hinder part of the brain. It branches frequently and supphes the integument and other tissues in the front of the head. 5380 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. A pair of Antennary nerves (n. a.,) originate behind the Tegumentary nerves. These long and slender nerves pass outwards at right angles to the long axis of the body till they turn sharply forwards towards the second Antennae. The Brain is connected to the remainder of the nervous system by a pair of long connectives—the Oesophageal Commissures (cm.)—which arise close together at the back of the brain and curve gently out- wards round the oesophagus, to approximate again as they approach the thoracic ganglion-mass. On either side of the oesophagus each commissure dilates to form a par-oesophageal ganglion, from which arise four nerves. Both of the two outside branches are small; the anterior one, which is the smaller, innervates the surrounding tissues, and the larger and posterior one supplies the muscles of the mandible. Stomatogastric system (figs. 39 and 37).—The two inside branches arise together and pass, diverging towards the mid-line in front of the oesophagus where each joins its fellow from the opposite side, to merge into a median unpaired nerve passing vertically up the front of the stomach. Three-quarters of the way up the anterior wall this median stomatogastric nerve enlarges to form the stomatogastric ganglion, from which several small - branches to the muscles and walls of the stomach arise. The stomatogastric nerve then mounts the stomach and, directly on attaining its dorsal surface, forms another ganglion, which gives origin to several small nerves, and finally terminates in a bifurcation above the pyloric portion of the stomach. After leaving the par-oesophageal ganglia, the commissures pass backwards and become attached close together to the front of the ventral thoracic ganglion- EUPAGURUS. 531 mass. A slender transverse nerve—the post-oesophageal connective—joins the two commissures a short distance behind the oesophagus. The Thoracic Ganglion-mass (fig. 37), in which the oesophageal connectives terminate, lies over the sternal artery on the endosternal plates of the third to sixth thoracic somites. Inward projecting processes from the dorsal parts of the endosternites partly bridge over the valley in which itis found. It is composed of three large masses of fused ganglia, which are divided from each other by constrictions; the first and second of these are somewhat rectangular in shape, and the third is pyriform. A shallow semi-circular groove on the third division marks the separation of the ganglia which are the centres for the fourth and fifth pereiopods from those which belong to the first abdominal segment. The Central Thoracic Nerve-mass is pierced in the mid-line in three places for the passage of arteries. The most posterior of the three is a huge foramen, through which the descending portion of the sternal artery passes; the others are small perforations. which are almost indistinguishable in any but specimens injected for the blood system (asc. a.). Seven paired ganglia take part in the formation of the anterior mass, and seven nerves radiate outwards from it on either side. Those supplying the mouth parts usually come off separately, but there is consider- able variation in their arrangement. The branches from the first and second Maxillipedes often coalesce before joining the main nerve trunk, and, less frequently, fusion takes place between the nerves supplying the pairs of Maxillae. The thoracic ganglion mass is symmetrical throughout, so only one side need be described. The First nerve originates close to the oesophageal 532 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. commissure and is sometimes bound up with it for a short distance. It is quite slender—the seven nerves increase 1m size in proportion as we go backwards—and passes directly forward to the mandible. The Second and Third nerves pass directly to the maxillae, and the Fourth, Fifth and Sixth to the maxillipedes. The Seventh nerve, which is very broad, comes off at the widest part of the anterior lobe and passes slightly forwards to the chela. With this and the succeeding thoracic nerves two small branches arise which pass upwards and innervate the neighbouring tissues. The central lobe of the thoracic ganglion-mass 1s the product of the fusion of but a single pair of ganglia, whose nerves supply the second pereiopod. The remainder of the thoracic limbs are innervated by branches arising from the posterior lobe. They all pass backwards and then turn sharply outwards, as they reach the segment for which they are bound. The thoracic nerve mass shades into the abdominal com- missures, which—at first bound together—separate themselves as they enter the abdomen. The Abdominal Nerve Chain (fig. 38) is of the familiar ladder type. There are five paired ganglia. Each pair, however, is almost indistinguishably fused, and they are connected by paired commissures. The five paired ganglia are situated in segments two to six, that belonging to the first segment being fused with the thoracic ganglion mass. From each ganglion branches are given off in a somewhat irregular fashion to the muscles, integument, and to the pleopods, and at least one pair of nerves arises from the inter-ganglionic commissures. EUPAGURUS. 533 The nerve chain lies under the bulky flexor muscles and over a thin layer of integumentary muscles. On entering the abdomen the chain slews to the left, passing through the ‘‘columellar’’ muscle to the first ganglion (second abdominal ganglion) in the second segment. This is placed well on the left side of the body, and in a lesser degree so is the third segmental ganglion, which is close to the second, and the fourth. From the fourth to the fifth ganglion there is a longer stretch of connective, which once more brings the chain into the mid-line of the body; and there is another long pair of connectives passing from the fifth through the flexor muscles, till they join the sixth ganglion on the dorsal surface of the muscles under the posterior end of the rectum. From this ganglion branches are given to the uropods, the telson and the alimentary canal. There is a ring round the rectum, but it is uncertain whether there is any actual junction between the two nerves. The histology of the nervous system in the higher Crustacea is a rather difficult specialised study, which the ordinary student of Zoology will probably not attempt. More advanced workers should refer to the detailed account of the histology of the shore crab (Carcinus), given by Bethe in the following papers :— Arch. f. mikroscop. anat., v. 44, 1895, p. 579. NOG are Boe --. v. 00, 1897, p. 460. SENSE ORGANS (Pl. IV). The sense organs consist of a pair of compound stalked eyes, a pair of otocysts, and a number of sensory setae scattered over the body. SS 584 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Tue EKyn* (Figs. 33 and 34). The optic peduncle, at the end of which the eye is situated, is a two-jointed structure. The basal joint is short and thick, and it bears on its inner side a spearhead shaped ‘‘squame’’; the distal joint is long and cylin- drical, but narrower in the middle than at either end. The two parts are loosely joined by membrane and the outer moves freely on the inner. The cornea takes up all the anterior end of the second joint. It is circular in outline except for a small invasion of the calcified portion of the stalk on its dorsal and inner side. The eye is compound—that is to say, it is composed of many separate, similar parts or elements, each of which is called an ommatidium. The cornea is facetted, and each such area is hexagonal in shape. A fine line bisects each facet diagonally from angle to angle. These corneal facets are the outer ends of the ommatidia, which, owing to the convexity of the cornea, converge inwards radially. An ommatidium (fig. 33) is a definite arrangement of five kinds of cells in a cluster about a central axis. The cells comprising each ommatidium may be enumer- ated as follows:—(1) Corneal hypodermis (secretes the facet of the cornea immediately above it); (2) Cone cells; (3) Distal retinular cells (Ivis cells, Hesse); these three kinds constitute the dioptric portion of the eye; (4) Proximal retinular cells, which, together with the rhabdome, constitute the receptive portion of the eye; (5) Accessory cells (Tapetum cells, Hesse). (1) According to G. H. Parker there are two.corneal cells (c. hy.), and the fine line bisecting the facet of the cornea is the line of their division, but Schneider states * See also Note, on p. 567. EUPAGURUS. 535 that they are four in number. These cells are squamous and tile-like, but their boundaries are very indistinct. (2) The crystalline cone (vit.) is composed of four cells, and it extends from the corneal cells to the distal end of the rhabdome. Lach cone cell has a transparent body tapering to its proximal end, which overlaps the distal end of the rhabdome. The nuclei are at the distal end of the cells. (3) There are two distal retinular cells (d. re.) at opposite sides of the cone cells. They are deeply pigmented and are contractile, their size varying with the strength of light. (4) There are seven provimal retinular cells (p. re.), and Parker has found that there is typically an eighth which has become rudimentary. These cells surround the rhabdome. Their distal ends—by the side of the cones—are bulbous and contain the large nucleus, the proximal end tapers off above the basement membrane. The optic nerve fibrillae pass through the cells to end in all probability in the “‘stiftchen’’ of the rhabdome (fig. 33). They run up the outside of each retinular cell, pass round the nucleus and return down the inner side. It is this bundle of fibrillae round the nucleus which gives the bulbous appearance to the distal end of the cells. The retinular cells are deeply pigmented from end to end and thus form a complete dark sheath round the thabdome. Parker found that in the darkness the pigment migrated completely into the retinal fibres beneath the basement membrane, so that the rhabdome became accessible to light from all sides. Similar changes are induced by darkness in the distal retinular cells (Iris cells), the pigment all retreating into the body of the cell at its distal end. In daylight the pigment extends down the proximal processes of the cells. 536 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The rhabdome is a complicated structure, narrow and spindle-shaped (figs. 33 and 34 and Text-fig. 2), which used to be described as consisting of four parts, a fact which induced Grenacher to conclude that it was secreted by alternate retinular cells. It is now known that the quadripartite appearance and form is illusory, and is due to the peculiar manner in which the retinular cells form the structure. TExt-FIG. 2). Every two retinular cells (reckoning the seventh one as double) take part in the secretion of one quarter of the rhabdome. These quarters—which may be separated and are known as rhabdomeres—are each made up of transverse plates alternately supplied by the two cells (fig. 34). Any one retinular cell would have a toothed or cogged appearance if it were separated with its own portion of the rhabdome. The whole rhabdome therefore is built up of a series of transverse half-plates and Text-fig. 2 would represent a diagrammatic eccentric longitudinal section in which the ‘ stiftchen ’’ of each lamella are shown alternately with cut ends and from the side. The arrangement reminds one of the dovetailing of the edges of a box. In transverse section the rhabdome is almost square, and it is surrounded by a distinct investing sheath (“‘ Schluss- leisten,’’ Schneider). Hach of the half plates bears a EUPAGURUS. 537 border of ‘‘stiftchen,’’ and it is probable, though not certain, that the nerve fibrillae, passing through the retinular cells from the optic nerve, communicate with them. At the distal end of the rhabdome is a pear-shaped cavity, first described by Parker, filled with a coagulable fluid (fig. 33). (5) Irregular cells, hghtly pigmented, are found at the base of the rhabdome and on both sides of the basement membrane. Parker, who calls them accessory cells, thinks they are probably mesodermic. The nerves from the ommatidia pass into a mass of nervous tissue, underneath the retina, which contains four successive ganglia, and thence to the brain.* Various observers have given conflicting accounts of the type of image which is thrown on the retina of the Arthropod eye. From the most recent researches, however, there is little doubt that the image in the compound eye is a single upright one for the whole retina, whose perceptive elements, the rhabdomes, receive each a single impression. Parker has succeeded in obtaining all the results of previous observers by preparing the eye in different ways, and by pointing out where they failed has practically proved that each ommatidium does not receive a small complete image. Tue Ovrocyst (figs. 35 and 36). The otocyst or auditory sac is situated in the proximal joint of the first antenna. There is a small bulbous prominence on the outside of the joint in which it les, and it opens to the exterior by a narrow * The classic paper on the Arthropod eye is by Parker in the Bull. Mus. Comp. Anat., Harvard, Vol. XXI, p. 45. In details of finer histological work it has been superseded by Parker's further paper in Mitt. a.d. Zool. Stat. z. Neapel., T. XII., 1897, and by Hesse’s in Zeit. Wiss. Zool. Wien., Bd. LXX., p. 347. 538 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. longitudinal slit on the dorsal surface, two-thirds up the joint from the posterior end. The opening is guarded by two fringes of setae, an upper fringe of simple styliform hairs springing from the inner edge and passing diagonally forwards across the opening, and a lower fringe of large, somewhat fusiform, densely plumose hairs springing from the outer edge of the opening, and directed at right angles to the upper fringe. The otocyst itself is attached by its anterior end, underneath the opening to the exterior, and extends backwards for about one-half the length of the entire joint. It is a simple gourd-shaped sac with chitinous unfolded walls, which are often—with the exception of a small portion of the dorsal surface—lightly caleified. The stalk of the gourd is at the extreme posterior end of the sac, and is turned towards the mid-line, so the sac appears to he on its side. This small caecum has been unfortunately named the ‘ ‘cochlea,’’ in reference to an imaginary resemblance to that structure of the vertebrate ear. The interior of the “‘ cochlea’’ is always minutely spinose. A shght carina runs from the ‘“‘cochlea”’ round the outer side of the sac, and a shallow groove from the same point along the ventral side contains the otic branch,of the antennulary nerve. The interior of the sac is not complicated by any irregularities, but follows precisely the lines of the outside. The sensory region is to be found on the floor, and the special ‘‘ auditory ”’ setae are roughly arranged in two or three rows diverging from the ‘‘ cochlea’’; the greater number of setae spring from the slight ridge of the otic nerve on the outer side of the sac, while the remainder are placed in an irregular row on the inner side supplied by a smaller nerve branch. They are of one kind only—small, straight and plumose, miniatures ~~ —— ee eee EUPAGURUS. 539 in all but the base, of the fringing setae already described (fig. 36). Each hair isa hollow tube attached by a membranous base to a knob-shaped podium, in which the single nerve fibre supplying the structure terminates. Thus the hair is only capable of extensive lateral move- ment at the membranous base in direct contact with the nerve element. Many sand particles, of all sizes small enough to enter by the orifice, are found free in the lumen of the sac or adhering to the setae. The nerve supplying the sensory region impinges on the sac at its posterior end on the ventral surface, and at once divides into a more ventral broad portion which curves nearly round the outer side of the sac, and a smaller branch passing to the inner side.* It is unnecessary to deal with the functions of the sac in detail. Prentisst gives an exhaustive account of the work of earlier observers and supplements it with his own experiments.