=W Le aera area cs as Po Reale lle ote he Ne caine ena aS Ge Fi ent i Hor 7 eaten tint - - ged ie abe ea Rell ae i ara er et ee Helis a Hime ctheeten Lay ee Pwerwer er 5 ah et Se as RE ERGOT 1 ee oth geome rnin th — . - : } £¥ wd # Pee ee ae ahs" it 4 mee Heke Te. es eee i ee, CRB. Sau nbn Tes Se Cre p-hae oo eet ROR HM ? e - a Sg 0 Rint ORF WR éwet *-@ : 2 ent Bi Ng Rh Sieche ne Hel BERND & a re “= Palette DA) Fe bee Ral thal t e e Fo Bg Sa Sic nbs = Aon nent 2. % Stipe Pe oeree Ct 1 eee ae - see OS ea e emt We; ete ts 44 Fe Meth Ab eh sitndts Coens etd t Oe 08 hae Hee HE oy 2 ante. Ce a DB Ne TO De Be ae So oRake earn fsa + ate erthe tice ten ~ - > - i > Men Ban © 2 Pfc ah tel Bs Ee ee ee eal ee Parana 7 i Baton In ed ~ “rie ee é Bad De RB AEP Rae BS Sr? "5 A Ee ge eh al Se oe es » — > = hati 7 . ~~ . y +e . ra » ;~* A 46 t4 0 aes we * a eer ee ee eee ee — ia ai) oi FC 7% iy ad PE r ert amin Wy =h 4s q iw STF O6 FR PROCKEDINGS TRANSACTIONS OL DEE LIVERPOOL BIOLOGICAL SUCIETY. | VOL. XVI SESSION 1901-1902. LIVERPOOL: C. Tinztine & Co., PrintErRs, 53, VICTORIA STREET, 179'0'2', 574.0642 5 Maw, dy, CONTENTS. I.—PROCEEDINGS. Office-bearers and Council, 1901-1902 . Report of the Council . Summary of Proceedings at the Ricci Dinner of the Society . Laws of the Society List of Members . Librarian’s Report (with list of Paes to ee . Treasurer’s Balance Sheet . I]. —TRANSACTIONS. Presidential Address—‘‘ The Fauna indicated in the Lower Keuper Sandstone of the i ene of luiverpool.” By H. C. Brasuey. Fifteenth Annual Report of the Liverpool Marine Biology Committee and their Biological Station at Port Erin (containing Guide to the Aquarium). By Prof. W. A. H=rpmay, D.Sc., F.R.S. Report on the Investigations carried on during 1901, in connection with the Lancashire Sea Fisheries Laboratory, at University College, Liverpool, and the Sea Fisheries Hatchery at Piel, near Barrow; containing ‘‘ Pleuronectes’? (L.M.B.C. Memoir No. VIII). By Prof. W. A. Herpmay, F.RB.S., ANDREW Scott, JAMES JOHNSTONE, B.Sc., and F. J. CoLe . PAGE. Wilile Vill. 1X. Ou, XIV. OD: Ogi eX 27 109 ry Iv. LIVERPOOL BIOLOGICAL SOCIETY. On some Red Sea and Indian Ocean _— i ANDREW ScoTrT “Chondrus”’ (L.M.B.C, Memoir No. D0. By Orto VY. DarBISHIRE : Snake Venoms, by W. Hanna, M.A., M.B.. The Place of Geology in Economics and Education. By Prof. C. Lapworsu, F.R.S§. PAGE. 397 429 ATI 485 OFFICE-BEARERS AND COUNCIL. Gx- residents : 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. 189293 ALFRED O. WALKER, J.P., F.L.S. 1893—94 JOHN NEWTON, M.R.C.S. 189495 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.S. 189798 ISAAC C. THOMPSON, F.L.S., F.R.M.S. 1898—99 Pror. C. 8S. SHERRINGTON, M.D., F.R.S. 1899—1900 J. WIGLESWORTH, M.D., F.R.C.P. 1900—1901 Pror. PATERSON, M.D., M.R.C.S. SESSION XVI, 1901-1902. Aresvent ; HHNRY C. BEASLEY. ADJice- Presidents : Pror. W. A. HERDMAN, D.Sc., F.R.S. Pror. PATERSON, M.D., M.R.C.S. Hon. Creasurer : T. C. RYLEY. Hon, Hibrarian : JAMES JOHNSTONE, B.Sc. Mon. Secretary? JOSEPH A. CLUBB, M.Sc. (Vicr.). Council : J. W. ELLIS, M.D. JOSEPH LOMAS, F.G.S. W. J. HALLS. JOHN NEWTON, M.R.C.S. Rev. L. pe BEAUMONT KLEIN, J. SMITE Hh. Ss D.Sc. I. C. THOMPSON, F.L.S. W.S. LAVEROCK, M.A., B.Sc. J. M. TOLL. Bev. T. S. LEA, M.A. J. WIGLESWORTH, M.D., ALFRED LEICESTER. | chal ie OF eae REPORT of the COUNCIL. Durine the Scssion 1901-1902 there have been seven ordinary meetings and one field meeting of the Society. The latter was held at Caergwrle, Flintshire, and was a joint meeting with the Liverpool Geological Society. The communications made to the Society have been representative of almost all branches of Biology and the exhibition of microscopic preparations and other objects of interest has been well maintained at the meetings. On the occasion of the lecture, entitled: —“ The place of Geology in Education and Economics,” by Professor Lapworth, F.R.S., of Birmmgham University, your Council issued special invitations for the meeting, and a large audience assembled. The Library continues to make satisfactory progress, and additional important exchanges have been arranged during the year. The Treasurer's statement and balance sheet are appended. No alterations have been made in the Laws of the Society during the past session. The members at present on the roll are as follows : — Honorary Members: .2).0..c..7-.- ae 9 Ordinary’ Members....G) pe: 5. ee 49 Student. Members. ..........:4:...s-s0+008 25 SUMMARY of PROCEEDINGS at the MEETINGS. The first meeting of the sixteenth session was held at University College on Friday, October 11th, 1901. ‘The President-elect (Henry C. Beasley) took the chair in the Zoology Theatre. _ 1. The Report of the Council on the Session 1900-1901 fee eroceedings,” Vol. XV... p. vill.) was submitted and adopted. 2. The Treasurer's Balance Sheet for the Session 1900- fiicee~ Proceedings,’ Vol. XV., :p. xxx1.) was submitted and approved. 3. The Librarian’s Report (see “‘ Proceedings,” Vol. XV., p- Xx.) was submitted and approved. 4. The following Office-bearers and Council for the ensuing Session were elected :—Vice-Presidents, Professor Herdman, D.Sc., F.R.S., and Professor Paterson, M.D., M.R.C.S.; Hon. Treasurer, T. C. Ryley; Hon. Librarian, James Johnstone, B.Sc. ; Hon. Secretary, Joseph A. Clubb, M.Sc.; Council, Dr. J. W. Ellis, W. J. Halls, Rev. L. de B. Klein, D.Se., Rev. T. S. Lea, M.A., W. S. Laverock, M.A.., B.Se., Alired Leicester, Joseph Lomas, F.GS., John Newton, M.R.C.S., Joseph Smith, F.L.S., I. C. Thompson, F.L.8., J. M. Toll, and J. age ed EH R.C.P eeeeix, Henry C. Be clic delivered the Presidential Address, entitled “The Fauna indicated in the Lower Keuper Sandstone of our District” (see “‘Transactions,’ p. 1). A vote of thanks was proposed by Dr. Newton, seconded by Mr. Lomas, and carried with acclamation. Ke LIVERPOOL BIOLOGICAL SOCIETY. The second meeting of the sixteenth session was held at University College, on Friday, November 8th, 1901. The President in the chair. 1. Professor Herdman submitted the Annual Report on the work of the Liverpool Marine Biology Committee and the Port Erin Biological Station (see “ Transactions,’ p. 27). The third meeting of the sixteenth session was held at University College, on Friday, December 13th, 1901. The President in the chair. 1. Prof. Lapworth, F.R.S., of Birmingham University, lectured on “The place of Geology in Hducation and Hconomics”’ (see “ Transactions,” p. 485). 2. Prof. Kendall, of Leeds, kindly gave an impromptu lecture on “Rivers and River Action,’ while waiting for Prot. Lapworth, who arrived late through train delays. —— The fourth meeting of the sixteenth session was held at University College, on Friday, January 10th, 1902. The President in the chair. 1. Mr. I. C. Thompson communicated a letter from Prof. Herdman, giving interesting details of the work of collecting Plankton while on his journey to Ceylon. 2. Mr. J. Johnstone, B.Sc., communicated the Annual Report of the investigations carried on during 1901, in connection with the Lancashire Sea Fisheries Committee, by Prof. Herdman, A. Scott, and himself (see “ Transactions,” p. 109). SUMMARY OF PROCEEDINGS AT MEETINGS. lle The fifth meeting of the sixteenth session was held at University College, on Friday, February 14th, 1902. The President in the chair. 1. Dr. W. H. Broad exhibited and described an Australian skeleton, and skulls of both the Austrahan and Maori types. 2. Mr. F. J. Cole gave an interesting lecture on the “ Evolution of the head of the flat fish,’ in which he described the life-history of the Plaice, and traced the probable track of the evolution of the asymmetry of the head. ‘The lecture was illus- trated by lantern slides. The sixth meeting of the sixteenth session was held at University College, on Friday, March 14th, 1902. The President in the chair. 1. Mr. I. C. Thompson communicated a second letter from Prof. Herdman, giving some further details of his doings in Ceylon. 2. Prof. Paterson gave an interesting paper on the “Morphology of the Sternum.”’ T'he lecture was illustrated by a number of specimens illustrating variations from the normal condition in the human breast bone. An animated discussion followed the reading of the paper. The seventh meeting of the sixteenth session was held at University College, on Friday, April 11th, 1902. The President in the chair. X11. LIVERPOOL BIOLOGICAL SOCIETY. 1. Dr. W. Hanna communicated a paper on “ Snake Venoms” (see “ Transactions,” p. 471). A discussion followed. 2. Mr. Andrew Scott’s paper on a collection of Copepoda, made by Mr. H. C. Robinson in the Indian Ocean, was communicated by the Hon. Secretary (see ‘Transactions,’ p. 397). The eighth meeting of the sixteenth session was a Field Meeting, held jointly with the Liverpool Geological Society, at Caergwrle, Flintshire, on Saturday, June 7th, 1902. 1. After tea a short business meeting was held. On the motion of Prof. Herdman from the chair, seconded by Mr. J. Lomas, Dr. Caton was unanimously elected President for the ensuing session. DINNER TO PROF. HERDMAN, F.R.S., AND MRS. HERDMAN. Under the auspices of the Society, a large and repre- sentative company assembled in the Adelphi Hotel, Liverpool, on Tuesday evening, May 6th, at a dinner held to do honour to Prof. and Mrs. Herdman. Professor Herdman had just returned from an important expedition sent out by the Colonial Office to investigate the Ceylon Pearl Oyster Fisheries, with the object of placing the industry on a more scientific basis, and it was thought to be a fitting opportunity to testify to Prof. Herdman a little of the esteem in which he is held by the Biologists of Liverpool. The Lord Mayor and SUMMARY OF PROCEEDINGS AT MEETINGS. X1ll. Lady Mayoress graced the proceedings by their presence, and the company included, in addition to the guests, Mr. H. C. Beasley (President), Prof. Paterson (Vice-President), Sir William Mitchell Banks, Dr. Carter, Mr. I. C. Thompson, Mr. J. Lomas, Mr. J. A. Clubb (Hon. Secretary), Mr. Hoyle (Owens College, Manchester), Dr. Wiglesworth, Mr. Alfred Holt, Dr. Klein, Prof. Mackay, Mr. Kermode (Ramsey) and others. After the loyal toasts, Sir William M. Banks, in a graceful and witty speech, proposed the health of Prof. and Mrs. Herdman, to which the former responded. Although prevented from speaking on the principal object of the expedition, viz., his work on the pearl oyster, because the Government report had not yet been presented, the learned Professor gave a most interest- ing account of other sections of his work and of visits to the notable “buried cities” of Ceylon, hidden in the jungle, and to Adam’s Peak, the sacred shrine of both Moham- medans and Buddhists. Other toasts were the “Lord Mayor and Lady Mayoress,” proposed by Prof. Paterson ; the “ Biological Society,’ coupling the name of the President, Mr. Beasley, proposed by the Lord Mayor; and the “ Visitors,’ proposed from the Chair, and responded to by Mr. Hoyle, of Manchester. . LAWS of the LIVERPOOL BIOLOGICAL SOCIETY. I.—The name of the Society shall be the “ LivErPoor BiotocicaL Society,’ and its object the advancement of Biological Science. Il.—The Ordinary Meetings of the Society shall be held at University College, at Seven o’clock, during the six Winter months, on the second Friday evening in every month, or at such other place or time as the Council may appoint. III.—The business of the Society shall be conducted by a President, two Vice-Presidents, a Treasurer, a Secretary, a Librarian, and twelve other Members, who shall form a Council; four to constitute a quorum. ITV.—The President, Vice-Presidents, Treasurer, Secre- tary, Librarian and Council shall be elected annually, by ballot, in the manner hereinafter mentioned. V.—The President shall be elected by the Council (subject to the approval of the Society) at the last Meeting of the Session, and take office at the ensuing Annual Meeting. VI.—The mode of election of the Vice-Presidents, Treasurer, Secretary, Librarian, and Council shall be in the form and manner following: —It shall be the duty of the retiring Council at their final meeting to suggest the names of Members to fill the offices of Vice-Presidents, Treasurer, Secretary, Librarian, and of four Members who LAWS. XV. were not on the last Council to be on the Council for the ensuing session, and formally to submit to the Society, for election at the Annual Meeting, the names so suggested. The Secretary shall make out and send to each Member of the Society, with the circular convening the Annual Meet- ing, a printed list of the retiring Council, stating the date of the election of each Member, and the number of his attendances at the Council Meetings during the past session ; and another containing the names of the Members suggested for election, by which lists, and no others, the votes shall be taken. It shall, however, be open to any Member to substitute any other names in place of those upon the lists, sufficient space being left for that purpose. Should any list when delivered to the President contain other than the proper number of names, that list and the votes thereby given shall be absolutely void. Every list must be handed in personally by the Member at the time of voting. Vacancies occurring otherwise than by regular annual retirement shall be filled by the Council. ~ VII.—Every Candidate for Membership shall be pro- posed by three or more Members, one of the proposers from personal knowledge. The nomination shall be read from the Chair at any Ordinary Meeting, and the Candi- date therein recommended shall be balloted for at the succeeding Ordinary Meeting. Ten black balls shall exclude. VIII.—When a person has been elected a Member, the Secretary shall inform him thereof, by letter, and shall at the same time forward him a copy of the Laws of the Society. IX.—Every person so elected shall within one calendar month after the date of such election pay an Entrance Fee of Half a Guinea and an Annual Subscription of One XVI. LIVERPOOL BIOLOGICAL SOCIETY. Guinea (except in the case of Student Members); but the Council shall have the power, in exceptional cases, of extending the period for such payment. No Entrance Fee shall be paid on re-election by any Member who has paid such fee. X.—The Subscription (except in the case of Student Members) shall be One Guinea per annum, payable in advance, on the day of the Annual Meeting in October. XTI.—Members may compound for their Annual Sub- scription by a single payment of Ten Guineas. XI1.—There shall also be a class of Student Members, paying an Entrance Fee of Two Shillings and Sixpence, and a Subscription of Five Shillings per annum. XITI.—AIl nominations of Student Members shall be passed by the Council previous to nomination at an Ordin- ary Meeting. When elected, Student Members shall be entitled to all privileges of Ordinary Members, except that they shall not receive the publications of the Society, nor vote at the Meetings, nor serve on the Council. XIV.—Resignation of Membership shall be signified wn writing to the Secretary, but the Member so resigning shall be liable for the payment of his Annual Subscription, and all arrears up to date of his resignation. XV.—The Annual Meeting shall be held on the second Friday in October, or such other convenient day in the month, as the Council may appoint, when a report of the Council on the affairs of the Society, and a Balance Sheet duly signed by the Auditors previously appointed by the Council, shall be read. XVI.—Any person (not resident within ten miles of Liverpool) eminent in Biological Science, or who may have rendered valuable services to the Society, shall be eligible LAWS. XVII. as an Honorary Member; but the number of such Members shall not exceed fifteen at any one time. XVII.—Captains of vessels and others contributing objects of interest shall be admissible as Associates for a period of three years, subject to re-election at the end of that time. XVIII.—Such Honorary Members and Associates shall be nominated by the Council, elected by a majority at an Ordinary Meeting, and have the privilege of attending and taking part in the Meetings of the Society, but not voting. XIX.—Should there appear cause in the opinion of the Council for the expulsion from the Society of any Member, a Special General Meeting of the Society shall be called by the council for that purpose; and if two-thirds of those voting agree that such Member be expelled, the Chairman shall declare this decision, and the name of such Member shall be erased from the books. XX.—EHvery Member shall have the privilege of intro- ducing one. visitor at each Ordinary Meeting. The same person shall not be admissible more than twice during the same session. X XI—Notices of all Ordinary or Special Meetings shall be issued to each Member by the Secretary, at least three days before such Meeting. XXII.—The President, Council, or any ten Members can convene a Special General Meeting, to be called within fourteen days, by giving notice in writing to the Secretary, and stating the object of the desired Meeting. The circular convening the Meeting must state the pur- pose thereof. XXIII.—Votes in all elections shall be taken by ballot, XViil. _ LIVERPOOL BIOLOGICAL SOCILTY. and in other cases by show of hands, unless a ballot be first demanded. XXIV.—No alteration shall be made in these Laws, except at an Annual Meeting, or a Special Meeting called for that purpose; and notice in writing of any proposed alteration shall be given to the Council, and read at the Ordinary Meeting, at least a month previous to the meet- ing at which such alteration is to be considered, and the proposed alteration shall also be printed in the circular convening such meeting; but the Council shall have the power of enacting such Bye-Laws, as may be deemed necessary, which Bye-Laws shall have the full power of Laws until the ensuing Annual Meeting, or a Special Meeting convened for their consideration. . BYE-LAWS. 1. Student Members of the Society may be admitted as Ordinary Members without re-election upon payment of the Ordinary Member’s Subscription; and they shall be exempt from the Ordinary Member’s Entrance Fee. 2. University College Students may be admitted as Student Members of the Society for the period of their college residence, on the single payment of a fee of Five Shillings and an entrance fee of Two Shillings and Six- pence. , LIST of MEMBERS of the LIVERPOOL ELECTED. 1899 1898 1886 1886 1888 1894 1889 1886 1886 1900 1897 1900 1886 1886 1901 1896 BIOLOGICAL SOCIETY. SHSSION 1901-1902. A. Orpinary MEMBERS. (Life Members are marked with an asterisk.) Annett, Dr. H. J., University College, Liverpool. Armour, Dr. T. R. W., University College, Liver- pool. Banks, Sir W. Mitchell, M.D., F.BR.C.S., 28, Rodney-street. Barron, Prof. Alexander, M.B., M.R.C.S., 34, Rodney-street. Beasley, Henry C., Prestpent, Prince Alfred- road, Wavertree. Boyce, Prof., University College, Liverpool. Brown, Prof. J. Campbell, 8, Abercromby-square. Caton, R., M.D., F.R.C.P., Lea Hall, Gateacre. Clubb, J. A., M.Se., Hon. Secretary, Free Public Museums, Liverpool. Cole, F. J., University College, Liverpool. Dutton, Dr. J. Everett, 44, Upper Parlament- street, Liverpool. Ellis, Dr. J. W., 18, Rodney-street, Liverpool. Gibson, Prof. R. J. Harvey, M.A., F.L.8., Univer- sity College. Halls, W. J., 35, Lord-street. Hanna, W., M.A., M.B., 25, Park-way, Liverpool. Haydon, W. H., 8, Amberley-street. XX. 1900 1886 1893 1897 1900 1898 1886 1895 1901 1894 1886 1896 1886 1888 1900 1894 1894 1886 1897 1890 1887 1897 1900 LIVERPOOL BIOLOGICAL SOCIETY. Hayward, Lt.-Col. A. G., Rearsby, Blundellsands. Herdman, Prof. W. A., D.Sc., F.R.S., Vicr-Prestr- DENT, University College. Herdman, Mrs., B.Sc., Croxteth Lodge, Ullet- road, Liverpool. Holt, Alfred, Crofton, Aigburth. Horsley, Dr. Reg., Stoneyhurst, Blackburn. Johnstone, James, B.Sc., Hon. Lrerartan, Fisheries Laboratory, University College, Liverpool. Jones, Charles W., Allerton Beeches. : Klein, Rev. L. de Beaumont, D.Sc., F.L.S., 26, Alexandra Drive. Layton, P., Glendale, Leyfield-road, West Derby Lea, Rev. T. S., M.A., St. Ambrose Vicarage, Widnes. Leicester, Alfred, Scot Dale, New Ferry. Laverock, W. S., M.A., B.Sc., Free Museums, Liverpool. Lomas. J., Assoc. N.S.S., F.G.S., 18, Moss-grove, Birkenhead. Newton, John, M.R.C.S., 2, Prince’s Gate, W. Nisbet, Dr., 175, Lodge Lane, Liverpool. Paterson, Prof., M.D., M.R.C.S., Vicz-PRESIDENT, University College, Liverpool. Paul, Prof. F. T., Rodney-street, Liverpool. *Poole, Sir James, J.P., Abercromby-square. Quayle, Alfred, 7, Scarisbrick New-road, South- port. ‘ *Rathbone, Miss May, Backwood, Neston. | Robertson, Helenus R., Springhill, Church-road, — Wavertree. } Robinson, H. C., Holmfield, Aigburth. Rylands, Ralph, 2, Charlesville, Claughton. 1887 (1894 1895 1900 1886 1895 1886 1889 1888 1886 1891 1896 LIST OF MEMBERS. XX. Ryley, Thomas C., Hon. Treasurer, 10, Waver- ley-road. Scott, Andrew, Piel, Barrow-in-Furness. Sherrington, Prof., M.D., F.R.S., University Col- lege, Liverpool. Smith, Mrs., 14, Bertram-road, Liverpool. Smith, Andrew T., 5, Hargreaves-road, Sefton Park. Smith, J., F.L.S., The Limes, Latchford, War- rington. Thompson, Isaac C., F'.L.8., 58, Croxteth-road, Thornely, Miss L. R., 17, Aigburth Hall-road. Toll, J. M., 49, Newsham-drive, Liverpool. Walker, Alfred O., J.P., F.L.S., Ulcombe Place, Maidstone. | Wiglesworth, J., M.D., F.R.C.P., County Asylum, Rainhill. Willmer, Miss J. H., 20, Lorne-road, Oxton, Bir- kenhead. B. Srupent MEMBERS. Bramley-Moore, J., 138, Chatham-street. Carstairs, Miss, 39, Lily-road, Fairfield Drinkwater, HE. H., Rydal Mount, Marlboro’-road, Tuebrook. Elder, D., 49, Richmond Park, Liverpool. Graham, Miss Mary, Ballure House, Gt. Crosby. Hannah, J. H. W., 55, Avondale-road, Sefton Park. Harrison, Oulton, Denehurst, Victoria Park, Wavertree. Hick, P., 3, Victoria Drive, Rock Ferry. Hunter, S. F., Westminster Park, Chester. Jefferies, F., 45, Trafalgar-road, Egremont. Jones, H., University College, Liverpool. XX. LIVERPOOL BIOLOGICAL SOCIETY. Knott, Henry, 11, Brereton Avenue, Liverpool. Law, Arthur, B.Sc., University College, Liverpool. Lawrie, R. D., Sunnyside, Woodchurch Lane, Birkenhead. Lloyd, J. T., 43, Ullet-road, Sefton Park. Mann, J. C., University College, Liverpool. Mawby, W., Clumber, Prenton-road, E., Birkenhead. Pearson, J., 43, Dryden-road. Stallybrass, C. O., Grove-road, Wallasey. Scott, G. C., 65, Croxteth-road. Smith, G., University College, Liverpool. Smith, C. H., University College, Liverpool. Tattersall, W., 290, Stanley-road, Bootle. Woolfenden, H. F., 6, Grosvenor-road, Birkdale. C. Honorary MEMBERS. S.A.S. Albert I., Prince de Monaco, 25, Faubourg St. Honore, Paris. ; Bornet, Dr. Edouard, Quai de la Tournelle 27, Paris. Claus, Prof. Carl, University, Vienna. Fritsch, Prof. Anton, Museum, Prague, Bohemia. Giard, Prof. Alfred, Sorbonne, Paris. Haeckel, Prof. Dr. E., University, Jena. Hanitsch, R., Ph.D., Raffles Museum, Singapore. Solms-Laubach, Prof-Dr., Botan. Instit., Strassburg. REPORT of the LIBRARIAN. TixcHANGES of publications have been arranged with the following institutions : — Basel—Ornithologischer Verein. Munchen—Ornithologischer Verein. Rennes—Société Scientifique et Medicale. Roma—Societas Zoologica Italiana. Zagreb—Societas Historica-Naturalis Croatica. The condition of the Library demands serious attention. Over one hundred new volumes are now received every year, and during the last two years no money has been forthcoming to provide for the binding of the books received. A considerable number of volumes have accumulated since the grants of £24 made by the Council two years ago, and it is very necessary that these should receive attention. A yearly grant of £10 would be sufficient to bind the volumes added during the session and those which have accumulated. The Library is now becoming a very valuable one, and is worth this expenditure. Lists of the publications added to the Library during the Session 1901-2, and of the Societies and Institutions on the Exchange List, are appended. 1.— PUBLICATIONS ADDED TO THE LIBRARY DURING. THE SEsston 1901-2. Adelaide, Trans. Roy. Soc. South Australia. Vol. XXV., pts. 1 and 2. 1901. Albany (U.S.A.), Bull. Buffalo Soc. Nat. Sci. Vol. 7., No. 1. Guide to the Geology and Paleontology of Niagara Falls and Vicinity. A.W. EHraban. 1901. XXIV. LIVERPOOL BIOLOGICAL SOCIETY. Amsterdam—Jaarb. Konink. Akad. Wetensch. For 1900-1901. Amsterdam—Verhand. Konink. Akad. Wetensch. Ser. 2. Deel VIL., No. 4-6. 1900-1. Amsterdam—Verslag Gew. Vergad. Wiss-en-Naturk afdeel. Deel IX. 1901. Amsterdam—HEnglish Translation of above. 1901. Amsterdam—Natuurk. Tijdschrift. Deel 60. 1901. Baltimore (U.S.A.), Memoirs Johns Hopkins Univ. Biol. Labt. IV.—5. 1900. Univ. Cisculars, Vol. 21, No. 155. 7 1902: Basel—Naturf. Gesellsch. Verhandl. Bd. 13, Heft 1—2, 1901. Namenverzeichnis v. Sachsregister. Bd. 6—12. 1901. Bergen—Crustacea of Norway. G.O. Sars, vol. 4; pts. 1—4. 1901. Bergen, Bergens Mus. Aarbog. Heft 1. 1901. Bergen, Bergen Mus. Meeresfauna von. Bergen. Heft1. 1901. Berlin—Sitzungsber. K. Preussichen. Akad. Wiss. Pts. 1—53. 1901. Berlin—Mittheil. Deutsch See-Fisch. Vereins. Bd. 17, Nos. 4—12. Bd. 18, No.1. 1901-2. Berlin—Zeitschr. £. Fischerei. Bd. 9, hefte 3-4. 1902. Berlin—Notes de Geographie Biologique Marine. §.A.S. Albert I., Prince de Monaco. Buenos Aires—Communicaciones Mus. Nac. T.1, nos. 8—10, 1901. Bordeaux—Proces. Verb. Soc. Linn. 1900. Bordeaux—Catalogue de la Bibliotheque. Fasc. 2, 1901. Bonn, Verhandl. Naturhist. Ver. Jahrg.57. 2nd Halfte. 1900. Bonn, Sitz. Niederrh. Ges. 2 Halfte. 1900. Brussells—Acad. Roy de Belgique. Bull. Classe des Sciences. 1899-1900. Brussells—Acad. Roy de Belgique. Annuaire. 1900-1901. Caen—Bull. Soc. Linn. de Normandie (Ser. 5). Vol. IV. 1901. Cambridge (U.S.A.)—Bull Mus. Comp. Zool., Harvard. Vol. 38 (Geol. Ser.). Vol. 35, No. 2-4, 1901; Vol. 36, No. 7-8, 1901 Vol. 37, No. 3, 1901. Cambridge (U.S.A.)—Ann. Rep. Mus. Comp. Zool., 1900-1901: Chicago, The Botanical Gazette. Vol. 31, Nos. 3-6; Vol. 32, 1901; Vol. 33, No. 1, 1902. Chicago, 6th Ann. Rep. John Crerar Library. 1900. Chicago Field Columbian Museum— Zoological Series. Vol. 2; Vol. 3, No. 1—3. 1901. Geological Series. Vol. 1, No. 8. 1901. Anthropological Series. Vol. 2, No. 4-5. 1900-1. Vol. 3, No. 1. 1901. Report Series. Vol. 1, No.6. 1900. Christiania, Forhandl. Vidensk-selskab. Aar. 1900-1901. LIBRARIANS REPORT. XXV. Chatham (N.B.), Proc. Nat. Hist. Ass. Miramichi. No.2. 1901. Dublin—Sci. Proc. Roy. Dublin Soc. Vol. 9, pts. 3-4. 1901. Dublin—Sci. Trans. Roy. Dublin Soc. Vol. 7, pts. 8-13. 1901. Edinburgh—Proc. Royal Phys. Soc. Session 129. 1901. Frankfurt—Bericht. Senckenb. Naturf. Gesellsch. 1901. Freiburg, I. B.—Ber. Naturf. Ges. 11 Bd. Heft 3. 1901. Geneva, Mem. Soc. de Physique et Nat. Hist. T. 32, Pt. 2. 1899-1901. Glasgow—19th An. Rep. Scottish Fish. Bd. Pt. 3. 1901. Gottingen, Nachr. k. Ges. Wissensch— Gesch. Mitth. Heft 1-2. 1901. Math.-Phys. Klasse. Heft 1. 1901. Giistrow, Arch. Ver. Freunde Naturg. Mecklenburg. Jahr 5. Abth. I.—ITI. 1900-1. Haarlem—Archives Mus. Teyler. Vol.7. Ser.2. Pts. 2. Pts. 3-4. 1901. Halle, Nova Acta Abh. k. Leop.-Catol. Deutschen Akad. Naturf. PaemoemN oe. 1-3-bds: 68, 69) No. 38; Bd. 70, No: 3; Bd 74, iNeweasaiad. 76; Bd. 77, No. 1-3; Bd. 78. 1895-1901. Halifax, Proc. and Trans. Nova Scotian Inst. Sci. Vol. 10, Pt. 2. 1900. Kobenhayn—Oversigt K. Danske Selsk. Forh. Nos. 2-6. 1901. Kobenhayn—Mem. Acad. Roy. Lett. Sci. Denmark (Ser. 6, Sect. Sci.). MoS INo} 8. 1901. Kiel, Schriften Naturwiss. Ver. Schleswig-Holstein. Bd. 12, Heft 1, 1901. Kiel und Leipzig, Wiss. Meeresuch. Kiel Komm, (N.F.). Bd. 4, Abt. Helgoland. Heft 2. 1900. Bd. 5, Abt. Kiel. Heft 2. 1901. Kyoto, Japan, Kyoto Imp. Uniy. Calendar. 1900-1. La Haye—Arch. Neerlandaises. T. 4, Livrs. 2-5. 1901. Lawrence (U.S.A.)—Kansas Univ. Quarterly. Vol. 10, No. 1-4. 1900-1. La Plata—Contribuciones al conocimiento de la Geologia de Buenos Aires. Publicaciones Universidad de La Plata. No.1. 1901. Leeds, Trans. Yorkshire Nat. Union. Pts. 24—7. 1900-1. Leipzig, Ber. Verhandl. k. Sachs. Ges. Wissensch. Bd. 53, I.—VI. 1901. Leipzig, Jahresber. Furstlich Jablonowski’schen Ges. Marz. 1901. Liverpool, Proc. Geol. Soc. Vol. 8, Pt. 4. 1900. Vol. 9, Pt. 1. 1901. Liverpool, Bull. Liverpool Mus. Vol. 3, No.2. 1901. London --The Naturalist, Nos. 532—41, 1901-2. London—Journ. Roy. Micros. Soc. 1901, Pts. 3—6; 1902, Pt. 1. London—British Mus. Cat. Cretaceous Bryozoa, Vol. 1. Jurassic Bryozoa. 1899-1896. London—Brit. Mus. Guide to Shellfish and Starfish Galleries. 1901. London—Contributions to The Malacostracan Fauna of the Mediter- ranean. A. O. Walker. 1901. (Presented by author.) XXVI1. LIVERPOOL BIOLOGICAL SOCIETY. London—Year-Book of Learned Societies. Manchester, Trans. and Report Micros. Soc. 1900. Madison (Wis., U.S.A.)—The Clays and Clay Industries of Wisconsin. E. R. Buckley. Wisconsin Geol. and Nat. Hist. Survey Bull. INGE Hemet. Le OO: Melbourne—Proc. Roy. Soc. Victoria. Pts. 1—2, 1900. Pt. 1, 1901. Monaco Resultats Campagnes Scientifiques. Fascs. 17-20. 1900-1. Montpellier—Acad. Sci. Lett. (Ser. 2). T. 2, Nos. 5-7, 1898-1900: ao Nons 190K Moscow—Bull. Soc. Imp. Nat. 1900-1, Nos. 1—4; 1902, Nos. 1—2. Montevideo, Anales Mus. Nac.T. 8, Nos. 20—21; T.4, Nos. 19—20. 1901. Miinchen, Allgemeine Fish-Zeitung. Nos. 8—24, 1901 ; Nos. 1—5, 1902. Mitinchen—Jahresber. II. Ornithol. Vereins. 1901. Nancy—Bull. Seances Soc. Sci. (Ser. 3). T. 2, Fase. 3. 1901. Nancy—Bull. des. Seances Soc. Sci. et de la Reunion Biologique. Ser. 3. T.1. Fasc 4—6. 1900. T.2. Fase 1, 190K Napoli, Rend. dell’ Accad. Sci. Fis. e Mat. Ser. 3a. Vol. 7, Fase. 3—12, 1901; Vol. 8, Fasc. 2, 1902. New York, Mus. Brooklyn Inst. Arts and Sciences. Sci. Bull. Vol. 1, IN@s dla UG, Paris, C. R. Hebd. Soc. Biol. T. 53, Nos. 13—41, 1901; T. 54, Nos. 1—7, 1902. Paris, Bull. Scientifique. T. 33—34, 1900-1. Paris, Bull. Soc. Zool. T. 25, 1900. Paris, Mem. Soc. Zool. T. 13, 1900. Paris, Bull. Mus. Hist. Nat. 1901, Nos. 1—8. Philadelphia, Proc. Acad. Nat. Sci. Vol. 52, Pt. 3, 1901; Vol. 53, 1901. Rennes—Bull. Soc. Sci. et Medicale. T.1i. to x., Nos. 1—8. 1892-1902. San Francisco, Proc. California Acad. Sci. Zoology. Vol. 2, Nos. 1—4, 6. 1899-1900. Stavanger, Aars-hefte Stavanger Museum, for 1900, 1901. Stockholm—Bihang. K. Svenska Vet. Akad. Vol. 26 (3-4). 1901.. Sydney—Rec. Australian Mus. Nos. 1—5. 1901. Sydney—Reports Australian Mus. 1900-1. St. Louis—Trans. Acad. of Sciences. Vol. 10, Nos. 9—11. Vol. 11, Nos. 2—4. 1900. St. John, Bull. Soc. Nat. Hist. New Brunswick. No. 19. St. Petersbourg, Bull. Acad. Imp. Sci. Ser. 5, T. 12, Nos. 2—o5,; T. 18, Nos. 1—3. 1900. Toronto, Trans. Canadian Institute. No. 18. Vol. VII., Pt. 1. 1901. Torino, Boll. Mus. Zool. Anat. Comp. Vol. XVI. Nos. 382-403. 1901. Tokyo, Annotationes Zoological Japonenses. Vol. 3, Pts. 1—5. 1901. LIBRARIAN S REPORT. XXVI. Tokyo, Journ. Coll. Science Imp. Univ. Tokyo. Vol. 18, Pt. 4; Volopeic. 2-5, 1901 Volo 16, Pt.; Vol. 17, Pt. 1, 1901. Upsala—Nova Acta R. Soc. Sci. Vol. 19 (Ser. 3). 1901. Upsala, Streptokockens och dess Toxins. Max. Bjorksten. 1900. Upsala, Studier ofver ostersjons Hafsalgflora. Nils Svedelius. 1901. Upsala, Beitrag zut Kenntniss der Spongienfauna des Malayischen Archipels und der Chinesischen Meere. Nils Eustaf Lindgren. 1898. Upsala, Otkast de grona algernas och Archegoniaternas Fylogeni. Knut Bohlin. 1901. Urbana (U.S.A.)—Bull. Illinois State Laby. Nat. Hist. Vol. 6, NomdheOOi: Venice, Catalogo Coll. d’Anat. Comp. R. Institute Veneto di Sci. Lat. ed. Arti. 1900. Washington, Proc. U. 8. Nat. Mus. Vols. 23—4 (in part). 1901. Washington—Bull. U.S. Nat. Mus. No. 50. 1901. Washington—Birds of N. and Mid. America. R. Ridgway. Pt. 1. Fringillidee. Wellington—Trans. and Proc. New Zealand Institute. Vol. 33. 1901. Wien—Verhandl. K.K. Zool.—Bot. Ges. Bd. 51. 1901. Wien—Ann. K.K. Naturh. Hofmuseums. Bd. 138, 14, 15, 16 (pts. 1—2). 1898-1901. Zurich, Vierteljahrschr. Naturf. Ges. Jahrg. 45. Hefte 3—4; Jahrg. 46, Hefte 1—2, 1901. IJ.—List or Socrreties, &c., WITH WHICH PUBLICATICNS ARE EXCHANGED. (Additions made during the current session marked with an asterisk.) AMmSTERDAM—Koninklijke Akadamie van Wetenschappen. Koninklijke Zodlogisch Genootschap Natura Artis Magistra. BautImorE—Johns Hopkins University. *BasEL—Naturforschende Gesellschaft. BaraviA—Koninklijke Natuurkundig Vereeniging in Ned. Indie. Brercen—Museum. ; Beruin—Konigl, Akadémie der Wissenschaften. Deutschen Fisherei-Vereins. BirMincHAmM—Philosophical Society. Botonesa—Accademia della Scienze. Bonn—Naturhistorischer Verein des Preussichen Rheinlande und Westfalens. XXVI1i. LIVERPOOL BIOLOGICAL SOCIETY. BorpEAux—Sociétée Linnéenne. Boston—Society of Natural History. BrusseLs—Académie Royal des Sciences, etc., de Belgique. BuEnos ArrES—Museo Nacional. Museo de la Plata. CaEN—Société Linnéenne de Normandie. CamBripGE —Morphological Laboratories. CamMBRIDGE, Mass.—Museum of Comparative Zoology of Harvard College. Cuicaco, U.S.A.—The Field Columbian Museum. The Botanical Gazette, Chicago University. The Johns Hopkins University. CHRISTIANIA —Videnskabs-Selskabet. Dupiin—Royal Dublin Society. EDINBURGH—Royal Society. Royal Physical Society. Royal College of Physicians. Fishery Board for Scotland. FRANKFURT—Senckenbergische Naturforschende Gesellschaft. FrreIBURG—Naturforschende Gesellschaft. GENEVE—Société de Physique et d’ Histoire Naturelle. GiEssEN—Oberhessische Gesellschaft fiir Natur und Heilkunde. GLAscow—Natural History Society. GoTTInNGEN—Konigl. Gesellschaft der Wissenschaften. Hatirax—Nova Scotian Institute of Natural Science. Haute, A.S.—K. Leopoldinisch-Carolischen Akademie der Natur- forscher. HaarLeEmM—Musée Teyler. Sociéte Hollandaise des Sciences. HELIGOLAND Ko6nigliche Biologische Anstalt. Inuinois, U.S.A.—Reports of the State Laboratory of Natural History. KieL—Naturwissenschaftlichen Verein fur Schleswig— Holstein. Kommission fur der Unterschung der Deutschen meere. KyoBENHAVN—Naturhistorike Forening. Danish Biological Station (C. G. John Petersen). Kongelige Danske Videnskabernes Selskab. Lawrence, U.S.A.—The Kansas University Quarterly. Lrreps—Yorkshire Naturalists’ Union. Lerpzia—Konigl. Sachs. Gesellschaft der Wissenschaften. Linte—Revue Biologique du Nord de la France. LivERPooL— Geological Society. Bulletin of the Liverpool Museums. LIBRARIAN'S REPORT. XX1X. Lonpon—Royal Microscopical Society. British Museum (Natural History Department). MancuesterR—Microscopical Society. Owens College. MARSEILLES—Station Zoologique d’ Hndoume. Musée d’ Historie Naturelle. MassacuusEetrrs—Tufts College Library. MrcKLENBURG— Verein der Freunde der Naturgeschichte. MELBouURNE—Royal Society of Victoria. Montevip—o—Museo Nacional de Montevideo. Mon trreLuipr—Académie des Sciences et Lettres. Moscou—Societé Impériale des Naturalistes. MuncuHen —Allgemeine Fischerei-Zeitung. *Ornithologischer verein. Mitiport—Biological Station. Nancy - Société des Sciences. Naporti—Accademia delle Scienze Fisiche e Matematiche. New Brounswick—Natural History Society. Oporto —Annaes de Sciencias Naturaes. Paris—Museum d’ Histoire Naturelle. Société Zoologique de France. Bulletin Scientifique de la France et de la Belgique. Société de Biologie. PHILADELPHIA—Academy of Natural Sciences. PiymoutH—Marine Biological Association. *“Roma—Societas Zoologica Italiana. *RENNES—Bulletin Société Scientifique et Medicale. Satem, U.S.A.—The Hssex Institute. St. Louis, Miss.—Academy of Sciences. Sr. PerERspuRG—Académie Impériale des Sciences. San FRancisco—California Academy of Science. SANTIAGO—Société Scientifique du Chili. STAVANGER—Stavanger Museum. StockHoLtmM— 336 ‘GO6T “G30 “3deg 03 4ST “990 ‘TOGT mp) ‘UHUOSVaNTL SAWIAYM O SOHL HiIM INOQOD0V NT 1G ALAIDOS TVOIDOTOIG TOOddSAIT AHL e ’ + Y “en QGICAL SOCLET TRANSACTIONS -00L BIOL INAUGURAL ADDRESS ON THE FAUNA INDICATED IN THE LOWER KEUPER SANDSTONE OF THE NEIGHBOURHOOD OF LIVERPOOL. By H. C. BEASLEY, Presipent. [Read 11th October, 1901.] I think no excuse is needed for the subject of my address being rather an unusual one in our Society, although it may even seem to some to be outside the limits of our science. I can only say that to attempt the study of Biology without Paleontology, and some know- ledge of Geology, could only be paralleled by an attempt to study man, to govern him or to legislate for him, with- out some knowledge of history and geography. I would therefore ask you to carry your thoughts back to a time when the portion of our Harth’s surface now occupied by South Lancashire and Cheshire was a comparatively barren waste, the material of its surface continually kept in motion by the wind, and occasionally by heavy rains, temporary torrents and probably some more permanent streams constantly changing their position, and affected by the same conditions that to a greater or less extent still prevail in the central portions of our continents—condi- tions very ill calculated to preserve any organic remains, but which have produced the beds of sandstone and con- 4 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. glomerate known as the Lower Keuper Sandstone so largely developed in our neighbourhood, particularly on the Cheshire side of the Mersey, and supplying the greater part of our building stone. These immediately underlie the beds formed by aqueous sedimentation in inland lakes, and known as the Upper Keuper Marls, in which the well-known salt deposits occur ; ‘below them lie the Bunter Sandstones. The Lower Keuper and the Bunter together form an alternating series of hard and soft sandstones, of which the Lower Keuper is the highest member. There is, however, reason to suppose that some time elapsed, and some change of conditions took place between the deposition of the uppermost beds of the Bunter and those at the base of the Keuper; at any rate in this district the conditions altered to the extent of preserv- ing certain traces of life in the Keuper and of retaining none in the Bunter. At this period the old fauna of the Paleozoic rocks had disappeared, and the new forms which charac- terise the Mesozoic period were coming to light. The vertebrate type of skeleton had thoroughly established itself, and in the course of development had reached the parting of the ways. The principal forms were represen- tative of the lower reptilia, but those differentiations were already well marked which were to give rise to the lizards, birds and mammals as we now have them; indeed, it is possible that lower mammalia had already been evolved, though perhaps not present in this part of the world till later. The birds are more doubtful. We have many peculiarly avian characters present in some of the reptilia, but of anything hke a Triassic bird we have no record in this country, and their course of evolution is very uncer- tain. The Trias, therefore, represents a period particu- larly interesting to the Biologist, and a complete know- ledge of its fauna would solve many questions that now a FAUNA—-LOWER KEUPER SANDSTONE. 5 perplex us. Such a complete knowledge we can, however, hardly expect to attain; but we may reasonably hope in the near future to add largely to the knowledge we possess. The thousands of feet of Shales, Marls and Sand- stones, probably approaching a mile in thickness, that intervene in this country between the coal measures, teem- ing with life at the close of the Paleeozoic period, and the Lias full of the remains of the life of the Mesozoic, are as a whole remarkable for their dearth of fossils, whilst the Bunter Sandstone (about the centre of the series) so largely developed in this neighbourhood is absolutely non- fossiliferous, though the pebbles enclosed in it contain remains of a much earlier geological period, and the Keuper above it yields us only very uncertain traces. It is with these slight traces that I propose to deal this evening. They consist of the footprints of vertebrates and the tracks of some invertebrates. A few other districts are, however, more fortunate, and in limited areas in our own country sufficient remains have been found to show that a numerous and varied fauna existed, whilst allied, if not actually similar, forms have been found in comparative abundance in the Trias of South Africa, India, Australia and the continent of Hurope, and in North America. Within the last year the announcement has been made of the discovery of a rich deposit of well-preserved vertebrate remains in the valley of the Dneiper, in strata of probably the same age, although spoken of as Permian, including examples of the same genera that are found in the similar deposits in South Africa and India, from which hitherto the greater part of our knowledge of the land animals has been derived; and it is to be hoped that shortly more detailed descriptions of the forms found will be published. According to the catalogue of British Fossil Verte- 6 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. brata (Woodward & Sherborn, issued i there were known to the British Trias— Fishes, 6 genera; Amphibia, 5 genera; Reptilia, 9 genera. Since 1890, however, the numbers have been greatly in- creased, mainly by the labour of Mr. E. T. Newton, F.R.S., upon material collected from the sandstones of Elgin, whence the bulk of our British Triassic vertebrate have hitherto been obtained. As might have been expected from the nature of the deposit, our district has yielded no trace of FrisHEs, though they have been found in beds of the same age near Nottingham, and a single specimen of Dipteronotus at Bromsgrove, Worcestershire. Turning next to the Ampursia, the earliest known four-footed air-breathing land animals were the Stego- cephala or Labyrinthodonts. The head was completely roofed in by bones, was connected with the vertebral column by either 2 occipital condyles, or none, the limbs were of pentadactyloid type, and the vertebral column comprised a well-developed and often long tail. We see in them a distinct step in the evolution of the vertebrates from the aquatic to the land type. They had not arrived at the dignity of reptilia; they are known to have been amphibia, and only air breathers in their adult condition. They seem to have been at their prime as to numbers and variety in Carboniferous and Permian times, but were giving way to higher forms in Triassic times. It was, until a few years ago, very confidently stated that the well-known hand-shaped footprints found at Storeton were those of the Labyrinthodon. This seems first to have been suggested by Sir R. Owen many years ago; but since then, as more material became available, 2 FAUNA—-LOWER KEUPER SANDSTONE. if the Labyrinthodontia have been thoroughly worked out, and our faith in the Labyrinthodont origin of the foot- print is somewhat shaken. The footprints were originally attributed to an unknown animal designated the Cheiro- thereum. At the suggestion of the late Mr. G. H. Morton, F.G.S., the specific designation storetonense was added to distinguish the more common Storeton form. This footprint, as found at Storeton, has roughly the form of the human hand, and varies in length from 54 inches to 9 inches. The smaller ones are as a rule very much alike, but the largest ones, which, however, are not at all common, have more fleshy digits, with the nail not so distinctly shown. ‘There are 5 digits of about the same proportions as those of the human hand: four slightly divergent; one—an outer one, greatly resembling the human thumb—is more divergent, curved laterally and posteriorly, but there is every reason to believe that it is the fifth digit. The integument of the sole of the hind foot is divided by constrictions into divisions forming pads, which may perhaps be considered to indicate the joints and phalanges of the digits, and all the digits are terminated by sharp, strong claws. Owing to the imperfections of all the im- pressions, it is not an easy task to determine the actual number of phalanges on each digit. The result of my examination of a great number of prints is in favour of 5 phalanges each to the three inner digits and 2 for the two outer, but as there is scarcely ever any marked constriction on the curved digit, the number of its phalanges is doubtful. At the base of each digit is another pad of the same character as those just described. They appear to cover the distal extremities of the metatarsals, the only portion of the metatarsals reaching the ground. There is a 8 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. tendency as age increases for two or more of these pads to coalesce. That at the base of the curved digit is larger than the rest, and serves to form the hinder and outer margin of the foot. On the other side there is generally no impression at all in the rear of the pads of the other digits. The function of the curved digit is not clear. That it was opposable is extremely doubtful; it is always found in the position shown in the specimens before you (Fig. 1, plate II.), and probably merely took some small share in the support of the body. In front of this hind foot, as we may suppose it to be, at a distance of a few inches, and in the same line, is usually found the print of a much smaller foot, which we may safely take to be the fore foot. It has five short, stout, tapering and rather widely divergent digits, the one corresponding with the curved digit of the hind foot being most divergent, in some cases pointing rather backwards than forwards. There are hardly any traces of divisions of the phalanges, nor are there of terminal claws. The footprint is rather broader than long, and is generally somewhat less than half the length of the hind foot. The print of the fore foot is generally less distinctly marked than that of the hind foot. If we take a series of . feet, they are found to be all nearly in a straight line; the axes of the right and left tracks are not more than about din. apart, often much less, whilst the stride, measured from the tip of the toes on one foot to those of the next - _ impression of the same foot, is between 3ft. 6in. and 4ft. The soles of both hind and fore feet were covered with small protuberances. This appearance was first described by Professor W. C. Williamson as being observed on a footprint from Daresbury, Cheshire,* and he points out * Quart. Jl. Geol. Socy., vol. xxlii., p. 56. 1867. a. se ee Oe ee le FAUNA—-LOWER KEUPER SANDSTONE. 9 that the arrangement of the scales corresponds very closely with that seen in the foot of the living alligator, “ and “many of them run across the foot in oblique lines, as is “common among living crocodiles, leaving no doubt that “they represent the scales and not irregular tubercles “such as are seen in the skin of the Batrachians.”’ He concludes “it is saurian if not crododilian in every “feature.” The figure shows a form resembling the fore foot of the Cheirotherium, though only four toes are shown there is a trace of there having been a fifth. During the past summer a number of good footprints have been obtained at Storeton from the second footprint bed from the top, and almost every one of them shows these scales. I was fortunately able to examine the foot of a young living crocodile in the free museum, and can confirm Professor Williamson's remarks. Now are these the tracks of the Labyrinthodon? The idea originated when the only bones found in the Keuper indicating an animal of such a size as might be supposed to coincide with that of the footprints, were those of the Labyrinthodon. ‘This, as we know after the discovery of material unavailable to earlier workers, was improbable. Professor Miall, in his report* on the Labyrinthodonts to the British Association, showed this most clearly; and the statement of Hans Gadow in his recent work on the Amphibia and Reptilia (page 83) seems to decide the matter. He says—‘‘'The spoors of Cheirotherium common “in the Red Sandstone of Germany and England, for “instance in Cheshire, belong to unknown owners; both “the large hind feet (which measure nearly half a foot in “length) and the much smaller fore feet had five digits, “the first of which stood off like a thumb. /Fvve-fingered “ Stegocephalt are unknown.” * Brit, Assoc, Reports, 1873, p. 243. 10 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. A five-toed animal frequently makes a print in which but four toes are recognisable, but the circumstances under which a four-toed foot could make an additional print of one toe would be very exceptional and would be readily detected. ? Another point may be noticed. The Labyrinthodon was a tailed Amphibian. In a few experiments I have made with the common water newt and the European Salamander, they always left a track made by their tails when walking over a soft surface. No such tail is asso- ciated, as far as I have seen, with these footprints. The impression of something that may have been a tail of an animal is to be seen on a slab in the British Museum, which is reproduced in Mr. Morton’s Geology of Liverpool.* Rather smaller but similar markings are also shown on a slab at Warwick. The British Museum example shows distinctly rows of scales, and if the impres- sion of a tail, it must have been made when the animal was stationary. It is uncertain, however, at present whether these are of animal or vegetable origin. If, then, the footprints known as Cheirotherium are not Labyrinthont, where are these of the Labyrinthodon ? I cannot answer the question, but I do not see that it affects the case very much. At the same time I feel an amount of disappomtment that such an interesting group of animals should not have left any distinct evidence of their presence here. There is plenty of room both for research and specu- lation here, as it is hardly likely that the Amphibia were absent altogether; but the brilliant imaginations of more than one artist and writer have failed to fill the gap satisfactorily. We have a few small, broad, fleshy foot- * Appendix, p. 300,”plate xxii. FAUNA—-LOWER KEUPER SANDSTONE. se prints that may possibly have been Amphibia, but we have no proof whatever of it. Reptizia.—We will try for a moment to find some more stable ground, and consider a form of which we have both the bones of the foot and a print to match. We are no longer dealing with the Amphibia, but with true reptiles. Rhynchosaurus articeps was described by Owen in 1842,* from remains found im the quarries in the Lower Keuper Sandstone at Grinshill in Shropshire. The sandstones in this quarry are a con- tinuation in that direction of the beds at Storeton and elsewhere in our district. In the same quarry numerous footprints were found, and Owen, although he had none of the bones of the extremities before him, suggested the probability that the remains were those of the animal that made the footprint. I was disappointed to find, however, that the footprints referred to were not figured in his paper nor described in detail, nor have I been able to find any slab that can be identified as the one having been seen by Owen, if in fact he did see them himself; he only quotes in his paper some correspondence with Dr. Ogier Ward, of Shrewsbury. Dr. Ward says—“ As they (the “remains) have always been found nearly in the same “beds as that impressed by the footsteps I have described, “T am induced to believe they are the bones of the same “animal.” Owen adds—* And in this opinion, from the “correspondence of size between the bones and the foot- “ prints, and from the circumstance of the absence of other “observed bones or footprints in the same quarry, I “entirely coincide.” Farther on, after describing some fragments of the pectoral arch, he says—‘‘ They indubit- “ably indicate a mechanism for locomotion on land which *Trans. Camb. Philosophical Society, vol. vii., p. 155, 1842, 12 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. “would agree with that of the animal which has left “impressions in the sandstone.” Although several kinds of footprints have been noticed in the Grinshill quarry, there is one form which is far more common than the rest, and is no doubt the one alluded to by Owen. Since that time much more material has been discovered; and Huxley has described and figured further specimens in Q.J.G.S., vol. 48, p. 689, where the extremities are well shown, and they are found to entirely confirm Owen’s suggestion. Numerous other finds have been made at Grinshill (and a few elsewhere), and as these footprints are also among the most common ‘ones found here, I think we may without hesitation take it as a fact that Rhynchosaurus was present here im Lower Keuper times. The Rhynchosaurus, besides being interesting to us as having belonged to the local fauna, has much wider interest from the position of the Rhvnchocephalide in the zoological series; and the fact that a representative of the family still survives in Sphenodon punctata in some of the small islands off the coast of New Zealand. This not only gives some hints as to the probable habits of Rhyncho- saurus, but also very materially assists in dealing with the imperfections that occur in almost all fossil remains. Although very lizard-like in outward form, the Rhyncho- cephalide, including Sphenodon and MHyperodapedon differ greatly from the lizards both in their bony structure and the anatomy of their soft parts. They are linked through Paleohatteria, which made its appearance in Permian times, with the Amphibians, but are truly reptilian and possess a single occipital . condyle. As the name implies, they were provided with a horny beak, but were not edentulus, Rhynchosaurus having a row of acrodont teeth anchylosed to the palate, FAUNA—LOWER KEUPER SANDSTONE. is another to the inner side of the maxilla, and a row on the mandible fittmg into a hollow between. These crushing teeth are, however, supplemented by the horny covering of the maxilla and mandible. The premaxille are pro- longed into a pointed and recurved beak, which was also encased by a horny sheath. The skull is short, broad and somewhat pyramidal in form. The species described and figured was probably two to three feet in total length, and the feet are considerably larger than many of the prints usually attributed to it. There are, however, many of the full size of Huxley’s figure, and the smaller ones present exactly the same features, the principal one being that the fourth digit is the longest, and this cannot too strongly be borne in mind when investigating the footprints. Unfortunately the prints are usually imperfect, and at times it is difficult to allot the correct numbers to the digits shown. The hind feet, you will notice; are the most perfectly preserved; the fore foot, or manus, is not so good, but I have here the photograph of a fore mb in the Shrews- bury Museum (Plate I., Fig. 2). The hind limb of the same not having been preserved, it is impossible to state the proportion in size between the pes and the manus. The footprints are so intricately mixed on all the surfaces recording them that it is not possible to trace— or rather, I should say I have not succeeded in tracing— any continuous track, or positively determining the fore and hind feet of the same animal. This is readily ex- plained if the Rhynchosaurus was like the Sphenodon in its habits, for on the only occasion on which I have had an opportunity of observing the latter, where they had room to move freely, they were intensely active without any apparent object, darting about in all directions, and it - would have been a difficult matter to trace the tracks of 14 - TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. any individual set of feet, thus presenting a marked contrast to the stately march of our unknown friend the Cheiro- therium. Although we have a pretty clear idea of the footprint of the Rhynchosaurus, a number of the prints merely attributed to it from their size and lizard-lke appearance, probably were made by other animals. Although undoubtedly it was a tailed animal, we have no distinct traces of the tail of the Rhynchosaurus. _ Another member of the family whose remains are perhaps more generally distributed in Great Britain 1s Hyperodapedon. Fairly perfect remains have been found at Elgin, and more fragmentary at Warwick and South Devon. We are indebted to Professor Huxley for a full description and figures (Q.J.G:S., vol. 43, p. 675, 1887). Through the kindness of Professor Herdman I have here a cast of the skull, which will give some idea of the struc- ture of the skulls of the Rhynchosauride. Hypero- dapedon was somewhat similar to Rhynchosaurus, but instead of two rows of teeth it had several, the roof of the mouth being nearly covered. It was a much larger animal, being six or seven feet long, and in many respects was more specialised. | Unfortunately we have no remains of the posterior extremity, but the whole of the fore limb we have fairly perfect. The manus seems to have been rather smaller in proportion to the size of the body with rather stouter digits, and was probably more expanded than that of the Rhynchosaurus. Judging from its somewhat wide distribution, we have some grounds for expecting its presence here, but its footprints have not been identified. The Telerpeton, another allied genus, was much smaller, not exceeding a foot in length, and resembles the true lizards more nearly than the forms just described. FAUNA—-LOWER KEUPER SANDSTONE. 15 Only two examples have been found, and these, though fairly perfect in other respects, want the extremities of the fore and hind limbs, so we have no means of recognising their footprints. The Rhynchosauride were very generalised reptiles, Hyperodapedon being the most specialised ; Sphenodon the least so, and probably for that reason this form has survived and illustrates from another point of view the remarks made by Professor Herdman some time ago on the effect of high specialisation on the Ammonites.* We will next consider the ANomoponrTI1A, essentially a Permian and Triassic group, interesting from their being directly intermediate in their skeletal characters between the highest Labyrinthodontia and the lowest Mammals. They are best known to us by examples from South Africa and India, described by Owen, Seeley and others; they are also represented in Great Britain by several forms allied to Dicynodon, found at Elgin, and finely worked out and described and figured by Mr. H. T. Newton, E.R.S.,+ who has included them in two new genera, Gordonia and Geikia, named after that well-known geologist, Rev. Dr. George Gordon, to whom we are mainly indebted in the first instance for the Hlgin fossils ; and Sir A. Geikie, F.R.S., Director-General of the Geological Survey. The principal bones known are those of the skull, a striking feature of which is the great lateral expansion of some of the bones, giving the head the appearance of being much larger than it really is. The brain space is remarkably small. The parietal crests extend down the posterior portion of the skull, and passing forwards form the temporal arch. There is a feature in Gordonia Traquari which will * Proc. Liverpool Geol. Soc., President’s Address, vol. ix., p. 6. + Some New Reptiles from the Elgin Sandstones, by EK. T. Newton, F.G.8., F.R.8., Phil. Trans. Royal Soc., vol. 184 (1893), B., p. 431. 16 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. interest those who remember Dr. Hanitsch’s researches regarding the pineal eye. Mr. Newton writes, describing the skull of Gordonia Traquari—‘‘ Between the anterior “part of the parietal crests is the large pineal fossa which, “as can be seen in the right half of the skull, forms a very “distinet cup opening below into the brain cavity. The “deep cup-like form of the pineal fossa is probably an “indication that 1t lodged a well-developed eye.” The Labyrinthodons have a well-marked pineal fossa; the pineal eye is present in Sphenodon, but it has not been detected in Hyperodapedon. Of the form of the limbs something is known, though not of the extremities. Ido not know whether I am right in my conjecture, but I should suppose that the broad humerus would very likely be accompanied by a short-toed broad foot. Another very remarkable form has been figured from Elgin, to which Mr. Newton has given the name Elginia Mirabilis ; * this he considers is more allied to Pareiosaurus than to Dicynodon. Of none of the species of Gordonia, nor of Elginia, have the bones of the feet been preserved, and to form an idea of the foot we must refer to their South African relations. The national collection con- tains a nearly complete skeleton, finely mounted, of Pareiosaurus bombidens described by Professor Seeley, and the short broad feet are clearly shown; and it is quite possible that a rather common form of footprint here may represent an allied animal. The Dicynodon remains at Elgin would represent an animal about the size of a terrier dog. Some years ago I had the honour of reading to this Society a short papert on a small footprint with short toes bearing strong claws which has been frequently found at * * Loc. cit., p. 473. + Trans. Liverpool Biological Soc., vol. xi, p. 179. FAUNA—LOWER KEUPER SANDSTONE. 17 Weston quarries and occasionally at Storeton. Professor Seeley considered that it bore much resemblance to a South African form (Keirognathus). The size of the foot would about suit such an animal as Gordonia Traquairi. These footprints have always been attributed to Chelonia since they were first observed, but we have no record of remains of Triassic Tortoises or Turtles having been found in this country, and though negative evidence is of little value, I think it would be safer to assign these to an Anomodont than a Chelonian. I may just note in passing that the small oval mark with marks of the claws figured in Morton’s Geol. Liv., and called by Professor Ant, Fritsch Saurichnites perlatus, and comparatively common here, is remarkably lke the footprint of a Terrapin, but there are intermediate forms that tend to connect it with the one supposed to be the footprint of an Anomodont. Drinosavria. Though the Dinosaurs flourished in the later part of the Mesozoic period, we find traces of them in the Keuper in the neighbourhood of Bristol. With their general form you are doubtless familiar. There is a great discrepancy in the size of the fore and hind hmbs. This discrepancy is also said to be shared by some of the earlier forms of the Crocodilia, but it is so great in some Dinosaurs that there is every probability that they walked on their hind legs, and as they reached, if not exceeded, the size of our largest Mammals, they must have presented a somewhat formidable appearance. The supposed bipedal forms were probably carnivorous, the quadrupedal herbi- vorous. Many most startling restorations have been made, but it seems to me that any of us with the skeleton before us can bring before our minds a sufficient picture of its general form. It has been thought that we have here a forerunner B 18 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. of our birds, and certainly there are many points of resemblance between them and the Ratite; but I believe the general opinion now is that they were not in the direct line of descent. Professor Miall, in his repert on the Labyrintho- dontia,* suggests that our Cheirotherium footprints are more Dinosaurian than Labyrinthodont, and it may be useful to us if we go into this question. I may at once admit we have nothing in our Sandstones that we can say is certainly a Dinosaurian footprint. A point that has occurred to me is that the Storeton footprints are more digitigrade than we have hitherto imagined, though the foot was occasionally put down so that the whole length of the metatarsals came in contact with the ground; at least, I think this was the case with the well-known print called Cheirotherium hereulis (Plate I., Fig. 1). The digitigrade character is shown well in a slab in the Owens College Museum, believed to have come from — Storeton (Plate IIL, Fig. 1). The Dinosaurs of the Wealden had 3 functional toes and have left us their foot- prints, but with the Triassic forms we are not well acquainted, and caution is requisite in working on Professor Miall’s hint. The dolomitic conglomerate of Durdham Down, Clifton, in which were found the remains of two genera of Dinosauria, the Paleosaurus and the Thecodontosaurus, is also exposed along the northern shore of the Bristol Channel, and near Newton Nottage, Glamorganshire, Mr. Sollas has noticed and described ta series of three-toed footprints: the toes are divergent and the footprint as a whole is entirely different from our Storeton prints. It will be noticed, however, that the individual digits are * Brit. Assoc. Reports, 1873. + Quart. Jour. Geol. Soc., vol. xxxy., p. 511. FAUNA—-LOWER KEUPER SANDSTONE. 19 something similar in form to ours. (See Plate II., Figs. 1 and 2.) Now if we refer to the Storeton print and imagine the outer digits becoming functionless and aborted, the three inner ones would consequently probably become more divergent, and we should have a footprint somewhat of the character of the Newton Nottage ones. The dolomitic conglomerate is supposed to be rather higher in the series than the Storeton footprint bed. The authorities of the Cardiff Museum have kindly had taken - for me a photograph of the Newton Nottage footprint, of which Plate II., fig. 2 is a reproduction. Several years ago the Rev. P. B. Brodie pointed out to me in his own collection, and in that of the Warwick Museum, several instances of impressions in slabs bearing the Cheirotherium footprints of what he believed to be the hind quarters of the animal, as if it had squatted down on the ground. At that time it was generally considered that the Labyrinthodont origin of the footprints was quite settled. An animal with a short thick tail could hardly have done this, and I was rather inclined to think that the markings might have been made by the anterior portion of the under surface of the body, as I noticed that Sala- manders and Newts often stopped suddenly and rested the front portion of the body at once on the ground. However, in his “ Outlines of Vertebrate Paleontology,” Dr. Arthur Smith Woodward, when describing the Dino- saurian skeleton (page 198), and speaking of the extension of the pubes and the ischia, says—‘ The symphysis is in “both cases much extended, evidently to serve as a kind “of ‘foot’ when the animal rested on its hind quarters. | “Certain impressions in the Triassic Sandstones of Con- “necticut suggest this idea.” He was evidently unaware of similar impressions nearer home. It certainly would render a sitting’ posture much more easy for an animal 20) TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. encumbered with a massive tail than it would have other- wise been. Without further evidence it would be most unwise to assert that the Storeton footprint represents the presence of a Dinosaur, but I think I have shown the possibility of such having been the case. On the other hand there also remains the possibility of the footprint having been made by one of those animals of whom we have no knowledge whatever, but which nevertheless we firmly believe at one time, probably during the period we are considering, to have existed, and to have formed the connecting links between the Amphibia and the Mammalia. In the Ann. & Mag. Nat. Hist., 2 Sees., vol. 6, 1853, Professor R. Harkness described several footprints from Weston Point, Cheshire. Most of them I have recognised there, but one form I have failed to satisfactorily identify. He says—“ Amongst these there occur impressions of a “'Tridactylous character, and the position these assume “are such as to indicate that they bear relation to the “footprints of bipedal animals. Length of print, 2 inch; “length of stride, 7 inches; 3 well-developed toes, centre “one twice the size of the other toes; and the general “ appearance of the impressions has a great similitude to “the Ornithichnites diversus of Hitchcock.” These American footprints are now considered Dinosaurian. Fifty years ago the Dinosaur was a greater stranger than at present, and it will be worth bearing Professor Hark- ness’s observation in mind when considering the traces of Dinosaurs in our district. As I have said, I have so far been unable to confirm Professor Harkness, but I hope to do so before long. Weston Quarries are a grand store- house of footprints, and I seldom go there without finding something new to me. Crocopit1a. “It is as yet impossible,” says Dr. A. FAUNA—-LOWER KEUPER SANDSTONE. a1 Smith Woodward, “to distinguish the Triassic ancestors “of the Crocodilia from those of the Rhyncocephalia and “Dinosauria.”* Of Stagonolepis, the subject of Huxley’s well-known paper,t the extremities are too little known to warrant our speculating on its presence here. Mr. E. T. Newton, F.R.S., has described an allied genus, Erpeto- suchus,{ from Hlgin, and though the extremities are pre- sent they are so imperfectly preserved that it would be unwise to try to match them with any of our footprints ; the few and weakly marked bones of the digit we have may have been so covered with flesh as to give the foot a form more or less differing from that of the bony skeleton. Another form also described by Mr. Newton in the same paper, “Ornithosuchus woodwardii,” presents so many points of resemblance to both the Parasuchia and the Dinosauria that it is evidently with great hesitation that he at last places it provisionally with the latter. The bones of the left hind foot, though not in position, are all well preserved, so that it may be possible to restore the foot and search for its impression. The remains which are the subject of the paper, and also of the Dicynodonts, &c., referred to earlier, are all in the Geological Survey Museum, Jermyn Street, London, and I must express my thanks to Mr. Newton for the ready assistance he has so kindly rendered me whenever I have referred to him. In his paper on Stagonolepis and the Evolution of the Crocodilia,§ Professor Huxley in 1875 remarked on * Outlines of Vertebrate Paleontology, p. 216 (1898). + Quart. Jour. Geological Socy., vol. xxxi., p. 423. t Reptiles from the Elgin Sandstone, description of two New Genera. Phil. Trans. Royal Soc., vol. 185 B., p. 574 (1894). § Quart. Jour., Geological Socy., vol. xxxi., p. 424. 92, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the very poor fauna indicated by the fossil remains of the Elgin Trias, whilst their evidently carnivorous habit would require abundant food. Since he wrote that his evident expectation has been fulfilled, and the remains of a more abundant, though still restricted fauna have been found; but that we at present know of anything beyond a very small proportion of the Triassic fauna is very un- likely. The more we examine the footprints in our local Sandstones, the more certain we are that they represent a far more varied fauna than was supposed. At one time local geologists were content to name all the larger ones Cheirotherium and the smaller Rhynchosaurus. The late Mr. Morton considered* that only six species were repre- sented. Since then (1897) so many other forms have been noted that even after making due allowance for imperfect impressions, and differences between fore and hind feet, there still remains evidence of a fauna quite varied enough to furnish the food supply required by Professor Huxley’s reptilian carnivora. Of the flora which must form the basis of any food supply we know very little beyond the natural casts of a few equisetiform plants. We have traces of a more plentiful flora in the Upper Keuper, and it is quite possible that Upper Keuper conditions may have prevailed at no great distance outside our area at the time our Lower Keuper Sandstone was being formed. The consideration of this very interesting point would, how- ever, lead us beyond the limits of this address. _ We have numerous traces of the presence of inverte- brata. Some we may safely attribute to worms or Gasteropods, others, consisting of sinuous double rows of minute pittings, closely resemble those made by minute crabs; but the tracks of invertebrates are even more un- certain than those of vertebrates. : * Geology of the Country around Liverpool. Appendix page 299. FAUNA——-LOWER KEUPER SANDSTONE. 23 There is in the Woodwardian Museum at Cambridge a slab with a winding track about ~ of an inch wide, which { presume is referred to in the following extract from the catalogue :—‘‘ There are 5 slabs also arranged on “the Hast side of the compartment showing footprints of “various reptiles, of a Crustacean, and rain prints and “sun-cracks from the N.S.R. of Cheshire.” I was quite inclined to agree with the catalogue as to its Crustacean origin when I saw it, but within the last month I have seen similar tracks on the Leasowe shore and have doubts as to their Crustacean origin. In several instances there was at the end of the track a small hole going down verti- eally into the sand, but on digging down I failed to detect the presence of anything that could have made the track ; further investigation will be made. The results of our investigations may be briefly summarised thus :— I.—We have seen that we have no actual evidence of the presence of the Labyrinthodontia. I1.—That certain footprints very commonly found here are almost certainly those of Rhynchosaurus and allied forms. I1J.—That as regards the Anomodontia we are not so sure but that some short broad footprints are probably due to reptiles belonging to this order. 1V.—That with regard to Dinosauria we are quite in the dark; unless the Storeton footprints or Harkness’ tridactylate prints at Weston should eventually be found to belong to them, we have nothing that seems likely to fit them. i V.—And of the early ancestors of the Crocodilia we have so far seen no traces in our district. VI.—Of Fishes, no traces. VII.—Of the invertebrata, Vermes and probably 24 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Mollusca have left decided traces, as have also other inver- tebrates unidentified. We must remember that there are numbers of foot- prints different from any I have so far described or classi- fied. The great proportion of these are of small size, varying from in. to an inch in length. From the nature of the traces of fossil remains so far discovered in the Trias in this country, it is highly improbable that we shall find remains of animals small enough to fit these prints. The smallest hitherto found is the Telerpeton elginense, measuring a foot in length; it is included in the Rhyncho- cephalia; only two specimens have been seen, and in those the bones of the feet were missing. There may be some among the smaller prints due to these, but it is impossible to say which until we are able to compare them with remains that we may hope will be found elsewhere, where the conditions were more favourable to their preservation. The Paleontology of the Trias is perhaps more interesting, and its study is likely to lead to more impor- tant results than that of any other geological period. The expedition to Greece this spring has enabled Dr. A. S. Woodward to bring back to the British Museum a great amount of material which there is every hope will enable us to follow the later stages in the evolution of the higher vertebrata with far more certainty than has hitherto been the case. The earlier and more important stages, which took place probably during the period we have been look- ing into to-night, are comparatively unknown. Let the members of this Society bear this in mind when in search of a field in which to expend their energies. Rather more scope is, I believe, allowed in a presi- dential address to the exercise of the imagination than would be permissible in a more technical paper. I fear, however, that I may have exceeded that liberal allowance. . FAUNA—-LOWER KEUPER SANDSTONE. 25 If my suggestions and suppositions have been, as I iear they have, out of all proportion to actual fact, I must. plead as an excuse the very small amount of fact available, and I can only ask the members of this Society to help te supply the deficiency. — 26 Fig. Fig. Fig. Fig. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. EXPLANATION OF PLATES. Puate I, 1.-Natural casts of footprints of Chewrotherrum herculis in Brit. Mus. Nat. History. See Proc. Liv. Geol. Soe., vol. ix., plate v. 2. Fore limb, W&e., of Rhynchosaurus from the Keuper Sandstone of Grinshill, Salop, from a photograph taken, with the kind permission of the Shrewsbury Museum Committee, by Mr. Forest, of Shrewsbury. Puate II. 1. Slab of Sandstone, probably from Storeton, with natural casts of two series of footprints in Owens College Museum, from a photograph taken by permission by Mr. Ward, of Man- chester. aandc,right pes; b, left pes; between a and b the print of the right manus is shewn. d, ce, f belong to another series. 2. Footprints from the Keuper of Newton Nottage, Glam., now in the Cardiff Museum. A 2-foot rule is shown against the slab. The length of the middle digit is nearly equal to that of the impression of the whole pes on Fig. 1. (1am indebted to the courtesy of the Authorities of the Cardiff Museum for the photograph from which this is taken.) Prats I. . = ¥, . cry { =! / y) 4 ad ’ 7 ! Me ~ : ; Li, bs Prats II. Fig. 2. = ee 27 FIFTEENTH ANNUAL REPORT OF THE LIVERPOOL MARINE BIOLOGY COMMITTEE AND THEIR BIOLOGICAL STATION at PORT ERIN. By Professor W. A. Herpman, D.Sc., F.R.S. Tne most important event that falls to be recorded this year is the arrangement concluded with the Government of the Isle of Man, as a result of which we shall in future occupy increased Laboratory accommodation and_ be responsible conjointly with a committee of the Tynwald Court for the conduct of a large Aquarium and Fish Hatchery. A detailed statement as to how this change has been brought about, as to the position of our’ Com- mittee in relation to the Manx Government and as to the probable effect upon our work will be given below. But it must be obvious to all that as this implies a removal from our present Biological Station to larger and more convenient buildings on a better site at the other side of the bay, it is clearly the most important event in the history of the L.M.B.C. since we first established our laboratory at Port Erin. This then is the last Annual Report which will deal with the present Biological Station. Next year’s Report will have to do with a much larger concern, in which more attention will be given to fisheries investigations and economic work than has been possible in the past. We have now had a Biological Station in working order for fifteen years. The first five 28 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Annual Reports recorded the work at the Puffin Island Station, and the next series of ten (ending with the present Report) dealt with the first Port Erin Laboratory. It is hoped that next year’s Report, the first of a new series recording increased space, staff, facilities and responsibilities, will also record an increase of workers and of work in the new combined Biological Station, Aquarium and Fish Hatchery. | During the past year the usual work, both educational and in research, has been carried on steadily. A party of students and investigators occupied the Laboratory in the Kaster vacation, and several collecting excursions were arranged for their benefit. The new University of Birmingham has, we are glad to report, engaged a work place permanently in the Laboratory, at an annual rent; and two students from the Zoological Department have already been sent by Professor Bridge to carry on work. Three Universities have now engaged work places in this manner for the benefit of their Biological staffs, and in the new Station we shall be able to offer increased space and facilities to any other teaching or other institutions (such as Museums) which desire to take advantage of the opportunities for marine biological work which we can afford. We publish now, as an Appendix to this Report, the “ Guide to the Aquarium,” which has been in preparation for some time. It will also be printed separately for use in the new Aquarium. Tue Sratton ReEcorp. During the past year the following naturalists have worked at the Biological Station, in addition to: the MARINE BIOLOGICAL STATION AT PORT ERIN. 29 Curator (Mr. H. C. Chadwick), who has been in constant attendance with the exception of his usual holiday. DATE. NAME. WORK, Hebruary 9th )\ Prof. Herdman ae ae eae fea : to 11th) Mr. I. C. Thompson wid Pa see) Official, April aA ror 4} Miss England, Owens College... ».. General, April 9th ycneida to Miss ite R. Thornely, Liverpool ... and Rand Polyzoa, April ie 29nd Miss Lunt, Owens College... can ... General, April 9 i Age ‘i Miss Jordan, Owens College Sy. ... General. April a ioe Prof, Herdman _... selec .. Tunicata. April a (My. F. W. Headley, Haileybury cones ) re ea May 2nd (Me. O. L. V. Simpkinson, do, ve | May 29th \ Mir Wilson, Manchester... Hee ... General. to June 3rd ) June 15th (Prof. Herdman a “ihe an ee Official to 18th | Mr. I. C. Thompson ties MUR aren Sen agree July 15th ) to Miss M. Clarke, University, Birmingham. General. August 17th j August Ps th Mr. Tattersall, Univ. College, Liverpool... General. August 13th ) ( Marine Insects to -Mr. A, D. Imms, University, Birmingham + and September 3rd | | General. Rephen EP Ba | Mr. H. Yates... Polycheta. September 21st {| Prof. Herdman : “a nap ny aes to 23rd { Mr. I. C. Thompson... ay bey a) Oierals Photography October find | Rev. T. S. Lea { of Marine Y j Animals. a Prof. Herdman . AS? Mc. LC. Thompson... ... + oNosten 0 Te ORsI Metta er SF Ee Mry A. ELolt; jun, +>... ae ae .» Hydrography There have also been, as usual, visits from several scientific men and Societies. 30 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Mr. Chadwick reports to the Committee as follows :— Curator’s REporT. “The work of the Station has been carried on steadily and -successfully throughout the year, and an average number of students have availed themselves of the accom- modation and facilities provided for the study of hving marine animals and plants. The Easter party was this year more than usually successful, and much good work was done. “In view of the addition of fish hatching and culture to my curatorial duties, I have devoted a good deal of time this year to the acquisition of knowledge of fishery matters. During the month of March I spent a fortnight at the Sea-fish Hatchery of the Lancashire and Western Sea Fisheries Committee at Piel, Barrow, and, under the able guidance of Mr. Andrew Scott, carefully studied the apparatus and methods used there in hatching the eggs of sea-fish. In trying to gain information from local fisher- men at Port Hrin I have been less successful. Owing partly to their lack of interest in anything that does not directly affect the capture and sale of fish, and partly to jealousy of each other, they can only with difficulty be induced to give information, and their statements. are often vague. One of them, F. Watterson, was, however, good enough to keep the record given below, of the fish taken by one boat during what is known as the “ winter fishing ”’ of 1900-01. Fishing was frequently interrupted by stormy weather, and the number of fish caught was said to be below the average. “Fishing with a drag net from the shore, locally kriowe ‘trawling,’ was carried on, as in previous years, early in October, but. always after nightfall. On several occa- sions large numbers of the Saithe or Coal-fish (Gadus virens) MARINE BIOLOGICAL STATION AT PORT ERIN. 31 were taken; while grey Mullet (Mugi chelo), Turbot (Rhombus maximus), and a fish rather mysteriously referred to as “Salmon-trout’’ made up the catches in small and varying numbers. The Saithe, locally known as “ Bloghan,” is extensively fished with rod and line, and the occurrence of fine and calm evenings at the time named favoured good sport. ‘The “ back” herring fishery appears to have been more than usually successful this autumn, and it is worthy of note that on the Hast side of the Island the capture of the fish involved the destruction of an enormous quantity of spawn. ‘““T have continued my investigation of the fauna of Port Erin Bay by collecting, at frequent intervals, on all parts of the beach and by occasional dredging excursions. The Nudibranch Galvina cingulata and the Crustacean Athanas nitescens are now recorded for the first time, the former having been taken in December, 1900, and the latter in March, 1901. Polycera lessont was also found, on June 18th. Two specimens. of the beautiful little Polychete Gattiola spectabilis were found in a rock pool early in February. This worm has not come under obser- vation for some years past. I have devoted a good deal of time to the study of the Compound Tunicates, and have made some careful drawings for Professor Herdman of a number of representative species. Mr. P. Nevill kindly sent some Compound Tunicates and other animals, obtained by diving, from below low-water mark at the Battery Pier, Douglas. “The Plankton fauna of the bay has resembled that of former years. Noctiluca occurred very sparingly in one tow-netting taken on January 11th, and in several taken in August. It is remarkable that this widely distributed organism should have been observed in enormous numbers on the north coast of Anglesey by Professor Herdman 32 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. during August this year and last, when it was scarcely represented here. Aurelia aurita, not uncommonly in- fested by the Amphipod Hyperia, was abundant within the limits of the bay in July and August; and during the latter month, for the first time since I assumed the curatorship, a species of Cyanea was well represented, but none of the specimens seen were of large size. P2lema octopus also occurred frequently, and some of the speci- mens measured 12 to 15 inches across the umbrella. No complete specimen of the Siphonophore Cupulita sarsi came under observation, but many detached nectocalyces were noticed in the tow-nettings in July and August. Pleurobrachia has occurred in varying numbers from May (when some of its early stages were seen) onwards, but very few specimens of Beroe ovata were noticed this year. A single Actinotrocha larva was taken on August 12th. Ovkopleura, seldom absent from the surface fauna, was extraordinarily abundant on January 11th and September 14th. Fish eggs were abundant on the surface in April, and in one tow-netting taken by Professor Herdman on the 10th of that month, those of the Flounder, Turbot, Witch, Ling, Haddock, Cod and Dragonet were identified by Mr. A. Scott. “Several valuable additions to the Station Library have been made during the year, the most noteworthy being six volumes of Challenger Reports, presented by the Lords of H.M. Treasury. “T have paid a good deal of attention to the orders received for living and preserved specimens, and have successfully supplied several workers with quantities of material for their investigations. It is, however, unfor- tunate that the majority of these orders are received during the winter months, when low tides occur after dark, and unfavourable weather makes dredging almost MARINE BIOLOGICAL STATION AT PORT ERIN. 33 impossible, especially in the absence of capable assistance. “ Nearly 500 visitors were admitted to the Aquarium during the season—a fairly large number when the secluded situation of the building and the comparatively small lodging capacity of the town are considered. “The projected Fish Hatchery has greatly increased the interest of fishermen and visitors in our work, and probably accounts for the marked increase in the number of the latter as compared with last year. Increased experience has enabled me to keep the animals in health for a much longer period than formerly, and the mortality amongst them at the time when the summer temperature was highest was much less than in former years. The conger noticed in last year’s Report is still alive and healthy. It takes food greedily whenever offered, and will snap at a hand held over the edge of the tank; but, though fed liberally at intervals, it does not appear to have grown appreciably. Another conger has occupied the same tank for some months past, but has only quite recently begun to feed. The lobsters have attracted an . extraordinary amount of attention on the part of visitors, and I have been able to make some further observations on their habits. I find that the carapace does not invariably split along the median line when the shell is east. The shallow wood tanks have not been disturbed since their establishment in the early spring of 1898, and now contain an interesting collection of well acclimatised anemones. ‘In addition to these, such Molluscs as 7'rivea, Tapes, Pectunculus, and various species of Venus have lived therein for months, the first-named for over a year, and a specimen of Linews marinus, that longest of long worms, has lurked under a stone since the early spring, always ready to display its sinuous length on the intro- duction of a few morsels of fish, which it swallows in a 34 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. peculiar snake-like manner. oqo ooo oqo o £. Sa Oe 62 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Subscriptions. Donations. Forward.. Headley, F. W., Haileybury College, Hertford si ao tee Henderson, W. G., the late, Liverpool Herdman, Prof., University College Hewitt, David B., J.P., Northwich Holland, Walter, Mossley Hill-road Holt, Alfred, Crofton, Aigburth ... Holt, Mrs., Sudley, Mossley Hill Holt, R. D., 54, Ullet-road, Liverpool ... Hoyle, W. E., Museum, Owens College Isle of Man Natural History Society Jarmay, Gustav, Hartford Jones, C.W., J.P., Allerton Beeches Jordan, Miss, Owens College, Manchester Kermode, P. M. C., Hill-side, Ramsey ... Lea, Rev. T. Simcox, St. Ambrose Vicar- age, Widnes ... Lea, Mrs. T. Simecox, ae Leicester, Alfred, Dacre Hill, Rock Hee Lewis, Dr. W. B., West Riding Asylum, - Wakefield >: Lunt, Miss A. J., 55, Gea: era. West Didsbury Manchester Nievodeantiet eee Meade-King, H.W., J.P., the late Meade-King, R. R., 4 Oldhall-street Melly, W. R., 90, Chatham-street Monks, F’. W., Brooklands, Warrington Muspratt, E. K., Seaforth Hall ... Newton, John, M.R.C.S., Prince’s Gate Forward ...£65 4 6 £S. as a oo INS) Sy fie) [ee eS eS NS DO hos to ey eS — ee i | a fae d. 0 Sao a So @2 eo See Ss © © fs. pe eae © ee 2 12 ie MARINE BIOLOGICAL STATION AT PORT ERIN. 63 Subscriptions. Donations. Se Forward...£65 4 Okell, Robert, B.A., Sutton, Douglas aS! Paterson, Prof., University College eal Rathbone, Mrs. Theo., Backwood, Neston 1 1 Rathbone, Miss May, Backwood, Neston 1 1 Rathbone, W., Greenbank eae apy ae) Roberts, Isaac, F.B.S., Crowborough ee, Simpkinson, Rev. O.L, V., Stoke-on-Trent 0 10 Simpson, J. Hope, Aigburth-drive lek Smith, A. T., 35, Castle-street ... dts | Somerville, Alex., Hillhead, Glasgow eat! Talbot, Rev. T. U., Douglas, Isle of Man 1 1 Thompson, Isaac C., 53, Croxteth-road... 2 2 Thornely, The Misses, Aigburth-Hall-rd. 1 1 Timmis, T. Sutton, Cleveley, Allerton ... 2 2 Holl. Me; Kirby Park, Kirby ... Pete eh il Walker, A. O., Uleombe Place, Maidstone 3 3 Walker, Horace, South Lodge, Princes-pk. 1 1 Watson, A. T., Tapton-crescent, Sheffield 1 1 Weiss, Prof. F. E., Owens College, Manchester lee | Wiglesworth, Dr., Rainhill es Wilson, J. H., 24, Bune Street, Son 0 10 Yates, Beaty, 79, Shude-hill, Neon ic eee dk Se. @ (epee 2 e7e7e 2 2 2S o7e 2] 2 S302 Soo = og ah OIE 6 SUBSCRIPTIONS FOR THE Hire oF CoLLEGEe ‘‘ WorK-TABLES.”’ Owens College, Manchester University College, Liverpool Birmingham University £10 0 0 Oo O-2 9 HO, OF 0 £30 0 0 ‘HLINS “L °V CP oute Gece Olds One ALG 9-81 -S Scat Ea E S- OL Le OF OL4G ORG i imei OS 3 iG 0 O O€ 9 GL 6 ea a <2 0) “9904409 punof pun payipny "9" SQIVYS S,"OD OSnOF Opn S,UvVUIyIOAA YS —! pun po seauTy JUOUMOpUT rresreees TOBT “sTe ‘ooq ‘oINSBoIy, onp soULTeg Cee eee cceeececeseneesereessece wmnienby 07 SUOTSSTUIP VY steeteeeeeeeeserseseeeeersseeserseeeeeeeen ACOTOQUT JURE “* pun (968T) UOTZRLOOSsW YSTJLIG WO 4ser0qUT eee ese cee rescsesssere SSUIMVIC, jo qysttkdog jo a[es sreeeeeeeeeePUNB T JO SOUIN[OA PUB SzLOdaxT JO 9[Bg eee escacoreeccoresccoecs sueuw1oedS “ISTH "qUN fo avs See eeersseoeseesssesesssnseessreeoeesesereee soreysg “paT “On 9snoPFy O[qng S,URULyIO AA YSIyAIg ‘pueplatd rtetteeeesseesesneeeertesecrseterss —° SOTQBT SAOAN 33 JO OIIY 10j ‘oI “SeSaT[OD ULOI] poatoooa QUNOWLY Tresrererers NOQATQDOI SUOTJVUOG pu suOTydrIOSqng Aq “TO6L 66 66 > ‘TO6T ‘ISTE saquieseq: ‘TOOdUAAL'T "UAUASVAUT, “NOH ‘NOSdINOHL ‘0 OVYSI 4 eeeee eee emcee weer ese ses SSH SHEESH SESHEHE HES EEEEHEEee solipung a4 Coane Se es UOL4VYG [BOLSO[OLG ULIGT WO Jo US 06 wet e tere reece ese e sense eee eseaeesse serene Ioyvany ‘KIBTRS 73 © steeeseesereres O09 ‘strauITIedg JO osVlIAIRD ‘eseqysog Go tretetteaeetiseertsesesseeeeteeeerretterseetes TOMIRAG jeorsojorq uN 4ytog ye snyvaeddy pur syoog 57 Beers rere essere osesesses saredoyy qyvoqg pur Chay ei qyeog ce LT octets -suorpipedxq Sutspeiq jo sesuedxqy j wee eee e nese ccs vescseseseerese. AXOUOTYBIS pur Ssurqyutg TT@ ccc soqeig Surarrisug pur syrodey suryuiag 0 g mr DOW ri Se So =H PN ReN ealg se Oarodo srreeeereeeenneT “asTe ‘oad ‘LoANSveLy, onp soured OF, “TO6T TH n ‘aauASvVady, “NOH ‘NOSdINOMW ‘) OVVYSI HIIM GNONODOYV NT 1G ‘AH LLINWNOO ADOTOIC ANIYVN TIOOCUHAIT WA Liverpool Marine Biology Committee, PORE ERIN PeeeOGICAL STATION. PGUIDE POP A WEL, AQUARIUM: Being a Short Account of some of the Common Marine Animals of the Neighbourhood. WITH ILLUSTRATIONS. PRICE THREE PENCE. LIVERPOOL: C. TIntinG & Co., PRINTERS, 53, VICTORIA STREET. EO) OF Zi, F 66 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Liverpool Marine Biology Committee. Executive. Chairman and Honorary Director of the Laboratory : Proressorn W. A. Herpman, F.R.S., University College, Liverpool. Honorary Treasurer and Secretary : Mr. Isaac C. THompson, F.L.S., 58, Croxteth Road, Liverpool. Committee. Mr. R. D. Darsisutre, F.G.S., Manchester. Pror. R. J. Harvey Grsson, F'.L.8., Liverpool. His Excettency Lorp HENNIKER, Isle-of-Man. Mr. W. HE. Hoyret, M.A., Owens College, Manchestems Mr. P. M. C. Kermope, Ramsey, Isle-of-Man. Mr. A. Leicester, Liverpool. Sir James Poors, J.P., Liverpool. Dr. Isaac Rozerrs, F.R.S., formerly of Liverpool. Mr. A. O. Warker, J.P., F.L.S., Maidstone. Mr. Arnotp T. Warson, F.L.S., Sheffield. Curator of the Biological Station : Mr. H. C. Cuapwick, Port Erin. MARINE BIOLOGICAL STATION AT PORT ERIN. 67 Gute To THE Port Erin Aouarium. Intropuctory Norte. Tue Port Erin Biological Station was established by the Liverpool Marine Biology Committee primarily for pur- poses of scientific research. The first building, the Laboratory, was opened by Sir Spencer Walpole, then Lieutenant-Governor of the Isle of Man, in June, 1892; and the second building, the Aquarium, was added in March, 1893, for the double purpose of permitting of observational and experimental work, and of enabling the public to see something of the wonderful variety and interest of life in the ocean and on the sea-shore. It is evident to us, both from our own limited experi- ence in this‘small Aquarium, and also from the history of other similar but larger institutions elsewhere, that much public interest can be excited and much useful educa- tional work accomplished by well-arranged and adequately stocked and properly kept marine tanks, especially if combined with scientific guidance and personal exposition. The latter, however, although very desirable, is not abso- lutely necessary, and is not always possible, as it some- times makes too severe a strain upon the limited time that the Curator can spare from his other duties. It is hoped by the Committee that the present little guide, drawn up by the Hon. Director, with illustrations by the Curator, Mr. H. C. Chadwick, will enable visitors to the Aquarium 68 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. to study the tanks and specimens for themselves with intelligent interest, to recognise representatives of the leading groups of marine animals, and to make some acquaintance with the nature and range, the beauty and the importance of the living things of our seas. The majority of the figures are original, and were drawn by Mr. Chadwick from specimens found at Port Erin; the rest were copied more or less closely from well- known works of the following authors:—Claus, Gosse, Savile Kent, Jeffrey Bell, Hickson, McIntosh, Watson, Balfour, Brady, Herdman, Sars, Korscheldt and Heider, Jeffreys, Day, and Alder and Hancock. Soon after this guide is printed, it is hoped that the old Biological Station will be vacated, and that the Liver- pool Marine Biology Committee will move into the more commodious new Laboratory and Aquarium now being erected in conjunction with the Government Fish Hatchery on the South side of the bay. The conditions and requirements of that new institution have been kept in view in choosing the groups and types to be described and illustrated in the pages that. follow. W. A. HERDMAN. University College, Liverpool, November, 1901. MARINE BIOLOGICAL STATION AT PORT ERIN. 69 PaO OZ, Ora. (Hig! 1) The lowest and simplest animals in the sea are not, as some seaside visitors suppose, the jelly-fishes, zoopiytes, and sea-anemones, nor even the sponges, but they are minute delicate creatures, the Protozoa, found swimming in the clear water or lying on the mud and sea-weeds, and Hie: T. for the most part far too small to be seen without the microscope. And yet they are of immense importance in the world. They are very numerous, and form the food of larger animals in the sea. Many of them are eaten directly by young fishes, and a French naturalist has 70 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. calculated that the Sardine takes as a meal about 20,000,000 of the small Ceratewm tripos shown in fig. I. at 2; while Professor Hensen has found 130 millions of them in 10 cubic metres of water from the Baltic. This and other kinds of Ceratcwm (1 and 3) are one of the chief causes of the luminosity or “ phosphorescence ”’ of the sea. Another little Protozoon which frequently causes the sea to sparkle with hight in the night is Noctiluca miliaris (fig. I., 5), which is occasionally present in great abundance in the Irish Sea. These all swim on the surface of the sea, but there are many other Protozoa which have heavy shells, and are usually found on the bottom or attached to other objects. A good example of this is Rotalia beccarw seen at 4, and belonging to the Foraminifera. In some parts of the world Foraminifera are so abundant that their minute limy shells accumulate as enormous deposits covering many million square miles of the floor of the ocean, and those that existed in former times now build up mountain ranges in some parts of the world. There are other Protozoa occasionally seen at the seaside, such as Lolliculina ampulla (No. 6), enclosed in a delicate shell and protruding its soft body, bearing a fringe of numerous delicate hair-like filaments, by the lashing of which food particles are wafted to the mouth; and Tvntennus campanula (No. 7), a somewhat similar form, which floats in the sea and can be captured by a fine muslin net. There is a group of microscopic plants, the Diatoms, which is worthy of attention because of its great import- ance as a food of animals. Diatoms are unicellular Alge, and a few of the commoner forms are shown in the figure: 8 is a Biddulpha, 9 a Coscinodiscus, 10 is Chaetoceras secundum, and 11 Bacteriastrum varians. Fully detailed reports upon the Foraminifera of our district by Mr. Siddall and others, and upon the Diatoms MARINE BIOLOGICAL STATION AT PORT ERIN. ie by Dr. Stolterfoth, will be found in the volumes of “Fauna of Liverpool Bay,’ published by the L.M.B.C. The rest of the marine plants, or sea-weeds, have been reported on by Professor Harvey Gibson. PORIFERA. (Fig. IL.) We all know the bath sponge, but some people do not realise that it is only the horny skeleton of an animal, and that there are many sponges living in our own seas, some of which also form horny skeletons, but which would not be suitable for domestic use because of their contain- ing numerous sharp-pointed glassy spicules or bristles which strengthen and protect the body wall. If we omit the minute and very simple unicellular Protozoa, sponges are the lowest of animals. They are the lowest of the “‘ Metazoa,’ or animals whose bodies are built up of more than one cell. All animals from sponges upwards to the highest are Metazoa, so the primary classi- fication of the Animal Kingdom is into—(1) Protozoa, the first, lowest and simplest animals, and (2) Metazoa, all the rest. Wherever there are rocks and sea-weeds you can find sponges at low tide. For the most part they are found on the lower surface of stones, or in crevices of rocks, or sticking on the roots of large sea-weeds. Fig. IL. shows 3 very common kinds of British sponges which are found almost everywhere round our coasts. Sycon ciliatum (1) and Sycon (or Grantia) compressum (2) like many others, have microscopic spicules made of hard chalk or carbonate of lime, while in most of our sponges, as 1n 72, - TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the crumb-of-bread sponge (Halichondria panicea), shown at 3, the spicules are of silica or flint. This enables us to distinguish two important sets of sponges, the Calcareous and the Siliceous. Sponges were at first thought to be lifeless, then for a time they were regarded as plants. Professor Grant, after whom a common sponge was called “ Grantia,” first Hie. EL. showed that they were animals, and that while alive a current of sea-water passes through the sponge—in by minute pores all over the surface, and out by one or more larger crater-like openings. The reports upon the sponges of our district have been written by Dr. R. Hanitsch. MARINE BIOLOGICAL STATION AT PORT ERIN. 73 COMLENTERATA. (Figs. IIT. to VI.) This important group of animals includes the plant- like Zoophytes, the Medusz or jelly-fishes, and our familiar Sea Anemones, as well as many animals, such as the reef-building corals, which are not found in our seas. BiG ell Fig. III. shows pieces of several of our commonest British Zoophytes. They are all colonies or assemblages of small animals united together and fixed to one spot so as to have a rooted plant-like appearance. But although rooted and branched, and known as animal-plants (Zoophytes), it must be remembered that these colonies are true animals, and are moreover not the lowest animals, or those nearest 74 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. to plants, but are distinctly higher than the Protozoa and the Sponges. A piece of one of the “ Sea-firs,” or Sertu- larian Zoophytes, is shown, natural size, at 3 (Sertularia abietina), where each of the little angular enlargements or projections on the stem and branches is a horny cup con- taining one of the members of the colony. _ Another Sertularian Zoophyte (Sertularella polyzonias) is seen en- larged in the living condition, under the microscope, at 1. The little members of the colony (the Zooids) are seen protruded from their delicate horny cases. Each has an open mouth surrounded by about 20 delicate filaments, the tentacles, by means of which the Zooid catches food from the surrounding water. Hach such Zooid is very similar in structure and appearance to the little fresh- water Hydra, and consequently these colonies are fre- quently called “ Hydroid Zoophytes.”’ Another common and closely related kind of Hydroid Zoophyte (Obelia geniculata) is seen at 2. This is called a ‘“Campanularian ’ Zoophyte because each cup containing a Zooid is bell-shaped and placed at the end of a ringed twig or handle. This figure also shows certain larger cases, in which are formed special buds that become detached as little glassy bells or jelly-fishes for the purpose of producing and scattering the eggs that will eventually give rise to new colonies. The fixed Hydroid Zoophyte thus gives rise by budding to free-swimming Medusz (like that shown at 10, fig. XII.); and the Medusa pro- duces eggs which give rise to fixed Zoophytes. Such a life-history is an example of “ alternation of generations.” Various reports upon the Hydroid Zoophytes, by Miss L. R. Thornely, will be found in our volumes. Mr. HK. T. , Browne has contributed some papers on the Meduse from work done at Port Erin. Many of the smaller jelly-fishes of our seas are there- MARINE BIOLOGICAL STATION AT PORT ERIN. 75 fore merely free-swimming stages in the life-history of Hydroid Zoophytes, and these are frequently spoken of as “Medusoids.”” Some of our larger Meduse, however, such as the Awrelia shown in fig. LV. are not produced as buds on a fixed Zoophyte colony, but have a somewhat different life-history. As fig. [V. shows, the fertilised egg of an Aurelia becomes an ovate free-swimming embryo Fic. IV. which settles down and grows gradually into a Hydra-like Zooid with a mouth and long tentacles. Then the body becomes transversely constricted and divided into many pieces, which, when completely separated, lie like a pile of saucers or soup-plates. As they float away from the pile each such ‘‘ Hphyra” is seen to be a little Medusa, and they grow into young Aurelias. 76 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Amongst the rarer of the large Medusze which enter Port Erin Bay there is one (Pelagia perla) which is marvellously phosphorescent, glowing in the water like a ball of incandescent metal. Sea-anemones are abundant and varied round the South end of the Isle of Man. Fig. V. shows several of _ the more important kinds found at Port Erin, most of /Halcampa chrysanthellum. 2 Actinia equina. 3. Metridium dianthus. 4Sagarlia venusta. 5 Bunoedes verrucosa which are generally on view in the Aquarium. Adctznza equina (or A. mesembryanthemum), No. 2, is the common dark red, smooth-bodied anemone which sometimes has a row of bright blue spherules round the body at the base of the tentacles. Metridiwm (or Actinoloba) dianthus (3) 1s the plumose anemone, found at low tide attached to the blocks of the old breakwater. It is generally of a pure MARINE BIOLOGICAL STATION AT PORT ERIN. VE white colour, but pink specimens are sometimes found. No. 4, Sagartia venusta, is a representative of a large group of small anemones to which the brilliant red and white ones of the Sugar-leaf Cave, and of the Clets in the Calf Sound, and the cave-dwellers (S. troglodytes) of pools at Fleshwick and elsewhere all belong. Halcampa chrysanthellum is a small and simple form found occa- sionally, and Bunodes verrucosa (or B. gemmacea), No. 5, is a pink anemone found in the pools at Port Erin and easily recognisable from its colour and evenly roughened or papillose surface of the body. The large “crass ”’ (T'ealza erassicornis) is often brilliantly striped and spotted with red and white, and usually attaches sand, shells and small stones to the outside of the body. We have one anemone (Anemonia sulcata), the “snakelet,” which is unable to retract the tentacles. Altogether we have found more than 20 different kinds of sea-anemones in the neighbourhood of Port Erin. Mr. J. A. Clubb, of the Liverpool Free Public Museum, is our local authority on sea-anemones. Sea-anemones are the British representatives of the reef-building corals of tropical seas. The coral animals are colonies of polypes, each of which is somewhat like a sea-anemone with a calcareous skeleton. Our nearest representative of the Mediterranean animal which forms the red coral of commerce, is Aleyonium digitatum, sometimes known as ‘“‘ Dead men’s fingers’ or “ Dead men’s toes.”’ This is a common, white, or orange colony, of fleshy consistency and lobed shape (see fig. VI., 1), which is found attached to the under side of the great blocks of the old breakwater at low tide. The surface of the colony is covered when alive and expanded with anemone-like polypes, each of which has 8 fringed tentacles surrounding a smali central mouth. No. 2 shows 78 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. a polype with its tentacles, and No. 3 some of the scattered spicules of carbonate of lime which are found imbedded in the flesh of the colony. No. 4 shows another much rarer animal (Sarcodictyon catenata), obtained by dredging in deep-water off Port Erin. It is closely related to Alcyonium, and figures 2 and 5 show that the polypes are very similar, although the colony of Sarcodictyon (No. 4) is merely a creeping red rootlet or ‘“stolon’’ connecting the bases of the small conical polypes and generally attached to a dead shell or a piece of stone. No. 6 shows the spicules, which are red, and cause the colour of the colony. Professor Hickson, of Manchester, has written our L.M.B.C. Memoir on Alcyoniwm, and Professor Herdman has contributed some papers on Sarcodictyon to our Reports. MARINE BIOLOGICAL STATION AT PORT ERIN. 79 ECHINODERMATA. (Figs. VII. and VIIT.) Star-fishes, Sand-stars, Brittle-stars, Feather-stars, Sea-urchins and Sea-cucumbers are all characterised by having plates and spicules of lime in the skin which may project from the surface as spines. Hence they are known as “ prickly-skinned”’ animals (Echinodermata). They also have as another important characteristic a remarkable system of tubes containing a watery fluid, parts of which can be protruded as suckers for locomotion. These suck- ing tubes can be seen acting as feet in star-fishes or sea- urchins creeping up the glass of an aquarium. In the Echinus shown at 5 (fig. VIII.) the short straight pointed projections are calcareous spines, and the longer flexible bodies are tube-feet, with suckers at their ends. 80 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. All the leading sections of existing Hchinodermata are found at Port Erin, as follows :— Crinoips, Feather-stars: Antedon rosaceus (fig. VIL., 1) is found in deep water off the cliffs. In the young (“‘pentacrinoid’”’) stage it is fixed by a long stalk to the blades of the great brown oar- weed (Laminaria), as shown at 2, and magnified at 3. te 260 P0205"! esa09.oD000aS wt = i epee. <0) Ly DIATE SO eet beet ya Nt ANS Mages ith) . Ts BIBS p she ap Ig 00.0: 00:00 eee ydebosaceca0 Sefer 00 ORS ac 09D; Mea poate, hed 1 Asterina gibbosa 2 Asterias rubens 3 Ophiothria fragilis 4 Cucumeria planci 5 Echinus esculentus Fie. VIII. ASTERIDS, the common star-fish, Asterias rubens (fig. VIII., 2), the Sun-star, Solaster papposus, and the little Asterina gibbosa (fig. VIII., 1) are all common at Port Erin, and are usually to be seen in the tanks of the Aquarium. We have fre- quently deep-water forms, such as the brilliant red Porania pulvillus, the flat pentagonal Palmipes placenta, and the pale strawberry Stichaster roseus obtained on dredging expeditions. MARINE BIOLOGICAL STATION AT PORT ERIN. 81 Oruturips, the sand-stars and brittle-stars, such as Ophiothrix frags (fig. VIII., 3), have no suckers on their tube-feet, and can be seen to have an interesting new method of locomotion peculiar to themselves; they jerk their bodies along by alternately curving and straightening their muscular many-jointed but fragile rays. Ecurinips, Sea-urchins. In addition to the “regular ” urchins, such as the large pink Hchinus esculentus (fig. VIII., 5), found on the rocks and breakwater at low tide, and the smaller dull green HF. millcaris, found in the rock pools, there are at Port Erin several kinds of the delicate “ heart” ’ or “oblique” urchins. The commonest of these is E-chinocardium cordatum, which burrows a few inches below the surface of the sand at low tide in the centre of the beach. HoLorHurips, Sea-cucumbers. The elongated, worm- like body has a mouth surrounded by a crown of tentacles at one end, while rows of sucking tube- feet run down the 5 angles of the body. The skin is strengthened by calcareous plates, often of delicate and beautiful shapes under the micro- scope. Cucumaria plana (fig. VIII. 4) is dredged from deep water; another kind, Synapta digitata, which has anchor-shaped spicules in the skin, and no tube-feet, is found burrowing in sandy gravel at low tide, in front of the old Biological Station. The eggs of all these common Hchinoderms develop first into minute larve which are quite unlike the parents in appearance and structure, and are found floating on the surface of the sea. A larval Ophiurid, called “ Pluteus,”’ G 82, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. is seen at 8, and a larval star-fish, called “ Bipinnaria,” at 7, on fig. XIT. Mr. H. C. Chadwick, the Curator of the Biological Station, is our local authority on Echinodermata, and has written a Memoir on Hehinus and several other papers for our series of volumes. VERMES. (Figs. IX. and X.) There are very many kinds of marine worms. Some are microscopic, some are parasitic in or on other animals, and some are lowly developed and very sluggish, and inhabit mud and decaying sea-weeds, such as species of Tetrastemma and Lineus, usually to be seen in our tanks. We shall only illustrate here a few of the higher forms, which are of fair size, of active habits, and are provided with feet or bristles on the segments of the body. These higher bristle-bearing marine worms, or “ Annelids,’ fall into two sets—the Hrrantia, those that wander freely, creeping over rocks and sea-weeds and under stones, and the Seden- taria, those that inhabit tubes either fixed or moveable. Amongst the commonest of our Errant Annelids are the Nereis pelagica (1) and the Polynoe (Lepidonotus squamatus) (2) shown in fig. 1X. No. 3 on the same figure is a sedentary Annelid, the little Spororbis borealis, which makes small spirally coiled white calcareous tubes on the surface of stones, dead shells, and coarse sea-weeds all round our shores. ‘The tube alone looks like a little shell, but it is a worm which builds it, lives in it, and which while alive can protrude from the opening a beautiful plume of delicate branched tentacles as is seen in the MARINE BIOLOGICAL STATION AT PORT ERIN. 838 figure (IX., 3). Serpula makes larger white calcareous tubes, and is frequently seen in our tanks. These are only a few of the very many kinds of bristle-bearing marine worms or Annelids (for a full list see the report in our “Fauna,” by Mr. J. Hornell). Other common species are the fisherman’s lug-worm, Arenicola marina, Ses \W oe \Vi RQ < SS Nig Pie. Ss, and the sea-mouse, Aphrodite aculeata, both found burrowing in sand. These and various other kinds are generally to be seen in the shallow table tanks of the Aquarium. Some of the Sedentary Annelids inhabit tubes made of sand grains, and one of the members of the 84 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Liverpool Committee, Mr. Arnold T. Watson, F.L.S., has devoted much time and trouble to a careful study of the methods in which these worms build up their very beautiful houses by selecting and cementing together particles taken from the surrounding sand and water. The 6 little drawings on fig. X. are copied from the illus- q) Ee) 9 4 a @ a) a 8) 6 9) ) :) 1) 1) D) .) D 9) ~ Fie. X. trations to one of Mr. Watson’s scientific papers, and they show the front end of the body and sandy tube of T'erebella conchilega, a common sedentary Annelid found in abund- ance sticking out of the sand at low water near Port Erin harbour. The middle figure in each row shows the head of the worm placing and sticking together sand grains on the top of its tube, like bricks on a wall. MARINE BIOLOGICAL STATION AT PORT ERIN. 85 In the upper one it is forming the outer coating, and in the lower the branched sandy filaments which surround the mouth of the tube, whilst some of the figures shew how the delicate tentacles capture and convey the sand grains, or building material. The right-hand lower figure shews the complete structure. ‘Two curious pelagic or free-swimming worms are shown in fig. XII., viz., Sagitta bipunctata at 2, and Tomo pteris oniscof ormis at 4. POLYZOA (Fig. XT.) On sea-weeds and under stones on the shore there are many beautiful little colonies of worm-like animals to be found, which, from their compound condition, are called Fig. XI. Polyzoa. Some are erect branched colonies (see fig. XI., 1 and 4) lke Zoophytes, from which they can only be distinguished by the microscope; others are flat and 86 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. incrusting (No. 3), and have a limy covering so as to be quite hard and brittle; some of the colonies form net- works extending for many square inches over the surfaces of stones and the blades of the great brown oar-weed. Flustra, the “sea mat’ (No. 1), is frequently found cast up amongst sea-weeds. A small piece is shown magnified at 2. Bugula (No. 4) is usually obtained by dredging; part of the colony alive and expanded with polypites and “pirds-head’’ processes is shown at 5. Forms lke Lepralva (3) are found under stones and on shells in rock pools. Specimens of these and other kinds of Polyzoa are generally to be seen in our tanks at the Aquarium. The reports in our “Fauna” are by Miss L. R. Thornely. CRUSTACEA. (Figs. XII. to XVIII.) Crustaceans are animals such as crabs and lobsters, shrimps and prawns, sand-hoppers and barnacles, and innumerable smaller forms, “‘ water-fleas”’ and the like, which abound in almost all parts of our seas. They all have segmented bodies and jointed legs, and a hard shell or covering to the body. They are, then, “ shell-fish”’ of © a kind, but they differ from the true shell-fish, such as oysters and periwinkles, in having segments and legs. Once the difference has been pointed out, no one can mistake a shrimp-like shell-fish for a cockle-like shell- fish. The former are Crustaceans and the latter Molluscs. It is better to reserve the term shell-fish for the Molluses. Among the most abundant of lower Crustaceans are the rock-barnacles or acorn shells (Balanus) which are so MARINE BIOLOGICAL STATION AT PORT ERIN. 87 abundant on rocks round our coast, and which by their white limy shells closely placed on the dark grey rock of Bradda Head give at low tide the appearance of a belt of whitewash encircling the base of the cliff. The ship- barnacle (Lepas) is closely related to Balanus. Its home is on the open sea, but specimens are occasionally drifted Hie, Sle in to Port Erin. Once we captured a floating ship’s bucket, which was covered inside and out with adhering barnacles, some large and some small. Most of the lower Crustacea (or Hntomostraca), unlike the barnacles, are free-swimming; and from their small 88 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. size, somewhat insect-like appearance and legs, and their active movements, some of them are often called “ water- fleas.” The most important group of the Entomostraca is the’ Copepoda. These little ‘‘ water-fleas”’ are exceedingly abundant in the sea, and are of great economic import- ance. It has been calculated that under each square metre of the surface of the Baltic there are one million Copepods, and that these use annually 4,730 millions of the small Ceratiwm (see before) as food. Herrings feed largely on Copepoda, and for a square mile of surface water it has been shown that the annual consumption of Copepoda is nearly 1,000 billion. Now a billion of Cope- poda yields not less than 1,500 kilograms of dry organic substance, and consequently in the 16 square miles of a _ certain Baltic fishery the German biologists consider there exists Copepod food for over 530 millions of Herring of an average weight of 60 grammes. Two common Copepods are shown in fig. XII., Temora longicornis at 9, and Pseudocalanus elongatus at 12. Each of these is about 4 of an inch in length. Myr. Isaac C. Thompson, Hon. Treasurer of the Committee, is a well-known authority on the Copepoda, and has written many reports and papers published in our volumes. When a fine muslin or silk net is drawn through the water of Port Erin Bay for a few minutes, at almost any time of the year, a number of small free-swimming plants and animals are captured. Such organisms are known collectively as “ Plankton.” Some of the more minute and simple of these (Protozoa and Diatoms) were shown in fig. I., while a number of the commoner and larger kinds of “ Plankton” are represented in fig. XII. They are evidently a mixture of young and old belonging to different groups. MARINE BIOLOGICAL STATION AT PORT ERIN. 89 peat . 1s “ Nauplius,’ the larval stage of the lower Crustacea, such as Copepoda. . 1s Sagitta bipunctata, the arrow-worm, adult. is the larval stage of a univalve Mollusc. i Go no . is an adult Tomopteris. onisciformis, a curious transparent worm. .-1s the larva of a Polyzoon. . is a larva of a Polychaete worm (Verine). . 1s the larva of a Star-fish. s “ Pluteus,” the larva of an Ophiuroid. tt (eps (On co . is an adult Copepod, Temora longicornis. 10. is Sarsia tubulosa, one of the Medusoids derived from a Zoophyte. 11. is Pleurobrachia pileus, an adult Ctenophore related to Meduse. 12. is Pseudocalanus elongatus, an adult Copepod:; and 15. is a pelagic fish-egg containing the young fish. Coming now to rather higher and larger Crustacea, Price XIII. illustrates the Amphipods or Sand-hoppers, and figure XIV. the Isopods or Sea-slaters. These two groups are closely related. In the Amphipods the body is compressed from side to side, the back is generally curved, the legs are long, and face some forwards and the others backwards (see fig. XIII., 1), while a favourite mode of locomotion is by a series of leaps. The leap is effected by means of the hindmost or tail legs, which are bent for- ward under the body, and then suddenly straightened out so as to toss the body up in the air. The Amphipod shown at 1 (Orchestia littorea) performs this action. Some kinds of these Amphipods are extremely common on our sandy shores, especially under stones or pieces of decaying sea- weed. Others, like the Corophium grossipes shown at 2, burrow in the sea-bottom, where some construct tubes and nests of mud or sea-weeds. The curious skeleton-like 90 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Caprella linearis (3) creeps up sea-weeds and Zoophytes, and is sometimes seen in eccentric and acrobatic attitudes, such as holding on to a branch by one claw or balancing on one hind leg. The commonest sand-hopper on Port Erin beach is ~ Orchestia gammarellus, and this sometimes, when a high 1 Orchestia lillorea 2 Corophium grossipes 3 Caprella linearis Pigs XE. tide is accompanied by a shower of rain, swarms out of the sea on to the land in great quantity. On several occasions during the last ten years these swarms have ascended the concrete walls and steps from the beach, and have invaded the Biological Station in great numbers, hopping over the floor and climbing the walls, so as to get on to tables and shelves. MARINE BIOLOGICAL STATION AT PORT ERIN. 91 The Isopods, unlike the Amphipods, have for the most part broader and flatter bodies (fig. XIV.), are depressed from above downwards, have the legs shorter and less conspicuous, and run or creep in place of leaping. The tail legs which were used for leaping in the Amphi- pods are in part breathing organs in the Isopods, and these parts are enclosed within flap-like folding doors. Many of the Isopods, although true water-breathers, can live the 1 Idothea ballica. 2. Astacilla longicornis 3 Ligia oceanica Pig. XIV. greater part of their time on land. JIdothea baltica, shown at 1 (fig. XIV.), is completely aquatic, and lives on green and brown sea-weeds, which it generally resembles closely in colour; while Ligza oceanica (No. 3) is found at or even above high tide mark, generally hiding in crevices of the rock or between the stones of a pier during the day and coming out to run about and feed at night. Astacdlla longicornis (2) is of a white colour, and can only be 92 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. obtained from the deeper water outside the bay by dredging. Our authority on the Amphipods and Isopods and all higher Crustacea is Mr. A. O. Walker, a member of the Committee. | _ The highest Crustacea, such as crabs and lobsters, — shrimps and prawns, are known as Decapoda because they have 10 large or conspicuous legs or claws, 5 on each side of the body. There are also about 14 other pairs of much smaller legs, jaws and feelers which are not so conspicuous. BiG. AaV.. Figure XV. shows (2) the common shrimp (Crangon. vulgaris) and (1) one of our common prawns (Pandalus annulicornis). Shrimps are nocturnal animals, lying for the most part during the day buried in sand with only the tips of the stalked eyes and the long delicate feelers pro- MARINE, BIOLOGICAL STATION AT PORT ERIN. 93 jecting above the surface. Prawns, on the other hand, are active during the day, prowling about constantly in search of food. They live amongst rocks and sea-weed. While alive their bodies are transparent or pale green, usually beautifully marked with blue, and sometimes green, yellow and purple lines. It is only after death that the prawns become opaque, and more or less red in colour. Shrimps are not so transparent when alive, and do not become so red when boiled. They are grey, and are usually speckled and mottled with black and white so as to be exactly of the same appearance as the sand in which they live. As the figure shows, the prawn has more of a hump on its back than the shrimp, and can be easily distinguished by the long spiny snout or “rostrum ” between the eyes. ‘here are many other differences, and it must also be remembered that we have several kinds of shrimps and several different kinds of prawns in our seas. The lobster (Homarus vulgaris) and the Norway lobster (Nephrops norvegicus) are allied forms commonly caught at Port Erin. The lobster produces from ten to twelve thousand eggs at a time, which adhere to the legs on the under surface of the tail of the female for many months until they are hatched.. Countless millions of embryo lobsters are lost every year through the “ berried ” females being sent to market, which might be saved if the eggs were cut off and reared in hatcheries. There is one little prawn, Hippolyte (or Vurbsus) varians, which is found amongst sea-weeds and in pools at Port Erin, and which is of most varied colour according to its surroundings. Specimens living amongst green weeds are bright green in colour, and even the eggs laid by the prawn are green; when amongst brown weeds, as it often is, 16 is of a dark brown colour, and when in red and ‘variegated weeds it is red, or speckled with various 94 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. colours. Moreover, individuals can to a considerable extent change their colour when the environment is altered. The first Port Erin Annual Report (1893) con- tained a short account of this animal, with a plate showing the chief colour variations. Since then Messrs. Gamble and Keeble have made a number of interesting experi- ments, and have shown that at night the colour of all varieties is a deep blue. The Decapoda or higher Crustacea may be divided into 3 sets :— (1) Those that have the tail part or abdomen stretched out behind the carapace or shield that covers the head and thorax, as in lobsters, shrimps and prawns (Macrura). (2) Those where the abdomen is smaller and is folded up underneath the carapace, as in_ crabs (Brachyura). (3) Those where the abdomen is neither completely stretched out nor folded up, and is often anomalous in shape (Anomura). Figure XV. shows Macrura, fig. XVII. Brachyura, and fic. XVI. two interesting kinds of Anomura, which we generally have on view in the Aquarium. No. 2 is c Galathea squamifera, the “ squat-lobster,’ of which one kind, of a blackish colour, is frequently found under stones at low tide in Port Erin Bay, while another bright red kind is obtained from deeper water by dredging. The abdomen, it will be seen, is partially turned under the body, but can be extended and flapped up and down when swimming. The other figure (1 in fig. XVI.) shows a “hermit crab” (Hupagurus prideauaii), with _ its anomalous abdomen tucked into an old Molluscan spiral shell, on the outside of which is a special kind of sea- MARINE BIOLOGICAL STATION AT PORT ERIN. 95 anemone, Adamsia palliata. These two very unlike animals, the hermit-crab and the sea-anemone, seem to be mutually helpful; the crab carries about and incidentally feeds the anemone, while the latter by its stinging threads _ possibly keeps off fishes and other enemies, and so protects its partner in this strange assoctation. Gs Vel. The highest of Decapod Crustacea are the Brachyura, or Orabs, which have the abdomen permanently tucked up under the carapace, so as not to be visible from above (see fig. XVII.). The 10 conspicuous legs, which give the name ‘“ Decapoda,” are clearly seen, while smaller 96 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. ones will be found about the mouth on the under side. The appearance of the edible crab (Cancer pagurus) and of the common shore crab (Carcinus menas) are well known ; and the figure shows, at 1 the “ Fiddler” or swimming- crab (Portunus puber) with flattened paddle-like hind legs, Fie. XVII. and at 2 one of the long-legged spider-crabs (Stenorhynchus phalangium). Some of the spider-crabs are frequently found to have their shells covered by a dense growth of small sea-weeds, Zoophytes, and sponges, which to some — extent conceal the crab from observation when it is in a MARINE BIOLOGICAL STATION AT PORT ERIN. oF rock pool or on the sea-shore at low tide. These sea-weeds are found to be attached to little hooked spines, and observations have shown that the crab attaches the sea- weeds to them itself, apparently with a view to its own disguise. We have generally some specimens of the spider-crab, Hyas araneus, showing this concealment in the tanks at Port Erin. Some other kinds of crabs are so shaped and coloured as to be very hke the stones and other objects amongst which they live. All the crabs, as well as lebsters and shrimps, as they grow larger, periodically throw off or “cast’”’ their hard shells so as to permit of expansion. This process of “ecdysis’’ may sometimes be seen taking place in an aquarium, and it is so complete that not only is the outer covering of the body shed, but every limb is drawn out of its hard sheath, and the coverings of the eyes and the delicate feelers and gills and even the cuticular lining of the stomach are all cast off. For some time after this the crab remains in a feeble and defenceless condition, but swollen up with water, while its new shell is forming and hardening. Such “soft ’’ crabs generally hide, are rarely caught, and are recognised as being unfit for eating. The life-history of the shore crab (Carcinus menas) is ‘interesting, and figure XVIII. shows some of the more important free stages. The developing eggs are carried about as an orange or dark brown mass underneath the | abdomen, and when the young animals hatch out they are called ‘“‘Zoeas*’ (1) and are quite unlike the old crab. They have a large jointed abdomen and several long spines sticking out from the body. They swim freely on the surface of the sea, and are frequently caught in the tow-net in summer and autumn. After a time the Zoea grows larger, casts its skin, and becomes the next stage, or ““ Megalopa”’ (2), which is much more like a crab, but H 98 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. has very conspicuous eyes (hence its name), and still uses the out-stretched abdomen for swimming on the sea- surface. The older Megalopa begins to haunt the sea- weedy shores and may be found in rock pools, and so gradually grows into the smallest size of crab. BIG. Vy Tee Several reports upon our Crabs and other Higher Crustacea, by Mr. A. O. Walker, will be found in our volumes. MARINE BIOLOGICAL STATION AT PORT ERIN. 99 MOLLUSCA. (Figs. XIX. and XX.) The Molluses, such as cockles and whelks, are the true “shell-fish.”’ They have no joints or segments, and no legs, and the soft body is covered by a hard limy shell which is generally in only one (univalve, such as whelk) or 7 Ja! a Xa Rm Au i, | i\\ I Ne Te y SATIN i i a” LAT : . \ Za im ! mint Lu su Fre. XIX. in two (bivalve, as in oyster and cockle) pieces, the valves. A few Molluscs, the sea-slugs (fig. XX.), have no shell when adult; while the Cuttlefishes have either no shell, or a shell of a very special kind unlike that of common univalves and bivalves. Figure XIX. shows a 100 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. group of representative Mollusca. 1 is the large scallop (Pecten maavmus) with the rounded valve below and the flat one above, the hinge where they join being at the figure 1. Round the opening between the margins of the valves is seen the soft edge of the body fringed with feelers and a wonderful row of gleaming eyes. No. 2 is also a bivalve (dLactra truncata), but 1s one which burrows in sand by means of the long blade-like “ foot” seen to the right of the figure (the animal’s anterior end), while at the opposite (posterior) end is seen a double-barrelled tubular arrangement by means of which supplies of water are drawn into the body and ejected. The mussel (J/ytilus edulis) and various kinds of Venus and Tapes are common at Port Erin. No. 3 is the curious little slug-like Molluse Chiton levis, frequently found under stones and in pools, and quite exceptional! in having the shell represented by a series of 8 pieces arranged along the back like a serres of overlapping tiles. This leads to the ordinary univalves (Gastropoda), of which we have an example in the common dog-whelk (Purpura lapillus) at 4. These animals have a broad creeping “ foot,” like that of the garden snail, with the head and mouth in front and the tail behind. The spirally coiled univalve shell is balanced on the back, and all can be drawn up into it when the animal retreats. In some cases there is a lid (the operculum) upon the tail which fits the opening of the shell. The yellow egg- capsules of Purpura are seen at 4a. From 10 to 20 eggs are as a rule laid in each capsule, but of these only one reaches maturity and emerges as a young Purpura. That one is in every sense representative of its brothers and sisters, as it has eaten all the rest. Various kinds of periwinkle (Lzttorina) and the only kind of Cowrie (Cyprea Europea) found in our seas are generally present in the Aquarium. MARINE BIOLOGICAL STATION AT PORT ERIN. 101 The two remaining animals shown in fig. XIX. are Cuttlefishes (Cephalopoda). No. 5 is the common squid (Loligo vulgaris), with 8 short “arms” and 2 longer “tentacles ’’ attached to the head, and all of them bearing suckers. Lo/igo has an internal shell shaped like a short Roman sword, and made of a flexible transparent horn-like substance. The remaining Cephalopod (No. 6) is a kind of “Octopus” called Hledone cirrhosa. It has only the 8 sucker-bearing arms, the body is shorter and rounder than in the squid, and there is no shell of any kind external or internal. The soft skin of the Cuttlefishes is coloured yellow, red and brown by little sacks full of pigment grains, and these sacks can be so varied in shape as to change the tint of the animal in accordance with its surroundings. In httle baby cuttlefishes from } to } an inch. in length this instantaneous change in colour, or “ blushing,’ can be seen most beautifully as the little animals just hatched from the egg dart about the tank from darker to lighter coloured parts. | Some Gastropods, such as the sea-hare (Aplysia punctata), found by dredging in the bay, have very small shells which do not cover the body. The common limpet (Patella vulgata) is frequent on the shore, and the beautiful transparent brown Helcion, with its radiating lines of delicate turquoise blue, is found at low tide on the blades and stems of the oar-weed. Reports upon the various groups of Mollusca, by Mr. R. D. Darbishire, Mr. F. Archer, Mr. W. HE. Hoyle and Mr. A. Leicester will be found in the volumes of our “Fauna.” There is one set of Molluscs related to the ordinary univalve Gastropods which have lost their shells. These are the Nudibranchs or sea-slugs, four common kinds of 102 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. which are shown in fig. XX. No. 1 is the large yellow sea-lemon (Archidoris tuberculata) frequently found in rock pools during the spring and summer; 2 is the rarer and smaller Polycera quadrilineata, marked with yellow spots and found sometimes creeping on the blades of Laminaria; 3 is Holts tricolor, one of the most graceful and brilliantly coloured of the sea-slugs; and 4 is the httle Doto coronata found on colonies of Zoophytes, upon which it feeds. The brightly-coloured projections on the back of Zolis have batteries of microscopic stinging threads which can be discharged instantaneously into any offending animal. Those sea-slugs which have no sting- ing organs are for the most part coloured and shaped so as to closely resemble their natural surroundings, and so escape the observation of their enemies, while those (like Holts) with offensive organs are conspicuous and_ bril- liantly coloured, as if to warn other animals to avoid them. In losing the shell these Molluscs have lost a pro- MARINE BIOLOGICAL STATION AT PORT ERIN. 103 tection against injury, and this loss is compensated by the colours and appearance of the soft bodies, which in some cases are of a protecting and in other cases of a warning nature. ‘The spawn of the sea-slugs is deposited in long ribbon-like or cord-like convoluted white masses on stones and weeds. A small piece contains many hundreds of minute embryos which, when hatched, have for a time ttle cap-like shells. This leads us to believe that the sea-slugs are descended from ordinary shell-bearing Molluscs. Papers and reports upon our Nudibranchs, by Professor Herdman and Mr. Clubb, will be found in our volumes. PUN CAT A : (Fie. XXL.) The Ascidians, or sea-squirts, are not so well known to the public as they deserve to be. They are very common, very varied and some of them very beautiful. Most of them when adult stick to stones or sea-weeds, and they are of two kinds—the Simple Ascidians and the Compound Ascidians. A Simple Ascidian, such as Ascidia (fig. XXIJ. 1), is a grey sack-like body from 1 to 6 inches in length, having a tough skin (the “Tunic,” hence Tunicata) and 2 openings through one of which the sea- water is drawn in, while it is squirted out through the other. When touched incautiously, the animal contracts and emits sudden jets of sea-water from both apertures, thus vindicating its title to the popular name “ sea-squirt.”’ The name Ascidian (from the Greek “ Ascos,” a leathern double-necked bottle) is given in reference to the bag-like 104. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. shape and the 2 apertures. There are many interesting and some puzzling points in connection with the structure and mode of life of Ascedza, but these would require many figures and a microscopic examination of the animal for their exposition. Another simple Ascidian which we fre- quently have in the Aquarium is Styelopsis grossularta (2), “the red-currant squirter of the sugar-loaf rock,” as it has been called, because of the myriads which cover with a red papillated surface many square yards of the cliff in the beautiful caves near Spanish Head. Compound Ascidians are colonies each member of Fie. XX. which is very much like a simple Ascidian in structure, but they are all united together by one covering or tunic. A common and very brightly coloured kind of Compound Ascidian is Botrylius, shown at 5 in fig. XXI., and com- monly found under stones about low-water mark. The colony is marked with bright stars and wheels, each ray of which is a separate member of the colony, with complete organisation of its own. There are many other kinds of Compound Ascidians (such as that shown at 4); they rival the sponges in their curious shapes and brilliant colours. MARINE BIOLOGICAL STATION AT PORT ERIN. 105 No. 3 is Clavelina, where beautifully transparent indi- viduals are united by a creeping root. It is sometimes found in the deeper pools at Port Erin. The egg of an Ascidian develops into a minute tadpole-shaped larva which has a back-bone running along its tail and a nervous system with a brain, containing an eyeandanear. In fact, the structure of this Ascidian larva is very like that of any young vertebrate animal, and if it remained in this condition for life it would be proper to classify it along with the lowest fish-like vertebrates. But it does not so remain. After a brief free-swimming existence it becomes attached to a rock or sea-weed, and settles down for the rest of its life. Then degeneration sets in. The backbone, the brain, the eye and the ear— all the evidence of its high organisation and active early life—break up and disappear, and the free tadpole becomes reduced to the sedentary sack-like Ascidian. This life- history is a good example of degeneration, but it also shows us that Ascidians are derived from ancestors which were once related to the backboned animals. There is one of the Tunicata which remains free- swimming all its life, and has a backbone in its tail. It is called Appendicularia, and we frequently catch it in the tow-net in Port Erin bay. The reports upon the Tunicata in our series are by Professor Herdman, and the first of the L.M.B.C. Memoirs is on “ Ascidia.” FISHES. (Fig. X XIT.) There are about 150 different kinds of fishes found in the Irish Sea around the Isle of Man. Some of these are the well-known edible fish belonging chiefly to the Cod I 106 ‘TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. family (Cod, Hake, Haddock and Whiting), the Flat-fish family (Soles, Plaice, Dabs and Flounders), and the Herring family. Others are rare fishes only occasionally seen, such as the Sturgeon, Torpedo, Tunny and Thresher. Others again are the voracious cartilaginous fish, such as Skates and Rays, Sharks and Dog-fishes. Finally, there are a very large number of curious and interesting little =~ Se 6, Bie. SX: shore fishes to be found in rock pools and under stones, some of which are generally to be seen in the Aquarium. Three of the more common of these are shown in figure XXII. No.1 is the Bull-head (Cottus scorpius), No. 2 the common Shanny (Blennius pholis), and No. 3 a little pipe fish (Nerophis lumbriciformis). The little sucker fishes (Lepadogaster bimaculatus), the Butter fish (Centronotus MARINE BIOLOGICAL STATION AT PORT ERIN: 107 gunnellus) and the Conger eel are also usually to be seen in our tanks. it Although most of these shore fishes lay their eggs in spring under stones or in crevices or on old shells in the sand, the majority of the fish we eat from the sea (with the exception of the herring) produce in enormous quan- tities eggs that are very minute and transparent, and which float freely in the open sea. These are known as “ pelagic,’ and the eggs of Cod, Haddock, Whiting and their relations, and of Sole, Plaice, Flounder and other related flat fish are of this kind. It is these pelagic eggs of our most important food fishes that can be obtained in millions at the spawning season and hatched artificially in sea-fish hatcheries, and so may be kept and protected during the first few days or weeks of their existence when they would otherwise be exposed to innumerable enemies in the surface waters of the ocean. But it cannot be too emphatically stated, and widely made known, that sea-fish hatcheries ought not to be merely for the purpose of hatching young fish and then setting them free in the sea. Hatching and Rearing of fish is the end to have in view, and scientific men who have charge of fish hatcheries will not be content till they have succeeded in rearing into young fish, at a reasonable cost, a large proportion of the fry which they can now hatch from the eggs by the million. Professor G. O. Sars first showed how the eggs of an edible fish (the Cod) could be hatched in small numbers as a labora- tory experiment; Dannevig in Norway and the U.S. Fish Commission in America have devised the apparatus and technique by which it has become possible with very slight mortality to hatch out such eggs on an industrial scale by hundreds of millions. The next advance must be in rearing. At present practical difficulties block the way, 108 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. but the Fishery Board for Scotland has had some success with Plaice, and the French at Concarneau with the Sole, and we cannot doubt that further investigation and experience will show us the best methods to pursue. It is at institutions like this at Port Erin, where a Scientific Laboratory is combined with the Hatchery, that experi- ments in feeding and aeration can be carried out which will eventually lead us to the successful rearing of the | young fish that we now hatch and distribute as fry. The Naturalist’s Dredge. 109 Report on the Investigations carried on during 1901 in connection with the lULancasnire Sua - FIsHEries Lagsoratory, at University College, Liverpool, and the Sea-Fisa Hatrcuery at Piel, near Barrow. Drawn up by Professor W. A. Herpman, F.R.S., Honorary Director of the Scientific Work; assisted by Mr. ANDREW Scott, Resident Fisheries Assistant at Piel; Mr. Jamrs JOHNSTONE, B.Sc., Fisheries Assistant at Liverpool; and Mr. Frank J. Cour, of University College, Liverpool. With Eleven Plates. CONTENTS. 1. Introduction and General Account of the Work ~ - =e LO 2. Sea-Fish Hatching at Piel - - : - - - 122 8. Note on the Physical and Chemical characters of our Sea Waters - = = - : : = - - =i lS 4, Memoir on the Common Plaice - - = = SMe) ary INTRODUCTION AND GENERAL ACCOUNT OF THE WORK. Tue work of the past year has been chiefly :— (1) The hatching operations and other similar work car- ried out at Piel by Mr. Andrew Scott ; (2) Laboratory investigations by Mr. Johnstone at Liver- pool, chiefly this year upon the Plaice ; (3) Some investigations upon the chemical and physical characters of the sea-water of our district ; (4) The work of the Circulating Fisheries Exhibition ; and (5) The Practical Laboratory Classes for Fishermen. Some of these matters which can be treated shortly I shall remark upon here, the others will be discussed more fully in the separate sections that follow. We have aimed at having in each of these Annual Reports, in addition to a short account of the work of the K 110 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. year, some more detailed contribution of permanent value to Fisheries Science. Thus, once we had the work:on the Chemistry and Pathology of Oysters and other shell-fish, and their connection with disease in man; once we had the account of oyster culture on the West Coast of France ; Mr. Johnstone in one report dealt with the reproduction of the common mussel, and in another he gave us a very full account of the cockle ; and last year the report contained a detailed description of certain very important fish parasites. This year we have what I suppose is the most complete account of a single fish that has yet been produced. It is a memoir on the common Plaice (Pleuronectes platessa), by Mr. F. J. Cole, of University College, and Mr. James John- stone. Mr. Cole and Mr. Johnstone have had this work in hand for the last two years, and the pages and plates that make up the greater part of this report represent an enor- mous amount of labour both in the laboratory and the study. The Plaice is one of our most important British fishes; it is one of those local and sedentary forms in regard to which our apprehensions may well be excited in view of the marked increase of fishing power in recent years. It was one of the fish to which the attention of the Parliamen- tary Committees of 1893 and 1900 was specially given, and in which all the Countries of Northern Europe are at present interested because of the scheme for an International Investigation of the North Sea. Under these circumstances any contribution to our knowledge of the Plaice must be especially welcome, and all knowledge it must be remem- bered is of value, and helps us to understand the nature and life of the fish in its manifold relations. For those readers, however, who do not feel interested im the details of structure, I may add that the Introduction, the discussion of the nature and origin of the asymmetry, and the two SEA-FISHERIES LABORATORY. Ver sections of the Economic Appendix, will be found the most readable and instructive parts. It is only fair to state that the eleven beautiful plates that illustrate the Structure and Life-history of the Plaice have been presented to us, as the cost of their production has been defrayed by a srant from Victoria University. Mr. Scott’s account of the Sea-fish Hatching work at Piel will be found on p. 122. During the past year the work has been done upon the Flounder, and over 138 millions of young have been hatched and distributed in suitable waters. Next year we hope to deal largely with the Plaice, and a supply of spawners, obtained by our steamer through the courtesy of the Fishery Board for Scotland from Luce Bay, has already been laid in. I desire to emphasise what I have pointed out before, that sea-fish hatcheries ought not to be regarded as merely for the purpose of hatching young fish and then setting them free in the sea. The Hatching and Kearimg of fish is the end to have in view, and scientific men who have charge of Fish Hatcheries will not be content till they have succeeded in rearing into young fish, at a reasonable cost, a sufficiently large proportion of the fry which they can now hatch from the eggs by the million. Professor G. O. Sars first showed how the eggs of an edible fish (the Cod) could be hatched in small numbers as a laboratory experiment. Capt. Dannevig in Norway and the U.S. Fish Commission in America have devised the apparatus and technique by which it has become possible, with very slight mortality, to hatch out such eggs on an industrial scale by hundreds of millions. The next advance must be in rearing. . It may be very useful to turn out large numbers of fry, but it is not sufficient as an ultimate aim; what we want to do ultimately is to hatch and rear fish. We must experiment 112 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. in the direction of how best to keep young fish alive at a moderate cost, till they attain a fair size. At present practical difficulties in feeding, and possibly in connection with the movements of the water, block the way, but Mr. H. Dannevig at the Hatchery of the Fishery Board for Scotland has had some success with the Plaice, and MM. Fabre-Domergue and Biétrix at Concarneau with the Sole, and we can scarcely doubt that further investi- gation and experience will show us the best methods to pursue. It is at institutions like ours, where scientific work is combined with the hatching, that experiments in feeding and aeration can be carried out which will eventually lead us to the successful rearing of the young fish that we now hatch and distribute as fry. The rearing of young Soles at Concarneau from the ege to a size of 35 mim., with a loss of only 50 per cent., is a striking and encouraging fact. The laboratory at Piel has been occupied by several scientific workers during the year. In addition to Mr. Scott, who has worked there throughout the year, Mr. Johnstone has paid several visits, and Mr. Cole, from University College, Liverpool, spent the greater part of September at Piel working at the anatomy of the Plaice. Dr. H. Lyster Jameson, from the Municipal Technical College at Derby, worked in the laboratory for short periods during the summer, carrying out some investigations con- nected with the formation of pearls in marine shell-fish. Mr. H. C. Chadwick, Curator of the Port Erin Biological Station, spent a couple of weeks in March studying the methods of sea-fish hatching. Amongst the numerous visitors who came to see the ex- hibition and the work going on in the establishment during the year were tle following :— SEA-FISHERIES LABORATORY. 113 _ Mr. Walter EH. Archer, Chief Inspector of Fisheries to the Board of Trade. Rev. R. B. Billinge, Furness Rural District Technical Instruction Committee. Rey. Dr. Hayman, Aldingham near Baicliff. Rev. T. Fowler, Flookburgh. Mr. F. J. Ramsden, Furness Railway Company. Mr. A. Aslett, Mr. F. Stileman, i . 5 The Mayor and Members of a Deputation from the Barrow Free Public Library Committee. Col. Turner and Members of the Stockport Corporation. Mr. Fell (twice). Mr. Ascroft (twice). Mr. Houldsworth. Professor Herdman (twice). ” 99 9 The Barrow Teachers, John Graham, B.Sc., P. H. Smith, B.Se., and J. K. Turner, B.A., who worked in the laboratory last year, were unable, through pressure of other duties, to follow up their studies in the laboratory, but hope to be able to resume them during the coming year. The travelling Fisheries Exhibition, which was fitted up in 1897, has during the last four years been on view in puble institutions in the following Lancashire towns :— Liverpool, Salford (1898), Preston (1898-99), Bolton (1899), St. Helens (1900), Piel (1900-01), University College, Liverpool (1899-1900), and finally Barrow (1901) where it is at present. This exhibition was transferred from St. Helens to Piel in November, 1900. Various repairs to the jars and speci- mens had to be made, and all the labels attached to the former had to be renewed, owing to leakage of spirit from 114 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. some of the jars which had been damaged in transit. The exhibit was thrown open to the inspection of the public early in 1901, and, with the exception of the periods when the classes for fishermen were being held, remained on view until the beginning of September. During the time it was at Piel the Barrow Town Council completed negotiations for its removal to their town. The exhibit was removed to Barrow early in September, and set up in the reference room of the Free Public Library, where it will remain for the ‘usual six months. . The exhibit during its stay at Piel was visited by between 3,000 and 4,000 people, amongst whom were parties of school children with their teachers from the Barrow Schools. Everyone appeared much interested in the various contents of the cases, and the majority went away with more correct ideas and impressions of the work of the Sea Fisheries Committee. The exhibit was of great service during the time the classes for fishermen were held. The specimens of the fishes, the food of fishes, and the prepara: tions of shellfish, were removed from the cases and arranged on the shelves of the laboratory, and referred to from time to time to illustrate many points which were discussed during the teaching of the men. During the summer I gave evidence before the Royal Commission on Sewage Disposal, as to the effects of sewage and other materials in effluents upon fish and shellfish ; and Mr. Scott has been able from time to time to make certain experiments for me in the tanks at Piel upon this question, which is of gieat practical importance in con- nection with some of our estuarine and shore fisheries. In regard to the Practical Classes for Fishermen which had been started in Liverpool during the previous year, three Courses of Instruction, the Third, Fourth and Fifth, _ SEA-FISHERIES LABORATORY. ~~ 115 have been successfully carried on this year at. Piel, and Messrs. Scott and Johnstone, who were mainly concerned in the work report to me as follows : “The Technical Instruction Commies of the coe Council having given a further grant of money to enable Fishermen to obtain instruction in the life histories, &c., of the Economic. Marine Animals, from our Scientific Department, arrangements were made for carrying on the Practical Classes at Piel, where a supply of living animals could be obtained easily, and where, during spring, the hatching of the eggs of Sea Fish could be shown. “Three Classes, each attended by ten men, were nels during the year, two in the Fish Hatching Season, and one in the Summer. A Fourth Class, to follow immediately after the third, was also proposed, but this was abandoned owing to the difficulty the men had in coming at that time of the year. The following are the dates when the Classes were held, and the names of the men who attended them :— “March 18th to 29th—John Wright, Southport; William Rimmer, Southport; Robert Wilson, Morecambe; David Willacy, Morecambe; Richard Woodhouse, Morecambe ; Daniel Hadwin, Flookburgh; Peter Butler, Flookburgh ; Samuel Bayliff, Baycliff; John Shaw, Baycliff; Robert Porter, Baycliff. — “April 15th to 27th—William J. Robinson, Formby ; Edward Rigby, Southport; Thomas Wright, Southport ; J. Johnson, Banks; J. Wearing, Banks; Samuel Colley, Sen., Fleetwood; Thomas Leadbetter, Fleetwood; Daniel Bell, Morecambe; James Dobson, Morecambe; James Swain, Morecambe. 3 “July Ist to July 12th—Thomas Hardman, Lytham ; John Robert Wignall, Lytham; Richard Wright, Fleetwood: 116 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. William Fairclough, Fleetwood; Robert Butler, Flookburgh; John Inman, Flookburgh ; Edward Robinson, Flookburgh ; John Hadwin, Bardsea; John Hartley, Bardsea; Thomas | Sumpton, Bardsea. ‘The classes were carried on by Mr. Johnstone, and the work was on the same lines as in the laboratory classes held at Liverpool (University College) in 1900*, each man, as before, examining everything for himself. As much of the material dealt with was supplied alive, the interest of the men was greatly increased by being able to watch the movements of the animals, in many cases through the microscope. A further important point in having the classes at Piel was the advantage of being able to practically demonstrate to the men how to save and fertilize the ripe eggs of fish, caught in the trawl, and to trace the develop- ment of the embryo from the moment the egg was fertilised until the young fish hatched out as a free-swimming larva. The study of the developing fish formed part of each day's . work in the case of the men who attended the first two classes. ‘This was not possible at the third class owing to the fish spawning season being over by the end of May. ‘Two lantern demonstrations were given to each class —one at the end of each week—and these were practically a review of the work done on previous days. A special lantern demonstration was given by Professor Herdman when he visited the first class, and this was open to the local residents, and was largely taken advantage of. ‘‘ At the conclusion of each course the senior member of the class, spontaneously, on behalf of himself and the other members of his class, expressed their indebtedness: to the Technical Instruction Committee of ‘the County Council, and the Sea Fisheries Committee. Some of the * Vide Fish. Lab. Report for 1900. SEA-FISHERIES LABORATORY. 117 men have also written long after returning to their homes, expressing the pleasure they had had in the fortnight’s work at Piel and their thanks for the practical instruction they had been given and for the plain way in which things were put before them. “ There can be no doubt that these classes are of practical value to the fishermen. All those who have been with us freely admitted that many of the views they held regarding the spawning, development, and rate of growth of fish and other economic marine animals were erroneous. We are convinced that it is only by allowing each man to study the animals for himself, make dissections and examine material with the microscope that lasting good can be obtained. A course of instruction such as is given to the fishermen would be of great help to the Bailiffs when collecting specimens and tow-nettings for the Laboratories. ‘Various members of the Committee visited the classes from time to time to see the progress of the work, including Mr. Fell, Mr. Ascroft, Mr. Houldsworth, Mr. Dawson and Professor Herdman, all of whom addressed the men on the objects and work of the classes.”’ We had hoped this year to have hada report from Mr. kh. L. Aseroft upon the tow-net gatherings taken throughout the district. The scheme for the periodic collection of gatherings from the surface of the sea at certain fixed places was started in 1900, and during that year about 150 samples of material were examined by Mr. Ascrolt and the results have been tabulated. During 1901 the work has been carried on, and about the same number of gatherings have been made, chiefly by Captain Wignall from the steamer “John Fell,’ by Mr. Eccles in Liverpool Bay, and by Mr. Wright in Barrow Channel and Morecambe Bay. Many of these have been examined, but Mr. Ascroft’s recent 118 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. illness has unfortunately stopped—we hope only for a time —this and other good work in connection with fisheries investigations in which he was engaged. The work that has been done of recent years by Scandi- navian Hydrographers, and the attention that has been directed to the matter by the International Conferences at Stockholm and at Christiania, and the appointment by the Board of Trade of an Ichthyological Research Committee, all emphasize still further the point that I dealt with in some detail in my last report, viz.:—the need for more exact and detailed knowledge of our coastal waters and their inhabitants. Such knowledge, both scientific and statistical, can only be obtained by some such scheme as I outlined last year, and by the use of a special steamer to supple- ment the information that can be derived from commercial trawlers. I have thought it important in the meantime to have some samples of water from different parts of our district examined as to their physical and chemical characters by the most recent hydrographical methods and by a competent chemist (1) with the object of noting what variations exist in the Irish sea, and still more (2) with a view of testing the methods as to their relative importance and practicability for future schemes of work at sea. Mr. Alfred Holt, Junr., B.A., (Cantab.), has kindly under- taken this work, and during the last three months has been examining samples of sea-water in my laboratory. I am glad to have from him the report which is printed at p. 128. At the Eleventh Annual Meeting of Representatives of Fisheries Authorities at the Board of Trade in June, 1901, the President, the Right Honourable Gerald Balfour, M.P., made some interesting observations bearing upon fisheries research which must carry weight, and, it is to be hoped, will receive the attention which they deserve. Speaking SEA-FISHERIES LABORATORY. 119 of the lamented death of Sir Courtenay Boyle, he referred to communications between them on the subject of the best means of “ improving and following up that scientific research into the life and habits of fish, the practical importance of which is coming to be more and more recognised.”” Then, in referring to the Report of the Select Committee on the last Immature Fish Bill, he said, ‘‘ It came to the conclusion that it would not be expedient to press forward the Bill in the absence of further information. It fully recognised the danger we were running of having our seas depleted of fish. It further recognised that one cause of such depletion was the capture and destruction of small, immature fish.’ And then he went on to point out the recommendations of that Committee, which were briefly (1) the international regulation of the North Sea, and (2) the effective pursuit of scientific investigation, and said ‘In the face of the conclusions arrived at by the Select Committee and of those recommendations, I think it is absolutely essential now that we should proceed upon the jines indicated by them before attempting any further legislation.” He then referred to the action of the Govern- ment in international negotiations, with the view of arriv- ing at some agreement as to protected areas, which has not yet resulted in any definite conclusions; and proceeded as follows :— “Next with regard to scientific investigation of the life and habits of fishes. The Board of Trade are at the present time arranging for a Departmental Committee, of which Sir Herbert Maxwell has undertaken to be Chairman, with the following reference which I will read out. ‘To inquire and report as to the best means by which the State or Local Authorities can assist scientific research, as applied to problems affecting the fisheries of Great 120 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Britain and Ireland, and in particular whether the object in view will be best attained by the creation of one central body or department acting for England, Scotland and Ireland, or by means of separate departments or agencies in each of the three countries.’ You will see, gentlemen, that that is a very wide reference, and I trust that the deliberations of this Committee, which is now in course of appointment, will end in some fruitful result.” So far the President of the Board of Trade, and I think all who are interested in the advancement of knowledge and the promotion of fisheries research will agree as to the 1m- portance of the announcement; but as I have had the honour of being appointed a member of Sir Herbert Max- well’s Committee on Ichthyological Research, it would be highly improper for me to make any comments upon the work that will be necessary in order to carry out Mr. Balfour's suggestions, or upon the results that are likely to follow. But quite apart from the Board of Trade Com- mittee, it 7s important that I should urge upon Lancashire my conviction that our local waters of the [Irish Sea ought to be investigated under the auspices of our local Cominittee. Whether or not a great national or international scheme of investigation be entered upon, it is most desirable that Laneashire, which has obtained credit for an advanced and enlightened policy in the past, should recognise its obliga- tions—moral if not legal—and should carry out an adequate programme of work at sea on similar lines to that of the Scottish Fishery Board to the North of us, and to that of the Irish Board on our West. The Fisheries Branch of the Irish Department of Agriculture has now an _ organised scientific department, with a well known marine biologist, Mr. Ernest Holt, as scientific adviser, and an efficient steamer, ‘‘ The Helga,’ measuring 150 feet in length, which SEA-FISHERIES LABORATORY. 121 is now working from Dublin as a centre in the Western part of our own area. If this could be supplemented by a Lancashire steamer devoted wholly to statistical and scien- tific work, the two working on a common programme, there would be a fair prospect that this the most definitely cir- cumseribed of the British seas * would be adequately in- vestigated. Itis only now a question of expense. Sufficient preliminary investigations have been made, we know exactly what we want to do, and the Irish steamer is now at work. All that is required is an additional steamer for scientific work in the Lancashire District and funds to carry out the scientific programme. In previous reports | have shown the suitability of the Irish Sea for such work, and I am interested to see that Dr. Johan Hjort, in a recent publicationt expresses a somewhat similar opimion in regard to some of the local sea-areas on the Norwegian Coast as compared with the North Sea. He says:—‘‘ We consider that the conditions affecting those srall localities on our Coast are exceptionally synoptic, and far easier to crasp than those of the exceptionally complicated and vast territory of the North Sea, in which the Plaice lives.” Finally, I should, perhaps, explain here (1) that my approaching departure for Ceylon, to carry out an investigation on the Pear] Oyster fishery for the Govern- ment, has necessitated the issue of the present report a few weeks earlier than usual, and (2) that although all the manuscript and the first proofs have passed through my hands, I have had to leave Mr. Jolinstone to read the pages for the press. W. A. Herpman. Untverstry Couuecr, LivERPoou. December, 1901. * The Irish Sea contains about 10,000 square miles, and is about one- twentieth part of the size of the North Sea. +Report on Norwegian Fishery and Marine Investigations, Vol. I., p. 152; Kristiania, 1900, 122 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. THe Fish Hatrcuery at Pret. By AnpRew Scort. In the operations carried on in the hatching season of 1901 only the eggs of the white fluke or flounder (Plewronectes flesus) were dealt with. The flounder is a fish which is fairly plentiful in the in- shore waters of our coast, and with the Plaice. forms the greater bulk of the fishes taken in the stake nets, especially in the northern part of the Lancashire area. It is therefore of considerable money value to the stake net fishermen, as well as to the small sailing trawlers that fish in the channels of the various estuaries in the district. Although not held in high esteem as an article of food by the fishermen them- selves, the white fluke finds a ready sale in the inland towns. The fishermen look upon the white fluke with a certain amount of disrespect, and have applied various uncompli- mentary namestothisfish. This 1s owing tothe questionable grounds which it frequents at particular times of the year. It is said to be more abundant, especially during the summer months, in areas affected by the discharge of sewage ~ from large towns, than in clean sea water. Thisis true to a certain extent, but the fish does not frequent sewer outlets merely for the sake of any food that may be brought down. It is, more than anvthing, because of the low specific gravity of the contaminated area, due to the great quantity of fresh water which finds its way along sewers, that the flounder frequents such localities. The flounder is essentially a brackish water fish, and is known to ascend far up rivers in summer. In some parts of the country it is known as the fresh water fluke, and is not uncommon in Jakes which have an unobstructed connection with the sea, SEA-FISHERIES LABORATORY. 123 On the approach of cold weather the fish migrate towards the sea. The majority of the sexually mature forms in time make their way out to sea tospawn. The movements of the immature flounders are greatly influenced by the conditions of the weather. When there is littJe or no frost they remain in the shallows of the estuaries. When frost of any severity sets in they quickly disappear into the deeper channels. It mild winters it is probable that even some of the sexually mature fish remain in the deeper parts of the channels and spawn there in the spring It is nota rare thing to find nearly ripe fish and occasionally partly spent ones in Barrow Channel in February, when the weather has been favourable. The food found in the stomachs of flounders varies con- siderably. Sometimes it is mollusca such as young mussels ; at other times we find only crustacea, Mysis and Corophium, and occasionally marine worms. The incubation of the eggs of the Flounder has formed the principal part of our hatching work hitherto, for two reasons: (1) Mature Fish are easily collected in Barrow Channel during the latter part of the year; and (2) little difficulty is experienced in transferring them to our tanks and in keeping them in captivity. | In future, however, we propose to devote more attention to the incubation of Plaice eggs, and have already secured a supply of mature fish for next (1902) season. Mature Plaice are not plentiful in the Lancashire waters, and after a week’s search, by the steamer, in the middle of November, only five were captured. Luce Bay, in the South of Scotland, was then suggested. This area was well known in former days for its large Plaice, and was fished with success by Fleetwood Sailing Trawlers, before 124 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. it was closed against trawling by the Fishing Board for Scotland. Permission was courteously given by that Board for our Fisheries Steamer to trawl in the Bay. It was late in the year for such in-shore waters, when we made our visit, yet a good number of mature Plaice were secured in a single day's trawling. The weather was favourable for the passage to Piel. After a run of nearly nine hours the fish were landed in good condition and placed in our tanks. The fact that we have to go to closed waters for our spawning fish, is a good proof that protected grounds, in which all trawling is prohibited, are undoubtedly a benefit to the fisheries. They are the means of preserving the maturing fish, and so of ensuring that at least some fish will be left to spawn. With no protection, and the improved methods for catching fish that are now employed, the adult fish, especially of sedentary species like the Plaice, would soon be as scarce as they now are in the Trish Sea between Lancashire and the Isle of Man, where they were formerly plentiful. During the hatching season of 1901 we had upwards of 250 flounders in the tanks. The ratio of sexes, as far as could be judged by size, was three females to two males. The males of flat fishes are, as a rule, smaller than the females; but there is no certain guide from external appear- ances unless the fish are ready to shed the reproductive elements. The females are then recognisable by the very swollen abdomen. Consequently there are usually a num-— ber of fish amongst the stock that do not reproduce owing to immaturity. These cannot be detected when the fish. are collected. ‘The fish were collected in Barrow Channel by Mr. Wright, as in former years, and kept in tanks till the spawning season was over, when they were set free, SEA-FISHERIES LABORATORY. 125 Throughout the whole period the fish were in the tanks they were fed on lug worm (Arenicola), which is plentiful in the vicinity of the hatchery. Mussels with the shells removed were tried at first, but were not eaten by the fish, and were discontinued after a few days. The first fertilised eggs were collected on February 28th. From that date onwards the numbers gradually increased, ‘until the maximum was reached in April. After that the numbers rapidly decreased, and the spawning was over by May 10th. During the spawning period nearly fifteen and a half millions of eggs were collected and placed in the boxes for incubation. ‘These eggs produced over thirteen and a half millions of fry, which were set free about the centre of Morecambe Bay. The period of incubation varied from eleven days at the beginning to six days at the end of the season—a reduction of time entirely due to the in- creasing temperature of the sea water, which is shown by the table of temperatures and specific gravities given below. It will be noticed from the table that the specific gravity during the hatching was satisfactory, and never fell below 1:026 till after the middle of May. The loss of eggs during incubation from all causes averaged about 11°5 per cent., practically the same as last year. A number of attempts were made to rear flounder larve, but these experiments failed owing to the difficulty of getting minute natural food in the waters of the channel. The following tables show the numbers of eggs collected and fry set free, and also the specific gravity* and tempera- ture of the water during the spawning season. *The figures given are simply the uncorrected readings taken with the Kiel areometers. L 126 TRANSACTIONS LIVERPOOL Eggs Collected. BIOLOGICAL Fry set free. SOCIETY. Feb. 28 235,500 ~~ - 210,900 March 13 March 4 571,000 : 432,000 em i 2500). 930,800 es BR dated] LS00dia tie 416,300 >See 14 392,700 - 349,000 April 1 fSpst AT LOOM. ais 428,000 _,, 1 F6.r B58 000m giz 318,600 1 25 595,500 529,900 9 » 28 614,000 545,000 9 gist 296 yor TOMO hee 702,400 9 April. fal e9985,000 - 876,400 16 5 Sih G28, OU Ory chet 736,700 16 i) 9h6 SALOON MODAL +: 887,000 16 Gs 90000034 += 800;000:. sym Kid? mx OPRO00" Law 825,000-. 5, 22 pt hing KOOOONG: see 888,000 ,, 26 ey 18/5 4800,0008d" 711,800.) ¢ a ee 11199 «te OOOO »eae 887,500 May 1 1 26. :800,000° .~ 711,900 .° (a 4 20's 1 31S40/000- face 747,400 |. “oan May 38 600,000 - 533,600 ,, 10 oe baedilis< gO UNG, ae 445,000 .; ame fel Oi x OOOO Oar fis: 444,800 ,, 20 15,430,300 13,658,000 All the Fry were set free by Mr. Wright, the Chief Bailiff, from his boat, between Walney and Morecambe Bay Ship. SEA-FISHERIES LABORATORY. 127 TABLE showing Temperature and Specific Gravity of the sea water pumped into the store tanks each day during the spawning season. = Date. | Temperature ces Date. | Temperature ae Feb. 4 42°C 1:0264 Mar.29 3°6° C 1:0268 3) Sikes a 10262 30 Ae 1-0264 6 3°6° ,, 1:0262 31 oO, 1:0268 fh 2) Ome 10264 April 1 D2 5 10266 8 4°2° ,, 1:0264 2 Does 1:0266 9 43° 5, 1:0264 3 ON Sayan 1:0264 10 4-8° ,, 10264 4 Silos 1:0262 ial Bee 1:0264 9) 54° ,, 1:0262 12 BOs, 10264 6 5:4° ,, 1:0264 13 SROr 5 1:0264 7 Gin, 10264 14 DEO, 1-0264 8 Gee 10264 15 a0” 1:0264 9 6°40 ,, 1-0262 16 a0 35 1-0264 10 GrOes, 1-0262 ay, Brae 55 1:0264 11 (GAs 1°0262 18 ele 45 1:0264 12 rho 1:0262 iy obo; 1:0266 13 di 1:0260 20 i ee 1-0266 14 Qe. 10260 21 ee 1:0266 15 6°4° ,, 10260 22 4-4° ,, 1:0266 16 Grhics 1:0260 23 AO), 1:0264 17 HEOo », 10260 24 BO: 5, 10268 18 HOe «5 10260 25 0A Sane 10268. * 19 CAS 1:0260 26 aS. 1-0267 20 ia os, 1:0260 27 Dib 43 1:0267 21 SOs: 10260 28 D075; 1:0267 22 rare: 1:0260 hae aT 54° ,, 1:0268 23 84° ,, 10260 2 5:4° ,, 1:0270 24 Oras 1-0260 3 Cee 1:0268 25 Sion 1:0260 + o> 4, 1:0268 26 SOR A 1:0260 5 DA, 1:0264 27 8:4° ,, 1-0262 6 Bere, 1:0264 28 ‘Sabre 1-0262 it Dea), 1:0262 29 Sree 1-0262 8 OPDr §, 10262 30 Saat. 1-0262 9 Se ee 1:0262 May 1 Oa 10260 10 oO", 1:0262 2 i oe ee 1:0260 a BOs 1:0262 3 Ea 1:0260 12 ot, 1-02€2 4 SHS Sr 1:0260 13 Br?) 5 10262 5 OBS. 1:0260 14 Oa. ., 10262 6 Soap 1:0260 15 66°, 10262 it O80 3, 1:0260 16 Or 5, 1:0262 8 OSes 1-:0260 17 JO 5, 1:0262 9 HOO 1:0260 18 2 oman 1-0262 10 10°4° ,, 1:0260 19 a0>7,, 1:0262 ach 10:6", 1:0260 20 4°4° ,, . 1:0262 12 10:87 ,; 1:0260 21 ae 1:0262 13 TOFS 1:0260 22 AO y5 1:0264 14 EDs, 5 1:0260 23 DOL. 5; 1:0266 15 a 1:0260 24 w0r";, 10266 16 ba re 1:0260 25 4:4° ,, 1:0266 17 18? 1:0260 26 BOE 5, 1:0268 18 1220" 55 1:0260 27 4:4° ,, 1:0268 19 12°2° ,, 10258 28 Oe 59 1:0268 128 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. THe DETERMINATION OF SOME PHYSICAL AND CHEMICAL CHARACTERS OF SOME SAMPLES oF WATER FROM THE IrisH SEA. By Aurrep Hout, Jun., B.A. (Cantas.) Having been requested by Prof. Herdman to examine for him some of the physical and chemical characters of the water of the Irish Sea, with a view to selecting the most practical and effective methods for their rapid determina- tion, I obtained a number of samples from different places, and estimated. as far as time allowed, the specific gravity, colour, chlorine, total salinity, alkalinity, carbonic acid gas in solution, and the lime. The ratios between these were then determined, in order to see if they were sufficiently constant to enable one to calculate from an accurate. determination of one character the values of the others. At the same time it was hoped that some knowledge of the movements of the water of the Irish Sea area might be obtained from examination of the values obtained. This will be discussed at the end of this paper. Though every care has been taken to obtain accuracy, the fact that I had not always at my disposal a sufficiently accurate balance forced me to use in the titrations known volumes of solu- tions instead of known weights of them, which undoubtedly may cause error. Further, for the same reason, some pro- — cesses had to be done volumetrically instead of gravimetric- _ ally, which though easier to perform do not produce quite such good results, — M = <3 SEA-FISHERIES LABORATORY. 129 Very little hydrographical work seems to have been done in the Irish Sea, though the Clyde sea-area immediately to | the north of it has received much attention; in fact almost the only analyses of the water seem to be those done by Thorpe and Morton in 1870 (J. C. S. xxiv. p. 506), so there is little past work to comment on. The working here described has been done mainly by. the methods employed by Dittmar, Knudsen, Jacobson, &c., and the working out of many of the results has been performed with the assistance of Knudsen’s Hydrographical Tables. The values obtained are given in considerable detail, which it is hoped may be of some value as showing the degree of accuracy obtained by different methods. 1.—COLLECTION OF THE SPECIMENS. These were obtained mainly from the Biological Stations and from our fisheries steamer, but not on any regular ex- pedition. For this reason I have not yet been able to obtain specimens from several desirable places, nor to obtain in all cases the temperature of the water at the time of collection ; further, the specimens are all of surface water, as a Mill’s water bottle which was ordered did not arrive early enough to be of use. I hope to use it in a further investigation on a future occasion. The samples consisted each of about a litre and a half of water, and were kept in glass bottles with ground glass stoppers till used in the laboratory. This method has the disadvantage of slightly increasing the alkalinity owing to the action of the water on the glass, but this increase is probably very slight since it was seldom ~ that the water was kept more than two or three days before being used for the determination of this character. 180 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 9.—DETERMINATION OF THE SPECIFIC GRAVITY. The specific gravity of the water at 17°5° C. (9 17°5) was determined by means of areometers made by Stegel at Kiel, a salinometer of Hicks, and in a few cases by a hydrometer of Negretti and Zambra. Several observations were made with the Kiel areometers © at different temperatures, and these values were then cor- rected for temperature and the glass of the instrument by means of Knudsen’s Hydrographical Tables. The temperature of the water at the time of the observa- tions was observed by means of a thermometer made by Stegel of Kiel, and graduated to 0°2° C. . By means of these determinations at different tempera- tures it was hoped that some of the errors due to a single observation would be avoided. The Negretti and Zambra hydrometer was a small pocket instrument, and it is remark- able how good are the values obtained by it, but at the same time it must be noted that all values obtained with it are about 0°0014 too low. This presumably is due to the scale not being accurately placed in the stem. The values of the Kiel areometers are given to five decimal - places, but the last place is obtained in the correction above mentioned, and is not read on the instrument except in a very few cases. In the annexed table the values obtained with these in- struments are given, and also, for comparison, that calculated from the chlorine value. In the case of the areometer read- ings the maximum and minimum are given so as to show the error between the readings at different temperatures. ~ The density of the water at 0° C. referred to distilled water at 4° C. was calculated from the above figures, and is given in the tables at the end of the paper. =~] 8. . Blackpool SEA-FISHERIES LABORATORY. Sprciric GRAVITY TABLE. LOCALITY. . Landing Stage (High Water) steeper ccscericcce . Landing Stage (Low Water) New Srishton ......... . Crosby Channel (1 hour CCG) Sah ee . 1 Mile N. of Bar Ship (Low Water)............ i i a iy . Piel (Barrow Channel) Port Hrin (High Water) . Port Erin (Low Water) . Fleshwick(High Water) . Douglas Bay (Low Water) Ce > 15 Miles S.E.. of BOWES oe. cece secnesee . 30 Miles S.E. of INA ces eies.seeaces | 45 Miles §.E. of MOVES 55 eccesssacsenes 5. Near N.W. Light Ship ey. tient Ship ...... . 2 Miles W. of N.W. (Clo) . 24 Miles N.W., 4 W. of Walney Light ...... 9. 10 Miles N.W. by N. 4 N. from Point of Ayre Light Ship, I.0.M. ... Sp. Gr. at 17°5 according to Kiel Areometers. (1.02312 | 1.02313 (1.01629 ( 1.01631 (1.02476 ( 1.02478 (1.02334 ( 1.02337 (1.02527 {1.02538 1.02388 1.02390 { ( (1.02516 (1.02517 (1.02584 (1.02585 ( ( 1.02588 1.02582 (1.02594 ( 1.02594 (1.02568 (1.02572 - (1.02601 | 1.02603 ( 1.02606 | 1.02610 (1.02587 | 1.02591 (1.02441 ( 1.02447 (1.02543 | 1.02544 {1.02546 ( 1.02546 (1.02549 (1.02551 (1.02575 ( 1.02576 Maximum and Minimum Readings Difference between of Kiel Areometers 0-00001 0-00002 0-00002 0-00003 0-00011 0-00002 0-00001 0-00001 0-00006 nil 0)-00004 0:00002 0-00004 0-00004 0-00006 0-00001 nil. 0:00002 0-00001 Sp. Gr. at 17°5 according to Hicks’ Salinometer. H e) iw) iS) bo 1:0260 1:0259 1:0259 1:0257 1-0261 1:0259 1:0244 1:0253 1:0252 1:025 1:0258 Sp. Gr. at 17°5 according to Hydro. meter of Negretti and Zambra. 1:0239 1-0226 1°0245 1:0245 1:0245 1-0230 131 calculated from Chlorine Values Sp. Gr. at 17°5 1:02315 1-01632 1:02466 1:02333 1-02529 1:02387 1:02520 1:02584 1:02587 1:02593 1:02571 1:02602 1-02608 1:02589 1:02441 1:02546 1:02546 1:02549 1:02576 182 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 3.—CoLOoUR OF THE WATER. ‘This is an unimportant character, but it was fourd to vary so much that it seemed useful to note it. The colour was observed by looking down a column of water about 20 inches high on to a brightly illuminated white surface. The words used to denote the colour are, it is hoped, not too vague. Colour. 1. Landing Stage (high water) - greenish erey. 2. Landing Stage (low water) - greenish orange. 3. New Brighton” - - - greenish brown. 4. Crosby Channel (1 hour flood) - - - - pale olive green. 5. 1 mile N. of Bar ship (low water) - - - - yellowish green. 6. Blackpool = - - - - greenish grey. 7. Piel (Barrow Channel) - - greenish grey. 8. Port Erin (high water) - - bluish green. 9. Port Erin (low water) - - pale grey. 10. Fleshwick (high water) - - bluish grey. 11. Douglas Bay (low water) - greenish grey. 12. 15 miles 8.E. of Douglas = -_ greenish blue. 13. 30 miles 8.E. of Douglas - pale bluish green. 14. 45 miles 8... of Douglas - greenish grey. 15. Near N.W. light ship - - pale olive green. 16. N.W. light ship - - bright yellow green. 17. 2 miles W. of N.W. light ship - - - - - grey green. 18. 24 miles N.W. 4 W. of Wal- ney light - . - - greenish grey 19. 10 miles N.W. by N. 3 N. from Poimt of Ayre light house, I.0.M. - - - - grey green SEA-FISHERIES LABORATORY. 138 - 4,—SuspenpED MatTTER. This was not estimated owing to the difficulty of filtering large volumes of water, and of weighing small amounts of ash. It was very abundant in the Mersey water at low tide, but not nearly so abundant at high tide. There Was quite an appreciable amount of suspended material in all samples off the Lancashire coast, but in the open sea, and round the Isle of Man, the water is practically clear. For the determination of the specific gravity and other characters, the sediment was allowed to settle and the clear water decanted off. 5.—EHstTIMATION OF THE CHLORINE. This was done with the greatest possible accuracy, both by Volhard’s method and also by titration with standard silver nitrate solution, using potassium chromate as indicator. The exact process by each method is given and also the results, for the sake of comparison. (a..—PREPARATION OF SOLUTIONS. The silver nitrate solution was prepared by dissolving the pure fused salt in sufficient water to make about a decinormal solution. This could then be diluted to any desired extent. It was standardised by titration against the sodium chloride solution (which see), using potassium chromate as indicator, and also by Volhard’s method It was restandardised about once a week, in order to be certain as to its exact strength from time to time. The sodinm chloride solution was prepared by dis- solving an accurately determined weight of pure, dry 134 (b -TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. sodium chloride in a known volume of distilled water. The sodium chloride was obtained from the ordinary crude salt by precipitation from a strong aqueous solution by means of hydrochloric acid. The precipi- tate was filtered, dried, and finally fused. The actual strength of the salt solution prepared was nearly <5, and this could then be diluted as required. The ammonium sulphocyanide solution was prepared by dissolving the pure salt in water in such proportions as to make it approximately decinormal. Its actual strength was not determined as it was titrated against the silver nitrate solution only to find the ratio between their strengths. Saturated solutions of the two indicators—potassium chromate and iron alum—were employed, one drop being sufficient for each titration. .)—VouHarp’s Merton. A sample of sea water (about 10°0 cc.) was titrated as a preliminary, in order to find about the amount of silver solution required. The accurate determinations were then done in the following way :— 10cc. of the sea water was measured from a pipette into a beaker, and mixed with a little distilled water. About 2cc. more silver solution was then added than the preliminary examination had shown to be neces- sary. The mixture was thoroughly shaken and allowed to settle, and the nearly clear supernatent liquid was filtered. The residue in the beaker was twice washed with distilled water, and the washings were mixed with the filtrate after they themselves had also been filtered. All the excess of silver was now found to be in the SEA-FISHERIES LABORATORY. 135 filtrate. It is to be regretted that the filtering could not have been done through a Gooch filter, as then the precipitated silver haloid could have been collected and weighed, and so would have formed an additional check on the values obtained by titrating the filtrate. This filtrate was poured into a porcelain dish, a drop of iron alum solution added, and titrated drop by drop with the sulpho-cyanide solution till a red colour appeared. ‘To this was then added enough silver nitrate solution to just destroy the colour, and this process of alternately titrating with the sulpho-cyanide and the silver solution was irequently repeated in a zigzag manner till a great number of determinations of the end point were obtained, the mean of which was considered accurate. (c..—Usine Potasstum CHRomatTE as INDICATOR. As in the previous case a sample of about 10ce. of the water was first titrated to find about how much silver solution was required. In the accurate determinations 10cc. of the sea water were mixed with some distilled water in a beaker, and then about 0°5ce. less silver solution than was required for complete precipitation was added. The mixture was well mixed and a drop of the chromate solution added, and then the silver solution was run in drop by drop till a permanent change of colour was obtained. The end poimt was obtained repeatedly by zigzag titrations with the salt and silver nitrate solutions. A mean of the values obtained was taken as correct. Considerable errors occur in both methods, but more especially in this, owing to the difficulty of obtaining a standard of colour which represents the end of the reaction. 136 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. In order to get as much accuracy as possible, a — sample solution coloured by chromate was used, and the end point was considered to have been reached as soon as the tint of the solution being titrated differed permanently from this sample. CHLORINE TABLE. 3 A ‘i is n rs Ao Arm. | 8a3 £423) $88 | 82 ans Soa | 648 | .ode euge |) g>3 | se.” Bad | Bh | ase 3-4 O ae iS, > > Landing Stage (High water).................. 16°84 16°79 16°76 Landing Stage (Low water).................. 11°82 11°81 11-80 New Brighton, cc n.eon ue .cscae Oe ee ideal 17°94 17°87 17°95 Crosby Channel (1 hour flood)............... 17°03 | 16°95) Gee 1 mile N. of Bar Ship (Low water)......... 18°38 | 18:33 | 18°32 BlaSk oak Gas «srs chacGiash des caieon Saonbetgoni dad 17-28 |) 17:30) sian Piel (Garrow /Chanmellr . 135... enc t sei. cone 18°32 18:26 | 18:24 Bort: nun Eliot water) Jac, eoaecean tecsnee re? 18°72 18°73 18°73 Pory fiaciun: (ow weaten):; ceincee- <<< ses care 18-77 | 18°7o0 nee Fleshwick (High water) .......0.cc0c00 18:85 | 18-79 | 18-80 Douglas Bay (Low water).................660 18°64 18-63 18°63 Lo.aailes SH Of Deum basi acaals dass ya ae ahee 18:90 | 18°86 18°85 30:miles 8:5. ‘of Douglas ...16.2icd see. aee 18°95 18°90 18°89 45 miles 'S.E.. of Douglas. .i2.cc ccs ceaseess 18°80 | 18°76.) eae Néar oN. We duisht Shipins.cnescd,p.). F.—Compound bones, 7.e., cranial bones to which ossicles or bones originally developed in relation to the system of sensory canals have become secondarily fused to their superficial surface :—Articular (Ar.), Dentary (D.), Frontal (F'r.), Pterotic (Pt.O.), Sphenotice (Sp.0.). We shall now proceed to describe the visceral skere- ton proper, taking the hyoid arch first and the branchial arches afterwards. 178 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 5.—Hyor Arcu* (Fig. 6). 3 | Ocular Side. | | Uro-hyal (U.Hy.).t-—A short bony rod but ecar- tilaginous in front and behind, and articulating with the upper hypo-hyals and slightly with the first basi-branchial. Hypo-hyals (./y.)—Two pieces, as in the Cod, partly of bone and partly of cartilage and loosely articu- lating in the middle line with the same elements of the other side. The upper one is perforated in the middle, thus giving a false impression as to the whereabouts of the suture between the two. Cerato-hyal (C./7y.).—A stout bar traversed in front (anterior face) by a longitudinal groove, the texture of the bone on each side of which running in different directions, thus seeming to indicate that the cerato-hyal, as well as the hypo- and epi-hyals, is either splitting or has been formed by fusion. : Epi-hyals (“p./y.). (eke doubler the lower piece being entirely cartilaginous and the upper partly so. The suture between the cerato- and upper epi-hyal is obscured by an overgrowth of bone as in Micropterus,t but may be seen on holding the hyoid bar up to the light. *Tt is here necessary to explain the precise significance of the prefixes basi- and hypo- as applied to parts of the visceral skeleton. The term basi- can only be applied to a median unpaired ventral element, and the term hypo- to the pair (2.e., one on each side), immediately succeeding it. Now whilst these three elements may, and often do, exist side by side in any one species, the basi- element may be absent, and a median unpaired ventral piece formed by the two hypo- elements fusing together, the result being a _ secondary basi-segment. In the latter case the terms basi- and hypo- are synonyms (and are used indifferently) ; in the former, they are not. - + The terms basi-hyal, glosso-hyal, ento-glossal and basi-branchiostegal have also been applied to this bone in Fishes by different authors, and the same terms, or some of them, have been applied to other elements in higher Vertebrates. The synonymy is too complex to be discussed here, + Shufeldt, op. cit., p. 819, and fig. 32, SEA-FISHERIES LABORATORY. 179 Inter-hyal (/.fy., figs. 5 and 6).—Possibly a sesa- moid bone developed in the inter-hyal ligament and not homologous with the other segments of the hyoid. This bone is incorrectly called by some authors the stylo-hyal— a term really a synonym of the pharyngo-hyal, represented in most fishes by the hyomandibular. The inter-hyal of the Plaice consists of a central bony rod with cartilaginous extremities articulating with the hyoid and symplectic and inter-operculum, as already indicated. Below the attachment of the inter-hyal to the upper epi-hyal is seen the prominence which is also connected with the inter- operculum. Branchiostegal Rays (7.F.).—There are the usual 7 of these rays, the first on each side meeting at their free extremities, and being closely bound together by strong fibrous connective tissue, appear to fuse. They are not all attached at the same plane as shown in the figure. The first 3 articulate with the cerato-hyal, the iast 4 at about the junction of the 2 epi-hyals. The last, however, is always attached to the upper or bony epi-hyal. The rays have cartilaginous extremities, but otherwise consist of a transparent milky coloured bone. ‘The first two cross and he under the others in the living state. Eyeless Side. The hyoid bar is slightly shorter and not quite so robust. The first pair of apparently fused rays are drawn over to the eyeless side as shown in the figure. The most tonspicuous difference is in the branchiostegal rays, which are, except the first, uniformly shorter and not so curved. The length and curve are faithfully represented in the figure, 180 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 6.—Brancniat Arcuzs (Fig. 7). Ocular Side. Basi-branchial I. (2.5r.1)—A triangular bone, with its apex wedged in between the upper hypo-hyals (see fig. 6). At its base it articulates with basi-branchial IT. and with the hypo-branchials of the first arch, but the latter articulation is not obvious dorsally, the head of the hypo-branchial fitting into a deep lateral socket formed by basi-branchials I. and IT. According to Cunningham this bone is in the Sole completely wedged in between the upper hypo-hyals and does not articulate with the first branchial arch at all. Branchial Arch I.—''he epi-branchial (H.Br.') bears a prominent tubercle on its anterior surface. The pharyngo-branchial (P.#r.1) is a ‘slender bone which articulates with the skull at the ventro-posterior margin of the jugular foramen in the prootic immediately below the hyomandibular cup. This somewhat curious connec- tion with the skull also exists in the Sole according to Cunningham, and in Sebastolobus according to Starks. Basi-branchial Il. (B.Br.2).—An hour glass shaped bone articulating in front with the basi- and hypo- branchials of the first arch and behind with basi-branchial IIl. and slightly with the hypo-branchials of its own arch. Branchial Arch II1—The hypo-branchial is wide but compressed dorso-ventrally. Where it articulates with the second basi-branchial it sends down a prominent spine. Another well-marked spine is borne on its anterior edge. The cerato-branchial is longitudinally grooved ventrally. As in the first arch, the epi-branchial bears a tuberosity, but it is much more prominent on this arch. ‘the first and last gill rakers are very small. The superior pharyn- geal bone of the Plaice in medium-sized fish consists of SEA-FISHERIES LABORATORY. 181 three pieces, which represent the pharyngo-branchials of the three arches to which they belong. These pieces are, however (and especially the anterior two), so closely bound together that they may, as we have known them to do in other forms, fuse up in old fish. The second pharyngo- branchial (P.6r.?) is a stout laterally compressed bone articulating with the third pharyngo-branchial posteriorly. Tt bore five teeth in one row. Basi-branchial III. (2.Br.*). A very thin laterally compressed bone, apparently wedged out of existence by the large hypo-branchials II. Its posterior extremity lies under and is covered by the two hypo-branchials ITI. Branchial Arch III.—The hypo-branchial is smaller than in arch II., but the ventral spine is both larger and longer, and articulating strongly with the same spine of the other side forms a bony arch traversed by the ventral aorta. ‘The anterior spine in hypo-branchial II. is absent. The cerato-branchial is grooved ventrally as in arch IL., but more deeply. The epi-branchial bears two large tuberosities at its distal extremity. The posterior of these articulates with the pharyngo-branchial III. (P.Br.*), the anterior by two strong ligaments with the epi-branchial IV. The pharyngo-branchial (P.6r.*) bears a strong process behind for articulation with the pharyngo- branchial II., and bears eight teeth in two rows. - Basi-branchial IY. (B.Br.*)—A very small nodule of cartilage wedged in between the bases of arches III. and IV. It is only connected with the fourth arch on the ocular side, the basal elements of this arch on either side meeting in the mid-ventral line. The morphological value of this cartilage cannot be determined on adult material. It is obvious that the branchial arches have undergone reduction from behind forwards. Thus there are only three segments in the fourth arch. Now it is 182. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. also obvious that the basal segment of this arch (C.Br.*) is serially homologous with the cerato-branchials, the missing element therefore being the hypo-branchial. Hence the fourth basi-branchial may represent either the two vestigial hypo-segments fused together (a primary basi-segment being absent) or it may have been formed by the basi- and two hypo- elements fusing up. Branchial Arch I¥Y—The cerato-branchial (C.6r. ) is slightly grooved ventrally. The epi-branchial (4.Br.*) is a stout L-shaped bone, and is strongly connected with the same segment of the preceding arch. The pharyngo- branchial (P.Br.*) is small, and bore six teeth. Branchial Arch ¥.—This is more reduced than any of the other arches, and consists of a single bone on each side in which there are practically no traces of asymmetry. This is the inferior pharyngeal bone of Cuvier, and appears to represent the cerato-branchial segment only of the arch.* The inferior pharyngeals (£.Ph.) are stout triangular-shaped bones separate dorsally but bridged in front ventrally by a tract of cartilage. Two irregular rows of teeth are borne on the pharyngeal surface, and in the specimen now described there were 12 on the ocular side and 14 on the eyeless. At the side and at the base of the outer row are situated the replacing teeth, which be- come functional as their predecessors wear away. | Gill Rakers.— These diminish both in size and number from before backwards. Their function is to pro- vide a rough filtering apparatus for the water passing out of the pharynx. ‘Their small size and number in the Plaice is due to the nature of the fishes’ food. In those fishes where the food might easily escape through the gill slits (e.g. Clupea), the gill rakers are much longer and more numerous. They are purely dermal and are not fused «Cp. Cunningham, op. cit., and W. K. Parker, Phil. Trans., 1873 (Salmo). SEA-FISHERIES LABORATORY. 183 on to the arches, the only connection between the arches and the rakers being that in older specimens and in some places the position of the raker is indicated on the arch by a faint elevation. Their number and position, however, was in the few specimens examined remarkably constant and symmetrical, so that the following formula may apply to either side of most individuals : — eat | at) i) | sie Hy po-branchial 2 3 0 0 0 Cerato-branchial .... 5 6 7 6 0 Epi-branchial 3 1 0 0 0 Gill Rays.—The gill filaments are supported by series of very delicate fragile gill rays fused together by their bases like a comb, which it is hardly practicable to dissect, but which are quite obvious in sections of the gills. They radiate out from the branchial arches as usual, and occur in pairs—one to each demibranch of the arch. Eyeless SG. a Branchial Arch I.—A1] segments slightly shorter and not so robust, the hypo-branchial markedly so, nor is the latter so deeply socketed into basi-branchials I. and II. as on. the ocular side. The pharyngo-branchial also articu- lates with the skull, but the depression in the skull with which it is connected is deeper and more marked. Branchial Arch II.—Practically no difference except that the basi-branchial articulation is stronger on the ocular side. Branchial Arch III].—The segments are of the same length, but are somewhat less robust. The ventral arch transmitting the ventral aorta has been already described.. 184 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Branchial Arch IV¥.—The cerato-branchial is less strong on this side, but on the other hand the epi- branchial is larger. The cerato-branchial does not articu- late with the fourth basi-branchial but with the corre- sponding segment of the ocular side. The Superior and Inferior Pharyngeals.—The asym- metry in the number of the teeth is so strongly marked in the mouth, where the ocular side is practically devoid of them, that it is interesting to enquire whether its effect has been felt as far back as the pharyngeal bones. In the inferior pharyngeal the two sides are practically the same, except that in the. specimen described the ocular bone bore two less teeth. The left superior pharyngeal, however, was appreciably the larger, and although it only possessed an advantage of one in the number of teeth, the teeth themselves were larger and capable of doing more work. ‘This is doubtless due to the fact that in an animal lying on its left side, its food, even in the pharynx, naturally gravitates to the latter side. f 7.—VERTEBRAL CoLuMN.* (Bigs 10011 a2 15, 14) ly eo: The vertebral column of the Plaice may be divided into a trunk and tail region only, distinguished in the former by the presence of ribs and in the latter by the haemal canal. Although the number of vertebre in the column is subject to variation, it usually happens that the first caudal vertebra is the fourteenth. Each vertebra is markedly amphicoelous, the anterior. and posterior faces being considerably scooped out in the *The structure and development of the vertebral column of Teleostean fishes has recently been studied by 8. Ussow (Bull. Soc. Imp. Nat., Moscou, 1900, p. 175). Also previously in Amia and other fishes, by O. P. Hay (Field Columbian Museum, Zool. Ser., vol. i., No. 1, 1895). SEA-FISHERIES LABORATORY. 185 form of a cone, the two cones being connected in each vertebra by the pin-hole notochordal canal (Canalis dicentralis). As all these spaces are occupied by the ‘remains’ of the notochord, the latter is absolutely con- tinuous from one end of the column to the other. The following description is based mostly on a large _ specimen of an extreme length of 52cm. In this animal the neural spines were inclined as follows: 1, shghtly forwards; 2, 3, 4, 5, almost upright; 6, shghtly forwards; (-13, all slightly curved (with the convexity forwards) and project more or less forwards; 14, largest spine (first caudal) and projects slightly backwards; from 1-14 the neural spines increase in length; behind 14 they all incline backwards, the inclination becoming more and more marked as the extremity of the tail is reached, and they also decrease in length. With regard to the haemal spines (of which the anterior ones are very much longer than the corresponding neurals), the first 5 incline shghtly forwards ; 4 is vertical; 5 looks backwards, and so do the remainder, the tendency becoming gradually exaggerated behind, and at the same time the spines becoming shorter until they are about the same Jength as the neural’spines. In the average specimen the posterior haemals are slightly longer than the neurals (ep. fig. 19). | In the posterior third of the body the vertebral column is situated about half way between its dorsal and ventral edges. In front of this region, partly owing to the slight upward curve of the column, but principally owing to the increased length of the haemal over the neural spines, the column is situated markedly nearer the dorsal than the ventral edge. In the anterior third it begins to bend down again slightly, and this is especially noticeable in the first 4 or 5 vertebra, the result being 186 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. that the skull when attached to the vertebral column is directed markedly downwards (see fig. 17). The anterior notochordal space in most of the trunk vertebrae (except the atlas) is perceptibly deeper than the posterior, so that the notochordal canal is situated nearer the posterior than the anterior face of the centrum. This is more marked in some vertebre than in others. | Atlas (figs. 10 and 17).—Body compressed from before backwards. Notochordal canal (V.C.) much nearer dorsal than ventral surface. Bears two large cartilage capped facets (C.F’.) for articulating with the paroccipital con- dyles, of which the left is perceptibly larger than the ~ right. ‘The anterior face of the centrum also articulates with the single occipital condyle on the basi-occipital, the connection of the skull with the vertebral column by means of 3 condyles being therefore very strong. Unlike all the other vertebrae, except about the last 5, the neural arch of the centrum is only perforated by one foramen on each side for the second spinal nerve. There is no trans- verse process, and only one rib, which belongs to the series of accessory ribs or intermuscular bones (A.#.'), and is attached to its vertebra higher up than any of the others, articulating at the junction of the neural arch with the centrum (figs. 10, 17). As in all the other vertebre (although the tendency is faint in the posterior caudals), and as first described by Traquair, the atlas is markedly asymmetrical, the neural spine being directed towards the eyeless side. The asymmetry here is obviously an adapta- tion to the habit of the animal in lying on its eyeless side. Superficially this side is practically flat, whilst the ocular side is convex. The asymmetry of the vertebre, there- fore, tends to a flattening of the eyeless side and an arch- ing of the ocular side (ep. figs. 11 and 13). The neural spine itself is in the form of a rolled plate forming a hollow SEA-FISHERIES LABORATORY. 187 eylinder, but the edges do not fuse behind. Except that the eyeless condylar facet is larger than the ocular one the asymmetry is not noticeable below the neural spine. The centrum is overlapped by the large ill-defined anterior zygapophyses of the 2nd vertebra, and itself bears faint posterior zygapophyses at the bases of the neural arches, whilst on the ocular side the latter sends back a hook-like process which fits outsede the neural arch of the second vertebra. This is the only trace of the characteristic method of articulation of the vertebre of the Cod. | Second Vertebra (fig. 17, V.?).—The neural arch is perforated on each side by two foramina for the roots of the third spinal nerve, but the bridge of ‘bone separating the right pair is extremely slender. The large irregular anterior zygapophyses are asymmetrical, that on the eye- less side being much the larger. The neural spine is also asymmetrical as in the atlas, but the asymmetry extends down on to the neural arch. A small pointed transverse process is present, with a long accessory rib (A.R.?) strongly attached to its base much lower down than the attachment of the first intermuscular bone. Both the centrum and neural arch bear post-zygapophysial facets not shown on the eyeless side. Third Vertebra (fig. 17, V.2)—Whole of the vertebra markedly asymmetrical, being more strongly developed on the eyeless side in every respect. Neural spine and spinal canal arch to the left. Anterior and posterior zygapophyses more strongly marked on the same side. The centrum not only bears a strengthening ridge (S.R.) which is much stronger on the eyeless side, but is itself more bulky on that side, so that the notochordal canal is eccentric in position. The transverse processes, like all those succeeding them, and as already described by 188 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Traquair (pp. 285-6) are asymmetrical—that on the eyeless side having a more ventral origin and inclination; but the asymmetry of these processes is not specially marked in this vertebra, and may indeed be practically confined to vertebrae 5-12 inclusive. The accessory rib (A.J?.?) is attached nearer the base of the transverse process on the eyeless side. Fourth Vertebra.—Much the same as 3, except: (qa) two moderate strengthening ridges are present on the eye- less side, and one on the ocular side with a deep cleft on each side of it; (6) a true rib is present, and is attached to the posterior surface of the transverse process half way between its extremity and the attachment of the accessory. rib. From this vertebra onwards the transverse ,:rocesses increase in length and the true ribs (which rapidly in- crease in length up to the 7th, the longest [see fig. 18], but rapidly decrease in length after this) gradually approach the tip of the transverse process, until at about the 8th or 9th vertebra they are obliquely attached to the tip. The accessory ribs, which from the 2nd to the 9th inclusive vary very little in length, are also attached in a backwardly descending line until about the 10th or 11th vertebra, after which, just as they begin to decline in size, they rise rapidly on the vertebra (cp. fig. 18), until pos- terior to the 14th or Ist caudal vertebra they are doubtless represented by the serially homologous tubercles situated on, and fused to, the centrum, and forming pseudo-trans- verse processes. Fifth Yertebra.—Neural spine almost flat and only curved backwards slightly at the lateral edges. Asym- metry slightly increasing. Sixth Vertebra.—Only one strengthening ridge on eyeless side and two on ocular. Asymmetry of centrum and transverse processes strongly marked, but more so SEA-FISHERIES LABORATORY. 189 anteriorly than posteriorly. The post-zygapophyses pro- ject slightly backwards as distinct processes. Seventh Vertebra.—One strengthening ridge on each side, but slightly cleft into two. Neural spine more com- pact and solid. Posterior zygapophyses are now distinct tubercles projecting backwards from about the mzddle of the neural arch. The anterior zygapophyses are, as hitherto, except in the first 3 or 4 vertebra, triangular processes projecting forwards from the base of the neural arch. . Kighth Vertebra (fig. 11)—'wo moderate and one weak strengthening ridge on the eyeless side and three of about the same character on ocular side. Posterior zygapophyses as in 7. Anterior zygapophyses much stronger on eyeless side. Neural spine for the most part consists of two hollow tubes placed side by side end con- nected by a narrow bridge of bone. Ninth Vertebra.—Two well marked strengthening ridges and rudiment of another on eyeless side and two on ocular side. ZAygapophyses getting weaker. Neural arch slightly, and neural spine markedly, asymmetrical, but the centrum is almost symmetrical with the notochordal canal in the centre. | Tenth Vertebra (fig. 18, V.10)—Two strengthening ridges on eyeless side and three on ocular. Zygapophyses somewhat reduced, and not much difference between those of the two sides. Centrum slightly asymmetrical and neural and transverse processes still obviously so, but the tendency is now on the wane. The accessory and true ribs of this vertebra are the longest of any. Behind both decline in length. Eleventh Vertebra (fig. 18)—Three strengthening ridges on eyeless and two cn ocular side. Asymmetry slightly less marked than in preceding vertebra. Zygapo- 190 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. physes slightly weaker and more symmetrical. The trans- verse processes are now increasing in width from before backwards, and bear a slight elevation to which the accessory rib is attached. Twelfth Vertebra (figs. 12 and 18).—Strengthening ridges as in 1]. Asymmetry slight. Post-zygapophyses faint and practically symmetrical. Transverse process proximally very wide from before backwards. Neural spine more consolidated, but still consists of 2 bony tubes placed side by side. Thirteenth Vertebra (fig. 18).—Three strengthening ridges on eyeless side, and two on centrum and one on transverse process on ocular side. Symmetry as in 12. Transverse processes only very slightly asymmetrical. Accessory rib rudimentary and attached to a prominent elevation near base of transverse process (A.R.13). Last vertebra to bear free ribs of either series. Behind the transverse processes and true ribs are converted into the haemal arch and spine. This gradual conversion, and the homology of the parts, is well shown in figure 18. Zygapo- physes as in 12. ‘Transverse processes very wide from before backwards. Fourteenth Vertebra (figs. 13 and 18)—The first caudal vertebra. Three strengthening ridges on each side. The neural and haemal spines are the longest of any, and both incline slightly backwards and towards the eyeless side. The neural spine, which is only about two- thirds the length of the haemal spine, is somewhat com- plex, and contains three longitudinal cavities, all of which open posteriorly at the top of the spine. The left anterior zygapophysis is much more prominent than the right, whilst the post-zygapophyses are feeble and no longer obvious as projections from the posterior border of the neural arch, ‘The posterior notochordal space, unlike SEA-FISHERIES LABORATORY. 191 those of the trunk vertebrae, is deeper than the anterior, and hence the notochordal canal is thrown further for- wards. The centrum is markedly asymmetrical, being larger on the eyeless side. The projection at the side of the centrum which possibly represents the remains of the accessory rib and its basal tubercle (A.2.*), with which it is serially homologous and to its present position on the centrum it has been gradually ascending from the trans- verse process, 1s larger and has a more ventral inclination on the ocular than on the eyeless side. Below the centrum are situated the haemal arch with its canal and the haemal spe. The latter is a thin curved laminate bone with the concavity directed forwards, and strengthened behind by two thin longitudinal ridges. In front it bears a wide longitudinal recess (Rec. Awv.') which lodges the large first axonost of the anal fin. The following points of interest may be noted in the caudal vertebre. Behind the fourteenth or first caudal vertebra the vertebral column has a much more uniform structure, except that the first few caudals represent inter- mediate stages between the characters of the 14th and those of a typical caudal vertebra (cp. figs. 18 and 19). The asymmetry extends right down to the extremity of the column, but is only very slightly developed in the last few caudals and in the epurals and hypurals of the caudal fin. Neural and Haemal Spines.—As we pass back the spines get more simple in structure, shorter, und project more posteriorly. Both spines are, however, always fur- rowed longitudinally for the reception,of the large verti- eal sheet of ligament connecting them with each other. The structure of the last vertebra will be described in the section on the caudal fin. 192 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Foramina of Spinal Nerves.—All the neural arches except that of the atlas and usually about the last 5 are perforated by two foramina on each side for the exit of the spinal nerves (figs. 12, 14, 17, 18, 19). The ventral foramen is usually situated a little anterior to the dorsal one. Of the last 5 caudals the last is not perforated at all, and the preceding 4 have only one perforation on each side (fig. 19). The last vertebra, as of course in all the other caudals, has both a neural and a haemal canal. Zygapophyses.—As shown in fig. 18, the anterior zygapophyses decline after about the 14th vertebra, and about the last 7 caudals have practically no zygapophyses at all. After the 15th the pre-zygapophysis is much re- duced, and only very slightly overlaps the vertebra in front or does not do so at all. Hence behind this vertebra the post-zygapophyses are entirely lacking. Strengthening Ridges.—These are disposed much the same as in the trunk vertebrae, except that in the hinder caudals there is a tendency for the ridges to be collected into one strong ridge situated mid-laterally on the centrum. This, however, does not obtain in all the pos- terior caudals (cp. fig. 19). Notochord.—All the caudals have a notochordal canal except occasionally the last. The centra of the most pos- terior vertebre are always less ossified than those in front, and hence the notochordal spaces are larger. The urostyle is deeply excavated also, but the excavation extends straight backwards and does not turn up. Accessory Ribs. The tubercles which have been identified as the remains of the accessory ribs are well marked on the anterior caudals, but diminish backwards and are practically absent on about the last 12. In the anterior caudals they occupy the position of the transverse processes of the trunk vertebra. SEA-FISHERIES LABORATORY. 193 8.—CaupaL Fin anp EXTREMITY oF VERTEBRAL COLUMN (Figs. 14, 15 and 19). The caudal fin when first dissected appears to be diphycercal, -but the asymmetrical articulation of the second hypural bone (Hp.2) at once establishes its heterocercal character. Nevertheless the caudal fin. of the adult Plaice is one of the most completely masked hetero- cercal or homocercal fins on record, and is hence of some interest. The termination of the vertebral column is peculiar, as in place of an upturned tapering bony “urostyle ’ formed by the ossification of the free extremity of the notochord, there is found an expanded fan-shaped plate which, with the second hypural, gives articulation to the greater part of the caudal fin rays. The proximal stout vertebra-like body articulating with the last true vertebra may possibly represent another vertebra, but it is not constricted off in Plaice from 15 mm. upwards, and in the absence of earlier developmental evidence is here described as the base of the urostyle. - Dissection of young plaice of a length of 45mm. shows the vertebral column terminating as above described, but similar preparations of still smaller forms of 15-17mm., where the notochord is yet unossified, prove conclusively that the fan-shaped plate is formed by the fusion of the upturned extremity of the notochord with a separate hypural bone (fig. 15, {.3), and hence the plate (U. + Hp.3) of the adult is a com- pound bone representing the urostyle and a third hypural fused together. It will be noticed in fig. 15 that the free surface for articulation with the fin rays is afforded exclu- sively by the third hypural—the urostyle taking no part in it. Apart from the independence of the urostyle and third hypural the tail of a form of the above length shows no essential difference from that of an adult, beyond those Q 194 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. differences incidental to its stage. The above description should be compared with the apparently similar one in Sebastolobus (Starks, op. cit.), and with the very dissimilar one occurring in the herring.* If the last distinct vertebra (fig. 14, V.43, 19, V.42) be now examined, it will be seen that the neural spine (W.S.43, 42) resembles the haemal spine (H.S.30, 29) in structure, but that both are peculiar. Each consists of a partly cartilaginous shaft behind and a thin laminate © portion in front. The posterior shafts so closely resemble the succeeding epural and hypural bones respectively as to suggest that an epural above and an hypural below have - fused on to the laminate portions, which latter are un- doubtedly similar to and perhaps represent the neural and haemal spines in front. As, however, we have no positive evidence of such a fusion, the spines in question are here described as simple neural and haemal spines. Wedged in between U + Hp. 3 and N.S. 43 (fig. 14) are two partly cartilaginous spines (Yp. 1 and 2) which are closely connected by ligament with each other and with the last neural spine, but which are not sufficiently long proximally to reach the vertebral column. The gradual increase in length of these spines as the animal grows older suggests that they may in senile forms become connected with the vertebral column. That they develop in the same way as the neural spines seems certain, although there are no vertebre ostensibly belonging to them. One is appreciably larger than the other, and there is a big gap between the second and U. + Hp. 3. They represent the epural or epiural bones of other authors. The second hypural bone (Hp. 2) is of the same shape and structure as the upper piece (U + Hp. 3), both being cartilaginous distally and strongly ossified proximally. * Duncan Matthews, Fishery Board, Scotland, Report v., 1886, SEA-FISHERIES LABORATORY. 195 It articulates as shown in fig. 14 with U + Hp. 3 above and in front, the latter articulation making the two ex- panded tail bones unequal. The first ostensible hypural (Hp. 1) is a wedge-shaped bone of the same structure as the 2nd, but much smaller. It is closely attached by hga- ment to the last haemal spine, but proximally does not reach the vertebral column. Hach bone in the tail giving articulation to fin rays bears a thin terminal cartilaginous epiphysis (cp. fig. 14). As in the other fins there is a pad of sub-cartilaginous tissue intercalated between the bones of the vertebral column and the proximal ends of the fin rays. This, as before, is embraced by the diverging halves of the rays (Ff.R.). The number of the latter in the caudal fin varied in the specimens examined around 20—sometimes more and sometimes less. What possibly may be regarded as the typical condition both as regards number and places of articulation is represented as follows (cp. fig. i4):— Shaft of last neural spine, 1; Epural 1, 1; Epural 2, 2; Hypural 3, 6; Hypural 2,6; Hypural 1, 3; shaft of last haemal spine, 1; total, 20. Hach fin ray is of the same structure as those of the pectoral and pelvic fins, with the exception that there are no articular processes connecting the individual rays with their neighbours, each ray in the caudal fin, therefore, being independent of those immediately above and below it. With the exception of about the three most dorsal and ventral, each ray bifurcates distally, but does not split up further to form a brush as happens in the caudal fin rays of the Sole according to Cunningham. 9.—Dorsat Fin (Figs. 17 and 19). The dorsal fin commences very far forwards in the pseudo-medial line, and in the specimen on which the 196 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. present description is based, which measured 52cem., the base of the first dorsal fin ray was only 6mm. from the posterior narial aperture of the eyeless side, z.e., well in front of the cavity of the brain. | As in the paired and caudal fins all the fin rays con- sist of two pieces. Hach fin ray is connected with two further skeletal pieces termed by Cope,* Baur,t and Smith Woodward the baseost and axonost, by T. J. Parker§ pterygiophores, and by Bridgel| radial elements. The axonost has hitherto been called ihe interspinous bone, on account of its position between two neural spines. The terms baseost and axonost are adopted in this work, and the precise connections between these two elements and the two pieces forming a fin ray will be described below. In the meantime it may be remarked that usually one or two axonosts are found between two adjacent neural spines in the dorsal and anal fins of the Plaice, whilst the baseost is always situated between and attached to the heads of two adjacent axonosts. The two halves of the fin ray diverge proximally and tightly clasp the baseost (ep. fig. 16). This mechanism was first described by T. J. Parker in Regalecus, and has since been described in the Plaice by Bridge. Each axonost, even in old specimens, consists usually of a bony cylinder filled with cartilage. The head is always hollow, and is filled up with a triangular plug of cartilage (fig. 16). | The first dorsal fin ray has no baseost, but its halves diverge as usual and embrace the head of the first axonost with only a small sub-cartilaginous pad between. It 1s also asymmetrical, the ocular half being slightly the longer. * American Nat., 1890. + Jour. Morph., vol, iii. t Catalogue Fossil Fishes, British Museum, and Vertebrate Paleontology. § Trans. Zoo], Soc., vol. xii Journ, Linnean Soc., vol, xxv ~ SEA-FISHERIES LABORATORY. 197 ‘The axonost lettered 1 + 2 in figure 17 is also asym- metrical, its head inclining to the eyeless side. As this bone supports two fin rays (unlike any other in the body, except the huge axonost 1 of the anal fin), it was carefully -examined in a very large plaice, and was there seen to present indications of three pieces, two of which possibly correspond to what would represent the first and second axonosts locked together, whilst the third is the partly cartilaginous proximal shaft wedged in between them and connecting them with the skull. If this interpretation of the first apparent axonost be correct, the first baseost (Bs. 1) will be situated between two axonosts as it should be, and not present an anomaly only found elsewhere in the skeleton of the plaice at the anterior extremity of the anal fin. Posteriorly near the head of axonost 1 + 2 isa recess into which fits baseost 1 for the second fin ray. Below this recess is a prominent projection which gives articulation to baseost 2 for the third fin ray. The second fin ray is asymmetrical, the ocular half being the longer. The third -axonost and fin ray are practically sym- metrical. The head of this axonost forms a cone, the second baseost articulating in front and the third behind. Below the head the axcnost bears leafy projections in front and behind. In the fourth axonost the leafy projections above are exaggerated and the shaft is reduced to a median ridge on each side of the axonost. This form of the axonost, 2.e., with a median spine on each side and thin laminz in front and behind, represents the typical structure of an axonost, and is admirably adapted for the muscles of the fin ray inserted into it. As described by Cunningham (pp. 47-48) in the Sole, each fin ray has six muscles, of which there is one on each side (the “right and left abductors’) for deflecting the fin ray to the right and left of the median 198 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. plane and which are not connected with the shafts of the axonosts, whilst the other four (the “ elevators and depres- sors’) are arranged 2 on each side, the anterior right and left pair arising from the anterior surface of the fin ray and being inserted into the lamina on the shaft of the axonost in front of the median spine, the posterior pair arising from the posterior surface of the ray and being inserted into the posterior lamina. The latter muscles elevate and depress the fin ray in the median plane. If the dorsal surface of the cranium cf a plaice be examined, there will be noticed in the pseudo-mesial plane a longitudinal trench-like depression which passes back- wards in a slight sigmoid curve from left to right on the left frontal and supraoccipital. This depression (see fig. 1) is connected with the extension forwards of the dorsal fin over the roof of the cranium. Into it fit usually axonosts 6, 7, 8, whilst the axonosts in front of these, though too short to actually reach the cranium, are con- nected with the depression by means of ligaments. Behind the attachment of the eighth axonost, the ceciput suddenly shelves down, and in this depression, 7.e., bounded in front by the reduced occipital spine and behind by the first neural spine, are situated the two suc- ceeding axonosts (9 and 10). Behind the 10th the axonosts become related to the neural spines as usual. The posterior extremity of the dorsal fin is only note- worthy in two respects: (a) in the presence of 4 axonosts between neural spines 36-37, the largest number found between any two succeeding neural or haemal spines, excepting the anterior extremity of the anal fin; (0) the last fin ray (71) articulates directly with the axonost (70) without the intervention of a baseost. The last four vertebre have no connection either with the dorsal or anal fins. In the specimen on which the above description was SEA-FISHERIES LABORATORY. 199 founded the last fin ray was characterized by its sigmoid curve and horizontal position. These features were doubt- less anomalies. 10.—Awat Fin (Figs. 18 and 19). The mechanism of the fin rays and their skeletal supports is the same as in the dorsal fin. The axonosts are, however, perceptibly longer than those of the latter fin, and they are sometimes called interhaemal bones to distinguish them from the interspinous elements. The structure of the anal axonosts is the same as that of the dorsal ones. The anterior extremity of the anal fin is interesting in many ways. ‘The posterior boundary of the body cavity is supported by a very stout bone which curves downwards and forwards from its roof, and terminates in a point behind the anus. Above it fits into a deep recess borne on the anterior face of the haemal spine of the first caudal vertebra (fig. 13, Rec.Av.'). The ventral point, to an extent indicated in fig. 18 by a ring, is in dead specimens almost invariably found perforating and projecting freely through the skin behind the anus. It seems highly im- probable that such a pathological condition can obtain during life, but the skin covering the point must be very thin.* This bone, in the lack of any evidence as to its development, is here called the first axonost, but it is certain that it is more than this. In no other part of the body is a baseost situated anywhere but between two * We are now certain that the point does not perforate the skin during life, but that the latter is somewhat easily ruptured when a plaice is handled_and allows the point to protrude. Also that the protrusion in dead specimens is due to contraction following on preservation. To make use, therefore, of this so-called external ‘‘ anal spine’’ in classification, as has hitherto been done, is absurd. Since this was written, we note that Kyle arrives at the same conclusion. 200 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. axonosts.- As therefore the first axonost of the anal fin supports two baseosts completely and another partially, it follows that it has been formed of at least 5 axonosts fused together; but, as before remarked, we have no direct evidence of this.t The first baseost is situated in a de- pression and the succeeding two on an elevation on the postero-ventral surface of the first axonost, whilst the second axonost is closely opposed for its whole length to the same surface. The axonosts 3 to 7 fit by their tips into a posterior longitudinal furrow borne on ihe first. It is obvious that, as the first axonost is situated between vertebre 13 and 14 and axonost 7 lies in front of the haemal spine of the latter vertebra, axonosts 1 to 7 and fin rays 1 to 8 are situated in a space bounded morphologi- cally by two adjacent vertebre. As previously men- tioned, in only one other part of the body are as many as 4 axonosts found in a corresponding position. The posterior extremity of the anal fin presents no features of special interest except that the last fin ray articulates with the last axonost without the intervention of a baseost. The mechanism of the fin ray has now to be described (see fig. 16). Each ray consists of two longitudinal distally segmented pieces (/’.R. a, 6) held together by a transverse ligament (/’.R. c). Proximally these two pieces diverge and embrace the baseost (Bs.), and also to a limited extent the axonost (Aa.). The articular surfaces bear pads of a peculiar kind of soft cartilage (47.C.). Hach half of the fin ray is connected with the baseost by a stout ligament (F.R. d). Now the only connection between the + Whatever doubts may arise on this point willbe settled by a reference to the condition in Solea, as described by Cunningham; and in Rhombus, as described by Kyle. . AL FIN SKELETONS eg TS ET A A Caudal or Post-Anal Pane ae it ab hae el A hl EES ee N 0 eal : HANRNNAMA BARRENS WANE Dorsal Fin nN Aa BR BL Bae ee it ! i pth . u Ek , A S an ‘9 q 3 3 F. J.C: a A i) a | | M | 3 nm -¥) 6 4 s- Afferent-7 filamentar vessel | oS 2 ; ' Capiliary plexus. Gee er oe eee -Gill ray. Efferent filamentar vessel: \ < fi rateete be Int. : ; Gill ray. . ee an a Poe Oe a i Capillary plexus. — » ss seaed Vascular lamella. or | Dad A. Diagrammatic transverse section through Branchial arch I. B. Trans- verse section of a double filament, showing the surfaces of two lamelle. C. Longitudinal section of a single filament in a plane at right angles to A. 934 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. These structures, the convex surface of the gill arch, the proximal ends of the gill rays and the ligaments, form a tunnel through which pass the efferent branchial vessels and certain of the nerves of the gill. A very definite httle muscle takes origin in the cartilaginous connecting portion of every two gill rays, passes obliquely downwards into the tissues of the opposite gill filament, and is in- serted into the upper portion of its gill ray. This is part of an extremely pretty mechanical arrangement. It has been stated that each half filament is in section an isosceles triangle, and that the two series dove-tail into each other on account of their alternate arrangement. Obviously the contraction of the little muscles described above must have the effect of approximating the two series and obliterating the spaces between all the separate filaments; conversely the relaxation of the muscles and the elastic recoil of the gill rays must separate all the filaments attached to a single arch, leaving a space between each two, and this is effected without any alteration in the total length of the gill. It seems extremely probable, though we have no experimental evidence on the point, that these movements do actually take place in life, and that they aid in the movement through the gill of the respiratory water. - Text-fig. 4, C. is a longitudinal section through a gill filament in a plane at right-angles with that of 4, A. It shews that each filament consists of a flattened axis which bears on either side a close-set series of lamelle. The axis is strengthened by dense connective tissue, and con- tains the gill ray and the filamentar blood vessels. Text- fig. 4, B. is a transverse section of a double filament between the centres of two lamelle. It shews the position of the axis and the gill ray. If the branchial blood vessels are injected from the ventral aorta, a series of vessels become apparent on the SEA-FISHERIES LABORATORY. 935 internal (with respect to the middle line of the gill arch) sides of the filaments. These are the afferent filamentar vessels (4, A. and B.), and they are connected with the afferent branchial vessels which run in the fused bases of the filaments outside the tunnel referred to. If, on the other hand, the system is injected from the dorsal aorta, a second series of vessels which run down on the outer surfaces of the filaments becomes visible; these are the efferent filamentar vessels, and they are vonnected with the efferent branchial vessels which run in the tunnel on the convex surface of the arch. At regular intervals along its course the afferent filamentar vessel gives off an arterial twig on either side of the axis of the filament which passes into the respiratory lamellee (4, B). Text-fig. 4, B. represents a surface view of two lamelle, the transverse section of the filament passing through the axis between two such lamelle. In a fortunate injection of the branchial system it will be seen that the lamellar branches of the afferent filamentar vessel on entering the lamelle immediately break up into very close capillary networks. ‘This capillary network, seen from the side, is represented by the transverse black lines connecting the two filamentar vessels in 4, A. Lach lamella has a wall which at the base is composed of cubical cells, but which over the flat surfaces is a thin squamous ~ epithelium. Within the space enclosed by this wall is the capillary network, and no other tissues. According to Plehn* the blood flows in spaces hollowed out of adjacent closely-fitting cubical cells. The capillaries have not the ordinary epithelial wall characteristic of such vessels. After having traversed this network the blood is received * Zum feineren Bau der Fischkieme. (Vorl. Mitth.) Zool., Anz, No, 648, 24 Bd., pp. 489-443, 1901. 236 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. by a very short vessel which opens into the efferent filamentar vessel. Respiration _is effected by rythmical swallowing movements of the mouth and co-ordinated liftings of the opercula. The water swallowed passes from the pharynx through the gill slits and over the surface of the gill fila- ments. Probably movements of the latter in the mode already suggested assist in this circulation of the sea water. The gaseous interchange between the blood in the respiratory lamelle and the water takes place through the extremely thin walls of the latter and the walls of the capillaries. Only two thin epithelia separate the two liquids, and through these carbon dioxide passes from the blood to the sea water, and oxygen from the sea water to the blood. _ The respiratory area of the gills can be approximately calculated. The lengths of the gill filaments vary, and the greatest number of lamelle counted on any one side of a filament was 225; probably 150 will represent the average number to a side of a filament; there are two series of lamella, of course, on each filament. Therefore we have :— | Holobranchs. No. of Filaments.| No. of Lamelle. | ‘i 83 x 4 99600 | IL. 78 x 4 93600 | aie ail 72x 4 86400 | | locrere “E 58 x 4 69600 Total ... 1164 | 349200 | SEA-FISHERIES LABORATORY. Daa Now the area of each lamella can be approximately calcu- lated, since it is nearly triangular. It is roughly 0°365 square millimetre. But since both the flat surfaces of the | lamella are in contact with the water, the respiratory sur- face is double this, and is 0°730 sq. mm. x 349,200 = 254,916 | sq.mm. That is over { square metre. The total respira- tory surface of the gills is therefore that of a square, the length of the side of which is } metre. These calculations apply to a plaice of about 22 inches long. The area of the skin of such a fish is approximately 2,340 sq. cm., or nearly 7 sq. metre. The respiratory surface of the gills is therefore about equal to the total area of the skin. The Efferent Branchial Vessels —The blood, after having passed from the heart and afferent vessels through the lamellar capillaries, is collected by four trunks on each side—the efferent branchial vessels. These open into the epibranchial arteries of each side. Posteriorly the two epibranchial arteries (A. ep.) unite to form the dorsal aorta; anteriorly they are connected together by a short anastomosing vessel (C2. c.). The loop thus formed is the circulus cephalicus. It is the reservoir into which the blood, after having undergone oxygenation in the gills, is poured, and from which it is distributed over the body. The efferent branchial system is best injected from the dorsal aorta after tying the celiaco-mesenteric artery. It can be displayed after cutting away the greater portion of the operculum of one side, removing the opercular, sub-opercular and inter- opercular bones. The remaining dorsal portion of the operculum is then forced outwards and held in position by a hook. The gill filaments should be cut away close to the arches. The vessels themselves are then seen, after dissecting apart and removing most of the muscles, pass- ing dorsally from the gill arches, The circulus cephalicus 238 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. and carotid arteries can be dissected by removing the greater portions of both opercula as indicated above, and ~ then cutting away the gills, having previously divided the efferent vessels as far away from their attachments to the epibranchial arteries as possible. The head is then placed ventral side uppermost, and held in that position by hooks. The ventral portion of the parasphenoid must be removed in order to study the course of the internal carotid trunks. The first and 2nd _ efferent branchial vessels (Hf. Br. 1, Ef. Br. 2) open separately into the epi- branchial trunk. The 3rd and 4th (Hf. Br. 3, Hf. Br. 4) unite together to form a short trunk. On the left side this opens into the left epibranchial, on the right it opens into the ccliaco-mesenteric artery (A. em.). It may appear, however, that the cceliaco-mesenteric, instead of taking origin from the epibranchial as represented in the figure, springs from the common trunk of 3rd and 4th efferent branchials. Immediately behind the union of the epibranchial trunks the subclavian arteries are given off from the dorsal aorta. Hach of these vessels (A. sel.) passes out trans- versely, then bends down ventrally and runs along the internal surface of the corresponding pectoral girdle, the muscles of which it supplies. Behind these vessels trans- verse arteries are given off from the dorsal aorta on either side, one to each segment. These vessels are not repre- sented in the figure. Several arteries leave the epibranchials to supply the muscles of the gill arches with blood. The most impor- tant of these is a paired vessel which leaves the epi- branchial immediately anterior to the place of entrance of the 2nd efferent vessel. It passes at first dorsally, then backwards and downwards over the 3rd and beneath the 4th efferent trunks. Approaching the middle line it runs SEA-FISHERIES LABORATORY. . 939 ventrally among the muscles on the anterior border of the pericardium, where it apparently breaks up; a much smaller vessel takes origin from the dorsal portion of the lst efferent vessel and runs backwards and downwards among the muscles of the lst and 2nd gill arches, where it breaks up. These vessels are represented but not lettered in fig. 22. Two fairly large trunks take origin on each side from the ventral portions of the Ist and 2nd efferent vessels. Apparently they do not anastomose in Pleuronectes. The first, which is the hyoidean artery (A. hy.), leaves the efferent trunk while still within the arch, and efter giving off a small twig, which breaks up-on the internal surface of the operculum, turns round dorsally and runs on the internal surface of the operculum externally to the cerato- hyal and symplectic bones. At the level of the upper extremities of the gill arches it breaks up into a number of branches which end in the filaments of the pseudo- branch (Ps. Br.). The Afferent Pseudobranchial Vessel.—The precise disposition of the afferent pseudobranchial vessels varies among Teleostean fishes. In the greater number the afferent vessel is the hyoidean artery, which, moreover, anastomoses with the circulus cephalicus, so that the blood in the minute vessels of the pseudobranch may be derived from that in all the efferent branchial vessels. This is the arrangement in Gadus. In others, of which Salmo is an example, the hyoidean artery is the sole afferent vessel, and does not anastomose with the circulus cephalicus. In addition to these types of blood supply, Maurer®* has described another in sow, where the afferent vessel of the pseudobranch is a twig of the circulus cephalicus and the * Beitr. zur Kenntniss der Pseudobranchien der Knochenfische, Morph, Jabhrb., 9 Bd,, pp. 229-252, 1883-4, 240 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. hyoidean artery contributes nothing. In Pleuronectes the organ is supplied by the hyoidean artery, and there is no evidence of an anastomosis of the latter with the circulus cephalicus beyond a doubtful communication between branches of the hyoidean and external carotid arteries. The Efferent Pseudobranchial Vessel is the ophthalmic artery. Blood, after traversing the capillaries in the pseudobranchial filaments, passes into this vessel (A.op.), which runs forwards along the roof of the pharynx covered over by the mucous membrane. The two ophthalmic arteries approach each other in the middle line of the body, then separate and perforate the prootics together with the superior jugular veins, passing through the jugular foramina (f. jug. fig. 2). Hach vessel accom- panies the jugular vein and optic nerve of its side, and reaching the eye perforates the sclerotic and breaks up in the choroid gland. This peculiar arrangement is common to all Teleostean fishes, and has not received any satis- factory explanation. Joh. Miller suggested that the pseudobranch was a gland furnishing an internal secre- tion, and that the object of the included capillary system of the pseudobranch was to equalise the intra-optical pressure by smoothing down the pulsations of the heart. But the blood in the ophthalmic artery has already passed through the branchial capillaries before reaching the pseudobranch, and there is no evidence of the elaboration of any internal secretion. The Pseudobranch.—It will be convenient to give some account here of the structure of this organ. It is situated on the inner surface of each operculum in a little concavity which lies behind the strong transverse muscles forming the roof of the pharynx, and which is formed by the abrupt termination of these in a posterior transverse ridge. It is situated mostly on the hyomandibular, but SEA-FISHERIES LABORATORY. 241 its ventral extremity les on the preoperculum. It is so situated that its attached base is exactly opposite to the dorsal portion of the first branchial arch, and ihe direction of its filaments is almost exactly that of those of the dorsal portion of the first holobranch, that is, posterior and shghtly dorsal. The first branchial cleft is therefore bounded posteriorly by the anterior demibranch of the Ist branchial arch and anteriorly by the pseudobranch. The afferent pseudobranchial vessel or hyoidean artery runs along the external or deep-seated part of the base of the pseudobranch, and gives off a vessel to each filament. The efferent pseudobranchial vessel or ophthalmic artery runs along the internal or visible part of the base, and receives a vessel from each filament. The filaments of which the pseudobranch is composed are strikingly similar in appearance to those of any one of the true demibranchs, and their structure is the same in all essential points. Hach is made up of a flattened axis, on each side of which are borne a number of lamelle. The afferent filamentar vessel runs down the internal (with respect to the attachment of the organ to its arch) edge of this axis; the efferent vessel runs up the external edge. Small twigs are given off from the afferent vessel into each lamella, and in each of the latter they break up into a capillary plexus, as in the true gills, which empties its blood into a corresponding twig opening into the efferent filamentar vessel. Only about one-half of each filament projects freely into the opercular cavity. The basal halves are all attached to each other and to the epithelium clothing the inner surface of the operculum. The lamelle are mostly free, but many are attached together by their edges. They differ from the lamelle of the true gills in that their wall instead of being a squamous epithelium is made i 942 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. up of nearly cubical cells and contains numbers of goblet cells, in this respect resembling the general wall of the pharyngeal cavity or the epithelium covering the bran- chial arches. pig Probably the pseudobranch is not a _ functional respiratory organ, though its structure is very similar te that of any demibranch of the posterior series of true gills. The walls of the vascular lamelle resemble mucous epithelia rather than membranes through which gaseous interchange may take place. And the blood reaching the organ has already passed through respiratory plexuses in the first holobranch. Undoubtedly it is part of the holo- branch which was formerly situated on the hyomandibular arch, and its situation suggests that it is the posterior demibranch of that gill. There are no traces of the pre- sence of a vestige of the anterior demibranch of this gill, and the structure of the organ is exactly that of a demi- branch, the respiratory surfaces of which are greatly modi- fied. Since no traces of the afferent vessel originating in the ventral aorta, which would have supplied a functional hyomandibular gill, are present, the vascular supply gives no certain indication of the homology of the organ.* The Pelvic Artery.—Hach of the 2nd efferent bran- chial vessels gives origin to an artery which almost imme- diately unites with its fellow of the opposite side, and the azygos trunk so formed runs backwards in the floor of the pharynx in the middle line of the body. Various small vessels are given off to the ventral portions of the branchial arches. This pelvic artery (A. pe.) then gives origin to a small vessel supplying the pericardium, the pericardial artery (A. per.), and continues backwards between the * Cp. the cranial nerves for a discussion of the nerve supply of the pseudobranch. SEA-FISHERIES LABORATORY. 243 pelvic arches almost to the musculature of the body wall surrounding the anus. The Carotid Arteries—The portion of each epi- branchial artery anterior to the entrance of the Ist efferent branchial vessel may be spoken of as the common carotid artery. It is a very short trunk which divides into two vessels. The outer of these, the external carotid (A. Car.*), curves round behind the pharyngo-branchial segment of the lst branchial arch, and runs forward on the ventral surface of the skull. Several branches are given off which break up on the internal surface of the operculum and on the base of the skull. The internal branches of the common carotids, the internal carotid arteries (A. car.), after perforating the skull at the junction of the prootics and parasphenoid by the carotid foramina (f. car. fig. 2), communicate by a very short anastomos- ing vessel (Cz. c.) which completes the circulus cephalicus. From this transverse anastomosing vessel three arteries take origin, which run anteriorly in the trough of the parasphenoid. ‘The two external vessels, which are the internal carotid arteries, 1un forwards towards the nasal region of the skull. The internal median vessel divides, and the two vessels so formed run forwards in the trough of the parasphenoid, or eye muscle canal, accompanying the eye muscles. Hach passes out with the corresponding optic nerve, and runs forwards towards the eye. The Visceral Arteries.—The cceliaco-mesenteric artery (A. cm.) is an unpaired vessel lying entirely to the right side of the body. After leaving the right epibranchial artery it passes over the external surface of the right precaval vein, and gives off a small branch—the cesopha- geal artery (A. w.), which breaks up on the wall of the esophagus, It then almost immediately bifurcates, and 244 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. from the point of division the celiac artery (A.ce.) is given off. From this artery a small vessel arises (A.hep.) which turns backwards and enters the liver on the pos- terior surface of that organ. ‘The two celiaco-mesenteric trunks then pass internally to the right lobe of the liver. One vessel runs in the mesentery, giving origin to branches which supply the greater portion of the intestine from the anus forwards. The other courses in the mesen- teric sheet connecting the liver with the duodenal loop, and supplies that portion of the intestine and the stomach. | The dorsal aorta gives origin to a pair of arterial trunks in each segment, which supply the muscles of the trunk. Towards the posterior extremity of the kidney, a large median vessel—the common genital artery (A. gen.) —is given off, and passes downwards through the posterior portion of the kidney, sending small branches to the kidney and suprarenal bodies. This divides into two branches, one of which goes to each ovary or testis and the adjacent portions of the body wall. The dorsal aorta then passes backwards to the tail in the tunnel formed by the haemal arches. With regard to the venous system, we propose to” describe the larger venous trunks only. All the blood from the head‘is returned to the heart via the paired superior and the unpaired inferior jugular veins. The Superior Jugular Veins (V. Jug.) are large thin walled vessels which will have been exposed in dissecting for the branchial vessels. They receive the blood from the eyes and adjacent parts, and accompany the eye muscles in the eye muscle canal, emerging from the latter through the jugular foramina (/. jug. fig. 2). They then run backwards on the ventral surface of the skull over the dorsal extremities of the branchial vessels slightly dorsal SEA-FISHERIES LABORATORY. DAD and external to the epibranchial arteries, receiving in their course vessels conveying blood from the head and brain, and enter the precaval veins at the dorsal and anterior extremities of the latter. The Inferior Jugular Vein (V. Jug.1) is an azygos trunk running backwards under the ventral wall of the pharynx immediately above the dorsal aorta. It then passes upwards on the anterior wall of the pericardium, and may enter either the right or left side of the sinus venosus, though its ending on the right side seems to be the more common one. The Hepatic Veins (V. Aep.) are short wide trunks coming from the liver, which penetrate the posterior wall of the pericardium and enter the posterior part of the sinus venosus. The Renal Portal System.— The afferent vessels of this system are the parietal veins, the caudal vein and the genital veins. The caudal vein (V. cd.) runs forwards from the tail in the haemal canal immediately beneath the dorsal aorta. It enters the kidney at the most dorsal and posterior angle of the latter organ, and divides into two vessels which run forwards in the kidney and break up, but do not apparently anastomose with the cardinal vein. A short venous trunk comes from each ovary (or testis) and the adjacent portions of the body. wall, and enters the kidney on each side near the extreme ventral tip of the latter organ. A series of veins from the muscles of the trunk enter the dorsal portion of the kidney on each side; these are the parietal veins. One such vessel is represented in fig. 22 as entering the anterior tip of the head kidney. The efferent. vessels of the system are the cardinal veins, which run forward in the kidney. The right car- dinal vein (V. card.) runs along the middle part of 246 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the kidney, and is visible on its ventral surface. We have said that the kidney at its anterior extremity is divided into two horns, which reach forward towards the heart. The right cardinal vein emerges from the kidney through the right horn and enters the posterior side of the right precaval vein. ‘The left cardinal (as in the Cod) is a short vessel which begins at about the anterior third of the kidney, traverses the left horn, and enters the posterior side of the left precaval vein. The two cardinals do not apparently anastomose with each other. The Hepatic Portal System. —The afferent vessels of this system are the portal veins carrying the blood from the stomach, intestine and spleen. The smaller factors of this system have much the same course and distribution as the branches of the celiac and cceliaco-mesenteric arteries. They do not, however, unite to form a single hepatic portal vein, but enter the liver as a variable number of separate portal veins. Commonly there are (1) a trunk receiving the blood from the spleen and the greater portion of the intestine, and anastomosing with (2) a vein receiving the blood returned from the loops of the intestine posterior to the pylorus; (3) a smaller vessel draining the region of the pylorus, and (4) a vein coming from the stomach. These vessels enter the internal sur- face of the liver principally on the larger left lobe, and run for some distance parallel to and immediately beneath the surface, so that their ramifications can be easily traced. Their precise number and distribution in the liver varies ; five such trunks are represented in fig. 21, cut off close to the liver surface (Vp.) The apparent calibre of the intes- tinal veins, and to a less extent the arteries also, is increased by the presence of the perivascular glandular tissue referred to above. ‘The efferent vessels of the hepatic portal system are the two large paired hepatic SEA-FISHERIES LABORATORY. IAT veins (V. hep.) which enter the lower portion of the sinus venosus on its posterior side. E.—THE NERVOUS SYSTEM. We shall commence our description of the nervous system with the brain and spinal cord, then proceeding to the cranial and spinal nerves, and finally to the sympathetic nervous system. 1.—TuHeE BRAIN AND SPINAL Corp.* (Figs. 28, 30, 31). The brain of the Plaice may be conventionally divided into four regions, including the following structures : — A. Hind -Brain-—This comprises the medulla oblongata, which itself includes many structures that can only be regarded as the continuations of corresponding ones in the spinal cord, and the cerebellum. The latter consists of a body and the anterior valvula cerebelli. ~ 5B. Mid-Brain. —Formed by a base (crura cerebri) and side wall, and the tectum opticum or tectum mesencephali (optic lobes). ) C. "Tween-Brain.—lRepresented by three parts: (1) the epithalamus (epiphysis generally and the ganglia habenulz); (2) the thalamus (optic thalami—thalamence- phalon); (3) the hypothalamus (corpus geniculatum, * The following works will be found to contain references either to the brain of the Plaice or to allied Pleuronectids :—Cattie, Arch. Biol., ii1., p. 150; le Roux, ‘‘ Recherch. Syst. Nerveux Téleostéens,’’ Caen, 1887 Mayne, ‘‘ Optic Nerves,’’ Todd’s Cyclopedia, part xxvi.; Malme, Bihang K. Svens. vet.-akad Handlingar, xvii.; Mayer, Verhand. K. Leop.-Carol., xxx.; and Steiner, ‘‘ Entstehung d. asymmetrischen Baues der Pleuronec- tiden,” 1886 ; a recent important work, by J. B. Johnston, on the brain of Acipenser (Zool. Jahrb., Abth. Morph., xv.), may be used as a starting point in studying the brain of Fishes in detail.: 948 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. corpus mammillare, infundibulum, lobi inferiores, saccus vasculosus and pituitary body). D. Fore -Brain.—This may be considered as including the epistriatum, striatum proper and the membranous ) pallium, together with the bulbus olfactorius. The roots of the cranial nerves will be described in the section on the nerves. In a dorsal view of a well-preserved brain we note the following characters :—First the relatively small size of the brain. This is seen also in the Cod and in Teleosts generally. The small brain lies in the large cerebral cavity, surrounded by a packing of areolar connective tissue loaded with fat, and seems to be very dispropor- tionate to the size of the fish. Then the asymmetry of it is at once striking. The spinal cord, on entering the brain case, turns slightly to the left, but opposite the cerebellum it swerves markedly to the right, so that a median line would pass through the left striatum instead of between the two striata. In the medulla the great reduction of the terminal bud system that has taken place involves the absence of the lobi vagi. Also the lateral line system is not suffi- ciently robust to have produced that exaggeration of the tuberculum acusticum known as the lobus linez lateralis. The medulla is therefore smooth, and presents no obvious traces of its ganglia. On removing the vascular covering of the fourth ventricle known as the choroid roof, the ventricle itself is seen to be apparently divided into two parts by the partial union over its roof of the medio-lateral portions of the tuberculum acusticum, forming an elliptic- — | shaped opening behind (calamus scriptorius) and a triangular one in front, with its apex directed backwards. The cerebellum, of which the body only is visible in the undissected brain, is small and globular. This is what SEA-FISHERIES LABORATORY. QA9 one would expect, seeing that it is connected with the general activity of the organism, and the Plaice is sluggish in habits. The mid-brain is represented on the dorsal surface on each side by the tectum opticum (optic lobe). These are very large bodies almost spherical in shape, and charac- terised in dead and preserved specimens, and doubtless in life also, by a deep furrow, which extends backwards in a curve from the anterior margin of each lobe for about half its antero-posterior diameter. As is usual in Teleosts, the “tween-brain hardly appears at all on the dorsal surface of the brain, being excluded from it by the meeting of the two striata and optic lobes. However, a small portion of its membranous roof is visible, and from this there is seen emerging by the triangular space formed immediately in front of the median apposition of the two optic lobes, the extremely fine pineal tube. Im sections it is seen to arise as an evagination of the roof of the third ventricle almost behind the ganglia habenul and in front of the posterior commissure. It then passes forwards over the pallium of the left striatum and swells into the large pineal gland lying on the pallium near the anterior extremity of the left striatum. By pressing apart the optic lobes there may be seen immediately in front of the exit of the pineal tube the ganglia habenulew and the plaited choroid roof of the third ventricle. In a well-preserved brain the membranous pallium of the fore-brain is very obvious. It is a large oval sheet, with its long axis at right-angles to that of the brain, and almost equal to that of the optic lobes. It is a very thin membrane, and appears thicker than it really is on account of the coagulated cerebro-spinal fluid in the ventricle. The corpora striata are also visible through the pallium. 250 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. On removing the pallium, it will be noted that there are no lateral ventricles, but a large single median prosocoele. In the floor of this are raised up the large corpora striata separated dorsally by a wide fissure, but connected below by the anterior commissure, and constituting the solid cerebral hemispheres of older authors. These are con- siderably smaller than the optic lobes, and the dorsal surface of each is marked by a somewhat complex furrow (“sulcus ” of former authors—see fig. 30). In front of and below the striata are the olfactory bulbs, from which the olfactory nerves originate. The left is smaller than the right. On the ventral surface of the brain the most notice- able structures are the appendages of the ‘tween-brain. The lobi inferiores are a pair of large bean-shaped bodies opposed by their median surfaces. In the middle line immediately in front of these is the spherical pituitary body. The apposition of the pituitary body and lobi inferiores is not complete, and a triangular space is left by which there emerges on to the ventral surface of the brain the red thin-walled saccus vasculosus. This is at its origin a very narrow tube, but it expands and passes straight backwards in the middle line over the opposed lobi inferiores. It is dilated behind, and ends blindly slightly posterior to the hinder border of the lobi inferiores. In the adult the pituitary body (lypophysis cerebri) and saccus vasculosus are essentially glandular organs receiv- ing a marked nervous supply from the infundibulum. According to most recent authors the saccus at least “probably forms part of a mechanism for secreting, or otherwise controlling the pressure of, the cerebro-spinal fluid. It may affect the heart beat and blood pressure by way of the vagus’ (J. B. Johnston). The crossing of the optic nerves is very obvious in the SEA-FISHUERIES LABORATORY. 951 Plaice, as it is effected some distance in front of the pituitary body, and is not hidden by the olfactory nerves on the ventral surface. It is also quite clear that they merely cross and do not exchange fibres, whilst their plaited nature is at once revealed by a little simple dissec- tion. On removing the optic nerves the two small and asymmetrical olfactory bulbs are well seen lying largely under the anterior extremities of the two striata. In the medulla the ventral fissure of the spinal cord is continued as far forwards as the base of the lobi inferiores, where it slightly expands. Regarding the ventricles of the brain, the central canal of the spinal cord appears in the sections as a pin hole. It begins to widen rapidly into the fourth ventricle (myelocoele) at about the posterior region of the auditory organ. The ventricle is at first very deep from above downwards and very narrow from side to side. It soon opens above, and is only closed in by the choroid roof. The peculiarity of the roof of this ventricle has been already mentioned. In front of the expanded portion it becomes completely roofed over by the tuberculum acusticum, and at the same time is reduced to a very small size. Opposite the junction of the medulla and cere- bellum it again expands, but does not communicate with a cerebellar cavity (metacoele), the cerebellum being solid. In front of the body of the cerebellum it passes into the aqueductus Sylvii (mesocoele—iter a tertio ad quartum ventriculum), roofed over behind by the valvula cerebelli and communicating on each side and in front with the large space enclosed by the tectum opticum (optocoele). In front, the latter opens below into the third ventricle (thalamocoele), bounded laterally and below by the thalamus (optic thalami) and above in front by the choroid roof. ‘he third ventricle is prolonged downwards and 252, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. somewhat backwards into the hollow infundibulum. If this be now traced posteriorly, it is found first of all to communicate with the cavity of the pituitary body. Almost at the same time, but more dorsally, it is pro- longed on each side into the large cavities of the lobi inferiores, whilst finally it communicates with the cavity of the fine stalk of the saccus vasculosus. The third ventricle therefore is continuous with the cavities of the pituitary body, lobi inferiores and saccus vasculosus. The infundibulum of the Plaice is difficult to delimit, as it is largely merged into the floor of the thalamus. Inciden- tally we may draw attention in the latter to the very large paired nucleus rotundus, which is very striking in sec- tions. Anteriorly the third ventricle passes into the large median ventricle of the fore-brain (prosocoele), roofed over by the pallium. The prosocoele is not prolonged into the bulbi olfactorii as a rhinocoele, the bulbs being solid. Cunningham makes two assertions on the brain of the Sole that appear to us to require confirmation. One is that the “position of the brain is almost entirely unaffected by the change which has taken place in the normal position of the fish,” and the other is that “ the left olfactory lobe is somewhat larger than the right, a differ- ence which is related to the great development of the left olfactory capsule.’ On the other hand, Malme states of the Sole (op. cit., p. 34) that “ insbesondere ist der rechte Lobus [striatum] (derjenige der Angeubeaaa viel grésser als der linke,”’ and again that in Pleuronectids generally “‘der Bulbus der Augenseite ist stets der grosste.’”” Malme’s observations agree with ours on the Plaice. Again, Cunningham apparently overlooks the work of Rabl-Riickhard on the brain of Teleosts, and describes what are really the corpora striata as receiving prolongations from the third ventricle. SEA-FISHERIES LABORATORY. 253 In the Spinal Cord we wish to direct attention to two peculiarities only. The first is the giant ganglion cells that are found in the dorsal fissure. Transverse sections of the cord will demonstrate these quite easily. They have been studied especially by J. B. Johnston,* Sargentt and Dahlgren.t The latter author, who has devoted his attention particularly to the Pleuronectide, states that these very peculiar cells are the first ganglion cells to be differentiated in the embryo flat-fish, and that they become an important and permanent apparatus in the adult. In an adult fish they are seen to form a row of very large nerve cells in the median dorsal fissure, and their neurites pass backwards to form an isolated fibre tract on the median side of each dorsal horn. Their exact distribution and function are unknown, but Dahlgren suggests that the neurites pass out with the dorsal roots of the spinal nerves and are connected with the sensory supply of the unpaired fins. Sargent finds in Ctenolabrus that the giant cells are connected with a fibre bundle passing forwards through the cord and medulla, and emerging by the ventral root of the trigeminus nerve. If this be true then the fifth nerve of this fish possesses a nerve component not hitherto recognised, and it would be interesting to study the giant cell apparatus from the point of view of the component theory. The second peculiarity of the cord is one which it shares with all Teleosts, and that is in the presence of the very interesting rod or fibre within the lumen of the central canal known as Reissner’s fibre. This fibre has been investigated recently by Sargent,§ who finds that it “ extends through the whole length of the canalis centralis * Jour. Comp. Neurol., x., p. 375. t Anat. Anz., xv., p. 212. t Anat. ae. RHigp. 201. § Anat, Arz., xvil., p. 33, and Proc. American Acad. Arts and Science, xxxvi., No. 25. 254 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. of the cord and continues cephalad through the 4th and 3rd ventricles to the anterior end of the optic lobes,” where it passes into the brain tissues. It is not a single fibre, but a collection of axis cylinders, and is therefore a fibre tract. Some of the fibres in the tract originate in cells situated at the posterior extremity of the central canal, and pass forwards to the tectum opticum. Others originate in cells in the tectum opticum and pass back- wards as far as the “ posterior canal cells.” The tract, therefore, contains fibres coursing in two opposite direc- tions. According to Sargent this unique apparatus forms a “short circuit between the visual organs and the muscu- lature, and has for its function the transmission of motor reflexes arising from optical stimuli.” It is most highly developed in active fish, and is entirely absent in the blind vertebrates of the cave fauna. 2.—THE Cranial Nerves (Fig. 23). In spite of the fact that the cranial nerves of Fishes have been more or less investigated for about two and a half centuries, it is only within the last few years that our knowledge of them has assumed a form likely to be at all lasting. Although these results were made possible as long ago as 1811 by the enunciation of Bell’s law, and although this law was very ingeniously developed and applied to Fishes in 1849 by Stannius, who has never received due credit for his work, it was only in the eighties that Gaskell stated his ‘‘ four root theory ” of the spinal nerves, which showed that there were represented in each spinal nerve four kinds of fibres instead of the two assumed by Bell’s law. The attempt to strictly apply the four root theory to the cranial nerves of lower vertebrates has not only been SEA-FISHERIES LABORATORY. 255 unsuccessful, but it has actually retarded knowledge by diverting the energies of investigators into an unprofitable channel. The work on the cranial nerves of the frog’s tadpole, published in 1895 by Strong, distinctly proved this, for he showed that, for example, there were three systems of sensory fibres in the cranial nerves of the larval frog, one of which must be considered characteristic of the head and not represented in the spinal nerves at all, and another only partly so. One of the first results of Strong's work was to show that the old system of classifying the cranial nerves of Fishes into ten formal pairs was essentially unsatisfactory, and that attention should be concentrated rather on the various definite systems of nerve fibres characterised by their structure, central origin and peripheral distribution, than on those heterogeneous collections of nerve rami “cranial nerves.” We must, however, in known as the the meantime adhere to the old classification, until suffi- cient work has been carried out on the new lines to justify a revision of the cranial nerves, and to ensure for its findings some permanent value. | The new theory of the cranial nerves is lena as the “component theory.”’ It takes advantage of the fact that the fibres forming them, and omitting the olfactory and optic nerves and the sympathetic, which present problems of an altogether special nature, fall by reason of their functions and certain structural relations into five fibre systems, three of which are sensory and two motor. Tach system is delimited by a uniformity of peripheral ter- mination and a special and characteristic origin in the brain, and each system may appear in a variable number of cranial nerves as a component of those nerves. It is therefore indispensable, as we have done in the Plaice, to work out the whole course of the nerves by means of serial 256 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. sections. Microscopic work either on the brain or the peripheral nerves only is inadequate, and dissection, as a means of research, has but a very doubtful value. The only fish which has been thoroughly investigated according to the component theory is Menzdia—in an important work published recently by C. J. Herrick, who truly remarks: ‘‘ Until each component can be isolated and treated as a morphological unit, and then unravelled in its peripheral courses through the various nerve roots and rami—until this is possible, no further great advances in cranial nerve morphology can be looked for even among the lower vertebrates, still less in man.” The five systems of fibres which variously compose the cranial nerves of the Plaice are as follows :— 1. General Cutaneous or Somatic Afferent System.— These fibres, which undoubtedly correspond to the cutaneous fibres of the spinal nerves, are derived from continuations of the dorsal horns of the spinal cord, which form two longitudinal bundles in the medulla known as the spinal vth tracts. These fibres in the Plaice leave the brain by the roots of two cranial nerves only—the vth and the xth. In the former case their ganglion is the Gasserian ganglion, in the latter the jugular ganglion. The cutaneous fibres in the facial nerve are distinctly derived from those of the fifth. The fibres of this system are distributed generally to the skin, and do not end in any specialised dermal sense organs. Hypertrophy of this system produces a corresponding hypertrophy of its centre in the central nervous system, as witness the remarkable lobes at the anterior extremity of the spinal cord of Prionotus (Morrill). 2. Somatic Efferent System.—Represented by the heavily myelinated eye muscle nerves (il1., iv. and vi.). This system is of course largely present in the so-called SEA-FISHERIES LABORATORY. 257 “hypoglossal” nerve, or first spinal, but we do not con- sider this to be a cranial nerve in fishes. 3. Communis (Viscero Afferent?) System. — Partly synonymous with the fasciculus communis system of Osborn and Strong. A striking feature about this sensory system is that it may innervate both ecto- and endo-dermal ~ surfaces, and it may therefore be disputed whether it is a visceral nerve that has invaded the skin, a somatic nerve that has invaded the visceral surfaces, or a complex of more than one component. ‘The latter seems perhaps the most probable. The fibres of the communis system are fine and lghtly myelinated, and are distributed peripherally as follows :—(a) to the special sense organs in the outer skin called “‘ terminal buds,” 7.e., to all the definite sense organs of the skin not belonging to the lateral line system. This part of the component has been reduced in the plaice; (b) to taste buds in the mouth; (c) to the general mucous surfaces without the interven- tion of sense organs at all. The ganglia and cranial nerves into which the system enters are: (a) the genicu- late ganglion (vii.), glossopharyngeal ganglion (ix.), and the intestinal and four branchial ganglia of the vagus (x.). Any communis fibres in the trigeminus arise from the communis facialis. The central origin of the component is the Lobus vagi, and the enormous vagal lobes of Carpiodes are simply due to the hypertrophy of the com- munis vagi component in this fish (Herrick), Further the so-called Lobus trigemini of some fishes (Amzurus) is due to the hypertrophy of the communis facialis, and hence it should be called Lobus facialis. 4. Wiscero Efferent System.—This comprises the motor roots of the vth, viith, ixth and xth cranial nerves. Each of the first two has its own motor nucleus in the brain, but the two latter arise from collections of cells U 258 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. supposed to represent the nucleus ambiguus. The fibres of this system are heavily myelinated. 5. Acustico Lateral System.—Includes the auditory and lateral line nerves. Let it be emphasised at once, what is taking a long time to filter down into the text- books, that the lateral line nerves can only be associated with two cranial nerves—the viith and xth. The lateral line fibres in the fifth nerve are always derived from the facial, those in the ixth (when present) from the vagus. The fibres of this system are distributed to the ear, to the sense organs in the lateral line canals, and to those lateral line sense organs lying free on the skin, and known as pit-organs. Its ganglia are the dorsal and ventral lateral ganglia of the facial, and the lateralis ganglion of the vagus, and its fibres are very large, being in fact the coarsest in the body. Its central termination is the tuber- culum acusticum of the antero-dorsal region of the medulla—associated with the cerebellum. ‘The hyper- trophy of the lateral line nerves produces an exaggeration of the tuberculum acusticum well marked on the surface of the brain and called by Johnston the Lobus lnez - lateralis. This lobe has also been called the Lobus trigemin1i by the older writers, and when associated with lateral line fibres it may well receive the name given it by Johnston. Otherwise it should be called the Lobus facialis (see above). Nervus Olfactorius*—l. (Figs. 25 and 28.) As considerable asymmetry is exhibited by these nerves, both sides will be described. *For the cranial nerves of Teleostean Fishes compare especially the following works ;—Allis (Amia), Jour. Morph., ii. and xii. ; Cole (Gadus), Trans. Linn. Soc., ser. 2, vii.; Desmoulins and Magendie (nerves of Rhombus), Anat. Syst. Nerveux, Paris, 1825; Herrick (Menidia, Gadus, and Amiurus), Jour. Comp. Neurol., ix., x., and xi.; Juge (Szlurus), Rey, Suisse Zool., vi; and Stannius (general), Rostock, 1849. The works of Herrick are most important so far as the Plaice is concerned, and should certainly be consulted. We have purposely adopted, as far as possible, the same reference letters, in order that the comparisons maybe facilitated. SEA-FISHERIES LABORATORY. 259 The right Bulbus olfactoriust lies mostly under the corpus striatum (the latter is the cerebral hemisphere of older authors). Behind, it is free, unconnected with the striatum and ends bluntly, but in front it acquires a firm connection with the striatum. Anterior to this again it separates once more from the striatum. So far it has been increasing in size, but it now begins to taper down, its ventral portion becomes fibrous, and its dorsal divided into two. The upper or cerebral portion disappears in front, and the remainder narrows down into the cylindrical nervus olfactorius. Both olfactory nerves lie to the right of the upper or left optic nerve. As the nerve passes forwards it becomes divided by connective tissue strands into two or more fasciculi, each of these again being further subdivided into small bundles of fibres. The right olfactory passes through the foramen olfactorium in the right prefrontal, turns up at once and breaks up in the olfactory laminze of the right nasal chamber. The left Bulbus olfactorius is not free behind like the right, but passes imperceptibly into its striatum. Nor is it situated below the latter, but between the two striata (see fig. 28). The appearance therefore of this portion of the brain is very asymmetrical, and suggests a rotation towards the right side of the ventral axis of the brain only. The left bulbus is perceptibly smaller than the right, but the left striatum extends further forwards than its fellow. The bulbus separates from the striatum in front, becomes fibrous at its right ventral corner and gives off the left olfactory nerve, which passes at once to the right side, so as to lie near the right bulbus. The left + This structure is also called by some authors the Tuberculwm olfactoriwm (Stannius) and Lobus olfactorius. We have no space to discuss the precise significance of each of these three terms, if indeed they have any (but see Elliot Smith, Jour. Anat. and Phys., xxxv., 1901). 960 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. bulbus has no direct connection with its nerve in front as on the right side, nor does it extend as far forwards as the right one. There is much more difference in the size of the two olfactory nerves than one would expect from the sizes of their bulbs; the left being only } the size of the right. Nor do its fibres take such an intense stain with the osmic acid. For some distance the two olfactory nerves course together, but finally the left separates from the right and passes upwards towards the eyeless side of the body. It then traverses the olfactory foramen in the left prefrontal, and at once passes straight upwards to break up in the olfactory lamine of the left nasal chamber. The left nasal organ is much smaller than the right (cp. fig. 25, n. olf., n. olf.1), and hence the small left nerve. It is also situated somewhat behind the right, and therefore the left olfactory is the shorter of the two. Nervus Opticus—Iil. As in all lower vertebrates, the fibres of the optic nerve arise mostly from the roof of the mid-brain (tectum opticum), and as is usual in Teleosts they pass forwards over the ventricle to collect at the anterior extremity of the optic lobe, and then course sharply downwards and forwards to reach the surface of the brain. The optic chiasma is a simple crossing without any intermingling of fibres, so that the nerve to the right eye, for example, arises exclusively from the left side of the brain. As in Menzdira the nerve to the left eye 1s uppermost at the crossing. Hach optic nerve, as is usual in Teleosts, consists of a thin wide ribbon so thrown into longitudinal folds as to form a round nerve, and each exhibits 34 folds.* If the optic nerve could be flattened out the width of the ribbon would * The number of the folds increases with the size of the nerve, judging from our sections of young plaice at different stages, and also from the condition in the adult (see fig, 28). SEA-FISHERIES LABORATORY. 261 be about 2 of the maximum thickness of the body. Fora time the right optic nerve lies directly under the left, and both immediately under the right bulbus olfactorius. The right passes straight out to its eye, but the left curves over towards the left side. Both reach the eye at about the same level, perforate the sclerotic and retina, and spread over the concave surface of the latter in the usual way. Owing to the fact that the left eye is situated over the. right, the optic chiasma is less emphasised in the Plaice than in a symmetrical fish. We now proceed to the description of the eye muscle nerves (fig. 23), taking them in their numerical order. Nervus Oculomotorius—Ili. The nucleus of the third nerve (iii.) lies dorsally on the floor of the mesocoele very near the middle line, and mostly just over the fasciculus longitudinalis dorsalis. There is no crossing as in the case of the patheticus. ‘The fibres of the right oculomotor curve round the fasciculus and pass backwards and downwards through the brain substance, to emerge as a large nerve on the ventral surface of the brain just above the lobi inferiores. Imme- diately it leaves the brain the nerve takes a sharp turn forwards, and in due course fuses with the patheticus. It passes downwards on the outer side of the lobus inferioris and between this and the v.-vii. complex. After liberating the patheticus again it courses downwards inside the skull, passes through the meninges, and enters the cup-shaped cavity formed by the parasphenoid and known as the eye muscle canal. Here it divides into a smaller upper and a larger lower nerve. Now the oculomotor consists mostly of large and well myelinated fibres, but it also contains 262 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. some small lightly staining fibres. These are for the most part handed over to the lower nerve, and collect at its outer side. Finally they pass over into the ciliary ganglion and hence form the radix brevis (fig. 26, ra. 6.) of that ganglion. The upper division of the vdalomatan (r.s.) passes into the Rectus superior muscle of the eye. Its small fibres are distributed to the smaller fibres of its muscle. The lower division soon after leaving the ciliary ganglion, to which it has been closely opposed, passes sharply downwards and forwards accompanied at first by the ramus ciliaris brevis from the ciliary ganglion (fig. 26, cul. 6.). It splits into three almost equal branches, which soon take up the following positions in the vertical pas and are as below: — (a) Dorsal branch (r. zt.). To rectus internus. Passes upwards and inwards and reaches the ventral surface of the [ower or right optic nerve. It subsequently breaks up in its muscle between and below the two optic nerves. (6) Intermediate branch (r. zf.). To rectus inferior. Divides into three principal twigs which enter their muscle in the order shown in the figure. (c) Ventral branch (0.2.). To obliquus inferior. Descends and crosses the palatinus vil. internally and for some distance lies just below and internal to it. It then rises, crosses the palatine again, and now lies to the inner side of the rectus inferior. From this point it courses almost straight forwards at the right side of the parasphenoid and ethmoid cartilage, and finally splits up to enter its muscle in the way shown in the figure. As regards now the left side, it may be noted at once that the distribution of the eye muscle nerves, except those coursing far forwards like the patheticus and the branch of the third to the inferior oblique, is not much SEA-FISHERIES LABORATORY. 263 affected by the torsion of the head, since the parasphenoid and its eye muscle canal are simply rotated en bloc to the right along their longitudinal axes. The distribution of the nerves is therefore the same, except that those of the left side have been swung upwards so as to lie nearer the dorsal edge of the body, and hence above those of the right side. In the case of the branch to the inferior oblique this rotation has caused the left one to be situated at first much above the right. In front, however, it begins to turn downwards towards the parasphenoid, and the right one at the same time rising, they eventually take up cor- responding positions at the sides of the parasphenoid and ethmoid cartilage. Finally the left turns upwards to reach its muscle in which it breaks up in much the same way as the right. Neither of the long eye muscle nerves (patheticus and the branch just described) of the left side reaches, at its final distribution, a much higher transverse level than that of the right. If a comparison be made with the eye muscle nerves of Menidia, as described by Herrick, it will be seen that in the two forms the relations of the nerves are essentially the same. Nervus patheticus s. trochlearis—lV. The fourth nerve of the right side (iv. 0.s.) consists of many large and a few small fibres all heavily myelinated. It has no connection with the communis vil. as described by Herrick in Menidia. The nucleus of the pathetic is situated dorsally close behind that of the oculomotor. The two pathetic nerves cross over the mesocoele as in all hitherto investigated vertebrates, so that, for example, the right nerve arises from the left side of the brain. The two nerves pass first backwards, then rise sharply over the mesocoele, cross, and leave the brain almost in the same 264 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. section so as to he wedged in between the axis of the brain and the optic lobe. It at once turns sharply downwards and forwards, and becomes closely opposed to the dorsum of the oculomotorius. For some sections the two nerves can be distinguished, but in front they appear to fuse completely, and cannot be distinguished even under the high power. ‘The pathetic is, however, given off again from the dorsum of the oculomotor, passes forwards and downwards, pierces the membranous wall of the brain case obliquely in front, and breaks up in the superior oblique muscle of the eye as shown in the figure. On the left side the relations of the nerve to the brain and for some distance in front are essentially the same as on the right side. As, however, it approaches the eyes (section 392 of chart), it begins to pass towards the lower or right optic nerve) Subsequently it takes up a position above and to the left of the upper or left optic nerve, having now crossed over the top of the parasphenoid and lying distinctly to the right of the morphological middle line. The two optic nerves having dipped down the left pathetic crosses over the left optic to its right side. The left optic now turns upwards towards its eye, so that the left pathetic lies considerably below it. The latter after- wards passes upwards to the left side of the frontal bridge, and is seen below the right pathetic. It finally breaks up in the left superior oblique in much the same way as the right. N-ervus’) abduceéens—VL The sixth nerve (vi. r.e.), which consists mostly of large well myelinated fibres together with some small — ones, arises from the medulla by two small rootlets some distance from the middle line. Both these rootlets have apparently a common nucleus situated far from the middle SEA-FISHERIES LABORATORY. 265 line and not far from the ventral surface of the brain. Soon after leaving the brain the abducens passes sharply downwards to reach the floor of the brain case. In front it passes downwards and forwards, perforates the meninges, enters the eye muscle canal, and at once reaches the rectus externus muscle which it supplies. The abducens is the most posterior of the eye muscle nerves (cp. chart), and on this account the two nerves exhibit practically no traces of asymmetry. Before we can proceed to describe the trigeminal and facial nerves separately, it is necessary to interpolate an account of the roots and ganglia of the trigemino-facial complex as a whole (fig. 23). As in Teleosts generally the fifth and seventh nerves at their exit from the brain, and also their ganglia, are so disposed that it is quite impossible to completely analyse them by dissection. Examination, however, of a series of Weigert sections enables us to do this without much difficulty. Macroscopically there are two roots to the facial nerve and one to the trigeminal, and three of the four ganglia of these two nerves are compacted together into one mass. Analysis by serial sections reveals the following facts : — The most anterior root of the complex (r.v.) is that of the trigeminus. It lies, however, largely internal to and below the second root, so that it is at first not obvious on dissection, and emerges from the brain just below the cerebellum. It is the only root of the trigeminus, and consists of a general cutaneous and a motor component. The nucleus of the latter les in the floor of the fourth ventricle, and the fibres pass right through the Gasserian ganglion first into the Truncus infraorbitalis (¢.cnf.) and then into the R. Mandibularis V (man. v.). On account 9266 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. of the fact that the large ventral nerve emerging from the ~Gasserian ganglion contains lateral line and communis components from the facial, the term 7’. ma«dlo-mandibu- laris, which refers to the unspht RR. maxillaris and mandibularis V, cannot strictly be apphed to it. The cutaneous component of the trigeminus arises from the spinal v. tract, and its ganglion is the Gasserian ganglion. Ti is distributed to the skin of the face and operculum. The second root of the complex (r.1.vw.) belongs wholly to the facial, and consists of 3 roots so closely packed together that it is difficult to separate them by dissection. ‘These roots are the dorsal and ventral lateral line roots and the communis root. The whole arise together at the same level high up on the medulla and much higher than and external to the exit of the trigeminus. ‘The ganglia of the lateral line roots are respectively the dorsal and ventral lateral line gangha, and that of the communis root is the geniculate ganglion. The dorsal lateral line root splits into the Ramus ophthalmicus superficialis vil. and the R. buccalis vii., whilst the ventral lateral line root is continued into the Truncus hyomandibularis as the R. mandibularis externus vu. The communis root splits into the communis v., R. palatinus vu., the R. Posttrematicus vii. and the R. mandibularis internus vil. Although the three com- ponents in this root are very compacted they retain their individuality under the microscope. ‘The communis root enters the brain first, and then the other two fuse and enter together behind and above it. The communis root in the brain passes at once into the fasciculus communis tract, and the fused two lateral line roots terminate in the tuberculum acusticum. The third root of the complex (r.2.vw.). is also entirely facial and constitutes its motor root. It arises SEA-FISHERIES LABORATORY. 267 behind the second root and much ventral to it. Its nucleus lies in the floor of the fourth ventricle very near the middle line, and the root below joins the ventral lateral line root preximal! to its ganglion as in Menzdia. After leaving the brain the motor root, which consists of deeply staining heavily myelinated fibres, becomes so confused with the antericr part of the auditory root that their separation is difficult even with the microscope. The auditory nerve, however, passes dorsally into the tuber- culum acusticum, whilst the motor vii. enters the brain below and immediately in front of it. The motor vu. passes into the Truncus hyomandibularis. Of the four ganglia of the complex (g. v.-vii.) only one remains distinct macroscopically. This is the ganglion of the dorsal lateral line root, which in front is situated just dorsal to the Gasserian ganglion, and behind overlaps externally the root of the trigeminus. It is entirely intracranial and is partly shown in the chart as the cells at the base of the R. buccalis vii. The other three ganglia are crowded between the brain and the skull wall and apparently form one mass also entirely intra- cranial except for the narrowed anterior extremity of the Gasserian ganglion which extends outside the skull along the R. ophthalmicus superficialis v. as far forward as sec- tion 472 (cp. chart). When these three ganglia are examined in serial sections it is seen that the most anterior is the Gasserian ganglion. ‘This overlaps exter- nally the geniculate ganglion situated behind it, which in its turn overlaps externally the ventral lateral line ganglion—the most posterior of the three. Although the three ganglia form a single very compact mass, it is not difficult to define their boundaries, even where, as in the ease of the first two, the character of their cells is much the same. In the ventral lateral line ganglion, the cells, 268 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. as is usual in these ganglia, are very small and not crowded, being scattered among the nerve fibres. The dorsal lateral line root, as already described, has a discrete ganglion, and a reference to the chart will show that the communis, ventral lateral line and motor roots enter the ganglionic mass above by two nerve bundles. The anterior one is the communis root and the posterior represents the ventral lateral line and motor roots fused together, the motor fibres of course having no connection with the ganglion cells. The entry of the trigeminus root into the Gasserian ganglion is described above. Leaving the compound ganglionic mass are three large nerve trunks: (1) the Truncus supraorbitalis; (2) the Truncus infraorbitalis; and (38) the Truncus hyo- mandibularis—all compound trunks into which both trigeminal and facial nerves enter. It will be seen on reference to the chart that the last is formed by three nerve bundles from the ganglionic mass uniting together. The most anterior of these arises from the Gasserian ganglion and thus forms the trigeminal cutaneous Vil. component of the hyomandibular trunk. In Menzdia the cutaneous vil. is extracranial, and is formed by two bundles from the Gasserian ganglion fusing together. In the Plaice there are one large and two very small bundles —all intracranial. The middle of the three nerve bundles above is the communis root, and the posterior the fused ventral lateral line and motor roots. The motor vii., as mentioned above, joins the ventral lateral line root proxi- mal to the ganglionic mass. At first they remain distinct, the motor vil. lying on the outer face of the ventral lateral line ganglion. Before leaving the ganglion, however, the two roots become almost too intermingled to be distinguished. Before proceeding to describe the divisions of the vth SEA-FISHERIES LABORATORY. 269 and viith nerves, it may be mentioned that the Gasserian ganglion is the only one to receive a prominent R. com- municans from the sympathetic. There also arises from the same ganglion a motor nerve which has traversed the ganglion and passes to the M. depressor operculi (m. d. op.). This is the most posterior nerve passing through the trigemino-facial foramen. The trigemino-facial foramen (represented by a ring in the chart) transmits the trigeminal nerve + the dorsal lateral line root of the facial + a communis vii. com- ponent. The jugular foramen (the posterior ring in the chart) transmits the hyomandibular trunk, comprising the remainder and greater part of the facial + a cutaneous component from the trigeminus. The various nerve rami may now be described under the names of the nerves to which they belong. | Nervus Trigeminus—yv. 1. Nervus ophthalmicus profundus (fig. 26, 0. pr.).— The root of this nerve (Radix ophthalmici profundi) arises on the right side from the root of the trigeminus near the brain, and proximal to the Gasserian ganglion. It passes downwards and forwards over the inner face of the latter ganglion between it and the brain, and enters the pro- fundus ganglion, which, though closely opposed to the inner face of the Gasserian, is absolutely distinct from it. From the profundus ganglion an apparently single nerve arises which leaves the skull cavity with the rest of the vth and becomes intimately attached to the sympathetic. We could not be certain whether a few fibres were not given off to accompany the R. ophthalmicus superficialis y., thus constituting a Portio ophthalmici profundi. The nerve from the profundus ganglion passed with the sym- pathetic through the skull wall again by a special small 270 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. foramen into the eye muscle canal. The two bundles separate in front, but for a time the union is so close that they could not be satisfactorily analysed. However, most of the profundus fibres proximal to the ciliary ganglion separate out as the Ramus ciliaris longus (cdl. l.), but a few of them accompany the sympathetic to the ciliary ganglion (cil. g.) as its Radix longa (re. U.). The R. ciliaris longus leaves the eye muscle canal in front and accompanies the right rectus superior muscle to the eye, which it enters from above. ee ote SEA-FISHERIES LABORATORY. 283 secondary and unimportant connection with the vagus, and the N. vagus sensu stricto. There are no intracranial branches from the vagus - complex, as_ stated by Stannius. R. lateralis vagi (r. lat. x.).—Arises from the tuber- culum acusticum, like the auditory nerve and other lateral line nerves, but appreciably below the exit of the latter and considerably above and somewhat in front of the root of the glossopharyngeus. It also arises considerably in front of the roots of the true vagus. The root (7. lat. x.+) passes downwards and backwards, lying immediately external to that of the vagus proper, and for a time between it and the posterior division of the acusticus, as above described. It has, however, no connection with either, and passes out of the same foramen (indicated by a ring in the chart) as the rest of the vagus, but external to the latter. As in Menidza the lateralis consists mostly of the large strongly myelinated nerve fibres, but also has many smaller ones. Immediately on leaving the skull the lateralis gives off the R. supratemporalis vagi (7. st. w.), at the base of which is a small ganglion distinct from the main lateralis ganglion. The supratemporal branch, as shown in the chart, is distributed on the ocular side to the 4 sense organs so far developed in the supratemporal portion of the lateral canal, and also to the first two sense organs in the main portion of the same, 2z.e., sense organs 1 to 6. After giving off this branch the lateralis expands into the lateralis ganglion (/. g. w.). The nerve arising from the ganglion passes upwards, and divides, as in the Cod, into the R. lateralis superficialis vagi (7. lat. swp. x.), coursing just under the skin in the neighbourhood of the main portion of the lateral canal the sense organs of the anterior half of which it supplies, and the R. lateralis profundus 284 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. vagi* (r. lat. prof. #.), coursing below the above, and between the dorsal and lateral musculature, far from the surface. The latter gives off no branches until it passes upwards and outwards to supply the sense organs of the posterior half of the main portion of the lateral canal. It is at intervals very closely connected with branches from spinal nerves, but no fibres are exchanged as far as we could see. The superficialis division, besides supplying its portion of the lateral canal, gives off in front and above, in fact as its first branch, the R. lateralis recurrens vagi (2. rec. #.). This is also a true lateral line nerve distri- buted to pit organs, and must therefore not be confounded with the R. lateralis accessorius (trigemini), although in some fishes its homologue appears to accompany the latter. Its course, which is very extensive and just under the skin, is shown in the chart, and it corresponds precisely to the similar branch arising from the facial, and called the R. lateralis recurrens facialis (/. ree. viz.). Nervus Vagus—x. Arises by a single large root, which is, however, formed by several large bundles (Stannius says 5) uniting just on the surface of the medulla, and which is further reinforced by two very small bundles in front, as shown in the chart. This root (r. x.) is quite distinct both from the roots of the glossopharyngeus and lateralis,t and in fact the roots of these three nerves are more distinct and clear in the Plaice than in most Teleosts. The vagus root * These nerves must not be confused with the R. lateralis trigemini of the Cod (cp. Parker’s ‘‘ Zootomy’’), which is not represented in the Plaice at all. The latter is a communis nerve supplying its own, and not lateral, sense organs. It has no connection typically with the trigeminal nerve, and should be called the R. lateralis accessorius. +Stannius states that fibres pass from this root to the root of the lateralis in the Plaice, but this is not the case. SEA-FISHERIES LABORATORY. 285 consists very largely of communis fibres from the Lobus vagi, but also contains motor and cutaneous components. In its intracranial course it is almost entirely covered by the root of the lateralis, and before it reaches its foramen in the skull, and whilst passing through it proximally, it bears a smallish ganglion distinctly separated from the other vagus ganglia. This is the jugular ganglion (Jug. g.), also found by Herrick in Gadus and Menidia. It is the ganglion of the cutaneous fibres of the vagus, and forms typically the R. cutaneus dorsalis vagi, and the R. oper- cularis vagi. R. opercularis vagi (r. op. «.)—This is given off directly the vagus leaves the skull, and at its origin is very closely opposed to the base of the R. supratemporalis vagi (see chart), but it does not fuse peripherally with it, as in Gadus according to Herrick. It passes forwards, and divides into antero-dorsal and postero-ventral branches supplying the skin of the opercular and supra-opercular regions. It contains both hght and heavily myelinated fibres. After giving off this ramus, the vagus swells into the large ganglionic complex (g. #. 2-5), of which only the first ganglion (g. w. 1) is completely distinct. 1.—Truncus branchialis primus Vagi (¢. «. 1). Arises from the dorsal aspect of the vagus on its inner surface. It passes inwards and backwards towards the first spinal sympathetic ganglion, to which it becomes closely opposed. It then bends forwards and downwards, and at once swells into its large ganglion (g. #. 1), which is quite distinct from the other vagus ganglia, as is general among Teleosts. ‘lhe motor component of the truncus passes over the external surface of the ganglion. Distal to the latter the truncus passes downwards and forwards and divides into an upper pre- 286 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. trematic + pharyngeal branch, and a lower R. post- trematicus. ‘The former passes forwards, and divides imto two rami, both of which at once turn downwards and back- wards. ‘These are the R. pharyngeus (ph. x. 1) and the R. pre-trematicus (pre. 1). The pharyngeus courses down- wards and immediately breaks up in the mucous mem- brane of the roof of the mouth. The pre-trematicus reaches the first branchial arch, lying just internal to the undivided post-trematicus ix. When the latter divides it thereafter accompanies the ventral division of it, but curves round the inner aspect of the elbow formed by the epi- and cerato-branchials. The R. post-trematicus (vost. 1.) gives off below just at its origin a motor branch, and shortly afterwards curves downwards, outwards and backwards to reach the second branchial arch. There it divides into two branches, just as in the ixth, and these bend externally round the epi- and cerato-branchial elbow, one lying above the cerato- branchial and the other below it. Thereafter their course resembles that of the post-trematicus 1x. 2.—T. branchialis secundus Vagi (¢. a. 2). The ganglion of this division is more or less massed with the remaining vagus ganglia (g. #. 2-5), and their boundaries are difficult to determine. The truncus arises from the internal surface of the ganglionic mass, like the first. A small mixed plexus of communis and motor fibres, not shown in the chart, may be described here. It arises by 3 roots—one from the second branchial ganglion, and two from the third. These three roots form a plexus from: which 3 nerves arise, two of which pass forwards and inwards and break up in the roof of the pharynx, whilst the third also passes forwards as a purely motor nerve, SEA-FISHERIES LABORATORY. 287 The truncus now courses downwards and forwards, and almost at once divides into an upper palatine + pre- trematic branch and a lower R. post-trematicus (post. 2). The former gives off 3 RR. pharyngei (ph. w. 2) to the roof of the mouth, and is then continued downwards on to the second branchial arch as the R. pre-trematicus (pre. 2). The latter, as it passes forwards, gives off from its upper border two motor twigs not shown in the chart, and finally breaks up as usual into two branches, which pass on to the third branchial arch, and the distribution of which is essentially the same as the corresponding divisions of the first branchial trunk. 3.—T’. branchialis tertius Vagi (¢. «. 3). Arises from the ventral edge of the compound ganglionic mass. ‘The two nerves it contributes to the pharyngeal plexus have been described above. Another nerve not shown on the chart arises posteriorly and internally from the base of the truncus. It passes sharply downwards and backwards to the roof of the pharynx. The truncus itself, directly it leaves the ganglion, divides into a palatine+pre-trematic branch coursing gradually downwards and forwards, and a R. post-trematicus, pass- ing sharply downwards and backwards. ‘The former divides as usual into a R. pharyngeus (ph. w. 3) and a R. pre-trematicus (pre. 5), the latter passing on to the third branchial arch. The R. post-trematicus (post. 3) breaks up into the usual two branches much sooner than usual,.as in Mendia. The anterior one gives off at once in front a motor branch. Both pass on to the fourth branchial arch and are distributed as usual. The T. branchialis quartus vagi is so closely asso- ciated with the remainder of the vagus that it cannot be 288 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. separately described. After giving off the branchialis tertius, the vagus passes backwards and splits into two large nerves. The upper one is the R. intestinalis vagi (r. intest. 2.), and the lower one contains the fourth branchial trunk, together with the RR. cardiacus et cesophageus vagi. The upper division gives off two branches, which join the rich csophageal plexus formed by branches of the lower division, and afterwards passes almost straight backwards as the R. intestinalis, wedged in at first between the kidney, thymus and roof of the cesophagus. It gives off branches to the esophagus from time to time, and passes downwards until it hes at the side of the latter structure. It ultimately splits into two, both of which break up in the lateral wall of the-csophagus and are lost before the stomach is reached. The lower division, before and after it separates from the R. intestinalis, gives off about 10 mostly motor nerves, which at once form an elaborate plexus in the region of the dorso-lateral wall of the cesophagus. These nerves and others are not shown in the chart. It then passes shghtly downwards and backwards, and gives off in front the fourth R. pre-trematicus (pre. 4), which passes sharply downwards and forwards. This at once gives off in front a small motor twig, and then courses straight on to the fourth branchial arch. It was not observed to give off a R. pharyngeus unless an extremely small twig distributed apparently to the side wall of the pharynx represented that branch. After giving off the fourth pre-trematicus, the lower division turns almost straight downwards, and then divides into four branches. ‘Two of these pass forwards at once into the ventral wall of the cesophagus, and repre- sent the final derivatives of the R. esophageus. The third accompanies the inferior pharyngeal bone, and is therefore SEA-FISHERIES LABORATORY. 289 the fourth R. post-trematicus (post. 4).* The last branch continues the downward course, gives off a motor branch behind, and then courses forwards and downwards in close contact with the roof of the pericardium. This may be the R. cardiacus (r. car: ?), but it does not actually pass on to the sinus venosus, and certainly contains a number of motor fibres distributed outside the heart. The true R. cardiacus may therefore have been overlooked, especially as Stannius proved by stimulation experiments that the vagus of the Plaice sent fibres to the heart. 3.—THE Spinat Nerves (Fig. 27). ae- Fourth Spinal Nerve. We describe this spinal nerve first since in most respects it may be taken to represent the structure of most of the other spinal nerves. The visceral fibres are not taken into account. The fourth spinal nerve arises by two roots—a dorsal largely sensory (d. 4) and a ventral motor (v. 4). Each root leaves the neural arch of the third vertebra by a separate foramen, as described by Stannius, and passes at once into a single large extra-vertebral ganglion (g. 4). The motor fibres for the R. medius and R. ventralis per- forate the ganglion, but those for the R. spinosus pass upwards internal to it. One lateral, one ventral and two dorsal branches arise from the nerve. ‘he two last are the R. communicans (sensory) and the R. spinosus (motor), whilst the former are respectively the R. medius (sensory and motor) and the R. ventralis (sensory and motor). 1. R.communicans (r. com. 4).—This sensory ramus * We differ from Herrick in naming two of the branches of the vagus. His fourth post-trematic (fig, 4, post 4) is apparently the pharyngeus iv., and his ‘‘ branches of the vagus for the inferior pharyngeal teeth ’’ (ph. v., same figure) are equivalent to our post-trematic iy, xX 290 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. arises from the antero-dorsal region of the ganglion, passes upwards, and fuses with the R. spinosus of the nerve in front (third spinal). 2. R. spinosus (7. sp. 4)—A motor ramus leaving the postero-dorsal region of the ganglion, and giving off near its base a posterior lateral branch for the inter- mediate portion of the dorsal musculature. It then passes dorsally, and fuses with the R. communicans of the nerve behind (fifth spinal). The resulting mixed trunk continues upwards and forwards in the dorsal musculature very close to the middle line, and is distributed to the dorsal portion of the dorsal musculature, the inter-spinal muscles and the dorsal skin. 3. R. medius (r. m. 4)—This mixed ramus, leaving the ventral extremity of the ganglion, courses laterally outwards through the ventral portion of the dorsal muscu- lature, and bifurcates. The upper division accompanies the intermuscular bone, and supples the ventral portion of the dorsal musculature. The lower division passes downwards into the lateral musculature (which it sup- plies), obliquely crossing under the R. lateralis profundus vagi (fig. 23, r. lat. prof. x.), to which it may be very closely attached, but with which it never mingles. The sensory fibres of the ramus pass out laterally to the skin, and supply that portion of it around the lateral sensory canal. , 4. R. ventralis (vr. v. 4).—This mixed ramus also arises from the ventral extremity of the ganglion, and is the largest of all. It passes downwards, and just over the kidney receives the R. communicans from the fourth spinal sympathetic ganglion (com. wv.). It then turns out- wards between the lateral musculature and the kidney, and afterwards downwards again between the lateral musculature and the liver. Finally it continues down- SEA-FISHERIES LABORATORY. 291 wards on the inner surface of the abdominal wall, and just under the peritoneum. This ramus supplies the ventral musculature and ventral skin. In the region of the appendages the limb girdles and fins are supplied from R.R. ventrales. In the specimen now investigated, how- ever, the fourth spinal was not connected with either the pectoral or pelvic appendage. ‘The fourth R. ventralis anastomoses below with the nerve 7. v. 2+38!1, as described below. The First Spinal Nerve. This nerve is a compound of at least two spinal nerves, ‘since it has two ganglia and most of its principal rami are in duplicate. It is, however, here described as the first spinal, on account of the difficulty of completely isolating its constituents. The ganglia and roots of the first spinal are situated in the bony tube formed by the exoccipital, and leading from the foramen magnum into the cranial cavity proper (see fig. 4). There is one main foramen for the nerve, which tunnels transversely the narrowed base of the par- occipital condyle, as shown in fig. 3 (above the lower letters Ee. O.). Another smaller foramen for the R. spinosus b. is situated immediately above this, and occasionally there is another larger one immediately below it for the R. ventralis, as shown in the chart. Usually, however, the latter nerve passes through the main foramen. There are thus at least two foramina for the first spinal nerve, and there may be three—all situated in the exoccipital. The first spinal has two perfectly distinct ganglia— an intracranial ganglion (g. ztcr.), and an extracranial ganglion (g. eatcr.). These two ganglia are connected by a large bundle of sensory and motor fibres which pass through the main foramen (indicated in the chart by the 292 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. oval dotted area). There was in the specimen sectioned a discrete patch of cells on the right side on the R. ventralis also, but in other examples these were con- tinuous with and part of the extracranial ganglion. We follow Fiirbringer and Herrick in designating the cephalic constituent of the first spinal by the letter d, and the caudal constituent by the letter ¢. It will be observed that the Plaice has three ventral roots instead of the two described by Herrick in Menedia,* and of these the extra one is undoubtedly the first (v. 6.*). The first spinal nerve of the Plaice has two dorsal sensory (mostly) and three ventral motor roots. Of the . two dorsal roots the first (d. 0.) is larger than the second (d. c.), and arises obviously from the spinal vth tract. They both pass into the intracranial ganglion. Of the three ventral roots, the first (v. 6.1) is very long and slender, and fuses with the second (v. b.). The third (v. ¢.) is very short, and is the largest of all the roots. All three ventral roots pass into the intracranial ganglion. | The following nerves arise from the intracranial ganglion :— ; 1. R. spinosus, b (7. sy. 6.).—A motor nerve, arising from the fused first and second ventral roots. It passes through the intracranial ganglion, and leaves the exocci- pital by a small foramen immediately above the main foramen (indicated by a ring in the chart). It then passes forwards over the top of the extracranial ganglion, rises sharply at the side of the auditory capsule, and afterwards turns forwards over the roof of the capsule to supply the dorsal musculature and interspinal muscles. This nerve does not anastomose with a sensory R. communicans lke the posterior RR. spinosi. * Stannius mentions only four roots in the Plaice also, having apparently missed the first ventral, _ SEA-FISHERIES LABORATORY. 293 2. R. spinosus, ¢ (7. sy. c.).—Large motor nerve from the third ventral root. It perforates the intracranial ganglion dorsally, passes a little backwards in order to leave the skull by the foramen magnum above, and then courses forwards and upwards. Arrived at the roof of the skull, it bends forwards over the latter, at first lying over _ the epiotic a little to the side of the narrowed posterior portion of the supraoccipital. It then fuses in the typical manner with the sensory R. communicans of the second spinal nerve, to form a conspicuous mixed nerve which courses forwards over the roof of the skull near the middle line to its distribution. 3. R. ventralis (”. v. 6+c).—This usually leaves the skull by the main foramen, but it occasionally has a foramen of its own situated below the main foramen, and above the paroccipital condyle, as in the specimen figured. It has a comparatively slight connection with the extra- cranial ganglion, but the latter ganglion does undoubtedly contribute fibres to it. The R. ventralis is formed as follows :—First of all the remainder and greater part of the first and second ventral roots, having passed under- neath the intracranial ganglion, and together with some sensory fibres, pass into the special foramen (indicated by a ring in the chart). They are immediately followed by the remainder of the third ventral root (also accompanied by sensory fibres from the intracranial ganglion), which, having perforated the intracranial ganglion, and instead of passing into the main foramen as usual, turned down- wards and entered the special foramen. ‘The ventral root thus left the skull by all three foramina. These two mixed trunks more or less unite in the foramen, and immedi- ately outside it in this specimen bore a small number of discrete ganglion cells. The latter, however, undoubtedly belong to the extracranial ganglion. The two trunks soon 294 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. separate again into two mixed nerves, and pass downwards and backwards. The lower one receives the R. communi- — cans from the first spinal sympathetic ganglion (com. 1). They subsequently unite again, and distal to the union a large sensory and motor nerve is given off, which curves downwards and forwards. This is the R. cervicalis or so-called N. hypoglossus (7. cerv.). It courses at first at the side of the pericardium opposite the junction of the auricle and ventricle, and the upper sensory and the lower motor components are quite obvious. In front, the two components separate out into a dorsal sensory and a ventral motor nerve. Shortly after giving off the above, the R. ventralis receives a sensory and motor anastomosis from the R. ventralis of the second spinal nerve (7. v. 21), thus forming the brachial plexus. The compound trunk (rv. v. 1) then courses downwards and slightly backwards, and gives off a motor nerve in front and behind to the muscles of the pectoral girdle (r. v.11 and vr. v. 17). It now passes through the scapular fenestra (see fig. 8— indicated by a ring in the chart), in order to reach the external aspect of the pectoral girdle, where the two com- ponents at once separate out into an anterior motor nerve (7. v. 1°) and a posterior sensory nerve (r. v.1), wh ich are distributed to the pectoral fin, the latter to its dorsal region. The following nerves arise from the extracranial ganglion :— 1. R. communicans, b. (7. com. b.).—A large sensory nerve from the extreme dorsal point of the ganglion. It passes forwards over the roof of the skull at the same transverse level as the R. spinosus, b., but external to 11. It ultimately passes first outwards and then downwards between the skull and the skin, and is distributed to the latter in the region of the auditory capsule. As the R. SEA-FISHERIES LABORATORY. 295 lateralis accessorius is absent in the Plaice, and as it cannot anastomose with the R. spinosus, this nerve is not an actual R. communicans in the Plaice. | 2. R. medius, b. (7. m. 6.)—Leaves the ganglion as two distinct strands—an anterior sensory and a posterior motor. The sensory section is small and passes outwards and forwards to the skin in the region of the lateral sensory canal. The motor section arises from the fibres of the fused first and second ventral roots which have passed underneath the intracranial ganglion, traversed the main foramen lying underneath motor fibres from the third ventral root, and perforated the extracranial ganglion. Immediately it leaves the latter ganglion it gives off a small anterior branch, whilst the rest of the nerve passes laterally backwards and breaks up largely in the dorsal musculature. 8. R. medius, c. (7. m. c.).—A large mostly motor nerve arising almost entirely from the third ventral root. The fibres pass through the main foramen, and perforate and leave the extracranial ganglion at its anterior aspect. Directly it leaves the ganglion, it gives off above a small sensory thread, which passes outwards and backwards towards the lateral sensory canal. The remainder and larger part of the nerve courses downwards, outwards and backwards in the dorsal musculature, in which most of its fibres break up, except also a few that pass outwards towards the skin. The Seeond Spinal Nerve. The second spinal nerve has a dorsal mostly sensory (d. 2) and a ventral motor (v. 2) root, and two extra- vertebral ganglia—a large dorsal ganglion (g. d. 2) and a smaller ventral ganglion (g. v. 2). The dorsal root passes backwards at once into the dorsal ganglion, but the 296 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. ventral root passes upwards and splits into two bundles, one penetrating the dorsal, the other the ventral ganglion. Both roots emerge from the atlas vertebra by a single © foramen (fig. 17). The following nerves arise from the dorsal ganglion: 1. R. communicans (r. com. 2).—A sensory nerve arising from the extreme dorsal tip of the dorsal ganglion. Passes upwards and forwards, bends forwards over the roof of the skull, and fuses with the R. spinosus e. of the first spinal nerve (g. v.). 2. R. spinosus (7. sp. 2)—A motor nerve passing upwards internal to the dorsal ganglion. After giving off a fine motor twig below, which passes upwards external to the dorsal ganglion (and not shown .in the chart), it liberates in front and above a larger motor nerve which at once splits into two bundles coursing laterally in the dorsal musculature—one anteriorly and the other pos- teriorly (see chart). Above, it receives the sensory R. communicans from the third spinal nerve in the typical manner, and bends forwards over the roof of the skull, keeping very close to the middle line. The following nerves arise from the ventral ganglion : 1. R. medius (7. m. 2).—A mostly motor nerve, which perforates the ganglion, and then turns laterally backwards in the dorsal musculature. It breaks into two —one coursing in the dorsal musculature above the R. lateralis profundus vagi, and the other crossing below it into the lateral musculature, and supplying the muscles in these regions. It seems to contain some sensory fibres also. | . 2. R. ventralis (7. v. 2)—_A mixed nerve perforating the ganglion and coursing downwards and backwards over the kidney and approximating to the R. ventralis of the first spinal nerve. It receives two Rami communicantes SEA-FISHERIES LABORATORY. 297 from the second spinal sympathetic ganglion (com. 72.), and sends a mixed bundle to the: R. ventralis of the first spinal nerve as above described (7. v. 21). Just at about the same place it fuses completely with the R. ventralis of the third spinal nerve, but the above anastomosis 1s derived from the R. ventralis 2, and contains no fibres from 3. The compound trunk (7. v. 2+3), after giving off a small branch to the inner surface of the clavicle (not shown in the chart), courses forwards and downwards, and gives off below two motor branches which pass at first downwards and then forwards to supply the ventral musculature. They anastomose with each other close to their origin, and the posterior one (r. v.2+3') also anasto- moses below with the R. ventralis of the fourth spinal nerve. The remainder of the trunk then splits behind into two—a small motor nerve and a larger mostly sensory nerve. The latter (r. v.2+3"”) is continued backwards on to the ventral portion of the pectoral fin. five Lhaird, Spirnal, Nerve. This spinal nerve has the usual two roots (d. 3 and v 3), and a single very large extra-vertebral ganglion (g. 3). Hach root has a separate foramen in the neural arch of the second vertebra (fig. 17). The sensory R. communicans (7. com. 3) contains a few motor fibres, which are liberated as a small bundle for the dorsal musculature (not shown in the chart). It fuses with the R. spinosus 2, as above described. The motor R. spinosus (7. sp. 3), after rising internal to the ganglion, courses at first back- wards, fuses with the R. communicans 4, and then turns forwards as a mixed nerve high over the roof of the skull and very close to the middle line. It gives off below the motor nerve to the dorsal musculature just like the pre- ceding nerve. 298 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The R. medius (r. m. 3) is a mixed nerve, but largely motor. It breaks up into the two branches as in the second spinal, the upper one for a time accompanying the intermuscular bone, and the lower the R. lateralis pro- fundus vagi (but not mixing with it). The R. ventralis (7. v. 3) is also a mixed nerve. It receives the R. communicans from the third spinal sym- pathetic ganglion (com. 111), and then fuses with the R. ventralis of the second spinal, as above described. It is thus seen that the pectoral girdle and fin of this specimen of the Plaice is supplied largely by the first spinal, but also to a certain extent by the second and third. It must, however, be emphasized that the limb plexuses are subject to great variation, that the above account is not a generalised description, and therefore takes no account of variations. Stannius, however, states that fibres from the RR. anteriores of the first three spinal nerves pass to the pectoral fin in the Plaice. With regard to the fifth spinal nerve, we need only mention that the R. medius arises from the R. ventralis, and that its lower division appears to completely fuse with the R. lateralis profundus vagi, but really is only very closely attached to it. The innervation of the paired fins of Teleosts has very important theoretical bearings. In the Plaice from which the spinal nerves were plotted out, the R. ventralis of the fifth spinal nerve, together with that from the sixth,* were the nerves which supplied the pelvic fin. Now if this fin is homologous throughout Teleosts generally, * Stannius states that the pelvic fin of the Plaice is innervated from the fourth and fifth spinal nerves, and this tallies with Cuvier’s scheme. In our sections, however, the fourth spinal nerve was not connected with the pelvic fin. SEA-FISHERIES LABORATORY. 299 which we assume will not be doubted, then we must con- clude that we have, in this clearly monophyletic group, a genuine case of fin migration, since the pelvic fin of Teleosts may be either abdominal, at the side of the anus, thoracic, just behind the pectoral fin, or jugular, in front of the pectoral. Further the fin must have moved from behind forwards, since it may be clearly deduced from the fossil forms that the abdominal position is unquestionably more primitive than the jugular. Now in Elasmobranch fishes, according to Gegenbaur’s hypothesis, the pelvic fin, having been formed from the branchial skeleton, must have migrated from before backwards, unless the addi- tional hypothesis of the extension of the branchial region further back than we have any knowledge, is evoked.t It must be noted at once, first, that all paleontological evi- dence is against such an assumption, and second, that this migration, if it occurred at all, must have taken place at a remote geological period. On the other hand, the migration of the pelvic fin of the Teleost is not only some- thing more than an hypothesis, but it must also have occurred within comparatively recent times. Now several attempts have been made to deduce the migration of the Elasmobranch fin from its innervation, and so far the Teleosts have been ignored, in spite of the fact that here we might with much more reason expect to encounter such evidence. Unfortunately, however, in the latter group, the jugular pelvic, as in the case of the Plaice, is supplied by the anterior spinal nerves of its region, and the abdominal pelvic, as in the several fishes investigated by Stannius, is supplied by the posterior nerves of its + It may, of course, be maintained, as it is in the case of some Elasmo- branchs, that the pelvic fin of Teleosts migrated first backwards and then forwards. We have ignored the former possibility (which after all would be purely hypothetical), in order to concentrate attention on the latter, where the migration theory may be the more satisfactorily tested. B00 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. region. Here, therefore, the innervation clearly proves nothing, and it may at least be doubted whether it proves any more in the case of the Hlasmobranchs. We refer now purely to neurological evidence, and are of course aware that the supposed migration of the Hlasmobranch fin is alleged to be supported by ontogeny also. Stannius (op. cit.) makes several references to the spinal nerves of the Plaice, and he quite realised the morphological value of the anterior extremity of the dorsal fin, since he carefully distinguishes between the forward extension of mixed spinal nerves over the roof of the cranium, and the sensory dorsal branches of the cranial nerves themselves. His work also contains a figure of the anterior spinal nerves of the Plaice (Taf. iv., fig. 1). 4.—T'nr Sympatuetic Nervous System (Fig. 26). Owing to the impossibility of satisfactorily dissecting the anterior portion of the sympathetic, we plotted it out from the same series of sections as were used in the case of fig. 25. As it is drawn to the same scale, the two figs. may therefore be compared. Our examination of the sympathetic commenced at the sixth vertebra, and. behind the seventh spinal nerve. It is described from behind forwards, right side first. The sympathetic cord may be conveniently divided into two parts, which we will call the cranial sympathetic, associated with the skull and cranial nerves, and the spinal sympathetic, associated with the vertebral column and spinal nerves. In each portion, the ganglia are numbered separately from before backwards. At the sixth vertebra the sympathetic is situated laterally below the centrum and the transverse process. It here sends a short Ramus communicans to the ventral ramus of the seventh spinal nerve (com. vu.), which SEA-FISHERIES LABORATORY. BOL crosses it at right-angles. In front of this is found the seventh spinal sympathetic ganglion (7’). At this region the two cords are connected by a transverse commissure below the dorsal aorta and bearing a pair of ganglia (7”), formed as shown in the figure, and the cord of the right side is also looped. ‘There are two RR. communicantes to the ventral ramus of the sixth spinal nerve (com. v.), but in front of this, beyond a loop for a renal vein and a very small ganglion in front of ganglion 5 (5’), there are no features of special interest until we come to the second spinal sympathetic ganglion. The sympathetic behind the second ganglion lies immediately above the inner dorsal angle of the kidney. The coeliac ganglion (g. coel.) lies close under the second spinal sympathetic (2’), and in front rises up to fuse with it. Jour nerves arise from the second ganglion. Behind, a pair (com. 7.) pass independently into the ventral ramus of the second spinal nerve, and thus form RR. communi- cantes 11. The sympathetic now les internal to the kidney, and just above the cceliaco-mesenteric artery. In front, a large third nerve arises dorsally, and soon splits into an anterior and a posterior branch. The former is continued into the first ganglion (1’) and thereafter into the cranial sympathetic, whilst the latter forms a promi- nent. ganglionated (2”) commissure under the dorsal aorta with the cord of the other side. ‘The fourth branch arises anterior to the third, and curved backwards on to the aorta, where it was lost. The second ganglion now tapers down, and terminates in close proximity to the kidney. The coeliac ganglion, which it should be noted arises from the rzght sympathetic cord, passes backwards after fusing with the second ganglion, and is situated just over the coeliaco-mesenteric artery. It also gives off four branches, The most dorsal one passes straight into the 302 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. kidney after a very short course. Of the three others two join to form the dorsal Nervus splanchnicus (n. sp.’) lying over the above artery, but before joining one of them gives off a thin twig which accompanies the esophageal artery. The fourth branch, after giving off a fine twig to the kidney, becomes the ventral N. splanchniecus (n. sp.”), lying under the artery. The latter nerve is for some part of its course opposed to the R. intestinalis of the vagus. When the coeliaco-mesenteric artery divides into a dorsal coeliac and a ventral mesenteric artery, the two RR. splanchnici also divide (ep. figure). From the first spinal sympathetic ganglion (1’) three nerves arise. One of these is certainly, and another pos- sibly, a R. communicans to the ventral ramus of the first spinal nerve (com. 1). The third seemed to enter the jugular ganglion of the vagus, but this is not certain. From sections 730 to 704 the cord is attached to the inner surface of the root and ganglion of the Truncus branchialis primus N. vagi, but as far as could be ascertained exchanged no fibres with it. The first spinal sympathetic ganglion occupies an intermediate position between the cranial and spinal sections of the cord, since it is con- nected both with the vagus and first spinal nerve. After leaving the first spinal ganglion, the cord is continued forwards as the cranial sympathetic, and from section 702 to 678 accompanies the superior jugular vein, during which it bears a very small ganglion (8). After leaving this vein it bears ganglion 7 and becomes attached to the inner surface of the glossopharyngeus ganglion and trunk (658-620), being wedged in between the latter and the skull, and bearing ganglion 6. In front again, when the glossopharyngeus splits up, it accompanies the ventral edge of Jacobson’s anastomosis (618-560), and swells into a very large ganglion (5) very closely related to Jacobson’s SEA-FISHERIES LABORATORY. 303 anastomosis. On leaving the latter it bears another moderate-sized ganglion (4), but no fibres were seen to be exchanged between any of these ganglia and the glosso- pharyngeus nerve. In front of ganglion 4, the cord rises upwards and becomes attached to the Truncus hyoman- dibularis, just as the latter emerges from the skull, the post-trematicus vii. lying below it. It now passes into the cranial cavity through the jugular foramen, and is so closely pressed against the T. hyomandibularis that we were unable to determine whether fibres were exchanged or not, although we believe not. Inside the cranium, it bears the small ganglion 3, from which the ganglionated intracranial most anterior commissure (3”) arises. The commissural ganglion is situated actually on the root of the sixth cranial nerve. From section 536 to 494 the cranial sympathetic accompanies the R. palatinus facialis, and is very closely attached to it. In front, it passes through the trigemino- facial foramen, and takes up a position between the skull and the origins of the maxillary and mandibular v. nerves. It now swells into the large ganglion 2, from which a very prominent R. communicans (com. v.') passes upwards to the T. maxillo-mandibularis. The first cranial ganglion (1) lies above the second, and is connected with it by a very short strand of fibres. Both the first and second ganglia give off a cord in front, but the two unite before reaching the ciliary ganglion. The first ganglion also gives off a nerve internally, which accompanies the ventral edge of the R. ophthalmicus superficialis v. The possibly corresponding nerve of the other side arises externally from the second ganglion, accompanies the superior maxillary v., and has a very small ganglion of its own. From the first cranial ganglion onwards the sym- pathetic is accompanied by the profundus nerve, They BO4 TRANSACTIONS LIVERPOOL. BIOLOGICAL SOCIETY. pass together through a special foramen in the ventral edge of the alisphenoid into the eye muscle canal. The - cord from the second ganglion also enters the canal by the same foramen. Before reaching the ciliary ganglion the profundus nerve separates from the sympathetic as the Ramus ciliaris longus (see profundus nerve), but some fibres are dispatched from it to accompany the sympathetic to the ganglion as the Radix longa. The ciliary ganglion itself (c2/. g.) is closely attached above to the main trunk of the oculomotorius, after the latter has given off the nerve to the rectus superior. The Radix brevis therefore is exceedingly short (rv. 6.). From the ciliary ganglon in front arises the R. ciliaris brevis (c/. 6.). This passes forwards in the eye muscle canal, accompanying the main trunk of the oculomotorius, until the latter breaks up. It then courses under the lower or right optic nerve as a conspicuous bundle, enters the eye ball with it, and there- after passes downwards and forwards towards the iris. As regards now the eyeless or left side, the sym- pathetic nervous system, like the nervous system generally, is not so well developed. This is especially noticeable in the gangha, which are perceptibly smaller than those of the other side. In front, the disturbance of the symmetry has dragged the sympathetic over to the ocular side. Generally speaking, however, the left s:de resembles the right in all essential respects, but the fol- lowing differences may be mentioned. In the spinal sympathetic the seventh ganglion (7) is in two parts, R. communicans vi. (com. v2.) is separated from its ganglion (6’), and R. communicans v. (com. v.) is situated between a large and a small ganglion (5! and 5"). Ganglion 2 gives off externally a large nerve which passes ‘backwards and downwards to the kidney. R. communi- cans ii. (com, it.) is single, but the first (com. 7.) is however SEA-FISHERIES LABORATORY. 305 double, the posterior of which bears a very small ganglion. No exchange of fibres between the sympathetic and the vagus was observed. In the cranial sympathetic only 7 ganglia were found instead of 8. When the cord reaches the glosso- pharyngeus, instead of becoming attached to the ventral border of the ganglion and subsequently to that of Jacob- son's anastomosis, it passes upwards internally to the ixth and becomes opposed to its upper division. This is due to the fact that when the ixth splits it forms a dorsal Jacobson’s anastomosis and a ventral post-trematicus, instead of the reverse as on the right side, and the sympathetic always accompanies the former. Ganglion 5 hes quite clear of and above the glossopharyngeus, in striking contrast to the condition on the other side. As the cord passes through the jugular foramen it is for a time very tightly wedged into the angle formed by the outgoing post-trematicus vil. and the hyomandibular trunk. We could not determine whether there was any exchange of fibres between the sympathetic and the facial nerve, but if present it is nct obvious. There is a large R. communicans (com. v.') to the base of the T. maxillo- mandibularis. The combined sympathetic and profundus nerve when they enter the eye muscle canal lie just above the ciliary ganglion. Instead, however, of passing straight down to the ganglion, as on the right side, they curve round the left rectus externus muscle, and describe an almost com- plete circle before reaching the ganglion. The few fibres forming the Radix longa and the sympathetic join with the fibres leaving the ciliary ganglion to form the R. ciliaris brevis. It is doubtful whether many of them enter the ganglion at all on this side. There are no other differences of importance between the two sides. Y 306 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. We are unable to agree with some of the remarks of Stannius on the sympathetic of the Plaice. He states that the first cranial ganglion is that connected with the facial nerve, that there is no ganglion corresponding to the glossopharyngeus, and that the rami communicantes for the first 3 or 4 spinal nerves arise from a common ganglion also giving origin to the NN. splanchnici. We have not examined the sympathetic posteriorly, but Stannius states that there are very large sympathetic nerves connected by a commissure perforating the kidney to reach the repro- ductive organs. ‘They also pass backwards with the ovary or testis into the cavity between the skeleton and the skin formerly supposed to be the posterior extension of the body cavity. The sympathetic nervous system of Fishes has recently been investigated in some detail by Jaquet* and C. K. Hoffmannt—the former studying its anatomy and the latter its development. Jaquet divides it into cephalic, abdominal and caudal portions. The first is stated to be connected with the ganglia of five cranial nerves—the “hypoglossal” [first spinal], vagus, glossopharyngeus, facialis and trigeminus, and fibres from the second and third ganglia are said to accompany the glossopharyngeal to the pseudobranch. Jaquet’s work contains a formal scheme of the Teleostean sympathetic (fig. 4), and also many statements which are not borne out by our examina- tion of the Plaice, and which seem to us to require con- firmation. The most important work on the anatomy of the sympathetic in bony fishes is that of Chevrel,t who investigated the relation of the ganglia to those of the cranial nerves, and who asserts that the first sympathetic * Bull. Soc. Sci. Bucarest-Roumanie, Ann. x., 1901. + Verhand. K. Akad. Wetens. Amsterdam, Sect. ii., Dl. vii., 1900. t Arch. Zool. Expér., Ser. ii., T. v. bis. SEA-FISHERIES LABORATORY. 307 ganglion is always associated with the trigeminus, except in the Physostomi, where there are no ganglia in front of the vagus. This is what we should expect, as the cranial sympathetic appears for the first time in the bony fishes, and the Physostomi are undoubtedly a primitive oe of Teleosts. F.—THE SENSE ORGANS. 1.—Tuer System oF LATERAL SENSE ORGANS oR SENSORY CANALS. (Figs. 23 and 29.) The obvious line seen at the side of the body in most Fishes, including the Plaice, and known as the lateral line (Seitencanal of German authors), is in our type a long tube or lateral canal, protected by a row of modified scales (lateral line ossicles), and opening on to the surface by pores at more or less regular intervals. ‘These pores may open directly into the canal or they may do so by the intermediation of a little tubule. At first the only sub- stance found in such a canal as this was a quantity of a jelly-like mucus, and hence these canals were called mucous canals, and were supposed to secrete the mucus on the surface of the body. The discovery, however, that they contained large sense organs, one of which usually occurred between two succeeding surface pores, and thai. the mucus was only of minor importance, and developed by the numerous goblet cells in the lateral canal itself to enable the sense organs to perform their function, and also that the mucus in the lateral canal was of quite a different character to that occurring on the surface of the body, conclusively proved that these lateral canals constituted a sensory structure and could not therefore be called mucous 308 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. canals. We hence adopt the term of sensory canals originally proposed by Ewart. Now the sensory canals are not confined to the body of the fish, but always extend on to the head, where, as a very general rule, they form a much more complex and important system of sensory canals, which, on account of their deeper situation and therefore less obvious character, are too often disregarded. In the Teleostean Fishes the innervation of this system is so remarkably constant in those forms in which it has been properly investigated as to justify its division on each side of the body into the following four canals, the extent of any one of these being determined by its innervation. That is to say, that part of the cephalic system of sensory canals called the infra- orbital canal is precisely that part of the system innervated by a single perfectly definite nerve—the R. buccalis facialis. One extremity of this canal is a natural blind extremity, the other is the artificial boundary beyond which its nerve does not extend. The four canals are:— (1) the lateral canal at the side of the body (“ lateral line” of systematists), defined by the branching of the R. lateralis vagi; (2) the supraorbital canal over the eye, defined by the R. ophthalmicus superficialis vil.; the infraorbital canal under the eye, defined by the R. buccalis vii.; and the hyomandibular canal on the oper- culum and lower jaw, defined by the R. mandibularis externus vii. These nerves are in this work only provi- sionally associated with the vagus and facial nerves, as their true morphological value cannot be discussed in a general treatise of this nature. Although much work has been done on the use of this undoubtedly sensory apparatus, its function is even yet a subject for speculation. This is due to the fact that owing to its very diffuse nature and the intimate relations SEA-FISHERIES LABORATORY. 309 of its nerves with the other cranial nerves, it has so far been found impossible to devise really satisfactory experi- ments. FF. 8. Lee, the latest investigator of the function of the lateral line organs, concludes that they are con- nected with the sense of pressure or equilibration, and even if this be not the case, there is some reason to doubt whether the latter can be located in the semi-circular canals as in higher vertebrates. The Lateral Canal (/at. c.)—This canal, in part the “lateral lne”’ of systematists, is supported during the greater part of its length by modified scales. Arrived at ‘the region of the shoulder girdle it tunnels through the post-temporal, and then for a short distance has no bony support. It now enters a chain of ossicles, undoubtedly metamorphosed scales, called supratemporal ossicles or extrascapule. The last or most posterior supratemporal is attached to the dorsal surface of the pterotic at the region of the posterior depression shown in fig. 1, and is larger than any of the others. It consists of 2 parts, one running longitudinally in a curve for the “ lateral line,” and the other transversely and somewhat forwards for the terminal portion of the supratemporal canal. Whilst in this ossicle the lateral canal on the ocular side anastomoses with the posterior extremity of the infraorbital canal, and then turns abruptly upwards almost at right-angles, and afterwards forwards, the latter or anterior portion of the canal being called by some authors the supratemporal canal (s. ¢. c.). The last supratemporal ossicle of the Plaice therefore corresponds to the second, third and fourth of the Cod fused together. In one Plaice examined there were in all 13 supratemporal ossicles on the ocular side, as described by Traquair, but the recurrent portion of the canal, usually present at its anterior extremity in the adult (see figs. 23 and 29) was absent in this specimen. 310 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The condition of this recurrent canal, it may be men- tioned, varies considerably. On the eyeless side the rela- tions of the supratemporal canal to the ossicles was essen- tially the same. The sections revealed a curious absence of sense organs in the anterior portion of the supra- temporal canal of the ocular side (fig. 23), there being only 4 sense organs as against 13 pores, but the canal on both sides of the body was not completely developed, like the infraorbital. On the eyeless side in the sections there was a break in the middle of the supratemporal canal occupied by three naked sense organs, only two of which, however, seemed to be canal organs. This break is of course converted into a canal later on in the ontogeny. The recurrent canal was also absent, and there were only eight pores as against 13 on the ocular side, although there were at least 7 sense organs as against 4, not count- ing the three naked sense organs above. The relative position of the sense organs was also different. In the lateral line itself the only difference of importance between the two sides was that the third or last otic sense organ of the ocular side was here innervated from the R. supratemporalis vagi, and hence belonged to the lateral canal, as in the Cod. Infraorbital Canal (zn/. c.).—After leaving the last supratemporal ossicle, in which this canal on the ocular side anastomoses with the lateral, it at once enters the pterotic, and immediately receives the hyomandibular canal, which comes up from below. There is no separate dermal pterotic as occasionally occurs in the Cod. The canal passing straight forwards, traverses the pterotic, sphenotic and right frontal. Arrived at the space between the first and second tuberosities (fig. 1) it anastomoses with the right supraorbital canal and turns sharply down- _ wards almost at right angles, afterwards curving forwards SEA-FISHERIES LABORATORY. oe under the eye. After leaving the frontal the canal is pro- tected only by the chain of very slender suborbital ossicles. the posterior of which are sometimes called postorbitals, and the last of which is attached to the frontal. These ossicles are much more conspicuous in the Cod. In one specimen examined there were 18 suborbitals on the ocular side. On the eyeless side the suborbitals are both fewer and larger, nor does the canal take such a wide sweep forwards, and is hence shorter (cp. fig. 29). It leaves the frontal in front almost exactly opposite the exit of the right infraorbital. From this point the canal extends forwards in a slight curve until it reaches the left lachrymal to which the first suborbital ossicle is attached. On the ocular side the lachrymal is quite distinct from the suborbital chain, and in the specimen examined the canal ended by a pore 11mm. behind and below the postero- ventral extremity of the lachrymal. On the eyeless side the canal passes on to the left lachrymal, on which it terminates. ‘There were 5 suborbital ossicles on this side, but three of these were each divided into two. ‘Traquair describes 13 on the ocular side, and 8 on the eyeless. In the sections the right infraorbital canal was not com- pletely developed, the first 7 sense organs being yet unenclosed in a canal, but lodged in small depressions of the skin. The supratemporal and infraorbital canals are therefore the last to be completed. ‘The portion of the P) canal in line with the “ lateral line,” and innervated by the R. oticus facialis, contained 3 sense organs on the ocular side, to the last of which attention may be drawn. On the eyeless side anteriorly the canal courses down- wards, but after leaving the lachrymal it turns sharply backwards almost at right angles. The whole canal is completely developed on this side, and is more robust. Its anterior portion has fewer sense organs, but those it 312 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. has are arranged more definitely with regard to the pores, z.e., there is always one sense organ between two adjacent pores, except between pores 2 and 38, where a sense organ was absent. The part of the canal innervated by the R. oticus vil. also differs from that of the ocular side in that it has 5 pores, between the first two of which no sense organ was found, and only the first two sense organs were innervated by the R. oticus vil. The sense organ corresponding to the third or last otic was on this side innervated from the R. supratemporalis x., and hence belonged to the lateral canal, as in the Cod. Hyomandibular canal (hy. c.)—This canal anasto- moses behind on the pterotic with the infraorbital on the ocular side, and the lateral on the eyeless side, as above described. It passes forwards for a little and then turns sharply downwards on to the preoperculum. It courses downwards parallel with the anterior edge of the pre- operculum, turns abruptly forwards with the same, and finally passes over the articular on to the dentary, on which it ends far in front by a pore. The positions of the sense organs and pores are shown in the chart. The canals of the two sides agree in all essential respects, except that in the sections, pore 7 was found to be want- ing. The full complement of sense organs, however, was present. . Right Supraorbital Canal (swp. c.)—This is the only complete supraorbital in the Plaice, the left being repre- sented only by vestiges. It anastomoses with the right infraorbital between the first and second tuberosities on the frontal, and passes forwards for a short distance, and then gives off almost at right-angles the supraorbital commissure (s. 0. ¢.), to join the supraorbital canal of the other side. It then passes forwards in the substance of the right frontal, leaves this in front and passes on to the SEA-FISHERIES LABORATORY. — 313 right nasal, on which it ends by a pore. It has only 3 pores and 4 sense organs, omitting those in the commis- sure. It is curious to find that opposite the entry of the commissure there is a small blind diverticulum, containing no sense organs, and corresponding exactly to a similar structure found in the Cod (see fig. 23).* The Left Supraorbital (swp. c.’)—Anastomoses with the left infraorbital just as on the opposite side, passes forwards within the left frontal for a short distance, and receives the commissure. Just opposite the latter point it gives off a surface pore below which may correspond to the blind sac of the ocular side. Between its anastomosis with the left infraorbital and reception of the commissure, it has one large sense organt but no pore (cp. other side, fig. 23). In front of the commissure the canal leaves the frontal, but still lies in a depression on it, and ends blindly a short distance anterior to the commissure. This description enables us to compare the condition in the Plaice with that of the T'urbot, as described by Traquair, and to correct the latter’s figure of the Plaice in some shght particulars. The other supposed remnant of the left supraorbital canal, discovered by Traquair, is situated far in front on the ocular side of the body very near the dorsal edge and above but a little behind the anterior extremity of the right supraorbital (figs. 23 and 29, sup. ¢."). It consists of a very small follicle situated, according to Traquair, on a minute ossicle representing a greatly reduced left nasal, and containing two surface pores, and, according to our sections, one sense organ. * Cole, Trans. Linn. Soc., ser. ii., vol. vii., pp. 157 and 180. + This sense organ, as well as the one on the left side of the supraorbital commissure, is innervated by the R. ophthalmicus superficialis vii. of the left side. This is quite a conspicuous nerve, in spite of the abortion of the greater part of its sensory canal. There can, therefore, be no question that these parts of the canal system belong to the supraorbital canal. 314 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. As, however, in the single series of sections on which fig. 23 was based it was innervated by the inner buccal of the right side, it either cannot represent the anterior end of the left supraorbital, or such an innervation must be anomalous. In the meantime, however, we shall follow Traquair, and regard it as belonging to the supraorbital system. Another very small follicle was found behind it, but it was very aborted and contained no sense organ. The innervation of the former structure suggests that it is a modified pit organ, especially as such occur typically in Teleosts at this region. - The Supraorbital commissure (s. 0. c.).—Arises from the canal on the ocular side, as above described. A sense organ is situated just at its origin, which projects partly into the supraorbital canal itself. The commissure passes upwards and forwards almost at right-angles in the sub- stance of the right frontal. It then bends sharply inwards at right angles (indicated by a circle in fig. 23), and at once enters the left frontal. Just at the turn an unpaired surface tubule (3) is given off, and this undoubtedly cor- responds to the fourth unpaired median tubule of the Cod. Its position in the Plaice is only apparently anomalous. The commissure passes almost transversely but slightly forwards across the body in the left frontal. Arrived at the other side it bends gradually downwards but stall for- wards (a large sense organ being situated at the turn), and thus passes into the left supraorbital. ‘he sense organ in the commissure on the left side is situated much higher up than on the other side, and is thus entirely within the commissure. It is innervated by the R. ophthalmicus superficialis vii. of the left side. The commissure also is passing forwards from right to left during the whole of its course. To sum up the supraorbital system, the right supra- SEA-FISHERIZS LABORATORY. 815 orbital canal has 3 pores and 4 sense organs, the left supra- orbital 3 pores and 2 sense organs, and the supraorbital commissure one median pore and a pair of sense organs. Only the two extremities of the left supraorbital canal are present, the whole of the intermediate portion having aborted with the corresponding part of the left frontal. The first two pores and first sense organ of the left supra- orbital appear to correspond to the same on the right. The whole supraorbital system is supphed by the two RR. ophthalmici superficiales vii. Besides the sense organs situated in the sensory canals, or canal organs, there are two other series of naked sense organs situated on the skin. These are known as Pit Organs and Terminal Buds. The former belong to the lateral line system, and are innervated by one or more of the four lateral line nerves. The latter are quite dis- tinct from the lateral line organs, and are innervated by an entirely separate system of nerves, the Ramus lateralis accessorius (= R. lateralis trigemini), belonging to the communis system. ‘The terminal bud system has been reduced in the Plaice. 2.—Tux Noss (Fig. 25).* The olfactory organ of both sides is described as if viewed from above, and not from the side. The external apertures of the nose, two on each side, are not symmetri- cally placed, and those of the left side are situated almost on the apparent mid-dorsal line of the body, immediately to the left of the anterior border of the left eye. The two apertures or nostrils of each side are sometimes called anterior and posterior nares, but the latter term is obviously inadmissible. *For the olfactory organs of the Pleuronectide, see Kyle, Jour. Linn. Soe., xxvii., and 18th Ann. Rep. Fish. Board Scotland, 1899, Part iii. 316 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Right Olfactory Organ. Anterior Nostril (a. nos.)—A small aperture situated on the anterior aspect and almost at the apex of a largish tube. Posterior Nostril (p. nos.)—A large aperture only slightly raised above the surface of the body. Both nostrils open into a large nasal chamber (n. ch.), the external wall of which is perceptibly thickened, and the internal wall of which is thrown into a vertical series of large folds or olfactory lamine (0. /am.). These lamin bear the olfactory cells and sensory hairs, to which the olfactory nerve is distributed (n. olf.), and run in a longitudinal direction. The nasal chamber is therefore the sensory chamber of the nose, and in most fishes is the only one present. There were 9 olfactory laminz in the right nasal chamber in our sections, but the most dorsal and ventral one is very small. Into the nasal chamber open the nasal sacs, the walls of which are non-muscular and non-sensory, but contain innumerable goblet cells. They therefore have a secretory function at least. ‘l'hese sacs are as follows :— Dorsal nasal sac (#7. sac.1)—Opens into the nasal chamber behind and above. Passes forwards and bifur- cates. The inner limb soon terminates, but the outer one passes far forwards, and although it is very narrow from side to side, it is very wide from above downwards. Its true extent therefore does not appear in the figure. Antero-ventral nasal sac (7. sac.”).—Has a common opening with the postero-ventral sac into the nasal chamber behind and below. Its outer wall is continued backwards into that of the third sac. Passes far forwards, narrow from above downwards, but wide from side to side, between the mucous membrane of the mouth and the 3 SEA-FISHERIES LABORATORY. Sy palatine bone. In front a portion is sent upwards inter- nally at right-angles to the main portion and internally to the palatine. This soon terminates, and the remainder of the sac ends bluntly below the palatine. Postero-ventral nasal sac (n. sac.*).—Opens into the nasal chamber as above described. It is very irregular in shape, and three-rayed in transverse section. It passes far backwards just above the mucous membrane and to the right of the palatine, being narrow behind and ending blindly just over the mucous membrane of the mouth below and internal to the sclerotic of the right eye. imeit Olfactory Organ. The anterior and posterior nostrils (a. nos.', p. nos.') are no different from those of the right side, except that the anterior tube is smaller and the posterior nostril is larger and more widely open. The left nose is situated at a transverse level posterior to that of the right, and is further much less developed. This is most evident in the nasal chamber (n. ch.*), which is obviously smaller and was in the sections only thrown into 4 olfactory lamin (0. /am.'), the dorsal one of these being quite small and the ventral one smaller than the two intermediate lamine.* ‘The figure does not admit of a - comparison as regards the nasal sacs, since their dimen- sions from above downwards cannot be shown. There are only two nasal sacs on the left side as follows :— Dorsal nasal sac (vu. .sac.‘).—Arises from the nasal chamber dorsally from behind. At first its shape in trans- verse section is that of an inverted right-angle—the verti- *The difference between the two olfactory organs is seen in the diameter of the right and left olfactory nerves (fig. 25, 1. olf., n. olf.'). The figure only illustrates the difference in diameter, the difference in bulk is even greater. 318 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. cal limb lying between the nasal chamber and the inter- maxillary cartilage, and the horizontal limb passing inwards over the top of the cartilage. In front, however, the sac hes wholly on the top of the cartilage fitting over it in a curve like acap. It ends very bluntly in front. Ventral nasal sac (7. sac.°).—Its position in the figure is somewhat diagrammatic, as it is really situated under the nasal chamber and only partly under the dorsal sac. It arises from the chamber ventrally from behind, and also passes forwards. It is of very irregular shape, and gives off externally a small limb which soon terminates. Its true extent does not appear in the figure, as it is situated obliquely dorso-ventrally. It narrows very much in front and ends blindly near the outer skin, and between it and the intermaxillary cartilage. There are no true posterior nares such as Kyle describes in one specimen of a Cynoglossus. The nasal sacs discharge their contents by the action of the jaw apparatus, and apparently fill again with sea water by the latter simply passing into the nasal chamber, and thence into the sacs, when the animal is swimming. No intrinsic muscular action is involved, nor are the nostrils valved. The non-fixed parasitic Copepod Bomolochus solee, Claus, is not infrequently found in the nasal chamber of the Plaice.* o.—— | HE. YES. We have only space to consider those features in the structure and relations of the eyes and their accessory organs which are peculiar to Pleuronectid fishes, and are in some way associated with the asymmetry of the head. The eyes are situated very near the anterior limit of the *For figures, see T. Scott, Eleventh Report Fish. Board Scotland, pl. v., figs. 1-10. SEA-FISHERIES LABORATORY. 319 eranium, and the lower or right eye is slightly in front of the upper or left. The prominent interorbital ridge formed by the frontal is continued a little way round in front of each eye, that portion in front of the left being formed by the mesethmoid and left prefrontal, and that in front of the right eye by the right prefrontal. The inter- _ orbital ridge is continued backwards into the line of tuberosities. In the dead fish each eye lies in a little concavity, and the skin round it is loose and thrown into folds. This appearance may also be seen in the living fish, but it will be noticed that the eyes often project very markedly from the surface of the head, and that their axes may be parallel or even convergent, while after death they are widely divergent. There are no eyelids, and the cornea is flattened. The orbits.—The left orbit (fig. 1) is bounded inter- nally by the right frontal and an anterior process of the left frontal, anteriorly by the mesethmoid and left pre- frontal, externally by the processes of the left frontal and prefrontal forming the pseudomesial ridge of Traquair, and posteriorly by the left frontal. When the cranium is placed dorsal surface uppermost the left orbit looks upwards and to the right. The right orbit is not bounded completely by bony walls as is the case with the left. Only internally and anteriorly do the bones adjacent to it lie close to the skin. Those are the right frontal and prefrontal. The bony structures external and posterior to the orbit are the parasphenoid bar and the alisphenoid. All these bones lie nearly in one plane, and the external and posterior walls of the orbit are formed by strong muscle masses. When the cranium is held dorsal surface uppermost the right orbit looks downwards and slightly laterally. The interorbital septum is formed by the right 320 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. frontal and prefrontal above, and by the ethmoid cartilage below. As seen in the dried skull (fig. 3) these structures bound a large fenestra. A membranous sheet stretches across this fenestra from the ventral edge of the right frontal to the ethmoid cartilage and completes the septum. In front the ethmoid cartilage is perforated by a wide opening. This is the ethmoidal fenestra. It is seen in fig. 3, and through it the internal surface of the left pre- frontal may be seen in the figure. When the cranium is held dorsal surface uppermost the interorbital septum is almost exactly horizontal. The Recessus orbitalis.—This is the term applied by Holt* to an accessory of the organ of vision present in all Pleuronectid fishes. It is an evagination of the mem- branous wall of each orbit forming a sac which les outside the orbit and the cavity of which communicates with that of the former by one or more openings. The recessus of the right eye les immediately behind the bulb and just underneath the interorbital septum. To expose it the skin must be very carefully removed from the “region immediately behind the eye from the interorbital ridge downwards. On removing a little connective tissue the organ is then seen. It is a conical sac of fatty appearance with the apex directed backwards. In a fish of about 22 inches in length it is about lem. in total length in the contracted condition. On cutting open its outer wall its cavity is seen to be somewhat reduced by bands of muscle fibres which cross it and are massed together on the internal wall. A seeker can be passed from its cavity into that of the orbit. On cutting away the skin round the eye and carefully removing the latter after dividing the optic nerve and eye muscles, the opening of the recessus can be seen immediately above the place where the *Holt—Proc. Zool. Soc., No. 29, 1894, pp. 413-446 SEA-FISHERIES LABORATORY. 321 external and inferior recti enter the orbit, and where the cavity of the latter is prolonged backwards for a littie distance round the recti. The recessus of the upper or left orbit has similar relations, but on account of the almost complete enclosure of the latter by bony structures it has a somewhat different position. It hes on the eyeless side of the head external to the fenestra bounded by the left frontal, left prefrontal, parasphenoid and alisphenoid. It must therefore be dis- sected from that side and is easily exposed by simply removing the skin and a little surrounding connective tissue. It is (in a preserved fish of 22 inches long) a round flattened sac of about 2cm. in diameter, of similar appearance and structure to the organ of the right side. li also opens into the orbit, and on removing the left eye the large aperture is easily seen immediately posterior and slightly above the place of origin of the inferior oblique muscle. It is situated beneath the pseudomesial ridge and pierces the soft wall of the fenestra mentioned. We have stated that the eyeball can be protruded from the general surface of the head to a remarkable extent. Now while the eye muscles provide an effective apparatus for the retraction of the eye, there is apparently no muscular arrangement which can bring about protru- sion. ‘This appears to be the function of the recessus. In life the cavities of the orbit and that of the recessus with which the latter is in free communication are filled by fluid which apparently originates by an infiltration of lymph from the capillaries outside the orbital wall. . The wall of the recessus being markedly muscular, it follows that its contraction will expel the contained fluid into the orbit and press on the internal surface of the eye-ball. Since the skin of the head round the eye is loose it yields, and the eye is accordingly protruded. Conversely the Z B22, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. relaxation of the wall of the recessus and the contraction of the eye muscles effect the retraction of the eye-ball. If the eye in a fresh or living fish be gently pressed fluid passes into the recessus from the orbit and the former can be seen to swell. The eye muscles (text-fig. 5) are the usual six pairs, two pairs of oblique muscles, and four pairs of straight muscles or recti. The superior oblique muscles (Ob/. Swp.).—Both right and left muscles take origin on the left side of the head. Tt will be remembered that the left prefrontal sends back- wards a long process which fits into a groove on the dorsal surface of the parasphenoid. At the beginning of this process the prefrontal is deeply grooved for the reception of the ethmoid cartilage, the groove being formed by two horizontal bony lamine, and on the upper of these laminze and on the adjacent anterior concave surface of the pre- frontal the oblique muscles take origin. The left superior muscle passes upwards and slightly backwards along the left side of the interorbital septum to its insertion on the eye-ball. The right muscle, however, immediately passes through the ethmoidal fenestra and so through the inter- orbital septum to the right orbit. It then passes upwards and backwards, diverging slightly from the left muscle, along the right side of the interorbital septum to its inser- tion in the right eye-ball. The insertion of these muscles is peculiar. Hach spits up near its distal extremity into anterior and posterior slips. The anterior slips (06l. swp.), which are the larger of the two, have wide insertions on the superior and anterior surfaces of the eye-balls. The posterior slips (o. s. a.) curve round the internal and superior surfaces of the eye-balls, crossing over the insertions of the superior SEA-FISHERIES LABORATORY. : 323 Text Fic. 5. Dissection of the Kye-Muscles. x3. The Cranium is seen from the dorsal surface and slightly from the left side. The eyeballs have been pulled out from the orbits. : VFR Sup Rnf.- *-N.Opticus. y Rink. . "ee : ‘oe AES N.Opticus.-“_- RnB. a Gupe et ee ee eR Ext _Eye Muscle Canal. Obl. Sup., superior oblique; Obl. Inf., inferior oblique] O.S.X., rotatory slip of superior oblique; R. Swp., superior rectus; FR. Inf., inferior rectus; R. Int., internal rectus; R. Ext., external rectus; R.F'r., right frontal; L.Fr., left frontal; R.P.Fr., right prefrontal; L.P.fr., left ‘prefrontal ; M.E., mesethmoid; M.H1., anterior portion of mesethmoid; Vo., vomer ; Pa.S., parasphenoid; Al.S., alisphenoid; Sp.O0., Sphenotic; f.olf., olfactory foramen ; f.tr.fa., trigemino-facial foramen, oA TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. recti, and are inserted into the superior posterior surfaces of the eyes. These posterior slips are the rotatory slips of — the superior oblique muscles, and their function* is to cause a rotation of the eye on its optical axis, a movement which is very exceptional among fishes as among higher vertebrata, and which is doubtless a special adaptation to the peculiar mode of life of the Pleuronectide. The extent of the rotation may be as much as one-eighth of a circle. Inferior oblique muscles (0. 7nf.).—Both right and left muscles originate in the left prefrontal in the same region as that from which the superior muscles take origin. The left muscle passes upwards and backwards along the external wall of the orbit and is inserted into the inferior middle surface of the eye-ball. The right muscle takes origin a little in front of the left, and, as in the case of the superior muscles, the proximal portions eross each other. It then passes through the ethmoidal fenestra with the superior muscle of its side, and passes upwards and backwards along the external wall of the right orbit, and is inserted in a corresponding position to that of the left eye. The inferior are slightly thicker than the superior muscles. The superior recti (7. swp.).—These are strong muscle bundles originating in a strong oblique partition crossing the eye muscle canal. They run forwards in the latter, slowly diverging from each other, and emerge on either side of the interorbital septum. They are inserted into the superior and posterior margins of the eye-balls under- neath the rotatory slips of the superior oblique muscles. The inferior recti (7. inf.).—Also rather thick muscles which take origin far back in the eye-muscle canal at about the transverse level of the articulation of the head * Bishop Harman—Journ. Anat. Phys., vol. xxxv., pp. 1-40, 1899, SEA-FISHERIES LABORATORY. 325 of the hyomandibular, on the internal surface of the parasphenoid. They emerge from the canal into the deeper parts of the orbits and are inserted into the eye- balls on the inferior and middle surfaces, just underneath the insertion of the inferior obliques, so that their extremities are hidden by those of the latter muscles. The internal recti (7. int.) Not so strongly developed as either inferior or superior recti. They originate near the place of origin of the superior recti on the partition in the eye-muscle canal referred to. They run forwards in the orbit close to the interorbital septum, and are inserted into the eye-balls on the anterior and internal surface underneath the extremities of the superior obliques. The external recti (r. evt.)—These are the most slender of all the eye muscles. They take origin on the internal surface of the parasphenoid far back in the eye- muscle canal, and leave the latter above and externally. They are inserted into the external and posterior surfaces of the eye-ball. A large portion of the distal extremity of each is tendinous, and contains little contractile tissue. With regard to the Bulbus oculi itself, we have only space to mention the more striking features in its anatomy. Blood vessels.—The afierent vessels of the bulb are (1) the ophthalmic artery, the origin of which has been already described, and (2) a small vessel springing from the circulus cephalicus between the origins of the internal carotid arteries. The efferent vessel is the superior jugular vein which begins its course in the eye. ‘These vessels lie in the eye-muscle canal. They emerge from the latter accompanied by the optic nerve of their side with which they are bound up by a common sheath of con- nective tissue. -Arrived at the eye all three perforate the 896 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. sclerotic. The ophthalmic artery breaks up in the choroid gland. The other artery appears to pass forwards with the optic nerve to the retina, but we are uncertain as to its precise distribution. The sclerotic consists of two layers, an external layer of tough fibrous tissue into which the eye muscles are inserted, and an internal cartilaginous layer of some thick- ness. The cartilaginous sclerotic is perforated for the entrance of the optic nerve and the blood vessels, the fibrous layer becoming continuous with the connective tissue surrounding the latter structures. The cartilaginous sclerotic ceases at some distance from the pupil, and the fibrous layer with another layer which seems to be a con- tinuation forwards of part of the choroid fuse with the skin of the head to form the cornea. In suitably prepared sections all these layers can be distinguished in the cornea, and the structure of the skin in that region does not differ materially from that in other parts of the head. The Argentea.—Internal to the sclerotic and in close contact with its internal surface is the peculiar layer so named. It covers the whole internal surface of the sclerotic as far forwards as the iris. It has a white silvery appearance by reflected light, but is opaque to trans- mitted light. No structure beyond wavy bundles of very fine fibres can be made out in it. The silvery appearance is said to be due to minute crystals imbedded in a cellular tissue. The Choroid.—This is the usual vascular and pig- mented layer. It lies between the argentea and the retina, is closely adherent to the latter, and comes away with it when removed. Anteriorly it passes into the iris. The Choroid Gland.—This structure is situated in the posterior wall of the bulb between the argentea and the choroid. It lies to the nasal side of the entrance of the a ee eS ee SEHA-FISHERIES LABORATORY. BT optic nerve, is elongated in the longitudinal axis of the body, and curves round the nerve so that its concave margin faces the temporal side of the eye. It is not a gland sensu stricto, but a rete mirabile. The ophthalmic artery on entering the bulb immediately breaks up into a number of short capillaries which run transversely to the long axis of the gland; at the lateral margin these turn backwards on themselves, and open into a very prominent vein which traverses the whole length of the gland. From this vein a very short transverse trunk pierces the sclerotic and forms outside the bulb the distal extremity of the superior jugular vein. We are unaware of any plausible hypothesis as to the function of this organ. The Retina presents no features of special interest. The radiation outwards of the fibres of the optic nerve towards its periphery is very striking. A prominent black line runs outwards from the place of entrance of the optic nerve to the temporal margin of the retina. This is the choroidal fissure, which here divides the retina, and by exposing the pigmented choroid beneath shews as a black line. The Processus Falciformis and Campanula Halleri.— A delicate fold of the choroid projects through the choroidal fissure into the vitreous humour. This is the processus falciformis. Its distal extremity is swollen out into a bilobed pear-shaped enlargement—the Campanula Halleri, which is attached to the lens. ‘These structures are said to form an accommodation apparatus. Accom- modation in the fish eye is effected not by an alteration in the curvature of the lens but by its approximation to the retina through the contraction of the muscular tissue in the above campanula and processus. ‘The elasticity of the suspensory ligament increases the distance between lens and retina. 328 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Discussion of the Asymmetry. We have now ascertained the facts which justify a fuller discussion of the causes and course of the asymmetry of the head. To satisfactorily understand the considera- tions which we put forward, the reader will find it essen- tial to follow our argument with dried crania both of a Plaice and Cod before him. We have already described the cranium in detail, but it will be useful to summarize those features relevant to the present discussion. | Note then that (a), the bony interorbital septum is formed by the right frontal alone, that it is a thin flattened bone lying in the morphological horizontal plane of the head, and that in front it is in contact with the ethmoid cartilage which is perforated by a wide fenestra; (B), that the left prefrontal has lost its primitive connection with the left frontal* but is still attached to the parasphenoid bar, while the right prefrontal, though still in contact with the right frontal has lost its connection with the parasphenoid bar, and is further distinctly anterior to the left bone ; (c) that all the oblique muscles take origin from the left prefrontal. Note now the differences between these relationships and those of the corresponding structures in the Cod’s skull. In the latter (4), the fused frontals form a broad root to the cranium, and internally and below two bony ridges form the bony portion of the interorbital septum, whilst the ethmoid cartilage is not perforated; (B), the right and left prefrontals are in contact with the frontals of their own side and with the parasphenoid bar; (c), the oblique muscles take origin from the upper portion of a strong membranous partition joining the frontal ridges * The present connection between the left frontal and left pen is purely secondary, as mentioned elsewhere. SEA-FISHERIES LABORATORY. 329 with the ethmoidal cartilage, and practically they arise from the lower portions of the median frontal ridges. Now if we suppose that the asymmetrical skull of the Plaice first began to appear in an ancestral form resembling the Cod, grave difficulties at once arise. For if a rotation from left to right of the orbital region of such a cranium took place, it is evident that although the left eye might ultimately look upwards, the right on the other hand must also move and would tend to become buried in the tissues of the head. Moreover it is probable that if a round fish such as the Cod adopted sedentary habits on the sea bottom, the flattening, if it occurred at all, would be a dorso-ventral one, as in the case of the skate. But if we assume that a laterally compressed fish (like Zeus, for instance) took to a bottom habit, and began to he on one side of its body, the changes necessary to bring about such asymmetry as we find in the Plaice would be much less violent. In such a form we may suppose that, following the lateral compression of the body, the eyes would-have moved to near the dorsal edge of the head, whilst the frontals would have become greatly compressed from side to side and probably elongated dorso-ventrally, like the right frontal of the Plaice. The eyes therefore being now close together near the dorsal median hne of the head, require to travel so much the lesser distance. Now when such a fish assumed a bottom living habit, lying on (say) the left side of its body, any variations in ~ the position of the left eye bringing it nearer the middle line than the right (7.e., nearer the upper side) would be of great advantage. This approximation to the middle line would be attained either by the attenuation of the left frontal or by a shifting of both frontals towards the right side. In the skull of the Plaice both these things have happened. 330 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. It is very remarkable that comparatively slight changes would have sufficed to bring about the distortion of the Plaice’s skull starting with such conditions and tendencies as we have indicated above. In the head of the Plaice the orbital region only has suffered extensive change. The otic region has undergone practically no change, and the prefrontal region certainly less than the orbital. The jaw apparatus is not affected at all by the torsion of the orbit, but has an asymmetry of its own (as described above), and this latter doubtless explains the asymmetry of the prefrontal region, which is of a different character to that of the orbital. We have, therefore, now to consider whether such relationships in the anatomy of the skull and eyes as obtain in the Plaice can be reason- ably expected to have followed from such a course of evolution as we have sketched above. There appear to us to be four difficulties requiring explanation. These are as follows :— (1.) The relations of the two prefrontals. As the right frontal bent over further to the right side, the right eye would be forced downwards. To make room for it the parasphenoid bar most probably bent over to the left to the position in which we now actually find it. The pre- frontal region lagged behind in this shifting, being unaffected except as regards the movements of the adja- cent parts (orbital region and jaw apparatus). If a Cod’s skull be examined it will be seen that the abortion of the left frontal would result in the separation of the left prefrontal from the remainder of the frontal area, and further that the greater rotation of the frontal over the prefrontal area would result ecther in the separation of the right prefrontal from the right frontal, or in its separation from the parasphenoid bar.. Now the latter having itself rotated to the left, we therefore find that in the Plaice SEA-FISHERIES LABORATORY. bol the right prefrontal retained its connection with the right frontal, but lost its connection with the parasphenoid bar. After the rotation of the orbital region the left. prefrontal grew backwards and the left frontal forwards, so as to form the secondary junction of these two bones already referred to. (2.) The downward shifting of the oblique eye muscles from practically the frontal to the parasphenoid bar. ‘This possibly began in the symmetrical but laterally flattened ancestor, as the frontals became attenuated from side to side and deepened dorso-ventrally. But it was continued in the asymmetrical fish. The object of the shifting of the eyes was to make dorsal vision possible with both eyes. In the Cod the origins of the oblique muscles are best adapted for lateral vision and for visual axes in approximately the same straight line. In the Plaice, however, the visual axes are directed dorsally, and to bring this about the oblique muscles had to shift ventrally so as to exercise a more effective pull over the eyes. ‘The origins of these muscles therefore moved down- wards towards the ventral region of the cranium and ultimately to the parasphenoid bar. (5.) The attachment of all the oblique muscles to the left prefrontal. We have already pointed out that the right prefrontal has lost its connection with the parasphenoid bar. This would doubtless have occurred in the earlier stages of the rotation of the eyes. When, therefore, in the final stages of the torsion, the oblique muscles in their downward passage over the interorbital septum arrived at the bar, the right prefrontal must have already left it. They thereupon continued their migra- tion on to the left side and became attached to the left prefrontal—the only convenient attachment remaining. (4.) The passage of the right oblique muscles through 332 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the ethmoid fenestra. Primitively these muscles did not pass through a fenestra. In the Cod’s cranium this does not exist, but there is a cartilaginous wall in front of the origin of the oblique muscles. In the migration ventrally of the origins of these muscles the latter passed behind _ and across to the left of the ethmoid cartilage to reach the left prefrontal. The former. then grew up behind and over the muscles, thus forming the fenestra. We have not studied the anatomy of the head in other Pleuronectids, and are unable to say whether the relations of the eye muscles above described are general. Cunningham (op. cit.) has described those relations in the sole, and it appears that they differ considerably from those we find in the Plaice. In the sole “the superior oblique of the ventral |right| eye arises from the small left [right is evidently meant] ectethmoid which is on the right edge of the interorbital septum; the inferior oblique arises from the external surface of the parasphenoid below the right ectethmoid. But both oblique muscles of the left or dorsal eye arise from the inner surface of the left ectethmoid.” Owing to this disposition the direction of the oblique muscles of the left eye is at right-angles to that of those of the right, and this difference has resulted from a rotation of the left ectethmoid. The asymmetry of the sole was produced according to Cunningham by the constant contraction of the oblique muscles of the left eye, so as to * turn the pupil into a horizontal direction and look along the edge of the head.” The eye thus pressed on the interorbital septum, and led ' to the absorption and distortion of the latter. At the same time the fulerum of this pull (the left ectethmoid) has itself undergone considerable rotation “so that the surface of attachment [of the oblique muscles] which originally looked outwards to the left came to look upwards.” SEA-FISHERIES LABORATORY. 330. In the absence of figures we find it difficult to follow Cunningham’s explanation, and we also find it difficult to believe that the same mechanical strain—that of the oblique muscles between the left ectethmoid and the left optic bulb—could have, at the same time, (1) rotated the bulb, (2) pressed on the interorbital septum so as to bend that over to the right, and (3) rotated the ectethmoid through a right angle. And we regard it as unjustifiable to: base such a mechanical explanation on the attachments of the muscles 7m an already asymmetrical skull. Tt is inconceivable that the oblique muscles were attached in the immediate symimetrical ancestor of the sole in the same way that they are now. In the Cod, for example, we find them arising symmetrically from the interorbital septum, and therefore any discussion of the possibility of those muscles producing distortion of the head should be based on the conditions present in an unmodified symmetrical cranium. But whatever the conditions are in the sole we find that in the Plaice Cunningham’s hypothesis is an impos- sible one. Unlike the sole, all the oblique muscles are attached to the left prefrontal (=Cunningham’s left ectethmoid), and the latter we regard as the least altered element in the orbitai or preorbital regions. That the surface to which the oblique muscles are attached now looks upwards we regard as more simply explained by supposing that the upper portion of the left prefrontal like most of the left frontal, with which it was most probably suturally attached, suffered abortion in the shifting of the left eye. And the shifting of the origins of the oblique muscles to it has been a result of, or has been concomi- tantly brought about by, the approximation of the eyes, and the increasing tendency to dorsal vision, 334 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 4.—Tne Har (Fig. 24). The auditory nerve is described with the other cranial nerves. As in Teleosts generally the ear is only externally enclosed by the ear ossicles. Hence it projects freely into the skull cavity internally, and is only separated from the brain by its own and the brain membranes. The utricular sac consists of a central chamber (utr., often divided into three portions, two of which constitute the utriculus sensu stricto and the third the posterior utricular sinus), and a wide ventral chamber or superior utricular sinus or canal commissure (uwtr.'). These, how- ever, may conveniently be called the central and vertical chambers of the utriculus. From the anterior end of the central chamber connections are effected with the ampullze of the anterior and external semicircular canals, at the posterior end with the ampulla of the posterior semi- circular canal and the other extremity of the external canal. The vertical chamber rises up almost at right- angles from about the centre of the central chamber, and receives above the upper extremities of the anterior and posterior semicircular canals. There is only one sense organ in the utriculus, the macula acustica recessus utriculi (m. r. w.), situated in a slight depression of the central chamber in front (Recessus utriculi). The three semicircular canals are disposed as follows :— Canalis anterior (a. s. c.).—Just above its connection with the central chamber of the utriculus it swells into a large ampulla anterior (amp. a.), the outer wall of which bears a transversely extending sense organ and ridge, the crista acustica ampulle anterioris (ant. er.). Above, the canal passes upwards and backwards into the vertical utricular chamber. Se eS a a a ee SEA-FISHERIES LABORATORY. DOD Canalis externus (ec. s. c¢.).—Sometimes called the horizontal semicircular canal to distinguish it from the other two vertical canals. Swells into the ampulla externa (amp. e.) immediately behind its connection with the utriculus in front, The crista acustica ampulle externe (eat. cr.) is situated on the floor of the ampulla behind, but in front it ascends upwards and outwards, so as to invade its external wall. The canal passes hori- zontally downwards and backwards, external to the rest of the ear, to communicate with the utriculus behind. Canalis posterior (p. s. ¢.).—The large ampulla pos- terior (amp. p.) occupies a similar position to that of the anterior canal. Its outer wall contains a transverse sense organ and ridge, the crista acustica ampulle posterioris (post. cr.). Above, the canal passes upwards and forwards into the vertical utricular chamber. The Sacculus (sac.) appears at first to be an absolutely closed bag in the Plaice, closely opposed to the utriculus below, but having no. connection with it. Irom its inner wall it sends upwards, however, a blind finger shaped process which must represent a vestigial ductus endo- lymphaticus (d. end.). There is no saccus endolymphati- cus. Into the base of the ductus there open two very minute capillary tubes (see figure), and as each arises from, and communicates with, the utriculus, they must together represent the canalis utriculo-saccularis. There is thus only a very slight communication between the sacculus and utriculus, and this of a very curious nature. The sacculus contains the large hard saccular otolith deposited in concentric lamine (oto.), and often called the otolith.* There is, however, a small but quite conspicuous * See Reibisch, Wiss. Meeresuntersuch, Abth. Kiel, N.I’., Bd. iv., p. 233 for an interesting discussion of the relation of the otolith to the age of the fish. Reibisch finds that it is possible to deduce the age of a Plaice from the conformations of the otolith. 333 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. otolith in connection with the macula acustica recessus utriculi, and another with the papilla acustica lagene, but none were observed in relation to the three cristz acustice, although it is possible that small concretions of chalk were there also. ‘There is a very large sense organ on the inner wall of the sacculus in front, known as the macula acustica sacculi (m. a. s.), and behind, the sacculus is pro- longed upwards and backwards into the digitiform lagena (/ag.), otherwise known as the recessus sacculi or cochlea, the inner wall of which, at about the roof, contains another sense organ, the papilla acustica lagene (p. a. 1.). soil constriction or definite sacculo-cochlear canal is not differentiated. The sense organ on the floor of the utriculus known as the macula acustica neglecta is entirely wanting in the Plaice. The ear and auditory nerve of Pleuronectes flesus have been described by G. Retzius,t who, with other authors, refers to the utricular, saccular and lagenar otoliths respectively as the lapillus, sagitta, and asteriscus. His description agrees very closely with ours of the Plaice, so that it is only necessary to poimt out that he did not succeed in finding either a reduced ductus endolymphati- cus or a utriculo-saccular connection. With regard to the latter he says:—‘ An der unteren Wand des Utriculus, ungefahr gerade unter dem Sinus superior, findet sich eine kleine, trichterférmige, hohle Verlangerung des Utriculus, welche nach hinten geht und sich zu einer feinen Diite verschmilernd an die Wand des Utriculus legt; ob aber dieser Canal blind endigt, was ich am meisten glaube, oder ob er vielleicht in den Sacculus (als ein Canalis communicans) ausmiindet, kann ich nicht mit Bestimmt- heit angeben.”’ + Anat. Unters., 1872, p. 52, Taf. v., figs. 10O—18. SEA-FISHERIES LABORATORY. oan G.—THE REPRODUCTIVE ORGANS. Some difficulty will be experienced in determining the anatomy of the reproductive organs, on account of the fact that sexual maturity does not occur until the Plaice has grown to a relatively large size, and that to examine the varying relations of the system in a really satisfactory manner fishes in various phases of reproductive activity must be examined. The ordinary marketable Plaice is as a general rule an immature fish. There is some consider- able difference in the size and age at which it becomes sexually mature in different localities, but it will be suffi- cient for our present purpose to say that under 17 inches of total body length in the female, and 14 inches in the male, the reproductive organs are generally immature. Only fishes of those sizes should therefore be dissected for these organs, and they are best examined some little time prior to the spawning season, that is daring November to January. We may here define several terms used in the follow- ing pages. The Plaice is spoken of as “ mature’ when it first begins to produce eggs capable of fertilization, or, in the male, functional spermatozoa. It is “ripe’’ when the ovary becomes distended with mature ova, that is imme- diately before the spawning season. It is “spent” or “shotten’’ when all the ova have been extruded in the act of spawning. ‘The same terms with the same signifi- cance are applied to the various phases of the male in respect to the conditions of the testes. Considerable differences in the condition of the repro- ductive organs may then be expected in Plaice of different sizes or of mature fishes captured at different times in the year. In the female fish of about 14 inches long ovaries and ovarian eggs are certainly developed, but the organs are represented by very minute structures situated in the AA 338 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. posterior wall of the body cavity. At this age, and for some considerable time afterwards, it is quite impossible to distinguish between male and female gonads without a microscopical examination. The growth of ovaries or testes is extremely slow during the first two years of life, that is up to 6-8 inches long. After this age the ovary can be readily distinguished from the testis. It is a paired conical shaped structure. The base just projects into the posterior part of the body cavity; the apex pro- jects backwards towards the tail, lying between the haemal spines and the muscles of the trunk. The oviducts are extremely difficult to dissect and do not open exter- nally. In the follawing year the organ rapidly develops. In male Plaice of the same size the testes are paired ridges of the posterior body wall projecting forwards into the body cavity, but having no extension backwards as in the case of the ovaries. | The Female organs. —Fig. 20 represents the condition of the ovary in a mature and nearly ripe Plaice. The specimen figured was captured in December. ‘The ovary is seen to project far forward into the body cavity, dis- placing various organs from their normal positions. Part of the posterior extension of the organ is indicated in the figure ; it really extends backwards to near the root of the tail. Its posterior portion lies along the external surface of the haemal spines. and is only separated from these by loose areolar tissue. ‘The overlying muscles of the trunk are very thin, and occasionally the ovary appears to be covered only by integument and connective tissue. In this condition it can be felt externally as a hard pad lying on either side of the ventral portion of the body behind the anus. The ovary of the ocular side appears to be, sometimes at least, more strongly developed than that of the eyeless side.. SEA-FISHERIES LABORATORY. 339 On spawning a very marked change takes place. Fig. 21 represents the condition of a mature and spent female. The ovary is seen to be considerably retracted, and is only just visible on opening the body cavity. Its walls are soft and flaccid, and enclose a large cavity. The posterior extension still exists, and is indeed not much shorter than in the ripe specimen. The condition of the fish is indicated externally by a shallow groove running backwards on either side in the position formerly occupied by the pad spoken of above. The flesh is lean, and the fish is generally regarded as in poor condition as a food. It appears* that after spawning the ovary never reverts to its former immature condition. That is, it is always possible to distinguish between a spent mature, and an immature fish. Similar contrasts are exhibited by the various phases of the testes, but on account of the relatively small volume of these organs the changes are not so striking and afford no external indications. The ovary of the Plaice, like that of the majority of Teleostean fishes is a sac the wall of which is continuous with that of the oviduct. ‘This is the cystoarian condition, and for an understanding of the morphology of such an ovary the other common type met with among Teleostei, the elasmoarian ovary, must be studied.t The internal wall of the cystoarian ovary corresponds to the external face of the peritoneal lamella which forms the elasmoarian organ, and to the outer visible surface of the ovary of an Elasmobranch fish—the surface from which the ova dehisce into the general body cavity. There can be no doubt from the work of Balfour and Parker{ on Lepi- dosteus, that the cavity of the cystoarian ovary into which * See Holt, Journ. Mar. Biol. Ass., vol. ii., p. 363. + See Howes—Hermaphrodite genitalia of the codfish. Jour. Linn. Soc., London, vol. xxiii., 1891, pp. 539-557. { Structure and development of Lepidostews, Phil, Trans., vol. clxxiii., Part 2, 1882. 340 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the ova dehisce is a closed portion of the celom. The cavity of the oviduct is also a portion of the celom. It does not appear to be a Miillerian duct like the oviduct of all other vertebrata, and its morphology is exceedingly obscure. It has no homologue among the genital struc- tures of the male fish. The external opening of the oviduct (Od., fig. 20, pl. V.) lies just within the lip of the anus on the posterior side of the latter. It may appear to be out- side the anus on the ventral body wall, and its variable situation is due to the extent to which the terminal por- tion of the rectum is contracted. In the immature fish the opening does not apparently exist, and even in the mature but unripe individual we have been unable to satisfy ourselves of its existence. If in a ripe female Plaice the body over the region of the ovaries be gently pressed, the mature eggs issue in a thick stream, and the opening can then be easily seen as a transverse slit behind the anus. After extrusion of all the eggs this slit seems to close up by the adhesion of its edges, and in dissecting such a spent specimen, though the terminal part of the oviduct can be traced to just behind the anus, some little pressure with a blunt seeker is required to force a passage. In the nearly ripe fish which has not yet spawned even a moderate pressure on the abdomen may not cause the extrusion of any eggs, though dissection may shew that mature ova are present in considerable number lying loose in the cavity of the ovary. The more nearly ripe the fish is, the more easily are the eggs expelled, until in some cases merely lifting it from the water in which it is lymg may cause the eggs to run from it. There is generally no bleeding from the edges of the forced opening in a nearly ripe fish, and sections of the region of the body wall behind the anus shew that it is formed almost entirely of dense fibrous connective tissue without many blood SEA-FISHERIES LABORATORY. 341 vessels. It appears to be the case that the efferent portion of the oviduct opens before each spawning, and closes again - by adhesion of its walls when the act of spawning is over. The external oviducal opening leads into a short chamber (Od.') into which both right and left ovaries open. Od." is the cavity of the right organ. The septum in the figure is the fused internal walls of both ovaries. All this terminal chamber in the ripe fish is filled up with ova which have dehisced from the ovigerous lamella. On the internal walls of the ovary are the ovigerous lamelle, longitudinal folds of the wall in which the ova are developed. ‘Text-fig. 3 represents part of a transverse section of the ovarian wall in a spent fish and shews a single ovigerous lamella. In this condition the wall is thick. Externally there is a loose connective tissue layer, and in the thickness of this a thin sheet of black pigment. Internal to this layer is an investment of unstriated muscle fibres of some thickness in the spent ovary, but very thin in the ripe condition. Within this, and filling up the thickness of the lamella, is a somewhat dense con- nective tissue stroma. The surface of the lamella is formed by an epithelium which in places has a rather _obseure structure, but here and there contains patches of small rounded cells, obviously a germinal epithelium. From this the ova proliferate into the thickness of the lamella, and come to lie freely in the stroma, at first near the surface of the former. Many such ova of different sizes are represented in the section. ‘he largest have a distinct zona radiata, the nucleus is large with a distinct nuclear membrane and with diffused chromatin. An obvious ring of large spherical nucleoli is seen in contact with the nuclear membrane. Often the nucleus is con- tracted away from the membrane, leaving a clear space. The Male organs.— The testes are undivided flattened 342. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. masses lying one on each side of the Ist axonost on the posterior wall of the body cavity. They are indistinctly lobulated, but not follicular as in the Cod and so many other Teleosts. They are much smaller than the ovaries in the female and project forwards only a little way into the body cavity. There is no posterior extension beyond the limits of the latter at any phase in the spawning cycle. They are tubular glands, but the walls of the seminiferous tubules are closely opposed and there is little or no con- nective tissue between them. The whole organ appears therefore as if divided up by a system of irregular trabeculz in the meshes of which are massed the sperma- tozoa. Towards the ventral and anterior extremity of the testes the volume of the organ rapidly diminishes, and if traced in serial sections the number of tubules becomes much less. Finally three or four such run forwards on each side laterally and dorsally to the terminal portion of the ureter. These unite, and a single duct on each side runs alongside the latter and opens into its terminal portion quite near the urinary papilla. The terminal portion of the ureter is therefore a urinogenital sinus. If the abdomen of a male fish when near the spawning season be gently pressed, the seminal fluid issues from this papilla. In the female it is a urinary papilla only, in the male a urinogenital papilla. SEA-FISHERIES LABORATORY. 343 APPENDIX—ECONOMIC. A.—Lirr-History anp Hastts. Spawning.—About the beginning of the year the reproductive organs of mature Plaice become ripe and spawning commences. Spawning—that is the complete extrusion of the contained ripe ova and spermatozoa, lasts over a considerable period on any one fishing ground. This is due to the fact that it requires some time for any one fish to extrude all its ova, and also to the considerable variation in the time of ripening of the reproductive organs among all the mature fish present on the spawning ‘ eround. ‘The duration of this “‘ spawning season ”’ varies in the seas round the British Islands. In the Danish seas it begins in November, attains a maximum in January and February, and ends in April. In the North Sea on the Scottish side it lasts from the middle of January till the end of May, with the maximum at the beginning of March. In Loch Fyne in the Firth of Clyde in 1898 no Plaice eggs were found till the middle of February and . none aiter June; the maximum number was found in April. In the Irish Sea the exact limits of the season have not been determined, but certainly it begins later than in the North Sea. The maximum period as deter- mined by the abundance of ripe female fish is at the end of March. From one quarter to half a millon eggs are extruded by a single female Plaice during its spawning season, the average number on the various fishing grounds being about 300,000. This number of eggs is small when com- pared with that of many other flat and round fishes. Generally the larger the fish the greater the number of eggs yielded. It is evident that during the spawning 344 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. — season an immense number of egg’s must be present in the seas round the spawning grounds, and this has been approximately determined in various places. In a series of remarkable researches on the quantitative estimation of planktonic organisms Hensen* has made an approximate determination of the floating fish eggs in various seas. In the North Sea in 1895 he found during three voyages an average number of 56°8209 Plaice eggs per square metre of the track of the vessel. From the known area of the North Sea (647,623 millions of square metres) Hensen determined the total number of Plaice eggs in that area to be 31°117 billions. It is evident that this number can only be approximately accurate, but there are reasons for believing that it really underestimates the total quantity. In much the same way, Williamsont determined the total quantity of Plaice eggs present in Loch Fyne during the first eight months of 1898, and found a total number of 483 millions to be present in the loch during that time. The Egg is one of the largest of those belonging to Pleuronectid fishes, and is on that account easily recog- nised in plankton collections. Its transverse diameter varies from 1°63 to 2.11 mm. It is enclosed in a fairly tough capsule, the outer surface of which is finely corrugated ; at one place, beneath which the germinal disc forms, there is a minute opening in the capsule—the micropyle. ‘There is no oil globule, and the contents of the egg are of a glassy transparency and apparently homogeneous. A small perivitelline space is present between the yolk mass and the capsule. Before ripening the ovary of the Plaice contains only opaque eggs considerably smaller than those extruded * Hensen u. Apstein—Wiss. Meeresuntersuch., Kiel Commission, Bd. 2 — (NB) Elett'2,. pi FL, 1897. + 17th An. Report Scottish Fish. Bd., p. 79, 1898. SEA-FISHERIES LABORATORY. 345 after ripening. In the final stage of maturation before spawning occurs these small opaque eggs acquire the characters of the ripe pelagic egg.* The nucleus breaks down and the chromatic matter becomes rearranged, and at the same time fluid of a low specific gravity, secreted by the follicular epithelium enters. As a result of this 1m- bibition of fluid the yolk becomes altered in such a way as to become nearly perfectly transparent. At the same time the egg becomes larger and its specific gravity becomes less. The immature ovarian egg has a mean diameter of 1°2lmm. and a mean volume of 0°9276 cub. mm. It is heavier than sea water. The mature egg has a mean diameter of 1‘88mm. and a mean volume of 3°479 cub. mm. It is very slightly lighter than normal sea water. The change in specific gravity during maturation is from about 1'07 in the immature to about 1°025 in the mature egg. Changes of this nature are general in the maturation of nearly all Teleostean food fishes, and as a result the eggs are pelagic—that is they float freely near the surface of the sea when extruded. In the eggs belong- ing to the other type—the demersal egg, of which the egg of the herring is the most familiar example—the specific gravity is greater than that of normal sea-water. As a result of this the eggs undergo their development lying on the sea bottom. | The Plaice takes about two weeks to extrude the whole contents of its ovary. Obviously in the limited space at the disposal of that organ ripening of all the eggs present would be impossible without injury to the fish. Spawning is therefore intermittent during the season of the fish, only comparatively few eggs being dis- charged at one time. As the latter mature they dehisce from the walls of the ovigerous lamelle and accumulate * Fulton—16th An. Report Scottish Fish. Bd., Pt. iii., p. 88, 1897. 346 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. in the cavities of ovaries and oviducts, and are expelled at intervals until the whole organs are exhausted. The fish is then said to be “ spent.” Fertilization takes place in the surrounding sea water into which the eggs are extruded. During the spawning season males and females are crowded together on the spawning grounds, and the spermatozoa of the former are shed simultaneously with the eggs. It is impossible to say what proportion of the eggs extruded escape fertiliza- tion. Probably it is very small, since unfertilized eggs are not often seen in plankton collections. Fertilized and unfertilized eggs would both rise towards the surface, but in the course of a few days the unfertilized egg becomes opaque, heavier, and finally sinks to the bottom and decomposes. Embryonic Development.—The period occupied by embryonic development varies with the temperature of the water in which the eggs are contained. The lower the temperature the longer is the period between fertilization and hatching. H. Dannevig* found that at 5°2°C. 21 days were required; at 6°, 184 days; at 10° 12 days; and at 12° 103 days. Among Pleuronectide there is a general correspondence between the size of the egg and the developmental period. Thus the Flounder (Pl. flesus) with an egg of 0°95mm. in diameter hatches out in 43 days at 10°C. At the same temperature the Sole (Solea vulgarts), which has an egg of 14mm. in diameter, re- quires 10, and the Plaice, with an egg of 1'8mm., 12 days. The changes in the ovum immediately succeeding fertilization have not been closely studied by any author. The spermatozoon enters the egg through the micropyle; at this time segregation of the protoplasm takes place, and the latter which had previously been diffused round *13th An. Report Scottish Fish. Bd., Pt. iii., p. 147, 1894. SEA-FISHERIES LABORATORY. 347 the periphery of the yolk mass now collects into a lenticu- lar mass—the germinal disc. When the egg is floating freely, the germinal disc lies downwards, the yolk being uppermost. This lower part of the egg has been termed a9 the “animal pole,” the upper part the “ vegetative pole.” A few hours after fertilization meroblastic segmentation begins, by the formation of a single vertical furrow which divides the germinal disc into two blastomeres. ‘This is followed soon by a second furrow transverse to the first and four equal blastomeres are formed. Up to the 8-celled stage at least there are no horizontal segmentation planes. After this stage both vertical and horizontal division planes occur and the germinal disc segments with increas- ing irregularity until it becomes a many-layered mass of small cells. The blastoderm is thus formed. The rim of the blastoderm now begins to grow out- wards and to envelop the yolk mass by a process of epibolic gastrulation. Towards the end of the 2nd dayt it has extended over the yolk so as to cover about 70° of the latter when seen in optical section. The growing margin of the blastoderm is slightly thickened. The space enclosed within this blastodermic ring where the yolk mass comes to the surface is the blastopore, and with the growth of the blastoderm past the equator of the ovum its area continually diminishes. At first it is circular in form and then becomes oval. After 6-7 days from fer- tilization it disappears entirely. The embryo begins to be raised off on the 3rd day after fertilization. It lies in such a position that the extremity which becomes the posterior one is situated against the edge of the blastopore. On the 4th day it has lengthened out considerably. The notochord and neural + Development is supposed to be effected at a temperature of about a. 348 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. axis are laid down, and the main divisions of the brain are visible. The optic vesicles are formed but are not yet invaginated, and no mesoblastic somites are as yet discern- ible. The tail projects as a slight swelling into the blastoporic area. Underneath the tail a small vesicle has appeared, which increases in size with the waning of the blastopore. This is Kupffer’s vesicle (fig. 32), a structure characteristic of the Teleostean embryo. It hes immedi- ately beneath the posterior extremity of the notochord, and in close relation to a slight depression under the thickened blastodermic rim beneath the tail protuberance —the “prostoma.” Its cavity is bounded by a regular layer of hypoblastic cells, or its dorsal wall is so formed, and its ventral wall is formed by the yolk. In some Teleosts it communicates with the exterior by a narrow opening. It is the invagination cavity of the (masked) Teleostean gastrula, and represents the archenteron. But from its large size and persistence it is probably a func- tional larval organ, and Sumner* has suggested that it subserves the nutrition of the embryo by aiding in the absorption of the yolk. On the 5th day constriction of the optic vesicles from the mid-brain is complete, and on the 6th they are invaginated and the lenses are formed so as to lie in the openings of the optic cups. About 18 pairs of somites are now present. The trunk has elongated considerably and the head and tail are now constricted off from the yolk mass; 8 days after fertilization the auditory vesicles are present, the heart is formed and is beating, and the vitelline circulation is being laid down. ‘The tail has increased considerably in length and about 30 somites are present. On the 11th day rudiments of the pectoral fin folds are present. * Mem. New York Acad., vol. 11, 1900, pp. 47-83. ' SEA-FISHERIES LABORATORY. 349 Pigmentation of the embryo begins on the 9th day by the formation of a row of yellow branching chromato- phores on either side of the body; on succeeding days these become very abundant and extend on to the head and cover uniformly the trunk and tail. Black pigment appears on the 13th day as a row of round chromatophores on each side of the body. Later on these become abun- dant and of a branching form. On the 14th day the eye becomes pigmented, and has a greenish-golden sheen. The little fish hatches out from the egg on the 17th day. It (fig. 35) is about 6°5mm. in total length—a rela- tively large size among newly hatched Pleuronectids. The yolk sac is very large. A continuous broad fin runs along dorsal and ventral margins of the body. and round the tail. The notochord is straight at the tip, and only rudiments of the pectoral fins are present. It is covered (except the yolk sac) with bright canary-yellow chromatophores, and branching black chromatophores are situated along either side of the body. ‘The eyes are greenish-gold in colour. The mouth is open; the gut is a nearly straight tube slightly dilated at one part and terminating in the anus at the posterior margin of the yolk sac. The csophagus is open, but has an exceedingly contracted lumen, and there is an extensive yolk sac circulation. A pronephros as described above also exists. The urocyst is in connec- tion with the hind gut, and does not open directly to the exterior. The young fish is still perfectly symmetrical. The larval period and metamorphosis.—The larval period lasts from the time of hatching until the definitive form and asymmetry of the adult has been acquired; that is till about 6 weeks from hatching. For the first week _ there is little change in the larva except that during that time the yolk is being gradually absorbed, and at the end of 8 days the yolk sac has disappeared. ‘he larva now 350 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. begins to feed. It is probable that it feeds before the yolk has been entirely absorbed. The food is necessarily small, consisting of diatoms and larval molluses. It grows very slowly, and at the age of 25 days from hatching is only about 78mm. in total length and about 1°6mm. in height. After this the increase in height is relatively greater than that in length. Larval crustacea now form the principal food. ‘The tail, which has hitherto preserved its embryonic homocercal character, now bends upwards at the tip, and ventral to this upturned portion fin rays begin to be formed (fig. 36). Up to 30 days after hatching the larva has retained its bilateral symmetry, and at this stage is precisely similar in form to the ordinary symmetrical Teleostean larva. The greater relative growth dorso-ventrally than longitudinally indicates the beginning of the metamor- phosis, and after the 30th day the left eye begins to move dorsally and anteriorly. 40 days after hatching it appears on the dorsal margin of the head just anterior to the right eye. On the 45th day the left eye has attained its defini- tive position on the apparent right side dorsal and anterior to the right eye. The larva is about 134mm. long and 63mm. high. During the period in which the eyes are rotating the young fish gradually acquires a new position in swimming; the vertical plane of its body slopes more and more from right to left as the eyes shift round so that in swimming the plane passing through both eyes is always horizontal. At the completion of metamorphosis the whole symmetry of the head has been profoundly dis- turbed, though that of the body remains as before, except that the opening of the ureter has shifted from the median ventral line to the right side. The horizontal swimming plane of the whole body has been rotated through a right- angle and the fish rests and swims on its morphological SEA-FISHERIES LABORATORY. 351 left side. The pigmentation now gradually disappears from the lower side. The larve now feed almost entirely on Copepoda, with which their stomachs are usually crowded; larval Molluses and larval Crustacea are also eaten. After the metamorphosis the food is changed, and the small fishes, 14 to 4 inches, feed largely on various Annelids such as Nerers and Pectinarza, on small Crustacea such as Mysis, and various Amphipods and small Crangons. Later on the fish adopts its definitive food, which is mostly Mol- lusea, the favourite forms being Cardwum, Tellina, Mactra, Scrobicularia, Donaxz and Mytilus. The character of the food changes little during the rest of its life. ~ Rate of growth.—A variable time is taken up by the changes above described, which were observed in larvee kept in aquaria. For instance, although the Plaice in the Danish seas may spawn as early as November, no larvee of 12mm. length are taken there till May. They therefore require six months to pass through the meta- morphosis. Two methods have been adopted for esti- mating the rate of growth subsequent to the larval period. The most obvious one is to keep a large number of young fish in captivity in aquaria, and to observe for as long a period as may be possible the changes in body length. This method is evidently open to the grave objection that the fishes live under artificial conditions, and these may influence their rate of growth. The other method is to fish often in water's which contain great numbers of’ Plaice of different sizes, and to deduce the growth rate from the erouping of the individuals of different lengths. When this is done and the results of measurement of all the fishes captured are tabulated, it is seen that those captured at any one time may be arranged into several groups in each of which the greater number are grouped round cer- $52 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. tain typical lengths, and if such experiments are kept up for some time an approximation to the rate of growth may be arrived at. Such experiments have been carried out both in this country and in Denmark. Dannevig* found that on the East Coast of Scotland the Plaice grows about three inches in the year. The average size at the end of the first year is 77°2mm., at the end of the second 156°7, and at the end of the third year 233'lmm. The experiments also show that it is during the warmer part of the year— May to October—that growth takes place. During the winter it is practically arrested. The period following the metamorphosis of the fish till the third or fourth year may be called the immature stage. It is characterised by the undeveloped condition of the reproductive organs, and by the gradual, outward migration of the fish towards deep water. The ovaries remain small and contain only small transparent ova. At a variable size and age sexual maturity is indicated by the gradual enlargement of the ovaries and testes and by the occurrence in the former of eggs containing yolk. After the first sexual maturity occurs the ovaries never revert to their condition prior to maturity, and it is always possible to distinguish a fish which has previously spawned. Sexual maturity.—The size at which first-sexual maturity occurs is variable within somewhat wide limits in the seas round the British Isles, and as a knowledge of this size is of considerable importance as a basis for fisheries legislation, great pains have been taken to esti- mate it for various localities. It may vary within very wide limits—thus in Danish waters spawning female Plaice of 7” in length have been exceptionally taken, * On the rate of growth of the Plaice. 17th An. Rep. Scottish Fish. Bd., p. 232, 1898. SEA-FISHERIES LABORATORY. Oe while in the North Sea immature female fish of 17” have been observed. In the male sexual maturity is first attained at a lesser size than in the female; in Danish waters ripe males 7 inches long, and in the North Sea 9 inches occur. The most convenient size* for purposes of legislation is that lowest size at which as many Plaice are mature as immature. This is the average size of first maturity, and it is of course lower in the male than in the female. In the northern part of the North Sea the female reaches maturity for the first time on the average at 154 inches, and the male at 124 inches. In the southern part of the North Sea these sizes are 154 inches for the female and 104 for the male. In the English Channel Cunning- ham found that nearly all Plaice were mature at 15 inches, and in the North Sea Holt found that at 17 inches nearly all the fish observed were mature. In the Danish seas much lower sizes than these have been estimated by Petersen.t Thus the average sizes at which Plaice first become mature are 10 inches in the Baltic, 11 inches in the Lesser Belt and 12-13 inches in the Kattegat. In the Irish Sea the smallest mature female observed was 13 inches in length, and the largest immature female 19 inches. The smallest mature male obtained was 10} inches long, and the largest immature male 15 inches. Sufficient fish have not been examined in this district to enable satisfactory average sizes for the first maturity to be established. It is probable that the Plaice spawns every year after sexual maturity is attained, but there is no certain evidence on this point, nor is it known what are the yearly increments of growth after the third year of life. In the * See Kyle, 18th An. Rep. Scottish Fish. Bd., Pt. iii., p. 189, 1900, for a discussion of this subject. + 4th Report of the Danish Biol. Station, 1894, p. 3. BB 354 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. largest fish obtained the reproductive organs are still func- tional. The maximum size for the North Sea seems to be 28 inches, for the Danish seas it is smaller, about 224 inches. When the Iceland Plaice fisheries were first exploited, very large specimens—over 30 inches in some cases—were obtained. Migration and distribution.— Wherever the distribu- tion in space of the Plaice has been attentively studied it has been found that a very well marked segregation in respect of the size of the fish exists. There is a close correspondence between the size of the fish and the depth of the water at the bottom of which it is found. The size increases with the depth. The fish does not exist outside the hundred fathom line, and indeed practically all the fishing is carried on in seas varying from 20 to 50 fathoms in depth. Since only the larger individuals are functionally reproductive, it follows that the Plaice spawns only in deep water, and it is the case that the spawning grounds are always situated at some distance from the shore. These spawning grounds are usually very definitely located in any district. Thus on the Hast coast of Scot- land such areas occur in the North about 16 miles seaward from Moray Firth, and further South off St. Andrews Bay and the Firth of Forth. In the Danish seas the fish only :pawns in the more open waters, such as in the eastern parts of the Kattegat, in the Belts and in the Baltic. In the Irish Sea the positions of some such spawning grounds have also been determined, and one notable area lies Kast from the South end of the Isle of Man in a depression having an average depth of about 23 fathoms and sur- rounded by water of 16-20 fathoms in depth. The bottom consists of soft bluish-black mud with an abundant fauna. Scrobicularia and Turritella are very abundant, and the SEA-FISHERIES LABORATORY. ODD Pennatulid Virgularia is also common and forms a con- stant food of various Gadide. Many edible fishes spawn here, Pleuronectids like the Plaice, Flounder and Dab, and Gadoids such as the Cod, Haddock and Whiting. During the spawning season ripe fish may always be taken by trawling on the ground, and pelagic eggs in various stages of development are found in plankton gatherings made at the surface. Another spawning ground exists further North, due Hast of the North end of the Isle of Man. On the West side of the Isle of Man are grounds due West of Dalby where other Pleuronectids, and probably the Plaice also, spawn, and it is very probable, though systematic surveys have not yet been made, that similar spawning areas he further South out from the © Lancashire and Welsh coasts. As we have already stated the Plaice emits its spawn at the bottom of the sea and the eggs rise towards the surface. Here their inshore migration begins. The developing embryo while still within the egg capsule has of course no power of movement of its own, and even after it has hatched and is a pelagic organism its powers of migration are extremely limited, so that its present move- ments are determined entirely by the combined operation of physical agents, waves, prevailing winds, tidal drift and currents, and from a consideration of the working of these factors the general course of the eggs and embryos from the spawning grounds can be determined. The general drift of small objects floating at or near the surface of the sea has been studied in the Irish Sea by observing the movements of weighted bottles designed to drift partially or wholly submerged. ‘I'wo such series of experiments have been made,* and their results shew that the combined operation of the various agents indicated *TLancashire Sea Fish. Laby. Reports, 1895, p. 12, and 1898, p. 30. 356 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. above is to carry small floating objects in an easterly and northerly direction. Thus eggs and embryos floating at the surface on the spawning ground to the South-east of the Isle of Man will travel easterly with a slight drift to the North to Morecambe Bay, the estuary of the Duddon and to the Cumberland coast. It is also evident that the young fish inhabiting the shallow waters further South, that is in the Ribble and in Liverpool Bay and the Che- shire coasts, must have originated elsewhere than in the spawning grounds referred to. Mr. R. L. Ascroft informs us that from his experience of the drift of floating wreckage it is probable that fish spawning far South in Cardigan Bay and off the Welsh coast generally produce the young fish in the southern and central portions of the Lancashire coast. Up to the present time the spawning areas off the Welsh coast have not been investigated. _ This first pelagic stage of the young Plaice is the period during which both embryonic development and larval metamorphosis take place. Up to the time when the rotation of the eyes is fairly in progress the young fish swims freely in the upper layers of the sea, and during that change it gradually sinks until, when metamorphosis is completed, it finally settles on the bottom. It is gene- rally agreed that the young Plaice during this change cannot, or at least does not, inhabit the sea at any great depth. It is probable therefore that should the larve begin to sink while still in deep water their destruction follows, and it seems essential that they should have nearly completed their larval changes not earlier than the time when they arrive at the shallow coastal waters. About 30 days after hatching the larve seek the bottom and this gives a period of over 40 days for them to complete their inshore drift from the spawning grounds. During this drift inshore the embryos and larve are SEA-FISHERIES LABORATORY. 357 naturally exposed to many dangers. ‘They are probably eaten by many pelagic animals, though there is not much published evidence on this point. In Loch Fyne, how- ever, the floating fish eggs are closely associated with great numbers of Copepoda, and this results in the eggs being eaten by the herring in the search of the latter after Cope- poda and other pelagic Crustacea, and pelagic fish eggs have been found in the stomach of that fish. It is possible, however, that physical events are at least as fruitful causes of the destruction of floating eggs and larvee as predaceous pelagic animals. The change from the pelagic to the demersal mode of living, for instance, happening when the larva is still in deep water. Remarkable conditions are present in the Baltic. Petersen* has shown that young Plaice (up to 2-3 inches in length) are entirely absent in that sea, though spawning fish are abundant, and, as Hensen has shown, fertilized eggs are there in enormous abundance. ‘The low specific gravity of the water affords the explanation. Ata specific gravity of 1°0140 (at 9°C.) a great number of Plaice eggs sink to the bottom, and at a specific gravity of 1:0120 (at 10°C.) all sink. The lowest specific gravity at which the eggs can drift about without any sinking is 1°0152 (at 9°8°), and if in their migration _ they enter water of less than this density their destruction follows. Now it happens according to Hensen that about once every month there occurs such a low specific gravity of the Baltic water that all the Plaice eggs sink. There is of course a possibility that the eggs may go on developing at the bottom, but this is unlikely. It is possible too that a low salinity of the water may prejudicially affect the processes of development, but this subject has not been adequately investigated. It is possible also that Plaice eges entering the estuaries on the Lancashire coast may * Rep. Danish Biological Station, 1V., 1894, p. 27. 358 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. be destroyed in this way, but the variation in the salinity of those waters has not been thoroughly investigated. Wherever spawning grounds may be located in the Trish Sea, it is hardly likely that a longer period than 40-45 days can elapse before the larva finds itself in suitable conditions on shallow sandy shores. The young Plaice now enters on its life in the ‘nursery ’ ground. Practically the whole of the Lanca- shire and Cheshire coast consists of ground of this charac- ter—flat, sandy shores with shallow water overlying. There are, however, several localities to which in par- ticular the term is applied; there is the whole of the shallow water round the mouth of the Mersey, the whole estuary of the Ribble; the ground out from Blackpool known as the Blackpool closed ground, the whole of Morecambe Bay and the estuary of the Duddon at the boundary of Lancashire and Cumberland. On all these ‘grounds vast quantities of young and immature Plaice up to fish of 2-3 years old are found. Very young Plaice and other Pleuronectids appear on these shores during June every year. ‘hey have as a rule completed their meta- morphosis, though a few may generally be got with the eyes in the course of rotation. ‘They are generally about + inch and less in length, but have assumed the perfect form of the adult (fig. 37). They may be found in great numbers in the shallow sandy pools left by the receding tide, where very many are stranded and perish. By the autumn these little fish have grown to about 2-3 inches in length. They are then present in great numbers on the banks or shallower waters of the nursery ground. In winter they disappear to a great extent from these banks, or at least are not taken in the shrimp trawl, and it is probable that they either bury themselves in the sand when the colder weather approaches (this is a common SEA-FISHERIES LABORATORY. 359 thing with much older Plaice), or they migrate to the deeper portions of the nursery ground such as the channels. The latter seems to be the case with the Mersey nursery. Great quantities of young Plaice are to be found there on the sandbanks, where the water is shallowest, during July, August and September, maximum quantities being taken in the latter month. During the winter months, however, comparatively few are found there, but they are abundant in the channels where the water is deeper. This local migration then goes on independently of the larger movement. ‘The Plaice move from the shallow water to the deeper as the colder months approach and from the deeper water in the channels to the shallow banks as the temperature rises. The young Plaice on these nursery grounds form part of an exceedingly abundant vertebrate and invertebrate fauna. ‘They are associated with other Pleuronectid and Gadoid fishes—the dab, flounder, sole and solenette (Solea lutea), with occasionally young brill and turbot and the whiting, haddock and cod. Young sprats (Clupea sprattus), sand-eels (Ammodytes), Cottus, sting-fish (Trachinus) and Centronotus are also found; all these with the exceptions of the sting-fish, sprat and solenette are young and immature fish. Of the Gadoid fish the whiting are very abundant. ‘These are young fish, in their first year probably, and generally not exceeding five inches in length. The invertebrates are usually crabs (Portunus) and star-fish (Astervas), and great numbers of shrimps (Crangon). The crabs alone often form nearly half the total bulk of the catch. _ These young fish are continually being captured in the shrimp trawl, which having a square mesh of } inch side, retains them. We may quote one single catch to give an idea of the bottom fauna of the Mersey nursery 360 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. ground associated with the Plaice during August. The catch was taken by a shrimp trawl the length of the mouth of which was 25 feet and with a mesh of 4 inch side. It was dragged for one hour over two miles of ground in six fathoms of water. The bottom was a mixture of sand and mud; the contents of the net were— Soles, 257; 11 were over 8 inches long, 4 of the catch were 2”-8”, the remainder 2”. Plaice, 265; 6 were over 8”; remainder 2-8”. Dabs, 896; 2 were over 8”, remainder 2”-4”. Skates, 18; 7” broad across pectoral fins. Whiting, 285; 5” long. Shrimps, 20 quarts (a quart contains from 200 to 400 animals). In addition to these about 200 Solenettes were caught, many other fishes (Z'rachinus, Ammodytes, Clupea sprattus) and a great number of Crabs. On the Blackpool Closed Grounds in the central part of the Lancashire shores even larger catches of young Plaice have been made. Thus in 4 drags with a shrimp trawl on— September 25, 1893, for a drag of 24 miles, 3,302 plaice were caught. December 28, 1893, ri oy AL oO OA ORT Aes Pr January 2, 1894, sy oot Hee sbge bo eres i February 14, 1894, tg ey TES age reese ep a oe Over 10,000 young Plaice, of 2’-4” mostly, being caught in these four drags alone. In the various nurseries the fauna associated with the Plaice varies somewhat, but in all shrimps are always found where young Plaice and other Pleuronectids occur. With increasing size the immature Plaice move out from the nurseries into deeper water. ‘This off-shore migration has been studied in an ingenious way by. ea So —_— SEA-FISHERIES LABORATORY. 261 Fulton* on the East coast of Scotland. Spawning takes place on the off-shore grounds out from the mouths of the Forth and St. Andrews Bay, and the eggs are borne inwards and supply the nurseries in those waters. Num- bers of Plaice on these inshore grounds were captured and marked by the attachment of a numbered label, and then liberated. After variable periods these fishes were re- captured, generally by the fishermen, and then returned to the Fishery Board officers. In this way the course after liberation was determined, and it was found that a slow migration from the South and round the North coasts of the Firth of Forth and then round Fife Ness into St. Andrews Bay took place, the fishes then moving outwards from these shallow waters to the spawning grounds. It is certain that some such movement takes place on the Lan- cashire coasts, though Fulton's experiments have not been repeated there. ‘The distribution of sizes is, however, sufficient evidence, backed with what we know of the actual movements in other places. We have seen that on the nursery grounds great numbers of young Plaice of about $ inch long are found during the early summer, and owing to the great quantity of these small fishes the average size at that time must be very low. ‘Towards September, however, these little fishes have entirely dis- appeared from the sandy pools, and the numbers of Plaice on the grounds slightly off-shore (up to 6 fathoms in depth) have greatly increased. ‘These fishes, which are now from 2 to 4 inches in length, are the same individuals which crowded the sandy pools between tide marks some months earlier, and the first part of their off-shore migra- tion has begun. Further out to sea within territorial waters generally the average size of the Plaice caught in the trawl nets is * 11th An. Report Scottish Fish. Bd., p. 176, 1892. —6B62 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. much greater. Probably about 9 inches will represent the average size of the fish caught'in Morecambe Bay and generally within the 3 miles limit. These fishes are now marketable, and in suitable places all along the coast great quantities at this size are caught in the stake nets. Larger individuals are of course often got, but on these in-shore fishing grounds mature Plaice are never or only very exceptionally captured. It is these immature fishes which in their gradual migration outwards form the mature Plaice population of the more open sea. At or near the spawning season they congregate on the spawning grounds. Briefly summarized then the migratory movements of the Plaice are (1) the passive drift in-shore of the develop- ing eggs and metamorphosing larve terminating as the larva acquires the adult form and settles to the bottom, and (2) the slow outward movement of the young fish, deeper water being continually sought as it increases in size. This movement ends as the fish becomes mature. Thereafter its movements are probably very limited. During the spawning season it probably does not travel at all. With the extrusion of spawn another generation begins the migratory cycle.* * We have described only the larger migrations which are part of the life movements of the Plaice. Smaller and local migratory movements are of course continually going on. Mr. R. L. Ascroft informs us of a curious instance which illustrates the connection between these smaller movements and physical events. A severe storm about 1885 was followed by a very marked increase in the numbers of Plaice in one of the channels of the Ribble estuary—the Bog Hole. For about four days great quantities were caught, one of the sailing trawlers getting as much as 180 score of fish (value £30) in a day. ‘The cause of this remarkable abundance was that the storm and rough water washed off the ‘‘ Sand pipes’? (Pectinaria belgica), which existed in great abundance on the neighbouring banks, into the channel, and the Plaice followed the food. edt ie — * 2 1 i ee ee Se SEA-FISHERIES LABORATORY. — 363 B.—Tue Puaice FIsuery. We are able to present here only a very brief sketch of the economy of the Plaice, and the reader who is suffi- ciently interested in this direction is referred to the very extensive literature which has now been published in Britain, Germany and Denmark. We propose to deal only with the methods in use for the capture of the Plaice, and with the causes of the apparent decline in value of the fishery, and the regulations which have been suggested for the future welfare of the industry. Round the British coasts the Plaice is fished for in three ways. It is caught by spearing, by means of stake nets and by trawling. Of these methods the latter is incomparably the most important. Comparatively few fish are caught by spearing, and this method is only pur- sued in shallow waters and then to a very limited extent. Stake-net fishing is much more important, and is carried on at many parts of the coast on the foreshore between tidemarks where conditions are suitable. The net is about a yard in width and is of variable length. In Lancashire waters it may not exceed 300 yards in length, and it has a square mesh of either 6 or 7 inches in peri- phery. It is stretched on a row of stakes driven into the sand in a straight line, at right-angles to the direction of the tidal flow. It may be provided with pockets. Fish swimming with the tide are caught in the meshes and are removed when the net is “fished” at low water. At sea the Plaice is fished by means of the trawl. ‘The trawl net is a conical bag of variable length. Its mouth is held open by means of a wooden beam on which the net is stretched, so that the open mouth is rectangular in shape. At either end of the beam are fastened iron frames, the “irons, the lower parts of which rest on the ground. ‘The 364 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. lower margin of the mouth of the net, that which rests on the ground, is laced on to a stout rope—the “ foot rope,” which is much longer than the beam and accordingly drags behind the latter in a wide bight. From either iron a strong rope proceeds—the “ bridles,’ the free ends of which are fastened together by the “ shackle.” To the shackle the trawl warp, either of rope or of steel strands, is fastened. When fishing the whole contrivance is dragged on the sea bottom, and after a variable time the net is hauled on board the vessel, and the apex of the cone, the “cod end,’ is untied, and the contents are allowed to drop out on deck. The dimensions of the trawl vary. In Lancashire territorial waters (within 3 miles from low-water mark), when the length of the beam does not exceed 18 feet, there must not be less than 50 rectangular meshes in the cir- cumference of the net, when it exceeds 18 and is less than 25 feet there must not be less than 60 meshes, and when the beam exceeds 25 feet the net must contain not less than 80 meshes. The mesh of the trawl net must measure (with a certain exception) 7 inches at its periphery. Within the territorial waters only sailing vessels may trawl. Outside on the high seas there are of course no regulations, and the trawl] may have any form and dimen- sions desired. When employed by steam fishing vessels the trawl beam may be as long as 50 feet, but the beam trawl seldom exceeds those limits. Since about 1896 the beam trawl has been largely “ce superseded in deep sea trawling vessels by the “ otter” trawl. In this apparatus the general form of the beam trawl is retained, but the beam is discarded, and its place is taken by a strong rope, the ‘* head line,’ to which the upper margin of the mouth of the net is laced. The foot rope is the same as in the beam trawl but the head line SEA-FISHERIES LABORATORY. 365 may be 120 feet lung. The mouth is kept open by being attached to “otter boards,’ which are very large and heavy wooden boards shed with iron, one edge of each of which rests on the ground. They take the place of the irons in the beam trawl. ‘They are set at an angle to the direction in which the net is dragged, and by being pressed outwards when pulled keep the net open. The net is hauled by two warps, one of which is attached to each otter board and passes in over one of the quarters of the vessel. The otter trawl is stated to have an efficiency 37-50 per cent. over that of the beam trawl. These are the two principal methods of fishing in 39 this country. In Denmark the “seine” net takes the place of the trawl. The Danish Plaice seine is a bag of netting about 20 feet long, the mouth of which is produced out into two wings of about 180 feet in length. The depth of the mouth and wings is about 7 feet. There are 5 or 6 meshes to the foot in the netting. The apparatus is used from an anchored vessel by being “ shot” in a wide curve at some distance from the vessel. It is then hauled by two warps, one attached to each wing. The net drags on the bottom in the same manner as the trawl. In Denmark the fish are landed alive, a custom which is quite exceptional in British fishing, the fish being brought to the port of landing preserved in ice. What the real value of the Plaice fishery in British waters may be is difficult to determine accurately. The official returns made by the Board of Trade collectors of statistics show that for the year 1898, 35,788 tons of Plaice having an initial value of £875,680 were landed at British ports. Of this total quantity 31,544 tons were landed at Kast coast ports, 2,355 tons on the South coast, and 1,882 tons on the West coast. It will be seen how important the Kast coast Plaice fisheries are, those grounds yielding 366 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. over 88 per cent. of the whole, while the South coast yields 6 per cent. and the Irish Sea only 5 per cent. It is gene- rally believed, however, that these official returns of the Board of Trade are imperfectly collected, and the above figures are to be regarded as minimum values. Accurate returns of the numbers of fish landed at Grimsby in one year alone are furnished by Holt.* For the year ending March, 1894, over 17+ millions of fish were landed at that port. Most of these fish were caught in the North Sea, a small proportion only in Iceland waters. We have seen that the Plaice, like other Pleuronectid fishes, is a permanent bottom living fish, has a compara- tively limited distribution, and a range of migration which is relatively small. On account of these habits it is pecu- larly liable to capture by present means of fishing, and at no stage in its life history from the metamorphosis onwards does it go outside the range of the fisherman’s operations. While yet on the nurseries it is caught by the shrimp trawler, on the inshore grounds it has become marketable and is caught in the stake and trawl nets, and in the open seas, when mature, it becomes the prey of the deep sea trawler. In many of these respects it contrasts with the commoner round fishes, such as the herring, cod or mackerel. While it is generally agreed that the supply of the last named fishes is practically inexhaustible, it seems no less clear that the abundance of Plaice and other flat fishes may be very sensibly influenced by the opera- tions of modern fishing, and in fact many arguments point to the conclusion that the flat fisheries on British coasts are declining. The present system of collecting statistics is, however, so incomplete that to make out an absolutely convincing proof of this is difficult, and it is only fair to * Holt—An Examination of the present state of the Grimsby Trawl Fishery. Jour, Mar. Biol. Assoc., vol. iii, (N.S.), 1893-5, p. 339. SEA-FISHERIES LABORATORY. 367 state that contrary opinions have been expressed. It is at first sight a paradox that year by year the total catch of fishes in British waters should increase, while the fishing grounds may be really deteriorating. Along with this increase in total quantity of fish caught, however, has gone on a marked increase in the catching powers of the fishing fleets and an extension of the area fished over. The introduction of steam into fishing vessels about 1850, and the use of ice for preserving the catches, made possible the use of larger and more efficient apparatus (the otter trawl latterly), and enabled the vessels to make longer voyages. With this change the small sailing boats began to decrease in numbers, and fishing instead of being car- ried on by vessels independently owned by masters or crews, became a great capitalised industry. Therefore although the annual catch has gradually increased, the average catch per vessel is now beginning to decrease, and the density of the fish population in the seas round the British Isles is less than it formerly was. The catches of 4 Grimsby sailing trawlers for every year since 1875 have been published by Garstang,* and all of these shew a marked decrease with hardly any fluctuations. In Danish seas the same decline has been noticed. Petersent has shewn that there has been a steady decrease in the size of the Plaice landed for many years, and it is obvious that the reduction in size of the fish landed is indicative of the reduction in number of those present on the fishing ground.t *See Garstang Mar. Biol. Assoc. Journ. for these figures and the elaboration of the above argument. + 4th Rep. Danish Biological Station, 1893. { From the relation between the average size at first maturity and the average size of all mature plaice captured, the change in the fish population of an area may be deduced. See Kyle— 18th An. Rep. Scottish Fish, Bd., 1900, p. 200, 368 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. It is worthy of note, however, that the decline in the annual quantity of Plaice taken from the North Sea may be regarded as the reduction of an ‘‘ accumulated stock” * and not entirely as the diminution of the number of fish annually coming to marketable size. At one time the North Sea was practically a virgin ground, and the large and numerous fish taken from it were a stock which had accumulated for many years and which were rapidly fished out. Obviously the estimation of the fluctuations of the fish population of a great fishing ground is a task of the utmost difficulty. We may mention the quantitative method of plankton investigation as one of the most pro- mising means of dealing with this problem. This method has been greatly developed during recent years by Hensen and the German Fisheries investigators, and it is now possible to make a rough estimation of the number of pelagic fish eggs of any species such as the Plaice, in an extended fishing ground. Only a rough approximation of the eggs present can, of course, be made since many difh- culties and sources of error are obviously to be considered. But the Hensen method is as yet the only serious attempt 99 at a “‘ census of the sea’’ which has been attempted, and it is possible that its refinement and thorough application may go a long way towards solving the question of fisheries impoverishment. We have stated that Hensen estimates the number of Plaice eggs floating in the North Sea during 1895 as about 31 billions. Now it is known that a mature female Plaice produces annually about 300,000 eggs and it was then easy to calculate that about 103 millions of mature female Plaice were present in the North Sea in that year. From the known ratio of the * See Hjort and Dahl, Rep. on. Norwegian Fish. and Mar. Investigations, yol, 14, nO. 1p. 151, 1900, SEA-FISHERIES LABORATORY. 369 sexes the total number of mature fish can be further cal- culated. Such determinations made from year to year would obviously give the fluctuation of the adult Plaice population. Of all the Pleuronectid food fishes the Plaice is the most important by reason of its relatively great abundance and on that account when the probability of the decline of the fishery became evident it was the object of much solici- tude on the part of the fisheries authorities, and many remedial measures have been proposed. In this country the continual destruction of immature fish has been the most obvious danger to the fishery, and the remedies have all been directed to the minimising of this evil. The idea underlying the remedies suggested has been to allow as many fishes as possible the chance of spawning at least once in their lifetime. This destruction of immature fish takes place in every form of fishery. Practically all the fish captured in inshore fishing, whether by trawl or stake net, are immature. LHven in the deep sea Grimsby fishing more than half the fish landed are immature. In 1894* of the Plaice landed at that port 7 millions were mature and 9 millions immature. Of the same quantity 9} millions were over 13in. in length and 63 millions under. At first sight therefore it might appear that the imposition of a size limit below which it would be illegal to land the fish would be an effectual remedy. If based on the size at which sexual maturity first occurs this limit would vary for different localities. It is obvious, however, that such a regulation is impracticable, since the Plaice becomes a marketable fish long before it becomes sexually mature. The imposition of such a limit would close the inshore grounds against plaice fishing altogether. Other size limits have, however, been proposed, and * Holt—loc. cit., p. 410. CC 370 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the adoption of some one will probably come in the future. In 1892 a conference held under the auspices of the National Sea Fisheries Protection Association proposed 10in. as the legal minimum size of marketable Plaice. Following this, in 1893 a Select Committee of the House of Commons recommended 8in. as the limit, being influ- enced by the existing legal sizes in other countries. In France the legal size of Plaice is 54in., in Belgium nearly the same, and in Denmark it is 8in. It is to be noted that the arguments as to the decline of the Plaice fishery are generally founded on the total weight of fish landed, not on the number of individuals, and this has suggested the ingenious ‘“‘ growth-theory ” of Petersen* for the betterment of the fishery. In Danish waters the weight of a 10in. Plaice is less than 4lb., and that of a 14in. fish is more than twice as much. Now if in the time required for a Plaice to grow from 10 to 14 inches the total mortality on the fishery ground is such as to reduce the number of individuals by one-half, the total weight of fish will remain much the same as before. But it is not likely that the mortality will be so great, since the Plaice is singularly free from disease, and at the sizes mentioned its enemies (predatory fishes) are few. It follows then that by deferring their capture until they have grown to 14in. in length a much greater weight of fish will be brought to the market. The utility of a size limit (the most profitable one to be determined by experi- ence) is therefore apparent. Though fewer fish are caught the fishing will become more profitable. The practica- bility of such a measure is greater in Denmark than in Britain. There fish are brought to the market alive and instruments of capture are designed to that end. Small fish taken can therefore be returned to the sea alive. Here, * Petersen—loc. eit., p. 48. el Ae ea Bak SEA-FISHERIES LABORATORY. 3871 with large trawls, heavy catches and long drags, most fish are dead when the net is hauled. The success of such a measure would therefore depend to some extent on the possibility of devising a mesh of such form and dimen- sions as would capture only moderately large Plaice with- out prejudice to the capture of other (round) fish trawled for. As far as inshore fishing is concerned the “ vitality ”’ experiments made by Mr. Dawsont for the Lancashire Sea Fisheries Committee have shewn that with moderately short drags (one or two hours) both with fish and shrimp trawls a great proportion of Plaice (81 per cent.) recover when taken from the contents of the net and placed in running sea water. The relative catching powers of nets with different sizes of meshes have also been ingeniously illustrated by the same writer. An ordinary fish trawl of 20 feet beam and with a square mesh of 7in. periphery was used. Round the catching portion of this net a similar net but with a mesh of 44in. periphery was laced. The combined net was dragged in the ordinary manner. Fishes which passed through the inner wide meshed net were retained in the outer one. In one such trial the inner /in. net captured 41 Plaice of about 9 inches in length, while the outer 4$in. net caught 349 Plaice of about 54 inches in length which had passed through the inner net. In another trial of this combination net the Tin. net caught 142 Plaice 74-91 inches long, and the outer 44in. net 390 fishes of 44 inches long. Correspond- ing results were obtained with the other fishes captured.t Petersen’s ‘‘ growth-theory,”’ it will be seen, proposes to remedy the exhaustion of the Plaice fishery by raising + See Lancashire Sea Fish. Laby. Rep. for 1893, p. 23. t See Holt—Journ. Mar. Biol. Ass., vol. iii., pp. 437-441, 1895, for a discussion of the probable results of regulation of the trawl mesh, SV TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the size and with this the weight of fish landed. ‘The author contends that there are already sufficient eggs and fry in the seas, and that it is not useful to attempt to add more. In this country the view has generally been that the decline in the fishery can be remedied by increasing the quantity of eggs or fry in the nurseries, either by increasing the number of spawning fish by the imposition of a minimum size limit or by artificial incubation, or by protecting the very young fishes on the nursery grounds. In the Irish Sea the nursery is also a shrimping ground, and the only means of attaining the latter object is by interference with the shrimp trawl fishery, for the results of experimental shrimp trawling which we have quoted above sufficiently demonstrate that enormous destruction of Plaice fry necessarily accompanies shrimp trawling in - most places where it is carried on. Various attempts have been made by the Lancashire Sea Fisheries Committee to obtain powers to legislate in this direction, and the area’ known as Blackpool Closed Ground is as yet the only fish- ing ground where shrimp trawling is forbidden in the interests of the young Plaice and soles which are reared there. The amount of destruction of young Plaice which — was due to shrimp trawling on that area will be seen from a consideration of the figures we have quoted above. The shrimping ground at the mouth of the river Mersey is an area on which shrimp trawling is extensively practised,* and where as we have seen great numbers of young Plaice unfortunately congregate. Hxperimental hauls with a shrimp trawl have been made for many years by the officers of the committee on a portion of this area, which the Committee recently unsuccessfully attempted to close against trawling during July, August and *See Lanc. Sea Fish. Lab. Report for 1900, p. 39, 1901, for a short account of this fishing ground. a SEA-FISHERIES LABORATORY. 373 September of every year. As the result of 7 years’ experi- mental fishing it was found that 567 young Plaice were taken in an average haul with a shrimp trawl on this ground in those months. Now during those 3 months 15 shrimp trawling boats on the average are fishing there every day, each boat making 3 hauls per day on five days per week, 2,925 hauls in all. Supposing each boat to have made the average catch of 567 young Plaice, over one and a half millions of young fishes would have been caught on this area alone during the three months men- tioned per year. It must be remembered that in the fishing as ordinarily practised the great majority of these are really destroyed. The enormous destruction of young fishes due to this method of fishing will be realised when we state that there are altogether about 100 boats employed in shrimp trawl- ing in the Mersey estuary, and the grounds seaward from the river, and that the above calculation applies to only 15 of these frequenting a particular area for 3 months. The Mersey is not the only district in which shrimp trawl- ing is practised. Just as active fishing is carried on in the Ribble estuary and in Morecambe Bay and in many parts of the coast, ‘‘ cart-shanking "—an equally destructive form of fishing, is practised. We believe we are under the mark in stating that the yearly destruction of young Plaice on the Lancashire and Cheshire coasts before the closure of the Blackpool ground due to shrimp trawling must be measured by the hundred million. It is a regrettable circumstance that regulation with a view to the protection of the young Plaice on the nursery grounds must to some extent interfere with the prosecu- tion of shrimp trawling, but it seems probable that the loss incurred by the latter fishery would be more than com- pensated by an increased number of Plaice on the fishing 374 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. grounds, and even if these were caught while still imma- ture fishes frequenting territorial waters there would still be a net gain. It is a question worthy of consideration therefore whether, in the interests of the Plaice fishery, some restrictive measures applied to methods of shrimp fishing would not be of benefit to the whole fishing industry. We are referring here to the method of fishing for shrimps with the shrimp trawl, which is a net of the pattern of the larger fish trawl described above but with a mesh of 2 inches in periphery. Other forms of shrimp nets are used, particularly the “shank” net, which is a net like a trawl but having the beam, foot rope and irons replaced by a rectangular wooden frame. A further improvement consists in attaching the lower edge of the net, not to the lower bar which drags on the ground, but to another bar, parallel to this but placed two or three inches above it. When disturbed the shrimp jumps, and, clearing the bar, enters the net, while the fish when dis- turbed swims off close to the ground and may escape through the space between the two bars. Experiments have shewn that these two nets capture relatively less fishes and more shrimps than the ordinary shrimp trawl. We have yet to refer to the artificial incubation of Plaice eggs as a means of recruiting a fishing area in process of exhaustion by overfishing. So far this has only been extensively practised in Scotland. Mature male and female Plaice are captured some time before spawning begins and are penned in a “ spawning pond.” Spawning and fertilization take place in the pond as in the sea and the fertilized eggs are collected daily and are put into the “ hatching boxes.” Through these a constant stream of sea water passes and they are kept in continual motion to avoid the clustering of the eggs and the risk of insuffi- SEA-FISHERIES LABORATORY. 375 cient aeration. The eggs develop in these boxes and the larve after being retained for some time are taken out to sea and “planted” in a suitable locality. It will be obvious from what we have stated above with regard to migrations that the larve must be set free in such a place that the prevailing winds and tidal drift will carry them to a nursery (which must be present in the area dealt with) in which the conditions for further development are suit- able and in such a time that the assumption of the demersal habit will coincide with the arrival of the larve on the nursery grounds. The ultimate aim of the hatch- ing operations is to rear the larve through the period of their metamorphosis under artificial conditions. It has, however, been found extremely difficult to rear even a small proportion through the period referred to since great numbers die during the period immediately following the absorption of the yolk sac. In practice, therefore, the larvee are set free before this mortality has seriously com- menced. The Scottish Fishery Board, in addition to their utilitarian object of adding to the number of young fish in the sea, have since 1897 been devoting attention to the interesting experiment of placing some millions of fry yearly in one limited area where they have reason to think they may be able to test the result by periodic observations on the young fish fauna. In the period between 1894 and 1899 inclusive the Board set free 136 millions of arti- ficially hatched larve, and since 1897 these have been planted in Loch Fyne, the area chosen for experiment. The argument for the utility of sea fish hatching rests to some extent on the hypothesis that the period during which the fish are being dealt with in the hatchery is that during which the mortality in nature is greatest. Since, in the hatchery, the eggs ans larve are safe from enemies or prejudicial changes in their physical surround- 376 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. ings, this mortality is avoided. It is most probable that during their pelagic life the eggs and larve are destroyed by being eaten by other animals or by physical changes, but unfortunately we have as yet no idea of the proportion of eggs or larvee so destroyed. Experience in the hatchery shews that it 1s during the period between the absorption of the yolk sac and the beginning of the metamorphosis that the mortality is greatest. This critical period 1s characterised by the change in the means of nutrition of the larva, which having used up the food yolk, begins to feed on planktonic organisms. If this mortality exists in nature, and if it should become possible to avoid it in the hatchery, then the gain would be very considerable, but until it shall become possible to rear the greater portion of the larve hatched through their metamorphosis all that is gained in the hatchery is the immunity of the eggs and larve and of the fishes in the spawning pond. From this latter point of view—the immunity of the fish yielding the eggs—the hatchery is to be regarded as a reserve of spawners, and its function becomes the more valuable the greater the reduction of the fish population in the area dealt with. It is to be regarded as effecting the same end as would be brought about by protection of mature fish on the spawning grounds—protection which at present seems impracticable, or protection of the fry caught in the course of other fishing—protection also apparently impracticable. We refer here to the treatment of restricted areas. Prob- ably the effective treatment of such an area as the whole North Sea by artificial hatching is at present impracti- cable. The deficit which the hatchery would have to make good is the assumed reduction of the mature Plaice population, and this most probably takes place on a scale which it would be difficult to approach by artificial opera- {ions according to our present ideas and methods. SEA-FISHERIES LABORATORY. 377 It has been suggested that much the same results would be attained by the removal and fertilization of the ripe eggs from Plaice caught in the course of commercial fishing and the immediate return of these to the sea with- out having undergone treatment in the hatchery. We do not know whether this is practicable, and at any rate, the number of ripe eggs in the ovary of a Plaice at any one time is only a small proportion of the total number pre- sent. This method of obtaining eggs for the hatchery has, however, been adopted at times. The trawling vessels have been boarded on the fishing grounds and ripe fish stripped,’ the eggs fertilized and taken to 66 have been the hatchery. As we have seen the most striking fact in the life history of the Plaice is its limited range of migration, and this has suggested the possibility of recruiting a limited fishing ground in process of exhaustion, by plant- ing artificially hatched larve on it. The most economical method of obtaining the eggs would be from fish caught in the course of commercial fishing. Obviously the scale on which the hatchery would most effectively work would be determined by a knowledge of the annual reduction cf the fish population by fishing operations. 378 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. EXPLANATION OF PILATES. Reference Letters. . cay.—Internal carotid arteries (the two outer ones). . car’ —Exxternal carotid artery. . Cm.—Coeliaco—mesenteric artery. . coe.—Coeliac artery. a a a . ep.—Right epibranchial artery. A.F'.—Anal fin. Af. Br. 1—4.—First to fourth afferent branchial arteries. A. gen.—Common genital artery. A. gen’—Right genital artery. A. hep.—Hepatic artery. A. hy.—Hyoidean artery. Al. S.—Alisphenoid. amp. a. amp. e, | 7Anterior, external, and posterior ampulle of the semicircular Leese canals. amp. p. An.—Angular. a. NOS. ) , : , -—Right and left anterior nostrils.; a. NOs’! .| ant. cr.—Crista acustica ampulle anterioris. Ao. d.—Dorsal aorta. A. @.—Oesophageal artery. A. op.—Ophthalmic artery. Ao. V.—Ventral aorta. A. pe.—Pelvic artery. Ar.—Articular. A.R.—Accessory ribs or intermuscular bones, numbered from before back- wards. A.R.*—Tubercle on fourteenth and many of the succeeding vertebre, representing probably a fused accessory rib. a. 8. ¢.—Anterior semicircular canal. A. scl.—Right and left subclavian arteries. A. sp.—Splenic artery. Aur.—Auricle. Az,—Axonosts or interspinous bones, numbered from before backwards. Ag.“ —Transverse ligament connecting axonost with skin. sb Az.» —Triangular plug of cartilage occurring in the head of every axonost. A. Zy.—Anterior zygapophysis. SEA-FISHERIES LABORATORY. _ 379 B. A.—Bulbus arteriosus. B. Br. 1-4.—Basi-branchials 1 to 4. Bda.—Bile duct. B. O.—Basi-occipital. Br. 1.—First holobranch. 1, the first visceral arch. Br. R.—Branchiostegal rays, numbered from before backwards. Bs.—Baseosts, numbered from before backwards. C.—Centrum. C27» C. Br.4 C. #.—Facet on atlas for paroccipital condyle. C. Fn.—Caudal fin. C. Hy.—Cerato-hyal. cil. b,—Ramus ciliaris brevis. cil. g.—Ciliary ganglion. cul. l.— Ramus ciliaris longus. | ~Censto-anchis of the first and fourth branchial arches. Cir. c.—Cireulus cephalicus. Cl.—Clavicle. Co.—Coracoid. com. 1—vu..—RR. communicantes between the sympathetic and the first seven spinal nerves. com. v.i—R. communicans between the sympathetic and the N. trigeminus. Cr. C.—Cranial cavity. d. 2—6.—Dorsal roots of the spinal nerves 2 to 6. D.—Dentary. d. b. . a | —Dors roots of the first spinal nerve. d. end.—Vestigial ductus endolymphaticus, with two minute utriculo- saccular canals opening into its base. D. F.—Dorsal fin. E. Br. E =. j | —tpibranchial of the first and fourth branchial arches. Ef. Br. 1—4,—First to fourth efferent branchial arteries. Ep. 1 Ep. 2 | ie and second epural bones. Hp. Hy.—Epi-hyals. Ep. O.—Hpiotic. 380 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Ep. P.—Epiotic process of epiotic. e. §. c.—External (horizontal) semicircular canal. Eth.—Ethmoid cartilage. Ex. O.-—Exoccipital. ext. cr.—Crista acustica ampulle externe. f. car.—Carotid foramen, transmitting the internal carotid artery. f. gl.—Foramen of the N. glossopharyngeus. f. jug.—-Jugular foramen, transmitting the superior (internal) jugular vein, the ophthalmic artery and the T. hyomandibularis facialis. F,. M.—Foramen magnum (occipital foramen). f. olf. —Olfactory foramen in the pre-frontal by which the N. olfactorius reaches the nasal chamber. F'.R.—Fin rays. F.R.«» —The two pieces forming a single fin ray. F.R.< —Ligament connecting the two halves of the fin ray. F.R.4—Ligament connecting one half of the fin ray with the baseost. F.R.< —The right abductor muscle of the fin ray. The elevator and depressor muscles do not appear in this section. F’, Sp. N.—¥oramina for the spinal nerves. F.. Sp. N.* —Foramina for the fourth spinal nerve. f. tr. fa.—Trigemino-facial foramen, transmitting the vth and viith nerves except the T. hyomandibularis facialis. f. vg.—Foramen of the N. vagus. 3—6.—Ganglia of the spinal nerves 3 to 6. . v—vii.—Massed ganglia of the trigeminal and facial nerves. . 1x.—Ganglion of the N. glossopharyngeus. x. 1.—Ganglion of the first branchial trunk of the N. vagus. x. 2—5.—Ganglionic complex formed by the second, third and fourth branchial + the intestinal ganglia of the N. vagus. ~e 2 & & . coel.—Ganglion coeliacum. d. 2.—Dorsal ganglion of the second spinal nerve. extcr.—Extracranial ganglion of the first spinal nerve. . inter.—Intracranial ganglion of the first spinal nerve. . v. 2.—Ventral ganglion of the second spinal nerve. © 7 RAS H. A.—Haemal arches, numbered from before backwards. H. Br.1 —Hypo-branchial of the first branchial arch. H. C.—Haemal canal. H. Hy.—Hypo-hyals. Hm.—Hyomandibular. Hm. F.1-*—Cup and facet for head of hyomandibular. Cp. fig. 5. SEA-FISHERIES LABORATORY. 381 HAp.} Hp.2 |—First, second and third hypural bones. Fip® H. S.—Haemal spines, numbered from before backwards. H. S.+—Last three haemal spines. hy. c.—Hyomandibular sensory canal. I. Cl.—*‘ Inter-clavicle.” I. Hy.—Inter-hyal. I. M. C.—Inter-maxillary cartilage. In.—Innominate or pubic bone. The figures denote its three parts. im. buc.—R. buccalis internus facialis. inf. c.—Infraorbital sensory canal. I. Op.—Inter-operculum. I. Ph.—Inferior pharyngeal bones, representing a fifth pair of branchial arches. Jac. anast.—Jacobson’s anastomosis from the ninth to the seventh cranial nerves. Jug. g.—Jugular ganglion of the N. vagus. lag.—Lagena. lat. c.—Lateral sensory canal. L. Fr.—Lett frontal. l. g. x.—Ganglion of the R. lateralis vagi. L. Le.—Left lachrymal. LL. Na. C.—Position of left nasal chamber. low. in. buc.—Lower division of the R. buccalis internus facialis. L. P. C.—Left paroccipital condyle. L. P. Fr.—ULeft pre-frontal. L. rec. vin. : sate, : a lateralis recurrens facialis and vagi. lL. vec. x. ) man.v. | ; Ei ie haw ee .. »~—R. mandibularis trigemini and facialis. man. vir. man. ext. vii.—R. mandibularis externus facialis. man. int. vii.—R. mandibularis internus facialis. m. a. 8.—Macula acustica sacculi. M. C.—Pads of soft cartilage (fibrous in parts). m. ad. op.—T wig from the N. trigeminus to the M. depressor operculi. M. E.—Posterior portion of the mesethmoid bounding the orbit in front. M. E..—Anterior portion of the same bearing the beak-like ridge for the intermaxillary cartilage. . 382 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. M. Pt.—Meta-pterygoid. m. 7. U.—Macula acustica recessus utriculi. Ms. Pi.—Meso-pterygoid. Maz.—Maxilla. mx. v.—R. maxillaris trigemini. N.—Cup shaped cavity at each end of centrum containing vestiges of the notochord. N. A.—Neural arch. Nc.—Notochord. N. C.—Notochordal canal in centrum placing the notochordal spaces (J.) in communication. . ch. nv. ch} n. olf. - n. olf N. S.—Neural spines, numbered from before backwards. N. S.t—Last three neural spines. 2. sac.1—*—The five right and left nasal sacs. nm. sp.! ) n. sp.'! j | Rie and left nasal chambers. | Riek and left olfactory nerves. —WNN. splanchnici. O.C.—Occipital condyle. Oc. S.—Occipital spine. Od.—Opening of oviduct. Od.‘—Common ovarial chamber. Od.“—Interior of right ovary. o. 1.—Branch of the N. oculomotorius to the inferior oblique muscle. o. lam. ) -—Right and left series of olfactory lamine. o. lam. | Op.—Operculum. Op. O.—Opisthotic. o. pr.—Nervus ophthalmicus profundus (trigemini ?) and ganglion. op. s. vii.—R. opercularis superficialis facialis. 0. s.—N. patheticus to superior oblique muscle. oto.—Saccular otolith. out. buc.—R. buccalis externus facialis. Pa.— Palatine. pal.—R. palatinus facialis. p. a. l.—Papilla acustica lagen. Pa. P.—Parotic process of pterotic and opisthotic. SEA-FISHERIES LABORATORY. 383 Par.—Parietal. Pa. S.—Parasphenoid. P. Br.1 —Pharyngo-branchial of the first branchial arch articulating with the skull. P. Br.2-4—Pharyngo-branchials of the peanchial arches two to four, form- ing the superior pharyngeal bone (S. Ph.). P. C.—Paroccipital condyle. P. Cl.—Post-clavicle. Per.—Pericardium. P. F.—Pectoral fin. ph. x. 1 ph. 2,2. ph. «. 3 Pl, F.—Pelvic fin. Pl. F'.’—Base of right pelvic fin. P. Mxz.—Premaxilla. )_rr. pharyngei of the first, second and third branchial trunks of | the vagus. ee jig and left posterior nostrils. p. nos.1 P. Op.—Pre-operculum. post. 1 post. 2 —RR. post-trematici of the first, second, third, and fourth branchial post. 8 | trunks of the vagus. post. 4 } post. vii.—R. post-trematicus facialis. post. 1x.—R. post-trematicus glossopharyngei. post. cr.—Crista acustica ampulle posterioris. pre. 1. | pre. 2. —RR. pre-trematici of the first, second, third and fourth pre. 3. [ branchial trunks of the vagus. pre. 4. | Pr. O.—Prootic. Ps. Br.—Pseudobranch. p. &. ¢.—Posterior semicircular canal. Pt.—Pterygoid. Pt. O.—Pterotic. P. Tp.—Post-temporal. P. Zy.— Posterior zygapophysis. Qu.—Quadrate. r. v.—Root of N. trigeminus. ry. 1. vii.—Dorsal (sensory) roots of N. facialis. 384 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. r. 2, vw.—Ventral (motor) root of N. facialis. r. 1.—Root of N. glossopharyngeus. r. 2.—Root of N. vagus sensu stricto. R.—Ribs, numbered from before backwards. r. @. @.—R. acusticus ampulle anterioris. r. a. e.—R. acusticus ampulle externe. r. a. p.—R. acusticus ampulle posterioris. r. car. ?—R. cardiacus vagi ? r. cerv.—R. cervicalis of the first spinal nerve (= ‘‘ N. hypoglossus.’’) vr. com. 2—6.—RR. communicantes of spinal nerves 2 to 6. 7. com. b.—R. communicans of the first spinal nerve. 7. €.—N. abducens to external rectus. Rec. Ax.1 —Longitudinal furrow on the anterior aspect of the first haemal spine for the reception of the first axonost of the anal fin. R. Fr.—Right frontal. . hy.—R. hyoideus facialis. . if. —Branch of N. oculomotorius to rectus inferior. . test. x.—R. intestinalis vagi. . 2t.—Branch of the N. oculomotorius to rectus internus. 1.—R. acusticus lagene. . lat. «.—R. lateralis ‘‘ vagi.’’ . lat. x.’—Root of R. lateralis vagi. r. lat. prof. «.—R. lateralis profundus vagi. r. lat. sup. «.—R. lateralis superficialis vagi. R. Lc.—Right lachrymal. r. m. 2—5.—RR. medii of spinal nerves 2 to 5. r.m. b. | rT. M. C. j R. Na.—Right nasal. R. Na. C.—Position of right nasal chamber. SS 2a RS eS —RR. medii of the first spinal nerve. r. op. «.—R. opercularis vagi. vr. oph. sup. v.—R. ophthalmicus superficialis trigemini. r. oph. sup. vii.—R. ophthalmicus superficialis facialis. 7. ot. —R. oticus facialis. RR. P. Fr.—Right prefrontal. r. 7. U.—R. acusticus recessus utriculi. v. §.—Branch of N. oculomotorius to rectus superior. r. sac.—R. acusticus sacculi. r. sp. 2—5.—RR. spinosi of spinal nerves 2 to 5. 7. Sp- 0, j—RR. spinosi of the first spinal nerve. T.Sp,€. ——— 7. 2 SEA-FISHERIES LABORATORY. 385 r. st. x.—R. supratemporalis vagi. r, v. 1.—R. ventralis of the first spinal nerve + an anastomosis from the second. SE De ) E Motor branches of the brachial plexus. TD. 1.2 j r. v. 1.3 —Motor _ 1.4 —Sensory branches of the brachial plexus to the pectoral fin. > (S vr, v. 2..—Anastomosis between RR. ventrales of the first two spinal nerves. 2+ 3.—Fused RR. ventrales of spinal nerves 2 and 3. 2+-3.’—Motor branch sending an anastomosis to R. ventralis 4. 2+ 3”.—Sensory nerve to pectoral fin. 2—5,—RR. ventrales of spinal nerves 2 to 5. ~ Debate, b-+-c.—R. ventralis of first spinal nerve. rx. b,—Radix brevis. rx. .—Radix longa ganglii ciliaris (accompanied by sympathetic). sac.—Sacculus. Sc.—Scapula. S. C.—Spinal canal. S. Cl.—Supra-clavicle. Sin. V.—Sinus venosus. Sk.—Outline of skull. S. O.—Supra-occipital. s. 0. c.—Supra-orbital commissure between the two supra-orbital sensory canals. S. Op.—Sub-operculum. S. Ph.—Superior pharyngeal bone of the eyeless side intact. The numbers denote the branchial arches to which its constituents belong. Spl.—Spleen. Sp. N.2—Thirteenth spinal nerve. Sp. O.—Sphenotic. S. R.—Strengthening ridges of the vertebral centra. s. t. c.—Supratemporal portion of the lateral sensory canal. sup. ¢c.—Right supraorbital sensory canal. sup. ¢. | vena of the left supraorbital sensory canal. sup. c.” Sy.—Symplectic. t. t. —-First, second and third Trunci branchiales vagi. t, Ses WwW 2 & DD 386 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Tb. 1—5.—The five tuberosities seen externally on the ocular side passing backwards from between the two eyes. Thm.—Thymus gland. t. hmv.—Truncus hyomandibularis facialis. t. inf.—Truncus infraorbitalis (trigemini et facialis). Tr. P.—Transverse process. U. + Hp. 3.—Urostyle and third hypural fused together. U. Hy.—Basi-hyal. up. wm. buwe.—Upper division of the R. buccalis internus facialis. Ur.—Urostyle. Uret.—Ureter. Ur. pp.—Urinary papilla. uty. - és ; | —centa and vertical chambers of the utriculus. . 2—6.—Ventral roots of spinal nerves 2 to 6. V.—Vertebral centra numbered from before backwards. V! is the atlas. v. b.! v. b. }+—Ventral roots of the first spinal nerve. V. C. j V. card.—Cardinal vein. Ven.—Ventricle. V. gen.—Genital vein. V. hep.—Hepatic vein. V. jug. | Vz jug. Vo.—Vomer. —Superior and inferior jugular veins. Vp.—Portal veins. V. pe.—Right precaval vein. Prate I. Vig. 1. Dorsal surface of an undried skull of a 65cm. Plaice. Natural size. The dotted line indi- cates the departure from the symmetry. The anterior extremity is somewhat schematic, and is drawn as if seen a little from behind. The fenestra in the ethmoid cartilage is only partially visible in a strictly dorsal view. SKA-FISHERIES LABORATORY. 387 Fig. 2. Ventral surface of the same undried skull. Natural size. The dotted line indicates the swerve of the ventral axis of the cranium towards the left side caused by the rotation towards the right of the orbital region of the eranium. The chondrocranium appears on the surface of the cranium in several places, and not always symmetrically. Fig. 3. Lateral view of the same skull seen from the right or ocular side. Natural size. The right nasal and right lachrymal are here fully shown, and do not appear in perspective as in figs. 1 and 2. Pruate LI. Fig. 4. The occipital region of the same skull viewed from behind. Natural size. The dotted line indicates the departure from the symmetry. The chondrocranium appears on the surface between the exoccipitals and epioties. Fig. 5. Lateral (moist) dissection of the opercular bones, palato-pterygoid arcade, and jaw apparatus of the Plaice, on the ocular or right side. Natural size. Hxtreme length of specimen J4cm. ‘The palatine has been rotated downwards in order to illustrate its shape, and the lower jaw has been depressed. In the natural disposition of the parts the lower end of the maxilla lies external to the . mandible. Fig. 6. Dorsal (moist) dissection of the Hyoid arch of a 34cm. Plaice. Natural size. In the living animal the stout hyoid bar is almost vertical and the basi-hyal projects forwards at right- 388 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. angles from its upper border. ‘The lower border of the bar in the figure is therefore the dorsal border, and the face shown is the anterior face. ‘The first pair of branchiostegal rays has been turned forwards. ‘They really pass straight backwards in the mid-ventral line. The branchiostegal rays are numbered from before backwards, and have been dis- played. | Fig. 7. Dorsal (moist) dissection of the branchial arches of a 34cm. Plaice. Natural size. The arches have been flattened out and displayed. On the right side the three pharyngo-branchials forming the superior pharyngeal bone have been separated and left attached to their respective arches, but on the left that bone is represented intact drawn from its oral surface. The arches are numbered from before backwards (i.-v.). Fig. 8. Lateral (moist) dissection of the right pectoral girdle and fin of a 34cm. Plaice. Natural size. The “ inter-clavicle ” in front is shown in its correct position relative to that of the pectoral girdle. The fin rays have been separated from the two fibro-cartilaginous pads with which they articulate. Fig. 9. Lateral (moist) dissection of the right pelvic girdle and fin of a 34cm. Plaice. Natural size. The fin rays are represented dis- articulated from the fibro-cartilaginous pad. ) Pare Ti Fig. 10. First or atlas vertebra viewed from the front of a 02cm. Plaice. Natural size. The acces- —_— <2 = a’ Fig. 11. Fig. 12. Fig. 13. Fig. 14. Fig. 15. SEA-FISHERIES LABORATORY. 889 sory ribs (intermuscular bones) have been rotated forwards so that their exact length may be indicated. The dotted line shows the extent of the asymmetry. The eighth trunk vertebra viewed from the front of a 64cm. Plaice. Natural size. The accessory ribs have been rotated forwards in order to introduce their full length. The dotted line shows the departure from the symmetry. The twelfth trunk vertebra of a 52cm. Plaice seen in optical longitudinal section, the ocular or right half of the centrum and right neural arch having been ground away. Natural size. The figure illustrates the amphicoelous character of the centrum, and the shape and extent of the notochordal ‘spaces. The fourteenth or first caudal vertebra of a 62cm. Plaice seen from the front. Natural size. The dotted line indicates the depar- ture from the symmetry. The same ver- tebra is shown in side view in fig. 18. Moist dissection from right side of caudal fin and termination of vertebral column of a 34cm. Plaice. Natural size. The fin rays have been disarticulated from the fibro- cartilaginous pad. Dissection from right side of posterior extremity of notochord and caudal fin supports of a young Plaice or lfmm. Drawn with camera. x 15. Notochord as yet unossified, but faint vertebral constrictions (6 shown in fig.) have appeared. The neural and haemal 390 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. spines and epural and hypural bones are beginning to ossify from without inwards. The fig. should be compared with fig. 14. It shows that the urostyle has not yet fused with the third hypural, and that the caudal fin of the young Plaice is of the ordinary homocercal type. Fig. 16. Longitudinal section through a fin ray and Fig. 17. Fig. 18. axonost of the dorsal fin of a medium sized adult Plaice, z.e., the section passing longi- tudinally through the fin ray and transversely to the long axis of the fish. Leitz 5, ocular 2. The figure shows the two pieces forming one fin ray, and their relations and connec- tions with the baseost and axonost. The section does not pass through the plane of the elevator and depressor muscles of the fin ray, or the longitudinal vertical ligament of the axonosts. Prats FV. Moist dissection from the eyeless or left side of the anterior part of the dorsal fin and first three trunk vertebre of a d2cm. Plaice. Natural size. The outline of the skull is introduced to show its ventral inclination and its relation to the first eight-ten axonosts of the dorsal fin. (Cp. table in text.) The first three vertebre also have a downward inclination. Moist lateral dissection from the eyeless side of the last four trunk and first three caudal vertebrae, and of the anterior extremity of — the anal fin and its supports of a 52cm. Plaice. SEA-FISHERIES LABORATORY. ool Two-thirds natural size. The ring at the ventral extremity of axonost 1 indicates how much of the latter protrudes freely from the body wall in dead specimens. Cp. table in text. 3 Fig. 19. Moist lateral dissection from the eyeless side of the last seven caudal vertebree and the pos- terior extremities of the dorsal and anal fins and their supports of a 52cm. Plaice. Natural size. The sigmoid curve of fin ray 71 of the dorsal fin and its horizontal position are abnormalities. Cp. with fig. 14 and table in text. : PuLatE V. Fig. 20. The viscera seen from the ocular side. Only the body wall has been removed and the muscles of the limb girdles dissected away. The ovary and rectum are opened to shew the external opening of the oviduct. The specimen was a ripe female. ‘Two-thirds natural size. Fig. 21. The viscera seen from the ocular side. The body wall and the superficial coils of the © intestine have been removed and the pectoral girdle, operculum, sub-operculum and inter- operculum dissected away. ‘The lateral wall of the pericardium has been removed. The positions of haemal spine 1 and axonost 1 are indicated by broken lines. The speci- men was a spent female. Two-thirds natural size. 392 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Pirate VI. Fig. 22. Diagrammatic representation of the principal blood vessels and their distribution. The principal viscera are introduced into the figure in order to shew the distribution of the vessels only. Their space relations to each other are not accurately shewn. The intestine 1s represented for simplicity’s sake as a single coil. The hepatic portal system is not shewn, nor the distribution of the carotid arteries. The arteries are cross hatched, the veins are uniformly shaded. About natural size. Pruate VII. Fig. 25. Reconstruction from serial sections of the cranial nerves of the ocular side. The. two scales in this and other figures refer to the numbers of the sections. Sensory canals coloured green. ‘Their sense organs and surface pores are numbered in each canal from before backwards. Eye muscle nerves cross striated. The numerals refer to the numbers of the cranial nerves. Note the relatively large size of the eyes in the young fish. The curve of the medulla shown in this figure does not exist in the adult, and is probably an abnormality. Pruate VIII. Fig. 24. Reconstruction of the left ear and auditory nerve seen from the inner or left side. This figure cannot be compared with fig. 25, the reconstruction being made on a somewhat SEA-FISHERIES LABORATORY. 393 larger scale, although from the same series of sections. ‘he nerve ramuli in front are a little diagrammatic, in order that they may be shown more clearly. viu., auditory nerve. ‘The reconstruction applies also to the adult ear, but the relative sizes of the parts are of course different. Fig. 25. Reconstruction of the right and left nasal ‘organs seen from above. Drawn to exactly twice the scale of figs. 23 and 26, and from the same series of sections. The disposition of the accessory secretory chambers is slightly diagrammatic for the sake of clear- ness. The termination of the olfactory nerves is not shown for the same reason. Fig. 26. The sympathetic nervous system seen from above, and plotted from the same series of sections and to the same scale as fig. 23. The dotted line represents the median line of the body continued straight forwards. The figure is diagrammatic in four respects : (1) the celac ganglion les directly under ganglion 2; (2) the first cranial ganglion hes immediately over the second on the ocular side; (3) the ocular ciliary ganglion lies over the third nerve; (4) the eyeless ciliary ganglion is external to the oculo- motorius. The cranial ganglia are numbered 1-8, the spinal 1/-7’. iii. is the Nervus oculomotorius, after it has given off the nerve to the M. rectus superior. PruateE IX. Fig. 27. Reconstruction from serial sections of the first EE 394 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. six spinal nerves of the right side seen from the lateral aspect. ‘The two crosses indicate the position of the foramen magnum. The cranial region is to the right of these, the vertebral to the left. The reconstruction is from the same series of sections as figures 23-26, but is not drawn to the same scale. The formal shading of the ganglia is omitted in the case of the first spinal for the sake of clearness. The roots of most of the spinal nerves lie internal to the ganglia and there- fore cannot be shown. ‘Their places of origin, however, are indicated by the oval dotted areas. ¢ Fig. 28. Transverse section through the fore-brain to illustrate the asymmetry of this part of the brain. The dotted line indicates the mid- vertical plane. Most of the brain therefore here hes to the right. Note the fibres col- lecting at the base of each bulbus olfactorius. These ultimately form the olfactory nerves. Drawn with the camera, Zeiss aa. oc.4. PLATE X. Fig. 29. Plaice split up the middle from below into two halves and spread out to show both sides of the sensory canal system. x #. The anterior extremity of the dorsal fin is not shown. The shading indicates the innervation of the sensory canals. Swpraorbital canals, cross hatched (R. ophthalmicus superficialis, vi.) ; Infraorbital canals, dotted (R. buccalis, vil.); | Hyomandibular canals, shaded (R. mandibularis externus, vu.) ; Lateral canals, SEA-FISHERIES LABORATORY. 3Y5 cross striated (R. lateralis, x.). The line of dashes represents the suppressed portion of the left supraorbital canal. Fig. 30. Dorsal view of the brain of a Plaice having an Fig. Fig. Fig. dl. eo: 4. 35. extreme length of 58cm. x 3. The pallium and the choroid roof of the fourth ventricle have been removed, but the asymmetrical position of the pineal tube and body is indi- cated. ‘he dotted line shows the departure from the symmetry. ‘he numbers are those of the cranial nerves. | Lateral view of the same brain with the pallium in situ.x 3. Numbers as in preceding figure. PuatE XI. Embryo Plaice on the 5th day after fertilization and before invagination of the optic vesicles. x 29. Embryo Plaice on the 9th day after fertiliza- tion. The black spots on the body and tail represent the yellow branching chromato- phores which appear about this time. x 29. Kmbryo Plaice on the 17th day after fertiliza- tion. The embryo is ready to hatch. The branching black markings on the body and tail are the black chromatophores. The yellow pigment is represented by the grey spots. x29. Nat. size of this and the preceding eggs = 1°88 mm. Newly hatched Plaice, 17 days after fertiliza- tion. The black pigment is represented by the stellar markings, the yellow by the grey . spew. x17, Nat. lenoth — 63 mim. Figs. 32—35 are drawn from the living eggs 396 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. and larva from material treated at the Piel Hatchery. The average temperature of the water in the hatching boxes during the developmental period was 7° C. Fig. 36. Larval Plaice at the beginning of the metamor- phosis. The yolk-sac has been absorbed, and the larva is beginning to feed. Note the beginning of the asymmetry—the left eye is more dorsal than the right. Note also the upturned end of the notochord. Nat. size = 15mm. x6. (After Ehrenbaum, Hier und Larven von Fischen der Deutschen Bucht. Wiss. Meeresuntersuch. Kiel. Komm. Bd. 2, Heft J., Abth. I., Plate 4, figayiss 1896.) Fig. 37. First bottom stage of the Plaice. The metamorphosis is completed. Note the relatively large size of the eyes and the small paired fins. x4}. Nat. length = 13 mm. (After Petersen, 4th Rep. Danish Biological Station. Pl. I., fig. 10. 1893.) OcuLaAR Side PUR ONE ETE S. EveELeEssS Sipe M‘Farlane & Erskine, Lith. Edin® ee) Mak ond ieee) 4 1 il aed | ' I ond EYELESS SIDE PERO MEG TES: Hm. Prats IT. OCULAR SIDE M.Pr. Ms. Pr MiFarlane & Erakine, Lith, Edin? PMx a) Prater ITI. | UH. 5. Fig. 14. oe NiSal 42, fete *-H.S. 28-29. EvELEsSS Sipe Viicen EYELESS SIDE Ocutar Side Everess SIDE Fig. 13. Fig, 12. Ss R.9. p F. J. Cole, del. Pp is U R @) N EK iC Pe S MFarlane & Erskine, Lith, Edin? M‘Farlane & Erskine, Lith. Edin® 5. ‘ mak PLEURONEOTE FJ, Cole, del. Lateral Line. Gall Bladder. 4 DBE SEING. 0... ; Suceedsevof : eee ee Posterior Extension of right Ovary. ae = =O _ eee id V.Card. Thm. 18.5 TT Kidney. sos. aoa \ ee Bs “Stomach. | ; J el; Os Liver 7 Bladder Posterior Extension of right Ovary. ' ie? S \ \ k Urinary Pe een ea ante _ Bladder. <1 Wil i J, Johnatone, del. Pp LE U R O N KE C TES S ; M‘Farlane & Erskine, Lith. Edin? {S Gu) GONG) SOLE GUIPA Yar ‘aurysag y ewelIey 3H ‘Tap ‘suo JsSuyop “Pp roe ‘ad ee ere @ eID x > sy oy iy iy Sy rae Par QT co ZI; Roe Osa eres 909°] roo ord Q WY DDINDINDD WII WII) rey day “peo; ah ¥ 3 = ee = a, ‘Puate VII. 40 o — SS PecrorRac Fin \ {0 mike r ( 7 : 4 7 waansese® 600 560 520 480 440 400 = my s o S $ = 3 FJ. Cole, del M'Farlane & Erskine, Lith. Edin® PLEURONECTES. ee i PU Sl ha * R : } 190 170 . 150 130 10 90 # PLATE Vibe i | Reese anos.’ EYELessS Evetess Sipe. Sipe oe 320 360 4008 440 460 520 560 680 720 760 amp. p. %, post. cr. 600 com.I. ne Com.M. OMAN ws! com. lV. | | 880 920 960 F.J. Cole, del. M‘Farlane & Erskine, Lith. Edin? PLEURONECTES. TAC OTM Ses Prare De Fig, 27 -COTL.1/YV, SY <- COM.1. Com SM. SS pallium, eprstriatum. AUB Me PAO, Fd ae big, =m o'9 striatum reat) ye “proper. ia) Ue (Ob, thy = C. striatum. ; 7 a coft a s 1B: olfactortus. right 7.U. 2+ 3 4 j ‘ B. 0%, acborius. Peta st »N. opticus. 7. CCrv. f T 1 T 1 _ 300 880 860 640 820 800 780 760 740 720 700 680 660 F. J. Cole, del. MFarlane & Erskine, Lith, Edin” PLEURONECTES. Pratt X. 3 4. << >. hy.c. / OPERCULUM, Ca/ Yr OPERCULUM. jee \\ Y iy 0 lat. Sy yy z & = y uo iy y A dy < é) a ty ; A) Oo 4) EveLess 1) Side. 1 fis ! it 10 ce Fe EH ¢ ve ae IO. .% 3. vi Malis =e O MEAG One NER VAES alec sean ogee Fi Pig. Sle. 5). ry ial aa j ty = Evetess Side ky {| Ocurar SIDE -->OPTic NERVES. II. i i 1 { > \ EB OMPACTORINUS a Ae ui Die ms A Gi : SS Optic CHIASMA _______ 2 te Paciium : } -----OCULOMOTOR. III. PINEAL APPARATUS---- Pinca. Apparatus..-/..¥. 2--PaTHETIC. IV. a nN me aT, TMG Pituitary ie STRIATA. See Boby ee VEN TRICIES. iil LoBpus INFERIORIS. Saccus VASCGULOSUS. y y yi Lp ij 7. a. VIII. (as Uf -if--- Trig + Fac. V-Vil. . /: Ne is V-Vil ? Pi CEREBELLUM oe) eee f a 3 SSS ABOUCENS. VI. “2.7 VV, By Wh Y 4, 1, SAC. VI, "t= Fac.+ Avot. VII-VIll. CEREBELLUM. E _.22~ VENTRICLE. IV. | -}-------GLOSSOPHAR. IX, Place X)-----=-- FO Fea MME MUNCIE ZS, S2e-che sace i) \--------LATERALIS. X. r.l.t r. a. p. Vill_-- De a ie sr pee rem a Ae ON Cem eae VAGUS Ae ee: Spinac Coro. _o» First SPINAL. eee SPINAL Corp. --- ‘ : ~ cy si ~~ >~_ First SPINAL _ F.J, Cole, del. MiFarlane & Erskine, Lith Edin PLEURONECTES. oa Notochord_____- : “evil Wee Wy Oe ik lmP(OSPIMG.-coscecco- Ne720N Ww yy LAND) LZ yj WA oS A Bigs. 32. KX Be). SSO SAN SIRE Kupffers Vesicle Dorsal Fin Fold | Yolk Sac Pectoral \-.- Fin ES ae). Intestine Dorsal PS pa IEP ee SS a : fold Ventral Fin OSGI S eRe Lise 5 ee Yolk Sac : ‘ . — eae, re erie a ec a es WO od eh i” Tea TSS oo oo - a Coad MeN) ‘ SONG i ie aa fe . Figs.32-35, A.Scott, del. M‘Farlane & Erskine, Lith. Edin’ Fig. 36, after Ehrenbaum. PLEURONECTES. Fig. 37, after Petersen. 397 ON SOME RED SEA AND INDIAN OCEAN COPE PODA. By Anprew Scort. (With Plates I-III.) [Read April 11th, 1902.] Two collections of sub-tropical Copepoda made by (1) Mr. H. C. Robinson and (2) Dr. H. Lyster Jameson, were eiven to me for investigation during the past year (1901). These collections, on examination, were found to contain a number of interesting species of Copepoda, including some forms apparently new to Science, and now described and figured. (1) Mr. Rosinson’s CoLiecrion. The first and most extensive collection was forwarded to me by Professor Herdman, F-R.S., my esteemed chief, to whom I am much indebted for the opportunity of examining what proved to be a profitable series of tow- nettings. This collection was taken between Suez and Colombo, by Mr. H. C. Robinson, in the latter part of March, 1901, during his voyage out to Siam. It was com- menced on March 21st, soon after the ship left Suez, and completed on March 31st, shortly before Colombo was reached. The collection represents roughly a continuous section of the Copepoda, &c., living near the surface of the sea between these two ports at that particular time of the year. This collection was made by attaching a fine tow- net to a tap in one of the bathrooms which was supplied FF 898 TRANSACTIONS LIVERPOOL BIOLOGICAL: SOCIETY. with sea water continuously pumped up from the sea by the ship's pump. The water was allowed to strain through the net day and night continuously throughout the period, except on one or two occasions. The contents of the net were taken out in the morning and evening of each day, and preserved in separate bottles. Mr. Robinson’s collec- tion was contained in twenty bottles, and represented ten day and nine night gatherings. None of the gatherings contained more than one c.c. of solid matter, whilst the majority contained about half ac.c. only. Although the gatherings were small in bulk, many of them were very rich in number of species. As a rule there was a con- siderable difference in the number of species of Copepoda found in the gatherings taken during the day and those taken during the night. The greatest number of species found in any day gathering was thirty-three and the lowest ten. On the other hand six out of the nine night gatherings contained over thirty-three species; the greatest number found in a night gathering was forty-two, and the lowest twenty-one. The average number of species for the ten days gatherings was slightly over nine- teen and a half, and for the nine gatherings collected during the night slightly over thirty-two and a half. Day “238: 20, a SO a OR ees oe 17 119" 30 (AO. AT) dG ss 1 TS eee Wiss Suh i eh animate te wnts 21 38 36 36 37 22 25 36 42 species. In addition to well-known oceanic Copepoda contained in the gatherings, the following new species were observed :— Candacia bradyi, Calanopia minor, Stenheliairrasa, Stenhelia erythrea, Delavalia inopinata, Delavalia minuta, Laophonte mornata, Laophonte herdman, Dactylopus robinsonu, Licho- molgus minor, The total number of species of Copepoda RED SEA AND INDIAN OCEAN COPEPODA. 399 observed in the Robinson collection was 86, belonging to eight families, as under :— Calanide - - - 15 species. Centropagide - eo TO) € Candaciide = - : : D i Pontellide - - - 8 “a Cyclopidz : = : 3 i Harpacticide - - - 29 r, Corycaeidee = - . - 9292 ¥3 Lichomolgide - - 1 $ The following list gives the period of time and date when each gathering was made. The numbers 1 to 19 represent the different bottles, and will be used in referring to the distribution of the species. 1. 9-15a.m. to 3-15 p.m.,and 3-15 p.m. to 5-45 p.m., 23.3.01. Com- menced 13’ S. of Suez. Position of ship at noon 29°09'N., 32°46'H. Sky clear, sea smooth. (Two bottles). *2. 7-15 p.m., 21.3.01 to 6a.m., 22.3.01. Shadwan light at end of Gulf of Suez passed about 9 p.m., dead calm. 3. 9-0 a.m. to 6-0 p.m., 22.38.01. Position of ship at noon 24°36’N., 36°08’ E. Dead calm. *4. 7-15 p.m., 22.3.01 to 6-20 a.m., 23.3.01. Slight N.N.E. breeze, ~ sea smooth. 5. 9-0a.m. to 5-45 p.m., 23.3.01. Position of shipat noon 19°53/N., 39°08’EH. S.E. breeze, slight swell. *6. 7-15 p.m., 23.3.01 to 6-10 a.m., 24.3.01. Strong S.E. breeze, ‘ sea moderate to rough. 7. 9-0 a.m. to 5-50 p.m., 24.3.01. Position of ship at noon 15°19’N., 41°55/E. Strong S. breeze, heavy swell. *8e 7-30 p.m., 24.3.01 to 6-15 a.m., 25.3.01. South breeze, moderate swell. (40’ W. of Aden.) *9, 7-15 p.m., 25.3.01 to 6-25 a.m., 26.38.01. Wind Hast, slight swell. (40’ EK. of Aden.) 10. 9-15 a.m. to 6-0 p.m., 26.3.01. Position of ship at noon 12°24'N., 49°24’'H. Wind Kast, sea calm. *11. 6-0p.m., 26.3.01 to 6-10 a.m., 27.38.01. Wind Hast, slight swell. 12. 9-0a.m. to 6-0 p.m., 27.3.01. Position of ship at noon 11°33’N., 54°53’EH., Wind Hast, nearly calm. 400 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. *13. 7-15 p.m., 27.38.01 to 6-10 a.m., 28.3.01. Wind East, sea calm. 14. 9-15 a.m. to 6-0 p.m., 28.3.01. Position of ship at noon 10°35‘N.., 60°22’E. Wind E.N.H., sea calm. 15. 9-0 a.m. to 6-0 p.m. 29.3.01. Position of ship at noon 9°36’N., 65°56’E. Wind E.N.E., sea calm. “16. WAS p.mez; 29.3.01 to 6.30 a.m., 30.3.01. Wind E.N.E., sea calm. 17. 9-15 a.m. to 6-20 p.m., 30.3.01. Position of ship at noon 8°37’N., 71°27°E. Wind E., sea calm. *18. 7-30 p.m., 30.3.01 to 6-50 a.m., 31.38.01. Wind E., slight swell. 19. 9-0 a.m. to 6-0 p.m., 31.3.01. Position of ship at noon 7°21'N., 76°53'H. Wind E., slight swell. * For the sake of simplicity, the night gatherings are marked with an asterisk, Notes ON THE COPEPODA. Calanus pauper, Giesbrecht. Occurrence, Nos. 1, 2, 4, 5, 6, 7, 8, 9, 11, 13, 14, 15, 16, 17, 1S. 19: _ This species has already been recorded from the Red Sea, &e., by Mr. Thompson, (Trans. L’pool Biol. Soe., Vol. XIV., p. 275), and from the Pacific Ocean thy ire Giesbrecht. Calanus vulgaris (Dana). Occurrence, Nos. 4, 6, 7, 8, 9, 13, 14, 16, 17, 18. A widely distributed and sometimes very common species in tropical and sub-tropical collections of Copepoda. Calanus darwini (Lubbock). Occurrence, Nos. 14, 18. There is no difficulty in recognising the adult female of this species, which has the last thoracic segment con- siderably prolonged on the left side, but immature females present some difficulty owing to the last thoracic segments ending in a minute tooth, as in Calanus propinquus. There is, however, a considerable difference in size between the two species. Calanus caroli, Giesbrecht, of which only RED SEA AND INDIAN OCEAN COPEPODA. 401 the male is known, has the fifth pair of feet very like those of the male Calanus darwint, and may easily be passed over as only a form of the latter. Eucalanus subtenius, Giesbrecht. Occurrence, Nos. 6, 7, 18. This species is closely allied to Hucalanus attenuatus, but is distinguished by the form of the forehead and its smaller size. It has hitherto only been found in the Atlantic and Pacific Oceans. Prof. Cleve records it from the Malay Archipelago. Eucalanus crassus, Giesbrecht. Occurrence, No. 8. A night gathering. The female of this species is easily recognised by its robust form and by the appearance of the thoracic segments, which are clothed with fine hairs. The species is widely distributed, and has been recorded from the Farée Channel by my father, Mr. T. Scott (XV. Ann. Rept., Fishery Board for Scotland, Part III. (1897), p. 312), and from the Moray Firth (XVIII. A.R., F.B.S., pt. III. (1900), p. 382). Dr. R. N. Wolfenden also records it from the Farde Channel, (Jour. Marine Biol. Asso., N.S., Vol. VI., No. 3, January, 1902). Dr. Giesbrecht records it from the Atlantic and Pacific Oceans and from the Mediterranean. It has also been recorded from the Malay Archipelago. Rhincalanus nasutus, Giesbrecht. Occurrence, Nos. 8,11. Night gatherings. There seems to be some doubt whether this Copepod should be regarded as a distinct species, or only a small form of Rhincalanus gigas, Brady. The fifth pair of feet of the female are very like those of R. gigas. Dr. Giesbrecht’s species measures 39 mm. to 51 mm. (female), while Dr. Brady gives 8°5 to 10 mm. as the size of R. gigas. RK. nasutus appears to have a wide distribu- 402 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. tion, and has been recorded from the Farée Channel, Atlantie and Pacific Oceans, and from the Mediterranean. Rhincalanus cornutus (Dana). Occurrence, No. 6. A night gathering. This species is easily recognised by its projecting fore- head, and is usually not nearly so rare in tropical plankton as R. nasutus. Its distribution is also more extensive. Paracalanus aculeatus, Giesbrecht. Occurrence, Nos. 2, 4. Night gatherings. This Paracalanus is not unlike the next species, but is easily distinguished from it by the structure of the female fifth pair of feet. It has already been recorded from the Indian, Atlantic and Pacific Oceans, and also from the Mediterranean. Paracalanus parvus (Claus). Occurrence, Nos. 1, 2,3, 4,5, 6, .7,°8, 9, 10; El iteine This species has practically a world-wide distribution. Acrocalanus gibber, Giesbrecht. Occurrence, Nos. 4, 5, 6, 7, 8, 9, 12, 15, 16, 19. This species resembles Paracalanus in size, but is dis- tinguished from that genus by the fifth pair of feet in the female being very rudimentary or wanting altogether. It is widely distributed in tropical and sub-tropical regions. Calocalanus pavo (Dana). Occurrence, Nos. 2, 3, 4, 6, 7, 12, 13, 16, 18. Perfect specimens of this species, which is so well illustrated by Dr. Giesbrecht, are very rarely obtained in collections taken by the ship’s pump, the beautiful caudal sete, as a rule, are broken off, and also the long sete on the antennules. The species is easily identified, however, when the caudal furca alone are present; they project at RED SEA AND INDIAN OCEAN COPEPODA. 4038 right angles to the abdomen. It has a wide distribution in the warmer waters of the sea. Calocalanus plumosus (Claus). Occurrence, Nos. 4, 5, 6, 7, 8, 9, 16, 18. This species is distinguished from C. pavo by its more slender form and three-jointed abdomen. In C. pavo the abdomen is two-jointed. The fifth pair of feet of the female are also different from C. pavo. Its distribution is somewhat similar to the above, but it does not appear to have been previously recorded from the Red Sea and Indian Ocean. Clausocalanus furcatus (Brady). Occurrence, Nos. 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 14, 15, 16, ies, 19. Closely allied to Clausocalanus arcwicornis (Dana), but easily distinguished from that species by the genital or first abdominal segment being shorter than each of the two following segments, and by the caudal furea being nearly twice as long as broad. It will probably be found to have a wide distribution. Euchaeta marina (Prestandrae). Occurrence, Nos. 6, 8, 9, 13, 14, 15, 17, 18. This is one of the most widely distributed and usually most abundant members of the genus. Scolecithriz dane (Lubbock). Occurrence, Nos. 9, 11, 16, 18. This appears to be a widely distributed species, but does not appear to have been recorded from the upper regions of the Indian Ocean. No. 9 gathering was taken about 40’ HK. of Aden. All the four gatherings were taken during the night. Centropages furcatus (Dana). Occurrence, Nos. 2, 3, 6, 8, 9, 16, 18, 19. 404 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Centropages orsinit, Giesbrecht. Occurrence, Nos. 4, 5, 8, 9, 11, 12. This species has only been recorded from the Red Sea, and the present collection extends its distribution into the Gulf of Aden. Centropages calaninus (Dana). Occurrence, Nos. 1, 2, 3. This species resembles C. violaceus in appearance, but the male is easily recognised by its fifth pair of feet. It has only previously been recorded from the Pacific Ocean. Centropages elongatus, Giesbrecht. Plate L., figs. 13 and 14. Occurrence, Nos. 4, 5, 12, 14, 18, 19. . This Centropages also resembles C. violaceus in appearance, but the fifth pair of feet in the male are quite distinct from C. volaceus or C. orsinw. Dr. Giesbrecht found this species in plankton collected by the aid of the ship’s pump by Dr. A. Kramer, when passing through the Red Sea at the end of July, 1895. The gatherings in which C’. elongatus were found by Giesbrecht were taken between 15° N. and 27° N. well inside the Red Sea. The Robinson collection extends the distribution into the Indian Ocean to near Colombo. The figures show a dorsal view of the male, which measured 2°2 mm., and the male fifth feet. Pseudodiaptomus serricaudatus (T. Scott). Plate L., fig. 6. Occurrence, Nos. 8,9. Both night gatherings, near Aden. This species was first discovered by Mr. T. Scott in a collection of Copepoda, &c., from the Gulf of Guinea, West Coast of Africa. It has since been recorded from India. Temora stylifera (Dana). Occurrence, | Nos. 6, 7, 8, 9, 10, 12, 13, 14, 16, 18, 19. RED SEA AND INDIAN OCEAN COPEPODA. 405 Temora discaudata, Giesbrecht. Occurrence, Nos. 1\2, 4,5, 6, 7; 8,9, 10, 11, 13,16, 18. These two species were widely distributed throughout the Robinson collection. Pleuromamma abdominalis (Lubbock). Weeurrence, Nos. 2, 3, 4, 6, 7, 8,9, 16, 18. This appears to be a widely distributed species, and is recorded from the Farée Channel and the Shetland waters by Dr. Wolfenden. It is also recorded from the Mediterranean, Red Sea, Atlantic, Pacific and Indian Oceans, and from the Malay Archipelago. Pleuromamma gracilis (Claus). Occurrence, Nos. 9, 13, 18.- All night gatherings. The distribution of this species is somewhat similar to the last, but it has not been found so far north as the Tarde Channel. Lucicutia flavicornis (Claus). Oecurrence, Nos. 2, 4, 6, 7, 9, 18. Candacia ethiopica Dana. Occurrence, Nos. 9, 13, 14, 15, 16, 17, 18, 19. This distinct species was observed in all the gatherings taken after leaving the Gulf of Aden. It has already been recorded from the Indian Ocean and Bay of Bengal by Mr. Thompson. Candacia catula, Giesbrecht. Occurrence, Nos. 6, 16, 18, 19. Giesbrecht records this species from the Pacific Ocean and Red Sea. Professor Cleve (Kongl. Svenska Veten. Akad. Handl. Band. 35, No. 5, p. 5), records it from the Malay Archipelago, which appears to be all the distribu- tion yet known. 406 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Candacia bispmosa, Claus. Occurrence, No. 11. A night gathering. This species has been recorded from the Mediterranean and Pacific Ocean only. Candacia truncata, Dana. Occurrence, Nos. 4, 9, 12, 16, 18. The distribution of this species is similar to that of Candacia ethiopica reterred to above. Candacia bradyi, n. sp. Plate L., figs. 9-12. 1883. Candace pectinata, part, Brady Rept. voy. ‘‘ Challenger ’”’ Copepoda, vol. 8, p. 67, pl. xxx., fig. 9 only. Occurrence, Nos. 8, 9. Both night gatherings, near Aden. Only the male of this species has been observed. Length 2mm. In general appearance it resembles the male of C. varicans, Giesbrecht, but the terminal spines of the last thoracic segment are much smaller and the abdomen is slightly asymmetrical. The chief difference between Candacia bradyi and the other described species is in the structure of the fifth pair of feet. The drawing, fig. 11, represents this pair, which is practically the same as the fig. (9) given by Professor Brady on Plate XXX. of his Report on the “Challenger” Copepoda, but is quite different from the fifth feet of the male of Candacia pectinata, occasionally taken in British waters. I have compared with specimens of C. pectinata from the Clyde collected by my father. Calanopia elliptica (Dana). Occurrence, Nos. 1, 2, 4, 6, 7, 8, 11. This species is widely distributed throughout the Robinson collection, and has already been recorded from the same region by Mr. Thompson. Calanopia minor, n. sp. Plate L., figs. 1-5. Occurrence, Nos. 4, 6, 7, 8, 11, 13, 16, 18. RED SEA AND INDIAN OCEAN COPEPODA. 407 Length of female, 1:15 mm. Length of male, 1:16 mm. This species resembles C. elliptica, but can be easily identified by its smaller size and more slender abdomen. The side view of the female abdomen shows it to be very little wider than the caudal furca. The species is mainly distinguished from C. elliptica, however, by the structure of the fifth pair of feet. The fifth pair in the female is one-branched, and each foot is composed of three joints of nearly equal length. The right and left feet are quite symmetrical. The second joint has one short seta on the middle of the outer margin. The third, or terminal joint, has one seta on the outer margin about two-thirds from the base and two on the apex, the inner one being rather longer than the joint. The inner seta on the right foot is rather longer than the same seta on the left foot. The fifth pair in the male is also one-branched, and each foot is composed of four joints. The basal joint of the left foot is very small, and only about two-fifths the length of the second joint. Second and third joints of nearly equal length. The second joint has a projection on the inner margin near the base. Fourth joint small and only about half the length of the third joint. The right foot is modified for grasping. See fig, 5. Calanopia americana, Dahl, (Ber. Ges. Freiburg N.S., Vol. 8, p. 21, t. 1, figs. 23-26), and Calanopia auriwillii, Cleve, (Kongl. Vet. Akad. Handl. Bd. 35, No. 5, p. 82, pls. 2 and 3), are very like Calanopia minor in general appearance, but the structure of the fifth pair of feet, both in the male and female, are different. Labidocera acuta (Dana). Occurrence, No. 8. A night gathering, 40’ west of Aden. Labidocera minuta, Giesbrecht. Occurrence, Nos. 7, 10, 16. 408 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The only localities recorded for this species are Pacific and Red Sea (Giesbrecht), and from the Arabian Sea by Professor Cleve. Ocean— Hong-Kong Pontella fera, Dana. Occurrence No.6. A night gathering, near the end of the Red Sea. This species has been recorded from the Pacific and Indian Oceanus only; the Red Sea is therefore a new locality for it. Pontellina plumata (Dana). Occurrence, Nos. 2, 9, 12, 16, 18. Pontellina plumata has a wide distribution, and has been recorded from the Mediterranean, Atlantic, Pacific, and Indian Oceans, but not from the Red Sea. Acartia negligens, Dana. Occurrence, Nos. 1, 2, 3, 4, 5, 6, 8, 9, 13, 14, Ib) tees: This is a widely distributed species, and has been recorded from the Mediterranean, Red Sea, and Pacific Ocean. The Robinson collection extends its distribution into the Indian Ocean. Cleve has recently recorded it from the Arabian Sea and Malay Archipelago. Acartia erythrea, Giesbrecht. Occurrence, Nos. 1, 5, 6, 8. No.1, Gulf of Suez; 3, 6, 8, Red Sea. Until recently the Red Sea was the only region where it was known to live. Mr. Thompson (Trans. L’pool Biol. Soc., Vol. XIV., p. 284), records it from the Indian Ocean, and Prof. Cleve, op. ct., records it from the Malay Archipelago. Oithona plumifera, Baird. Occurrence, Nos. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 16, 1G: RED SEA AND INDIAN OCEAN COPEPODA. 409 Oithona plumifera has not previously been recorded from the Red Sea. Mr. Thompson records it from the Indian Ocean, and Professor Cleve from the Arabian Sea and Malay Archipelago. Oithona similis Claus. Weeurrence, Nos. 1, 2, 5,.6, 7, 8, 9, 10, 15, 16, 17, 18, 19. This Ozthona has already been recorded from the Red Sea and Indian Ocean by Mr. Thompson. Professor Cleve records it from the Arabian Sea, and doubtfully from the Malay Archipelago. Oithona minuta, T. Seott. Occurrence, Nos. 4, 7, 8, 12, 16, 19. This very small but quite distinct species occurred sparingly in the gatherings referred to. It does not appear to have been recorded from any other region excepting the Gulf of Guinea, where it was first found. Longipedia coronata, Claus. Occurrence No. 1. Near Suez. Not previously recorded from this region. FEictinosoma atlanticum (Brady & Robertson). Occurrence, Nos. 1, 4, 8, 11, 16, 17, 19. This species has a wide distribution, and ranges from the Farée Channel to the warm seas. Euterpe acutifrons (Dana). Occurrence, Nos. 1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 13. This species has also a wide distribution. Setella gracilis, Dana. Weemrrence, Nos. 1, 2, 4, 5, 6, 7, 8, 9, 11, 12, 18, 15, 16, 17, 18, 19. Miracia efferata, Dana. Occurrence No. 15. A night gathering. 410 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Clytemnestra scutellata, Dana. Occurrence, Nos. 4; 6, 7, 8,9, 11, 12, 13, lo, 17, 2S7no Ectinosoma atlanticum, Euterpe acutifrons, Setella gracilis, Miracia efferata, and Clytemnestra scutellata, have already been recorded by Mr. Thompson from the greater part of the region traversed by the Robinson collection. Stenhelia irrasa, n. sp. Plate IIL, figs. 6-10. Occurrence, Nos. 4, 5. Description of the Female—Length ‘76 mm. Body elongate, slender; rostrum small and slightly curved. The abdomen is ornamented with a few rows of minute spines on the dorsal and lateral surfaces near the posterior end of the joints. The antennules are short and five-jointed ; the fourth joint is smaller than any of the others, and the fifth joint in some positions has an indication of a dividing line near the middle. The formula shows the proportional lengths of the joints. Proportional lengths of the joints - 6 2 383 1 8 Number of the Joints - - = A 205 23.) Antenne, mandibles, maxilla, and foot jaws somewhat similar to those of Stenhelia oma, Brady. First four pairs of swimming feet also resembling those of S. ama. The fifth pair of feet are small and foliaceous. The inner branches are sub-triangular, and furnished with three plumose sete on the inner distal margin and two on the apex. The outer branches are pyriform in shape, and furnished with two plumose sete on the outer, and two on the inner distal margins, and one on the apex (fig. 9). Caudal furea very short. ‘ Remarks.—This species, though somewhat like Sienna ima, is readily distinguished from it, and any of the other members of the genus, by the structure and proportional lengths of the joints of the antennules, and by the form of the fifth pair of feet. RED SEA AND INDIAN OCEAN COPEPODA. 411 Stenhelia erythrea, n. sp. Plate IIT., figs. 11-14. Occurrence, Nos. 4, 5. Description of the Female—Length ‘79 mm. Body elongate, slender; rostrum prominent and_ curved. Abdomen without any ornamentation. The antennules are moderately long and slender, eight-jointed; the fifth and sixth joints are shorter than any of the others. The formula shows the proportional lengths of the joints. Proportional lengths of the jomts - 12 12 8 8 38 2 4 7 Number of the joints - - ah ee GAGs oes ob. OH ing, sv 78 The antenne, mandibles, maxille, and foot jaws are similar to those of S. irrasa. The first four pairs of swimming feet are somewhat like those of S. 7ma. The fifth pair of feet are larger than those of S. wrasa, and more elongated. The inner branches are furnished with ' four plumose setz on the inner distal margin and two on the apex. The outer branches have four plumose sete on the outer distal margin, one on the apex, and one on the inner margin near the apex (fig. 14). Caudal furca very short. Remarks.—This species is distinguished from S. irrasa by the structure of the antennules, and by the form of the fifth pair of feet. Delavalia mopinata, n. sp. Plate III., figs. 19-22. Occurrence, Nos. 1, 4, 12, 19. Description of the Female—Length ‘63 mm. In general appearance somewhat similar to D. palustris, Brady. The antennules are eight-jointed, and resemble those of D. emula, T. Scott. The formula shows their proportional lengths. Proportional lengths of the joints - 6 5 5 44 38 4 8 4 Number of the joints’ - - aqeeleee Oe Gide Men MGre eur B The antenne, mandibles, maxille, and foot jaws are 412 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. similar to those of D. palustris. The first pair of swimming feet have the inner branches composed of two joints, as in D. palustris, but the first joint is proportionally shorter and the second joint longer and narrower than in that species. The second joint is furnished with two sete on the inner margin and two at the apex; the outer branches are armed like those of D. palustris. The second, third, and fourth pairs of swimming feet resemble those of D. palustris. The fifth pair of feet have the basal joints only slightly produced. The apex of the jjoints is irregu- larly angular, and furnished with four sete placed equi- distant from each other. The outer branches are sub- quadrangular in shape, being longer than broad. They are furnished with one sete on the outer margin near the apex, and four on the apex, the second from the exterior being shorter than the other sete (fig. 22). Caudal furea _ slightly longer than the last abdominal segment. Remarks.—This species at first sight is not unlike Delavahia palustris, but on examination is easily dis- tinguished from it by the proportional lengths of the joints of the antennules, the structure of the first feet, and also of the fifth feet. Delavalia minuta, n. sp. Plate IIL, figs. 15-18. Occurrence, Nos. 1, 3, 4, 19. Description of the Female—Length ‘48 mm. Some- what similar in shape to the last species, but smaller and with rather longer caudal furca. The antennules are eight-jointed, and resemble those of D. robusta, Brady. The formula shows the proportional lengths of the joints. Proportional lengths of the joints - 5 8 5 4 4 4 38 56 Number of the joints - - . -1.1, 2 (3. 4 = (6) The first pair of swimming feet have the inner branches two-jointed, like those of D. znopinata, but the basal joint is proportionally longer, and the second joint shorter and RED SEA AND INDIAN OCEAN COPEPODA. A418 wider throughout its length. The second, third and fourth pairs of swimming feet are similar to those of D. inopinata. The fifth pair of feet have the basal joint very small and triangular in shape, and furnished with two sete at the apex. ‘The outer branch is pyriform, and resembles that of D. robusta. The inner and outer margins are each furnished with one seta, while the apex has three (fig. 18). Caudal furca equal to the combined lengths of the last two abdominal segments. Remarks.—This species is easily distinguished from D. inopinata by the structure of the fifth pair of feet and the longer caudal furca. Laophonte pygmea, T. Scott. Occurrence, No. 1. This species does not appear to have been recorded from any other region outside the Gulf of Guinea, where it was first found by Mr. T. Scott. Laophonte inornata, n.sp. Plate IL. figs. 9-14; Plate I., fig. 16. Occurrence, Nos. 1, 3, 5. Description of the Female—Length ‘66 mm. Body slender, with very angular jointed thorax. Rostrum small and entire, with a minute seta at each side. Antennules slender, seven-jointed. The fourth and fifth joints are very small. The second joint has a minute but distinct - tooth on its lower surface. The formula shows the pro- portional lengths of the joints. Proportional lengths of the joints - 8 8 8 2 2 8 6 Number of the joints - - < 210; . Laophonte inornata, n.sp., female, foot of fourth pair of feet. x 210. . Laophonte inornata, n. sp., female, last abdominal seements and caudal furca. x 100. Lichomolgus minor, n.sp., female, dorsal view. eT. ~] RED SEA AND INDIAN OCEAN COPEPODA. 427 . Lichomolgus ninor, n.sp., female, rostrum. x 175. . Iichomolgus minor, n.sp., female, antennule. x 210. . Lichomolgus minor, n.sp., female, antenna. xX 175. . Lichomolqus minor, n. sp., female, anterior foot jaw. VAP . Lichomolqus minor, n. sp., female, posterior foot jaw. xe 710: . Iachomolgus minor, n.sp., female, foot of first pair Oneeta. — LO: . Lichomolgus minor, n.sp., female, foot of fourth pair of feet. x 150. . Lichomolgus minor, n.sp., female, foot of fifth pair - OIC te te FD: . Inchomolgus minor, n.sp., female, last abdominal seoment and caudal furea. xX 175. Puate IIL. . Dactylopus robinson, n.sp., female, left side. Ae . Dactylopus. robinsonw, n.sp., female, antennule. ANS . Dactylopus robinsonii, n.sp., female, foot of first pair of feet. x 216. . Dactylopus robinsonu, n.sp., female, foot of fifth pair of feet. x 216. . Dactylopus robinsonii, n.sp., last abdominal segments and caudal furca. x 100. . Stenhelia irrasa, n.sp., female, left side. x 77. . Stenhelra rrrasa, n. sp., female, antennule. x 216. . Stenhelia wrasa, n.sp., female, foot of first pair of feet. xX 154. 428 Ric. “9: Fig. 10. Fig. 11. Fig. 12. Fig. 13. Fig. 22. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Stenhelia wrrasa, n.sp., female, foot of fifth pair of feet. x 216. Stenhelia irrasa, n.sp., female, last abdominal segments and caudal] furca. x 100. Stenhelia erythrea, n.sp., female, left side. x 77. Stenhelia erythrea, n.sp., female, antennule. 2G: Stenheha erythrea, n.sp., female, foot of first pair of feet. x 185. . Stenhelia erythrea, n.sp., female, foot of fifth pair of feet: ~~ x« ALG. . Delavalia minuta, n. sp., female, left side. x 77. . Delavalia minuta, n.sp., female, antennule. x 216. . Delavalia minuta, n.sp., female, foot of first pair of feet.” a ae : et - ent Bahn ——— > - os . wa i = . 4 ry Lh a a 2 a ak e “ : = ‘ : i.) ‘ = , ; 4 \ _ ~ ; : ! 5 F * = NY oe ge ao ee a Trans. L’poon. Brot. Soc., Vou. XVI. Big! Andrew Scott de/ COPEPODA. Prats II. lee UL : = COPE PODA 429 fees €. MEMOIRS. No. IX.). CHONDRUS. BY Otto V. DaRBISHIRE, Owens College, Manchester. CONTENTS. AMET TCIM Cocaine cielsneceecvececerscnaveecescaibodccannessseeeatedosass 430 Introductory remarks. The collection of material and its preparation for the herbarium and the microscope. PE SvaMMmrUISTORISPUS (1i.)) STACKH. © ......ssccccnccccccesdsecsccerudenss 435 A. External morphology of the vegetative organs ......... 435 B. Anatomy and histology of the vegetative organs ...... 438 HPMEP AMAL OMANOL LIVCrSWOOU Seerseicuernise «ctersivinn svsaineieaiees 438 PPR ANAT ONAN (OL TNC LOOU wacces csc verececics sonseetses) form the system of “collecting cells,” the central cells The whole arrangement is 9) form the “ conducting tissue. based on the assimilation, collection and conduction of food. ‘The assimilating cells have been called the cortical layer, the two other tissues the outer and inner medulla respectively. We will employ the nomenclature based on the physiological function of the respective tissues, although the other terms, cortex, inner and outer medulla, are equally good. y The tissues just mentioned are seen at their best and in their most characteristic condition a short distance behind CHONDRUS. 439 the youngest part of the shoot. The youngest or most actively growing part of a shoot is found at the end furthest away from the basal attachment organ. A longitudinal section of a young frond should now be eut at right angles to its surface, and rather near a median longitudinal line. The material should be fresh and the sections should be mounted in sea water. These should be examined first, but others can also be examined after being mounted in glycerine (50 per cent solution in water) or glycerme jelly (fig. 7). The Central Conducting Cells will be found to be elongated ina longitudinal direction. They are fairly narrow, and they possess fairly thick walls. The peculiar nature of the walls becomes very apparent when a section is mounted and examined in fresh spring water. In this case, owing to the rapid absorption of water by the cell walls, the sections rapidly curl up. This central tissue of much elongated cells resembles more a strand of interwoven filaments than a close paren- chymatous tissue. By this Chondrus crispus may, as already pointed out, be distinguished from the species of several allied genera. But it has this feature in common with Gegartina mamillosa. ; The cells of the conducting tissue are connected with one another at certain poinis. These points become very evident if the cell walls of a section have been allowed to swell up in water or dilute glycerine. The cell walls encroach on the cell cavity, leaving only a narrow canal of varying length leading apparently from one cell to another. A fine wall, which does not swell up, is stretched across the canal, thus forming a pit, as we find it in the higher plants. The pit membrane probably allows of the cytoplasm of one cell communicating with that of the other. On each side of this pit is a small cap, consisting 440 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. of what appears to be coagulated cytoplasm. The struc- ture of the pit will be referred to again, when discussing the histology of the shoot subsequently. Connected with the central elongated cells of the con- ducting tissue are the Collecting Cells. These are much shorter than the central cells, and as we pass further out they diminish still more in size. They form a rather closer tissue than the conducting cells, and they are extensively connected by pits, with or without the above- mentioned protoplasmic caps, with any of the neighbour- ing cells they may come into contact with. The nearer we come to the outside the more regularly do they come to le in rows. Finally there arise from them the very regular rows of Assimilating Cells, which run parallel to one another, but are curved upwards and outwards at a certain very definite angie with regard to the longitudinal axis of the whole shoot. The assimilating cells possess numerous pits, which are however all destitute of caps. The whole body of Chondrus crispus consists of a com- plete system of very long and very much branched hyphe. The assimilating cells form the apical branches of these hyphe. As a general rule the divisions in these threads will take place at right angles te the longitudinal axis of each cell row. But there is evidence to show that some of the divisions are more or less at right angles to this direction. Hyphal tissue of this kind has been distinguished as plectenchyma. The filamentous nature of the tissues becomes very apparent if the growing point of a frond is examined in a longitudinal section, when one can see spreading out in a fan-shaped fashion the hyphe of all the three tissues (Pl. IL, fig. 6). In transverse section the cells of a young plant differ little in appearance from what is seen in longitudinal section, except that the conducting cells appear rather CHONDRUS. A441 round, but still slightly oval in outline. In the case of the flat frond, they are usually elongated in a transverse direction and parallel to the two flat surfaces. There is no difference to be noted in the other tissues. I have already referred to the growing point. It is that part of the plant where the formation of new cells is going on most actively, but it is, strictly speaking, not the only part of the plant which is growing. Cell division is going on very rapidly in this region, as may be seen by looking at the size of the cells. The formation of new cells is, however, not confined to this region, but is also going on, though probably less rapidly, at the tips of nearly all the assimilating cell rows. The innermost cells of these rows gradually become collecting cells, and new rows of assimilating cells are formed by branching. New cells may also, though rarely, be formed by short tube- like cells growing out from older conducting cells. Thus far the formation of new cells, as part of the process by which Chondrus crispus grows, has been described. The growth in lengih of the shoot is brought about by the cells of the conducting tissue becoming more elongated, by the collecting cells becoming larger and in the end passing into conducting tissue, finally by the assimilating cells gradually passing into the collecting cells and new assimilating cell rows being formed by the branching of the older ones. The cells of the conducting tissue measure about 8-10u in length at a point about 100u back from the shoot apex, at further intervals of 100u they increase on the average to 10-144, 20u, 380-40u, 50u, being finally 80u at a distance of about 800u from the apex. The collecting cells, with a measurement of 4-84 in their longest diameter at a distance of 100u from the apex, increase at intervals of 100u to 8-10u, 10-12u, 449 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. and 20u. This may be taken as their greatest diameter, for after this they would be reckoned part of the conduct- ing tissue. The assimilating cells vary very little in diameter, being about 4-6 x 8-44 near the apex, and rarely rising above 8 x 3-4u in the lowest regions just above the basal disc. Their longest diameter is generally parallel to the longi- tudinal axis of the whole row of cells. The increase in thickness of the lower regions of the shoot is brought about not by the addition of thick layers of assimilating tissue, as is the case with Phyllophora Brodiet. The assimilating layer in Chondrus is 20-254 deep in a flat frond of about 850u in thickness, but in a frond which was 840u thick, the thickness of the assimi- lating layer was only 25-30u. The increase in thickness is in fact due to the assimilating cell rows forming new cells at their tips, whilst their inner cells gradually pass into the collecting cells, and these gradually pass into the conducting cells. The increase in thickness is noticeable in the central tissue only to any extent. It is taking place here at the expense of the outer layers, which are, how- ever, continually being renewed by the formation of new cells at the tips of the rows of assimilating cells. It is probable that a good deal of sliding of cells occurs as the growth in length takes place. The increase in length is probably caused not by the central cells actively growing in length, but by their being drawn out passively during the active lateral extension of the assimilating layer. But frequent longitudinal slits have failed to indi- cate in what way tension is distributed in the tissues. The central tissue is very well separated by the filamentous nature of its constituents in the younger parts of the shoot, but in older parts it assumes more and more a pseudoparenchymatous appearance. By this change the CHONDRUS. 443 tissues become firmer and the shoot, as a whole, is there- fore much strengthened in these older parts. The walls of the conducting cells are very much thicker and firmer in the older part of a shoot than in the younger one. 2.—Anatomy of the Root. The basal attachment organ, or the root part of the whole plant, does not-show any differentiation into the three tissues met with in the shoot. It forms a flat plate of tissue, from which the upright shoots arise. Its out- ward form depends entirely on the nature of the sub- stratum to which it is attached. It is thickest, however, at the points from which the upright shoots arise, and it becomes thinner towards its margin. The lower surface of the attachment organ penetrates into all the numerous crevices of the rock in order to firmly fix the plant. The cells nearest the substratum, forming what might be called the “ Attachment Layer,’ are of very varying shape, and are very irregularly arranged. Their position _and shape depend on the varying minute nature of the substratum. They have thick walls, and form a layer of cells touching the surface of the rock which may be two or three cells deep. But in cases where they have pene- trated into and completely filled out some small hole, they may form a mass of thick walled cells, connected only by small but very firm strands of much elongated cells to the main mass of the root (fig. 9). The greater mass of the root tissue proper is made up of very regularly arranged rows of almost square cells, which run more or less at right angles to the surface of the whole attachment disc. These rows of cells are, strictly speaking, always slightly curved. At the point where a shoot arises they have a convex side turned towards the lower end of the shoot, passing finally into and adopting 444 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the curve of the assimilating filaments of the shoot. Then again, near the periphery of the whole attachment organ, where the latter is still very thin, the curved rows of cells have their convex sides turned towards the margin. Seen in surface view the cell rows are observed to grow out in a fan-shaped fashion towards the margin. The growth of the rows of cells is here mainly, if not exclusively, apical. Transverse divisions in the apical cells are common, longitudinal at the most extremely rare. The upright rows of cells will be seen to be completely undivided (fig. 10). The whole attachment disc grows in circumference by the formation of new rows near the margin. But it grows ‘in thickness by the elongation through apical cell forma- tion of the old cell rows. The cells once formed do not change their form and size to any great extent, as soon as they have attained their full size, about 3 to 4 cells behind the tips of the filaments. The whole plant is covered by a protective membrane, which is not very thick in older shoots, but is very distinct near the apex of a shoot. It becomes a very deep layer in certain parts of the basal attachment organ. On either side of the insertion point of an upright shoot, it is usually very well developed. It is here produced by successive layers of wall substance being separated off from the apical cell of each filament (Pl. III., fig. 10). The cells of the attachment organ are usually full of starch. They are reddish in colour, but the latter is not as dark as in the assimilating cells of the upright shoot. 3.—Histology of the Shoot. The cell walls of the central cells are not very thick when examined fresh and in sea water (Pl. IL, fig. 8). They do, however, swell up very much in spring water CHONDRUS. 445 or in dilute glycerine. One can distinguish three layers in the cell walls, which are best differentiated in. case of conducting cells. when a longitudinal section is stained in hematoxylin and mounted in dilute glycerine. The middle lamella is seen to be fairly thin, but can nevertheless be well made out. It is common to all cells. Each cell is surrounded by a wall, which lies immediately inside the middle lamella, and does apparently not swell up very much 11 water. Then follows an innermost layer, which is in its turn lined by the protoplasm. This layer shows a very distinct concentric stratification, and is apparently most affected by fresh water. It swells up very much indeed. With regard to the protoplasm inside the cell wall very little can be said. It consists of the cytoplasm, and con- tains a roundish nucleus, one or more plastids, starch and vacuoles. The cyptoplasm never occupies a very large space of the cell cavity. The latter is usually taken up by one or more large vacuoles. The cytoplasm of the larger central cells consists merely of a very fine mem- brane, which les between the vacuole and the cell wall. No fine partitions formed by cytoplasmic lamelle can be seen stretching across the vacuoles. In the outer collecting, and still more in the assimilating cells, the cytoplasm appears as a slightly frothy liquid. Fine lamellz are seen to stretch across the vacuoles. It must, however, be understood that the frothy appearance of the cytoplasm so easily seen in many alge affords no indication as to its ultimate structure, as is so often supposed. It has already been mentioned that the large central conducting cells are in communication with one another by means of pits. The pit membranes are thin portions of the wall which do not swell up in water or glycerine. II 446 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. Their position, therefore, becomes very apparent if we allow the other portions of the wall to swell up. The innermost of the three layers, of which the al wall is composed, does not apparently take any part in the formation of the pit, except by its being interrupted at these points. The large pits of the central conducting cells have on either side a cap, which is most likely of protoplasmic origin. The cap is a short cylinder, the one open end of which (fig. 12, 13) overlies the pit membrane, with which . it is co-extensive. At its other end the cap is closed, a small depression being noticed in the centre of the wall. Itis at this depression that the cytoplasm is most firmly attached to the cap. This depression corresponds with the thinnest portion of the pit membrane. In younger cells nearer the growing point the caps on the sides of the pits in the central tissue are not so marked. It is from observations made in. such parts that the protoplasmic origin of the cylindrical caps is made likely. The sides of the cylinder are seen to be continuous with cytoplasmic strands. They seem, in fact, to be hardened portions of the cytoplasm. Owing to the complete absence of any hard woody tissue in the thallus of Chondrus crispus, it seems very probable that these hard caps have the important function to per- form of preventing the collapse or closing up of the open- ing on either side of the pit. The cells of the collecting tissue usually have smaller pits, which may or may not be devoid of any cap-like structures. The pits connecting the assimilating cells are usually quite unprotected, but nevertheless form clearly marked thinner portions in the separating cell wall. The Plastids met with in Chondrus crispus occur in two different forms, namely, as rhodoplastids and as leuco- CHONDRUS. 447 plastids. Both these are, however, only modifications of the same organ. The Rhodoplastids are best developed in the assimilating cells (fig. 14, 15). They are seen here to be of a dark red colour. The red colour is made up of a mixture of chloro- phyll and phyccerythrin, the latter completely obscuring the former. The latter may also be extracted by sub- mersion in fresh water for some time, preferably in warm water. The plant will remain green, the chlorophyll being insoluble in water. The outermost cell of the assimilating filament has a very small rhodoplastid. The latter is represented by a very much reduced flat structure, which fits into the outer end: of the oval shaped cell. The remaining part of the cell appears colourless. The other assimilating cells possess very well developed dark red rhodoplastids. They form here cylindrical plates, which line two or three or even all the radial walls, and sometimes even the outer tangential wall. They do not form a closed cylinder, for they are open along one side. Each cell here contains only one rhodoplastid. The Rhodoplastids are well developed in these assimi- lating cells, but as you pass on to the collecting cells, they gradually change. The red colour becomes fainter, they get drawn out and become very finely divided.. When we get nearer to the conducting celis, the rhodoplastids have become almost invisible. Very finely divided narrow strands are seen of a very faint pink colour. These are the plastids. The fine strands are interrupted here and there by rather larger and more deeply stained masses. Finally in the most central of the conducting cells the finely divided rhodoplastids have disappeared, their place being taken by small roundish leucoplastids. These are almost colourless, but often show a very faint greenish 448 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. tint. These leucoplastids, of which a great many are often found in each cell, have been derived from the typical rhodoplastid of the assimilating cells. The Leucoplastids of the conducting cells and the faintly coloured rhodoplastids of the collecting cells are both very active in depositing starch. Starch is never noticed in the assimilating celis. The starch grains take the form of flattened discs. They stain brownish when treated with iodine. The floridean starch is slightly different in its reaction after treatment with iodine from the starch of the potato, the grains of which stain blue with iodine. 4.—Histology of the Root. The histology of the root calls for no special remarks. The cell walls do not swell up much with fresh water. The pits also are not of the same large form met with in the shoot. The cells of the root are found to be quite full of starch, which by its presence almost completely obscures the rhodoplastids. The root organ is clearly red, but the red plastids are hardly visible. They are apparently finely divided, consisting of darker red masses, which are con- nected with one another by faintly coloured strands. C.—PHYSIOLOGY OF THE VEGETATIVE ORGANS. Under the heading of Physiology, reference may be made to the functions of the three tissues of the shoot. It is, as already mentioned, to their supposed physiological function that they owe their names. The Assimilating Cells are obviously correctly named. Assimilation is conducted by means of the rhodoplastids. The fixation of carbon dioxide and the subsequent elabora- tion of complex organic from simple inorganic compounds Ss lee CHONDRUS 449 may be assumed to be going on through the activity and under the influence of the rhodoplastids. Nothing definite however is known concerning the importance and function of the phyccerythrin in the rhodoplastid. The rhodoplastids in the assimilating cells are on the whole well developed and of a dark red colour. The apical cells of these assimilating rows have, however, only a very small rhodoplastid each. This is a general rule, and it may be due to the fact that these apical cells are actively growing and dividing. The substances built up are apparently removed very rapidly to the next inner cells away from the assimilating tissue. ‘This latter, at any rate, contains no traceable quantities of starch. The food substances are in fact pro- bably collected by the collecting cells from the outer layers, and are then passed on to the large conducting cells. They are then stored or passed up or down the shoot, according to the direction in which any part of the plant in need of food may draw them. A certain faint red colour may often be detected in the finely divided rhodoplastids of the collecting and of the conducting cells, but it is impossible to say whether it enables assimilation to bé carried on. In the centre of the shoot the red colour has disappeared, and in place of one red rhodoplastid we get numerous very faint green leucoplastids. Starch is found very abundantly in the collecting and in the conducting cells. Both these tissues, therefore, probably act as storing tissues. In the root organ the cells are all found to be full of starch. The root is evidently a very important organ for the storage of food. It is not likely that assimilation is going on very actively in the root. The rhodoplastids are faint in colour and very finely divided. 450 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. The whole structure of Chondrus crispus is very typical for a water plant. No hard tissues and no special water conducting cells are found. The plant as a whole is not able to keep itself upright except when in the water. The arrangement of the tissues 1s such that the plant is flexible, but not very elastic. ‘The shoot is bent to and fro by the waves and the tides, but owing to the substance being very tough the shoots are very rarely torn off the substratum. Chondrus crispus, is, in fact, very rarely found in the entangled masses of seaweed which are thrown on to the beach after a gale. D.—TuHeE REPRODUCTIVE ORGANS. The reproductive organs of Chondrus crispus are fairly well known. Vegetative reproduction seems to play practically no part in the life of marie plants. If it does occur in isolated cases it certainly plays no important part in the general biology either of the red alge in particular or the sea in general. The power of reproduction is, in the case of Chondrus crispus, confined to special cells or spores. These may be produced asexually and sexually. In the former case, they are called “tetraspores.” In the latter they are known as “carpospores,” which are the ultimate products of the fusion of the male nucleus of a “ sperma- tium”’ with the female nucleus of the “egg cell.” This fusion—or process of fertilisation—has never actually been observed in our plant, but may safely be assumed to occur. The nemathecia, the organs which produce the tetra- spores, the antheridia giving rise to the spermatia and the procarpia which harbour the egg cell, are never met with on the same shoot. It is impossible to say from the ‘ CHONDRUS. 451 observations to hand as yet whether the shoots bearing different reproductive organs are borne on the same root. It is highly probable, however, that they are not. 1.—The Nemathecium. The tetraspores are formed in great numbers in certain younger portions of the frond. They make their appearance during the winter months, probably from December to March. When held to the light shghtly oval but elongated dark spots may be seen near the apical and younger portions of the frond. These darker portions may be accompanied by a slight bulging out of the assimi- lating layers, but this is never very marked. Hach dark part is a nemathecium, containing tetraspores (fig. 19). In a longitudinal or in a transverse section (fig. 20), through a nemathecium the dark colour of the latter is ‘seen to be due to a dense and rather irregular mass of small round cells. These may be the finished tetraspores, or their mother-cells. Hach mother-cell gives rise to four tetraspores—hence their name. The whole internal tissue of the nemathecium consists of irregular rows of cells, which on the one hand join on to the collecting and a few of the conducting cells, and on — the other hand pass into the assimilating layers (fig. 21). It is, however, before they enter the latter that their cells swell up at the expense of the neighbouring cells, which have a large store of starch. When these cells have attained a certain size they divide into four cells each. They are, in fact, the tetra- sporangia or mother-cells of the tetraspores (fig. 22). ‘The original cell-rows are at first easily made out (fig. 21), but gradually the cells by their growth exert a certain amount of pressure in all directions and the regularity of the cell rows is disturbed. ‘The surrounding sterile cells gradually 452, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. give up all their store of food material, and finally collapse almost entirely. The tissues never break down entirely, but they do get fairly loose when the spores escape on maturity. The division of the protoplasm in the spore mother-cell takes place by the formation of several walls, but always in such a way that the resulting four tetraspores are arranged either in one plane round a common point, or in the fashion of a pyramid of four billiard balls, or in two pairs, the wall separating the two spores of one pair running at right angles to that of the other pair. The spores are said to have been formed by cruciate division. The tetraspore 1s, on its escape, found to be a round, non-motile and naked reproductive cell, which soon after its escape is surrounded by a firm cell wall. It contains a large amount of food material, starch forming an im- portant constituent of the latter. The protoplasm of the spore is also seen to include a rhodoplastid. The latter is rather difficult to make out, owing to the large amount of starch present. It seems to be of the form met with in the old cells of the conducting tissue of the shoot. It consists apparently. of larger and darker portions regularly distributed just side the cell wall of the spore, and these are connected by fine strands. Fresh tetraspores, fixed with iodine, were heated and mounted in glycerine jelly. They then showed the rhodoplastids—now quite green— and their ramifications very well. When it has escaped, the mature tetraspore is probably able to proceed to germination at once. How soon it starts and how rapidly it continues to grow in nature it is still impossible to say. Probably it starts very soon. The tetraspores have not the appearance of resting spores. By employing a method, which gave me good results when applied to the tetraspores of Actinococcus subcu- CHONDRUS. 453 tanéus, the small parasite living on Phyllophora Brodici, I was able to germinate some tetraspores of Chondrus crispus. The latter were dredged near Kiel, in the Baltic, and sown in a sea-water culture in the Botanical Institute of that University. Small portions of parchment paper were first thoroughly soaked for a lengthy period, up to six hours, in running water, so as to remove any acid present. The pieces of parchment were of a size to be conveniently put on to a glass slide, and covered with a large coverslip for purposes of microscopical investigation. These strips of paper were put on to the bottom of small glass troughs2” x 3” x 6” being a convenient size. The troughs were filled with fresh filtered sea water, and kept in a cool and fairly dark place in the Laboratory. For the first two or three weeks constant attention must be paid to the condition of the water in the cultures. ‘The water must be removed imme- diately on the appearance of the slightest milkiness, the outward sign of bacterial activity in connection with some dead organism. A number of cultures should always be set up, as some will always succumb to some adverse circumstance. A portion of a fresh frond bearing a nemathecium may be placed, as soon as obtained, on one of the strips of parchment in aculture. After a certain time the spores will be seen to have escaped, and to be lying about on the parchment... The frond may now be removed, the spores remaining in the culture. When the spores begin to germinate the strips of parch- ment can be put on to slides and be examined with the microscope. They must be kept supplied with plenty of fresh sea water, and be guarded against too strong light. They may not be kept out of the cultures too long. A coverslip may be employed, but with great caution. 454 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. If the water in the cultures is once quite clear, it only wants adding to very occasionally. In the case of Chondrus crispus, I observed that the tetraspore underwent division without at first growing very much in bulk (fig. 27, 28). Then, however, after having formed a small heap of cells, which are all very much smaller than the original tetraspore, longish filaments seem to be formed (fig. 29). These consist at first of unbranched single rows of cells. Finally the commence- ment of the formation of flat plates has been observed, and in the end no doubt a normal flat attachment organ is formed, from which the upright shoots arise. JI have not however been able to follow out the growth of the germinating tetraspore to this stage yet. 2.—The Spermophore. The spermatia or male cells are found on young portions of the frond. The latter are temporarily modified only for this purpose. Later on they evidently again take on the functions and the structure of an ordinary vegetative shoot. They have been called spermophores (fig. 30. 31). The spermophores of Chondrus crispus are small and narrow, slightly flattened leaves. They appear white owing to the fact that the rhodoplastids of the assimilating layers are but poorly developed. They are 3-4mm. long and barely Imm. broad. The general structure of the spermophore does not differ from any ordinary young portion of the thallus. The difference lies in the nature of the last few cells of the - assimilating filaments. The last two or three cells appear to be colourless owing to the rhodoplastid, though present, being very much reduced. These two or three cells together form an antheridium, or male organ. The last cell of the row, the spermatangium, gives rise to one CHONDRUS. 455 spermatium, or male cell. This escapes as a colourless, small round cell, devoid at first of any cell wall, with a diameter of 4-5m. It is non-motile. A fragment of a plastid seems to be present in the spermatium, but this is not revealed by any appearance of colour. When the spermatia have escaped they cease developing any further till they come in contact with the female organ or carpogonium. The antheridia form a layer, which extends over almost the entire surface of the spermophore, hence the white appearance of the latter. The spermatia are found to be mature between October and December. 3.—The Carpophore. The development of the female cell of Chondrus crispus has not yet been made out properly. The following account of its development and structure is based, there- fore, on the few established facts, and on our knowledge concerning the state of affairs in nearly allied genera. Certain portions of the upright fronds take on the function of carpophores, which carry the female organs. They are first very short, being barely 1-2mm. in length. In this condition they show various characteristic struc- tures. The central conducting tissue is seen to consist of slightly elongated cells filled with starch. These cells are destined to play an important part later on in the forma- tion of reproductive cells. In the assimilating layer certain of the cell rows, instead of carrying out their normal func- tion, have developed into procarpia, of which the carpo- gonia form parts. ach procarp consists originally of four cells (fig. 36). The large basal cell is seen to be con- tinuous with the collecting cells stem inwards. Further outwards it is continued into the two intermediate cells, and finally the one celled carpogonium. This consists of 456 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. a swollen lower portion, which contains the egg cell and an upper and slightly drawn out part called the tricho- gyne, which projects beyond the outer limits of the assimi- lating layers into the surrounding water. The trichogyne is the receptive organ for the egg cell. The spermatium becomes attached to the trichogyne, but only in a very few alge has the fusion of the male nucleus of the sperma- tium with the female nucleus of the egg cell been observed (fig. 36). Shortly before the supposed fertilisation the large basal cell has a small cell cut off called the auxiliary cell. The procarp at this point therefore consists of five cells. After fertilisation the trichogyne is cut off from the fertilised egg cell by a complete closing up of the passage between the two divisions of the carpogonium. The tri- chogyne, now functionless, soon withers away. The fertilised egg cell—the oospore—now grows out, and forms a protuberance in a direction towards the auxiliary cell. This outgrowth is a sporogenous hypha. Its contents fuse with the contents of the auxiliary cell, but as far as has been observed in other cases no fusion of nuclei takes place. The sporogenous hypha has only been fed by the auxiliary cell. From the auxiliary cell a number of filaments now grow out. They are, however, only continuations and branches of the sporogenous hypha just mentioned, and represent sporogenous hyphe them- selves. They grow towards the starch-laden collecting cells. These filaments are long-celled and very thin. In their course: they form secondary pits with numerous neighbouring collecting and conducting cells. When they reach the latter they draw on their large store of food, and finally give rise to the carpospores. The end cells of short branches arising from the sporogenous hyphe, or their last two or three cells give rise each to one carpospore. In CHONDRUS. 457 the end the carpophore contains a mass of loose carpo- spores embedded in a mass of exhausted sterile cells. The mass of carpospores forms the cystocarp. The mature carpospore is not unlike the mature tetra- spore. It is roundish, and at first unprovided with a definite wall, which, however, it very soon acquires. Its contents are very dense, a large amount of starchy food being present. The general colour of the carpospore 1s red. This is due to the presence of a rhodoplastid, which occurs in a very much divided form. The whole mass of carpospores forms a fairly large cystocarp, which causes a very marked bulging out of the outer assimilating layers of the carpophore. In this way the latter may be distinguished from a frond bearing nemathecia. What the fate of the carpospores is, we do not know. Presumably they soon germinate, and thus give rise to new plants. Our knowledge concerning the development of the sexual organs of the Rhodophycee is still in a very unsatisfactory condition. The botanist who wishes to obtain any definite results in this connection must, how- ever, live near the sea for a lengthy period, and have a sufficient amount of time at his disposal to carry out extensive and careful continuous observations. E..—Ecouoey. As a species Chondrus crispus is found to be fairly widely distributed, being common on the shores of the northern Atlantic Ocean. It forms one of the commonest plants on the seashore in the L.M.B.C. distriet—in fact, along the whole British coast, as long as the substratum is hard rock and the water is clear. It is a species which 458 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. grows best in the temperate zone. I have no doubt that the distribution of the species of marine alge depends on the same factor as that of terrestrial phanerogams. The limits of the distribution of phanerogamic species as a rule coincide roughly with isothermal lines. | The distribution of the plant form represented by Chondrus crispus in any given small district is dependent not on the temperature, but on quite different factors. It is impossible to say as yet fully what these factors are. The following account is therefore only short. To begin with, it may be stated that a firm sea bottom is generally necessary for the growth of alg in general. Stones which roll about with every tide never bear red or brown seaweeds, at the most only a few green ones. Sand is always quite barren. Certain alge occur very regularly at certain heights above or below certain fixed levels. I have lately been fixing these heights for a few alge in Port Erin Bay as a preliminary to some more detailed investigations into the vertical distribution of marine alge. If we call the level of dead low-water mark of an ordinary spring tide O, then we can divide the shore into a series of regions. We will begin from the highest point. Pelvetia canaliculata extends from 12‘to17' above O. These plants are often left exposed by the sea water for days. The highest individuals are often moistened only by the spray of dashing waves. Fucus vesiculosus extends from 3’ to 13’, but not in the same condition. In an upper region, 9/ to 13’ above O, the plants are small, rarely fertile, and possess no vesicles. In the lower region the plants are normal. Ascophyllum nodosum extends from 6! to 11’ above O. Fucus serratus forms a very distinct region, 3! tert above O. CHONDRUS. 459 Laurencia pinnatifida begins at about 6’ above O, and is closely followed by Laminaria digitata, 5' above O. Lami- naria saccharina begins a few feet lower down. Sacchorhiza bulbosa and Alaria esculenta still accompanied by Lami- naria saccharina and digitata, the latter having about reached its lower limit, are then met with at about 3’ below O. Halidrys siliquosa is found at a still greater depth. These are the chief plants met with in descending from the highest to the lowest water-marks. The data mentioned so far refer to plants which lie exposed on the surface of the rock when the tide recedes. Jt is important to mention this, as many plants rise to a greater height when growing in pools. Laminaria digitata may rise to 9' above O, and probably higher still ina pool. Exposed, however, its upper hmuit appears to be 4’ lower. The plants at the former heights are much smaller than those growing exposed lower down. We can say that alge exposed when the tide recedes attain their best development in size and reproductive powers in the lower part of the region to which they belong. As they rise to the upper limits they become smaller. They may, however, be found above their normal limit in pools. The higher pool plants are always smaller than the lower exposed ones. Chondrus crispus, as a plant lying quite exposed when the tide recedes, extends from 3/ to 4! above O downwards. It has been actually observed to about 3’ below O. Asa general rule the upper plants are shorter, broader and thinner (PI. L., figs. 4,5), than the lower ones. The latter are stouter, very much longer, and the frond is divided into narrower lobes than are found higher up. When growing in pools Chondrus crispus has been found up to a height 460 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. of 9’ above O, being often fairly broad, but never very -high. It is a plant which is completely exposed only for a short time. » Little is known as to the reason why longer and shorter exposure causes a difference in the habit of an alga. We practically know nothing about the distribution of and the meaning of the plant forms met with in alge. Long submergence in sea water is evidently conducive to increase in size and strength. This is possibly due to the necessity of providing for an increase in assimilating power. The forms which are left exposed long become smaller and often rather close set. Plants with bladders are restricted to a limited area, which is probably exposed at every tide, but the significance of the bladders, from an ecological point of view, I have not yet been able to fathom. Halidrys seliquosa occurs, with bladders, quite isolated, at great depths. So far it can only be said that marine alge, as a whole, are at their best when least exposed. Certain species, however, by the possession of certain structural or other peculiarities are able to live in localities which must be considered less favourable. ‘They were driven there by the strong competition prevailing in better localities. Pelvetia canaliculata was probably unable to stand the competition of the moister parts of the sea shore, and was thereby driven to its present position. Many of the green alge seem to be at their best in the higher regions. Y h — = " s 7 —s ' & « F - - k ' 1 3 = \ - ‘ 7 ‘ ‘ F i a - J ‘3 : : a - q Be . i ' , = t ' a \ ~. - =| 7 > 4 A : > al " - 7; > ‘ - ay pa A = i . 4 ‘ . ; be ’ “ - y ‘ Ww i 1 ; ’ i , , ‘ > i a 7 ~ 4S 1 = 7 - ; = 1-2 po : lee, a PLATE VI. Ty & t B.C a Seo ol . Memoir IX. SLUth CHONDRUS. > “pee - vO - a ke > , 4”? 7 _ ® ~ i 7 : . 7 1 = 3 a ' * . i , 1 i : 1 0 t P ‘ p Q i = oe - =~ . - \ \ ‘ - t ce y j ’ ] 2 rH > ~ & ES Ss < BS EN . Ww N Ss iS} : & S S 5) amy (a) Zi ao. =< OO bd hee| fat = (e) s = Bae ts ENS eS) 8 aoe S : > os 1 | ae <_— 7 ay te ‘ x f) 4 { py iy = é \ z ~ a ‘ = = | a t a) f; \ 1 Peibees i ' | ‘ aoe “ee fn / r = i ‘ x ie Pi D =_ ‘ a yet n ra \ " 1 fi i i VAN 1S) vo ZS . RA, RO. + 20. CHONDRUS. 469 Longitudinal section of a frond containing a nemathecium. x 43. Section showing the undivided spore mother- cells lying in rows, which are continued into the assimilating filaments. Fresh material. x 1075. Mass of divided tetrasporangia, surrounded by the sterile cells in a nemathecium. Fresh material. x 1075. - Form of cruciate division of a sporangium. Diagrammatic. Another form of the same. Diagrammatic. Another form of the same. Diagrammatic. Single free tetraspore. It is filled with food material; the darker portions represent parts of the much divided rhodoplastid. x about 3000. PLATE VI.: Tur NEMATHECIUM AND THE LL SPERMOPHORE. Free tetraspore, some time after its escape, and surrounded by a wall. In elycerine jelly x 1075. A tetraspore, having germinated to four cells. In glycerine jelly. x 1075. Germinal product of a tetraspore forming a rhizoid-like outgrowth. In glycerine jelly. x 1075. Frond bearing spermophore at its tips. x 2. Two spermophores. x 12. Outer layers of the tissue of a spermophore. The assimilating cell rows end in antheridia. The last cell of each antheridium, the sperma- tangium, gives rise to one spermatium. In glycerine jelly. x 1075. Fig. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. : ed. Puatse VII.: Tue CAarPoPHore. Frond bearing several cystocarps. x 2. Longitudinal section of a carpophore, showing the spore mass of the cystocarp bulging out. x 43. Group of carpospores surrounded by numerous sterile cells. The two lowest are shown with dark spots, which represent portions of the finely divided rhodoplastid. x 1075. Diagrammatic view of the procarp. The single arrow line shows the sporogenous hypha grow- ing out from the fertilised egg cell. The three arrow lines indicate the course adopted by the several sporogenous hyphe growing out from the auxiliary cell towards the nourishing cells of the centre of the carpophore. 471 SNAKE - VENOMS. By W. Hanna, M.A., M.B. [Read April 11th, 1902.] Venomous snakes are pretty well distributed all over the temperate and tropical regions of the world, with the exception of New Zealand and Oceanic Islands. They are divided into two great classes : — 1. Poisonous colubrine snakes. 2. Viperine snakes. ~The chief aim of the paper is to draw attention to the differences in the two great classes, especially as regards the poison apparatus, and more particularly the venom. The two types to be considered are the cobra, represent- ing the colubrine, and the daboia, or Russell’s viper, repre- senting the viperine snakes, these being the two snakes with which the writer has more intimate acquaintance. The venom of snakes is secreted in a gland which is the homologue of the parotid salivary gland in other vertebrates. It is a compound racemose gland with large alveoli. These have an epithelium of short columnar cells enclosing a capacious lumen, in which the secretion is stored. The glands are placed one on each side of the head, behind the orbit and beneath the masseter muscle. In the cobra they are of very large size. The poison duct passes from the anterior margin of the gland forwards along the upper jaw; it is longitudinally folded on itself for the greater part of its length, and lined with epithelium. The duct has opening into it, throughout its length, a series of small glands, completely surrounding it. It has A472, TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. been supposed that in the cobra these small lobules are mucus glands. ‘Thus in the Ophidia are to be found the only animals in which an admixture of mucus is present in the parotid saliva. Before reaching its termination the duct doubles on itself, and opens upon a small papilla on the anterior wall of the mucous sheath surrounding the base of the tooth. The fang is attached to the maxilla, is tubular and slightly curved. The canal for the poison is really on the outside of the tooth, being formed by the longitudinal reflection of the margins of a fang, which has, as it were, been flattened out transversely. It has two openings. The basal one, near the papilla of the duct, is on the anterior surface; the other opening is on the same surface of the tooth within a short distance of the point. In the largest specimens of the cobra, the fang does not often exceed 4in. In the viper it is much longer and beautifully curved, but never exceeds 4in. in length. In the vipers the fang is so long that it cannot, as in the cobra, be received into a pit in ihe lower lip. Complete depression, when the mouth is closed, is therefore brought about by a slip of the ecto-pterygoid muscle which passes - to the mucous sheath surrounding the fang. When the snake opens its mouth the fangs are erected. . This takes place to a greater or less’ extent in. different snakes. The sheath of the fang is drawn tightly over the anterior surface, and the aperture of the poison duct and the opening at the base of the fang are brought into apposition. | The muscles acting in the closing of the jaws are the masseters and internal pterygoids. The masseters have some of their fibres inserted into the tough fibrous capsule of the poison gland, and when contraction of the muscle SNAKE-VENOMS. 473 eecurs the gland is compressed and the poison dis- charged. | By the arrangement of folds of mucous membrane round the base of the tooth, as is well seen in the sea snakes (Hydrophide), and especially in the cobra and viper, any injury or loss of the fang does not affect the apparatus for the transmission of the poison to the new tooth. Regarding the rate at which the venom is discharged, it has been found by Nicholson that a cobra could not eject through the fang with more force than would be necessary to expel one drop in three seconds, so fine is the interior orifice ; a viper, on the other hand, can eject much larger quantities. The orifice is larger and the poison not nearly so viscid as cobra poison. The writer has seen a specimen ~ of Russell’s viper, when much irritated, ejects a fine stream of poison to a distance of several feet. The poison, then, in cases of snake bite, is discharged through the duct by the mechanical pressure of the muscles which lie in the neighbourhood of the gland, and are used in closing the jaws. Cases, however, are known where the poison has been discharged reflexly from simple pressure on the fang. The gentleman who was the writer's co-worker in India was one day cleansing the mucus from the mouth of a cobra, which was being held by a snake charmer, preparatory to expressing the poison, when he inadvertently pusned the top of his thumb against the fang. He fancied that as the cobra had not bitten him he had not received any poison, although the fang had penetrated deeply; he did no more, therefore, than suck the wound. In about two hours he had weakness of the limbs, drowsiness, vomiting, and was unable to feel in his thumb and first two and a half fingers. The parts swelled, and it was only after a considerable time that he recovered by energetic treatment with Calmette’s antivenine. He 474 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. ultimately lost the tip of his thumb as a result of necrosis and death of ihe tissues. Here, without doubt, a con- siderable amount of poison had been injected, simply by reflex contraction of the muscles from pressure on the tip of the fang. A few words might be said regarding the keeping of snakes and taking their poison. The snakes were usually brought in by snake charmers during the early part of the rainy season. Later, the grass grows so long that they have difficulty in obtaining them in quantity, and at times they were scarcely obtainable from the neighbourhood of Bombay, either through the grass in the jungles being long or the proverbial laziness of the native, who promises, but never performs much. The snakes were kept in wire cages, or biscuit boxes with wire netting over the front and a door at the back. Snakes have been kept for over a year in this fashion. The snake charmer came once a week or ten days to feed the snakes. His method of procedure was as follows : — Having shaken or pulled the snake, be it cobra or viper, out of the box to the ground, he allows it to make off, and following, he grasps its tail with his left hand and elevates it, so that the snake is unable to turn upon him—it simply hisses loudly. He allows it to steady its head on the ground, and while so doing he gently and firmly places a strong, slender stick across its neck, pinning its head to the ground. He now lowers his left hand, and places the tail under his naked left foot, and with the left hand grasps the neck firmly close to the head, the stick keeping the head steady until he has accomplished his object. By taking the tail in his right hand, he has now complete control of the snake. His first object is to take poison from the snake. After washing the mouth (if mucus or dirt is present) with a fine SNAKE-VENOMS. A475 stream of water from a wash bottle, the snake man, steady- ing the tail under his toes, compresses the poison glands gently and gradually with the thumb and forefinger of his right hand. The poison is forced along the ducts, and issues from the mouth in drops; these are received into a clean watch glass held underneath. Cobra venom comes out much more slowly than that of the viper, the poison of the latter being of a more watery consistence. A rather different method is adopted in taking that of the viper, the fangs being so long and the sheaths large, much of the poison would be lost. In the viper, then, a fine piece of string 1s passed round the fangs ; they are drawn forwards, and made to rest inside a watch glass, which has been put into the mouth. The glands are then compressed in the usual way. Regarding the quantity of poison obtained, a fresh, full- grown cobra will give from 10 to 20 drops of poison. A large specimen will give 25 to 28 drops, the quantity being greatest in wet weather; in captivity, however, the amount gradually diminishes, and is reduced to 5 to 10 drops. ie yur Self-immunisation, then, does not seem to gin that natural immunity to their own venoms which - fs a? amongst the poisonous snakes. 485 THE PLACE OF GEOLOGY IN ECONOMICS AND EDUCATION. By Prof. C. Larworrnu, F.R.S. [Read December 13th, 1901.] Your distinguished and enthusiastic member, Professor Herdman, wrote to me some months ago, giving me an account of the aims and functions of this Biological Society, and invited me to come to Liverpool and give you a “talk” upon some geological subject. This year I have been exceptionally busy with extra duties and responsi- bilities, and while I felt I could not possibly decline the request so kindly conveyed, I begged my friends, Prof. Herdman and Mr. Lomas, to defer my visit as long as they possibly could, in the hope that I might find time to prepare something more than a crude geological “ talk,” but that I have found to be impossible. I learn from our Principal, Dr. Oliver Lodge—for the gift of whom Birmingham University owes Liverpool an especial debt of gratitude—that you are very desirous of giving Geology its natural and proper position as one of the great sciences taught to the Degree students in Liverpool College, and that you hope to give the subject eventually the dignity and status of a Professoriate. With this movement I have naturally the deepest sympathy, and shall be pleased to aid it by any means in my power. With this in my mind, I suggested to Prof. Herdman that it might perhaps best accord with the wishes of the Society if I spoke upon “The Place of Geology in Education and Feonomics,”’ and Prof. Herdman, in his turn, being not only scientific but practical, hinted that in MM 486 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. this age and in this district the economic side of the science naturally possesses the widest interest. Indeed, at a meeting of Biologists lke the present, there is no necessity for making a defence of, or an apology for, the science of Geology, or to claim for it its natural place and status in any University curriculum, side by side with the science of Biology. Biology and Geology are sisters, and have long been mutual helpers, and it is almost impossible to say which of the two has most benefited by the progress of the other. The great biological ideas of evolution in general, of the doctrine of descent, of the survival of the fittest, of the origin and meaning of the great biological regions of the globe, even the prevalent biological opinions of the present days respecting the origin of man himself, are all of them the natural consequences of the great discoveries made by geological science. Without the results arrived at by the geologist, and the proofs of the uninterrupted geological evolution of the past lands and waters of the globe, pre- senting the collection and classification of the fossilized remains of various assemblages of living beings which have successively peopled them, these great biological conceptions might well have originated as intellectual theories, but they would for ever have remained figments of the imagination—reasonable it may be in themselves, but wholly incapable of proof. The whole science of biology has attained through geology a grandeur cr an immensity undreamt of by the most sanguine of our forefathers. As the discoveries of astronomers have proved that the laws which prevail in this little world of ours rule in all directions through a universe of worlds, as far as man’s powers can grasp in an infinity of space, so the discoveries of geology and paleontology have shown us that the laws and principles GEOLOGY IN ECONOMICS AND EDUCATION. 487 that rule the biology of the present, have prevailed unbroken from the dawn of existence through what has been termed “half an eternity of time.” But on the other hand, 1t is equally impossible to over-estimate the benefits which geology owes to biology. The original biological demonstrations of the Italians, Steno and Moro, made about the year 1740, that the fossil fishes found in the Tertiary beds of Italy agreed in struc- ture with the living fishes of the Mediterranean, and that their skeletal structures showed that they must have once been living beings which inhabited a vanished sea, formed the first of those immovable logical foundation-stones upon which the great science of historical geology has gradually been erected. Again, no doctrine in historical geology has had so vital an effect, so world-wide an influence, as that cf the identificaticn of the individual geological formations by their organic remains. And even at the present day it is the biological or palonto- logical section of historical geology which, at bottom, is the more powerful. I can confidently assert (even from my own experience, and mine is only a type of the experience of others) that whenever the geological section of historical geology—stratigraphy—and its biological section—paleontology—are in conflict, it is the biological side which is invariably the victor. The whole history of the progress of geology is starred with names of biologists and palzontologists who have enriched that science by their ideas or their discoveries, from Moro to Cuvier, to Hdward Forbes, Agassiz, Huxley, Wallace, and to the great Darwin himself. I have said that there is no need to apologise for the existence of the science of geology, or to claim a place for it among those sciences beneficial to humanity, to biological men. I wish, however, I could say as much for 488 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. the side of the economist and the British public at large. It is strange how so few of those who interest themselves in the commercial progress of the British Islands and our great Colonial Empire are aware how great a part is played by matters purely geological, and by the minerals and mineral wealth, which naturally falls to be dealt with by practical geologists. And here, perhaps, I may quote what I wrote upon the matter some years ago when treating of some of the work done by geologists and by geology in Britain. “It is a fact which no one dreams of disputing, that the primal cause of the uninterrupted progress of our country, almost from the days of the great Elizabeth down to those of the greater Victoria, has been the vast store of mineral wealth that Nature has placed round the homes and at the very feet of our people. Talk of the great landed nobles as we may, boast of the sturdy yeomen of the land and the hardy sailors of the seas, yet at the back of them all, at the back of all our national progress and prestige, le the great coalfields and iron- fields, which have founded and fed our great manufactur- ing districts. These in their turn have furnished employ- ment and subsistence to our teeming populations, have brought wealth, leisure and influence to our middle classes, and have afforded to the nation at large the means of trade and inter-communication at home, of transport and commerce on the seas and of colonisation and conquest abroad.” Let us consider the economic relations of geology in Britain alone, and endeavour to realise, at any rate in outline, the enormous value of the mineral products with whose nature and distribution the geologists have to deal. The monetary value of our mineral products at the pit mouth alone, according to the latest published Blue Book (1900) on the subject, amounted to more than 135 millions GEOLOGY IN ECONOMICS AND EDUCATION. 489 sterling. Indeed one can hardly over-estimate the importance and! variety of those British mineral produc- tions, the places and characters of which are mapped out, described and studied by our practical geologists. These mineral productions include not only the coal, ironstone and limestone deposits worked by the coal miner, the vein- stones wrought by the ore miner, searching for tin, copper, lead and the lke, but they embrace all that long array of mineral material employed by the architect in almost every kind of building construction, or by the engineer in making and maintenance of roads, aqueducts, and railways. A few years ago coal was ignorantly sought in every geological formation. But since the coalfields have been mapped by geologists, and the maps and_ sections published for the people, this waste has practically ceased (at all events in those cases when the owners and speculators have consulted competent geologists, or have been themselves familiar with tthe results of geological research). By means of a certain amount of geological knowledge, and the ability to understand and to utilise geological maps and publications, the landowner in a coal district can now ascertain broadly the extent and value of the coal or iron seams on his estate; the mining engineer can fix on the best place for his new shafts, and can estimate beforehand the amount and quality of his needed engine plant. The borer for coal, iron or water, if he has only a fair amount of geological knowledge, can in most cases determine for himself beforehand the thickness and nature of the strata which he will have to pass through, and consequently the probable costs and profits of his undertaking. “Not only has the advance of geological science, and that faith in its results which has gradually made its way 490 ‘TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. among a few practical and commercial men, prevented waste inside the coalfields themselves, but it has stimulated mining and commercial enterprise outside them. It has already led to the successful working out of profitable coal seams far outside the visible limits of our actual coalfields, away under the red rocks and other barren formations, where none but a geologist would ever have dreamt of sinking for profitable minerals. And more, it has demonstrated the probability—and in some cases almost the certainty—that most of our present visible coalfields are connected together underground by a continuous chain of hidden coal seams, which are all destined sooner or later to be worked with profit.” Leaving altogether out of account the recent discovery of coal in Kent and elsewhere, a discovery prompted solely by the geologist and by geological inferences, we find that all our existing coalfields are extending their borders deep under the red rocks which surround them to even greater and greater depths and over broader and broader stretches of country. There can be no question that on the enlarge- ment of our present coalfields, through the combined discoveries of geologists and the advancement of mining engineering, the future prosperity of Hngland mainly depends. When all our coalfields have been discovered and worked out, it has been well said “the main-spring of our commercial enterprise will be gone.” How important, therefore, it is for the well-being of our people that the study and practice of geology shall be encouraged and fostered by the men of enterprise and commerce who deal with the mineral resources of the land. Of course the value of a knowledge of geology, geological mapping, and the like, to those who work in the search of metalliferous ores of copper, tin and the like, has been acknowledged from the first. Indeed, it was the GEOLOGY IN ECONOMICS AND EDUCATION. 491 ancient ore miners and ore mining schools of Germany and Britain which originally laid the foundations of practical geology itself. But the advance of geological science and mining engineering during the last fifty years has opened out an enormous series of ore-bearing deposits, unknown and unthought of by the ore miners of a century ago. Such, for example, are all the bedded iron ores of our Hnglish secondary deposits—those of the Lias and the Oolite—which indeed at the present day afford two-thirds of our total iron supply. Whole districts like those of Cleveland, in Yorkshire, and Central Northamptonshire, and towns like Middlesbrough, Wellingborough, and Kettering, have rapidly sprung into great wealth and importance in consequence. It was the stratigraphical geologist who first made known the exact places of these rich deposits in the stratified rocks, following them from point to point, and putting them down on his maps, so that the miner and the mineowner might know where to seek them, and how to work them to the best advantage and the greatest profit. But the utility of a knowledge of geology is almost as great to the architect and engineer as it is to the mining man. ‘The discoveries of British geologists have placed it beyond question that almost every kind of stone used in building construction has its own place in the scale of British formations, and its fixed range across country can be determined by the working geologist. ‘The freestones of Portland, Bath, the famous building stone of Barnack, York, Nottingham, the millstone grits, the carboniferous limestone beds so largely employed in the North of Kngland, have had their geological places determined years ago, and it is part of the training of a geological student and a practical geologist to know where they are and how to seek for them whenever he is consulted upon the subject. 492. TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. And it is precisely the same with all the great varieties of clays, of which, in the form of bricks, most of our great towns are built. They have all their known and their ascertainable positions, and it is the duty of the geologist to ascertain and study and describe the various rocks and rock-sheets themselves in detail, and it is his business to be familiar with those not only available for building purposes, but also those suitable for road making and the hke. Over most of our English geological formations the local road metals are soft and indifferent, but in certain districts, such as Charnwood Forest, Shropshire, Cornwall and Devon, rocks excellent for road making purposes occur, all familiar to the working geologist. Every single district in Britain is bound down irrevocably by the geological conditions of that district as respects its fuels, its building stones, its road metals, its cements and the like, conditions which render these materials relatively cheap and relatively costly, as the case may be. But each district can repair its own deficiencies from elsewhere, or can enrich itself by parting with its surplus, by taking advantage of the geological conditions of other areas. The information obtained and codified by the geologist, properly interpreted, enables the landowner and the business man to ascertain in what other districts the rock he requires is obtainable, where there is likely to be monopoly or a superabundance, and where there is likely to be the greatest demand; and it is to geology and the geologist that the District Councils, contractors and engineers must apply for information as to the nearest district or locality whence they can obtain the minerals they require in the needful abundance and of the necessary quality. In matters of water supply, again, the knowledge and the special training of the practical geologist are of the GEOLOGY IN ECONOMICS AND EDUCATION. 498 very first importance. The relative thicknesses or special natures of the local geological formations round a village, town or city make all the difference between success and failure in a water supply both as regards quality and quantity. But it is almost like carrying coals to New- castle to make an assertion like this in Liverpool. All the city is well aware that its original water supply owed its first success, as well as its subsequent failure, if | may eall it so, purely to geological considerations, namely, to the thickness, the characters and dislocations of geological formations in and around the city itself; and all the water- bearing formations of the British Islands, hke those of Liverpool, have each their fixed geological position, which the trained geologist knows, or should be able to ascertain for himself or for his employers. Or further, if we have to deal with the great surface water supplies brought from a distance, like that of Vyrnwy brought into your own city, Thirlmere for Manchester, or Rhuyader for Birmingham, we find that the water engineer is dependent upon the facts furnished to him by geology and the geologist. The catchment basins of the reservoirs must be floored by an impervious geological formation, his great retaining dams must lie on solid geological ground and guaranteed safe by the practical geologist. It is to the geologist that he applies for information for the necessary materials of which his dam is to be constructed—puddle, clay and building stone. rom the geologist and the geological maps and sections he should obtain the desired information respecting the extent, the character and the range of all the rocky material his aqueduct must be cut through—whether in open work or in iunnel—along its entire track from his storage reservoirs to his district of supply. When we realise that the original cost of such great overground waterwork undertakings to companies or 494 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. to ratepayers is enormous, that on the stability of the works themselves and their immunity from all chances of accident depend the lives of thousands, and upon their proper construction from end to end depend the daily health and comfort of millions of people, the need of accurate geological information and its efficient utilisation in waterwork engineering is beyond all question. But geology not only has its uses for the miners, the architects, the County Councils and the engineers, but is altogether bound up with the art of agriculture—the oldest and most widespread profession, if I may call it so, in the world. All these soils cultivated by the agricul- turalist are the broken up débris of the geological forma- tions, and they vary from place to place and from district to district in fertility and barrenness in proportion accord- ing as the geological formations change, or their materials have been transported by geological agents in the past. Aud with agriculture and the comparative richness of our soils is bound up the fact that each geological formation plays its individual part in the comparative fertility. or non-fertility of every broad district of country, considered as a whole. I have no doubt that the dwellers in Lancashire and Cheshire could furnish me with hosts of examples, but I will take two examples selected from the country best known to me, namely, the English Midlands: The long stretch of country underlain by the Triassic pebble-bed formation of the Midlands, poor in sub-soil and weather- ing to gravel, is even at the present day a region of heath land and forest land; dry, barren of population, and of but little surface value. But side by side with it upon its outer border runs for hundreds of miles a narrower band of country floored by the formation known as the waterstones. This waterstone band, rich in GEOLOGY IN ECONOMICS AND EDUCATION. 495 underground waters and weathering easily into open sub- soil, has been settled upon for untold generations. The earliest dwellers in the land fixed upon this waterstone band for the sites of their homes, the barons of feudal times for their castles, and their retainers for their villages, the manufacturers and merchants of later times for their places of trade and residence, and upon it to-day are situated most of the chief towns of the Midlands and their fashionable suburbs. Its rich soil has been culti- vated for centuries, and year by year more and more of its extent becomes enclosed for parks, gardens and private estates. And so we might go on to shew how the health of our people individually, and indeed many of the most dominant factors in the hygiene of our towns and villages, such as the dampness or dryness of the soil, sites for town and village sewage disposal, water contamination and the lke, depend upon geological fact, and how necessary in most cases is the careful application to these of sound geological knowledge and practice. But I have said enough, and perhaps more than enough, to shew how the practical parts of geological science are bound up with the wealth, the health and comfort of the people at large, and how all of us are more or less affected, from the economic point of view at any rate, by geological facts and geological knowledge. The more that know- ledge is added to by the geologist, and the more accurate and the more widespread it becomes; and further, the quicker and the cheaper that knowledge is applied and utilised by those concerned, the better will it be for the health, the wealth, the comfort, and the progress of the entire community. But this purely economic side of geology is only one of the many aspects and departments of the science. In the ‘496 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. very earliest stages of its history it was more or less bound up with mineralogy, which stands related to chemistry as paleontology to biology, and with this inorganic chemistry it has developed side by side. But it has added to mineralogy the great sub-science known as petrology or petrography, which deals with all the mineral constituents of the earth-crust and with their groupings and inter- relationships, actual or theoretical, present and past. Indeed, within the last ten years or so, to not a few who call themselves geologists, petrography is the be-all and end-all of the science itself. Fortified by the advantages afforded by the invention of the microscope and its great improvement in recent years, as well as the advance in chemistry and optics, some of us are tempted to pay too much attention to the study of rocks and rock slides, to the neglect of other branches of the science. There is no hkelihood that this side of geology can be ignored. It has opened out to us the grandest views of the origin and evolution of rocks in general. The day is fast approach- ing when, taught by Nature’s methods, the student of this branch of geology may learn to imitate and manufacture in their laboratories even the natural jewels which are the most valuable of all the mineral products known to mankind. The second stage in the history of our science after its mineralogical childhood was its glorious youth, when in company with its biological sister it entered upon the study of fossils and of the geological formations. And with what a wealth of natural facts and natural phenomena has this branch of our science enriched human knowledge and human philosophy. It has unravelled the structure of almost all of the rock formations of the British Islands and made them the accepted model for the whole scientific world. It has proved that in these formations we have GEOLOGY IN ECONOMICS AND EDUCATION. 497 the past history of our planet from the dawn of existence down to the present day, written in characters that every trained geologist can interpret and every conscientious student of nature must accept as true. It has destroyed the old and cramping notions that for man’s behoof the earth and its living tenants have been created and that without him it would have neither use nor meaning. It has replaced this vain-glorious conception, by the wider knowledge and more ennobling view of the present day, that this earth of ours reaches back through an immensity of time transcending all human conception and that it has been for an infinitude of generations the home of animated beings all bound together in one great family, one great chain of progress, by a mutual kinship and a common experience of birth, joy and suffering, life and death. At the present day no man can be called a well-educated man who does not recognise how much this historical branch of our science has done to increase our knowledge of nature and to broaden the outlook of human philo- sophy. And so vital do I take this knowledge to be to the biologist, the political man, the student of mankind, the teacher, the theologian, the practical man, and even the ordinary man of the world, that I would urge upon each and all of them the necessity of making themselves acquainted with at least the principles, the methods, and the results of geological science. The third stage in the development of our science of geology might be described as its geographical stage. The initiation of this stage we owe to the great Hutton and his apologist Playfair, who were the first to discover or to suggest that all the geological phenomena of the great rock formations could be interpreted in the light of the physical geology of the present. But this branch 498 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. remained under a cloud of misapprehension and unbelief for nearly a century, and it was reserved for the genius of Charles Lyell, hardly more than fifty years ago, to lift that veil and compel the thinking members of mankind to recognise that geology is in effect the sum of the countless geographies of the past, and that the geography of our own time is merely the geology of the present. But it is only of very late years that the geographers themselves have been willing to admit this fact and to employ geological science in their own interpretation of geographical phenomena. Nowadays, we are threatened, however, with a flood of geographical literature coming from their direction. Now, simply because its inhabitants speak a kind of geographical language, Lesley, Gilbert, Suess, Penck, and Davis have shewn hew in the matter of mountain chains, plains, rivers and the coasts of the present day we see in each and all a link in the unbroken chain of geological cause and effect. . What was, a few years ago, to the geographer a geographical phenomena, to be accepted merely as a topographical fact and nothing else, becomes endowed with interest and with life, when it is shewn in this way to be a passing phase in the unbroken course of geographical evolution. But I am still of the opinion that much of what is written is beyond the grasp of the average geographer. For the proper study and appreciation of this so-called branch of geo- graphical science, a knowledge of the principles and the practice of stratigraphical geology is absolutely indispensable. At the present day the science of geology is entering upon its fourth and highest stage, in which the science of physics, or natural philosophy, is destined to play the most important part. Now that the general distribution and characters of the great geological formations have GEOLOGY IN ECONOMICS AND EDUCATION. 499 been sketched out nearly all over the world, and now that it has come to be recognised that they owe their present positions and their relationships to the actual outward form of the earth’s surface, to changes in position brought about by the deformation of the earth’s crust and its various parts, we are beginning to codify the effects of that deformation and to set about the task of discovering the laws which rule in the process. We have as yet, it is true, done little in this department, but the great works of Suess, Heim, Bertrand and many others, all tend to show that the grander deformational effects have been brought about by the same causes, and are certain eventually to fall into line with, and perhaps become compressed under, a common nomenclature with the corresponding results worked out by the physicist in his laboratory at home. It is very difficult to say at what period of life a pupil or a student should properly commence the study of geology. It is the one science among the natural sciences the principles and illustrations of which may be largely taught in the common language of the pupil. By means of such language alone the teacher or indeed the pupil for himself may build up the ideas of precise phenomena in more or less scientific terms. To the average school- boy it is an exhilarating and mind-expanding subject when properly taught. It is a subject which unlike chemistry, physics or even zoology, demands no great expense in the matter of laboratory apparatus. A col- lection of minerals, hammers, a clinometer or compass, a map and a bag for carrying his lunch and his fossils, and you have the complete outfit for every member of a school class setting out on its first geological excursion. The collection of his first rocks, his first fossils by a school- boy, who knows just enough geology to be aware what they mean or what they imply, is a pleasure never to be 500 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCTETY. forgotten, and every fresh out-door discovery gives him a. thirst for more knowledge of the subject and more out- door delights. And, if no more results from the excur- sion than this, yet as Sydney Smith puts it: “If you make children happy now, you will make them happy twenty years hence by the memory of it.” But with a good geological teacher infinitely more may result. Even as a science of observation alone, geology trains the boy to observe accurately, to record correctly, to compare and to systematise, and at every fresh step there is a fresh inference to be drawn or a new fact to be explained and accounted for. Not only so, but the science of geology branches out in all directions and the boy picks up almost insensibly in the course of his work some of the more important results obtained in other sciences, in chemistry, in physics, in biology, in physical geography, in meteoro- logy, and his mind becomes stored with facts of value for him in his after life. His reasoning powers become strengthened, broadened and stimulated by the host of inferences and deductions, inductions and verifications he has made during his geological progress. He learns the use of maps and sections, his eve becomes trained to note the form of the country, the distribution of its rock form- ations and all their relations to nature and to man. “When we recollect how many of the hundreds and thousands of the pupils in our public schools are destined to become landowners, agents, architects, engineers, officers, and the like, and it may be pioneers and dwellers in the great colonies and dependencies of the Empire, it appears almost a crime that at least the outlines of geological science and physical geography are not taught in every one of our public schools.” That geology should be taught in every University College goes without saying. I think I have said more GEOLOGY IN ECONOMICS AND EDUCATION. 501 than enough already to show that no civil engineering course can possibly be complete without it; it is indis- pensable to the student of mining, it is almost as necessary for the metallurgist, and more than good for the biologist himself. For agriculturalists and County Councillors, for architects, and for doctors desirous of qualifying in the matter of hygiene and public health, if it isnot an absolute necessity—at all events it is most highly desirable. To the traveller, whether in Britain or abroad, a knowledge of the science adds immensely to the interest and value of what he sees. To the theologian, the student of history, of humanity and of human philosophy, it gives that clear conception of man’s place in Nature which it should be their duty to ascertain as much as it is his pride to teach ; and to the so-called educated man at large it presents that broad outlook over the whole realm of Nature which is the natural supplement and correction of ‘his one-sided culture. To the landscape painter and the lover of scenery for its own sake there is hardly any need to point out the interest and value of a knowledge of geology. Tor the words of Hugh Miller himself—no mean judge of geology or landscape—“ Geology may be properly regarded as the science of landscape. It is to the landscape painter what anatomy is to the historic one, or to the sculptor. In the singularly rich and variously compounded prospects of our country there is scarce a single trait that cannot be resolved into some geological peculiarity in the country’s ' framework, and which does not bear witness to some striking event in its physical history. Its landscapes are tablets roughened and engraved, like the tablets of Nineveh with the records of the past.” But it has been said, and said often, that the study of geology is destructive of man’s feeling for beauty and mystery, and fatal to the exercise of the imagination and NN 502 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. of the poetic faculty. No assertion could be farther from the truth. There is no science which demands so frequently the highest efforts of the imagination, nor one which is more crowded with those mysterious problems of Nature and so beloved of the poet. The reply given half a century ago to a poet who complained that “the rocks were stratified by geologists as cloths are measured by the mercers, and are in consequence no longer redolent of that emotion of the sublime which was wont to breathe forth of old from broken crags and giddy precipices ” remains to-day as true as when it was spoken.—‘ The poets need be in no degree jealous of geologists. The stony science, with buried creation for its facts and its domains and half an eternity charged with its annals, possesses its realms of dim and shadowy fields, in which troops of fancies already walk like disembodied ghosts on the old fields of Elysium, and which bid fair to be quite dark and uncertain enough for all purposes of poetry for ages to come.” Speaking as an old Geological Professor and teacher, I must acknowledge that I hold Liverpool to be an excellent centre for a School of Geology. You have in your College itself already a Scheol of Engineering and a School of Biology. You have in your great city a host of people who are, or who cught to be, interested in knowing all that there is to be known of the natural products of Britain and of foreign countries for the purposes of commerce and of trade, and who ought to be desirous of securing for themselves and their sons that special knowledge which shall enable them to know where to seek for and how to secure those productions wherever they are to be obtained. You must, in addition, have a host of persons of leisure, of travellers to whom the study of geology would be a relief and a means of adding to their enjoyment and to their culture. GEOLOGY IN ECONOMICS AND EDUCATION. 503 You have within easy reach of Liverpool City some of the finest exhibitions of Post-Tertiary geological deposits in the British Islands. The glacial deposits of Lancashire and Cheshire, as Mr. Mellard Reade and Mr. Lomas have shown, are crowded with geological problems yet awaiting solution. Your Triassic rocks, in spite of all the excellent work my old friend, Mr. Morton, did amongst them, are rich in problems equally mysterious and fascinating. The wonderful series of dislocations which have brought about and fixed the site of the great Dee-Mersey depression, which constitutes the very foundation of the wealth and prosperity of Liverpool itself, are still unsystematised and still unexplained. You are within easy reach of the coal- fields of Lancashire and Flint, and it is yours to discover the hidden places of the Cheshire coalfields that probably he to-day deeply buried below the barren red rocks -between, awaiting the progress of geological research to render them available for the use of future generations. The lovely Paleozoic districts of North Wales, the Isle of Man and the Lake District itself are within the limits almost of a day’s excursion. With all such advantages of position, and with all the daily growing appreciation of the economic and the intellectual benefits of the science, surely it is not too much to hope that a vigorous and successful career is before your Geological School. But after all, success or failure does not so much depend upon the utility of a science, either economically or intellectually, as upon the enthusiasm of its teachers and its votaries. ‘hat enthusiasm is, indeed, whether confined to the individual or communicable to others, its own great and excellent reward. Nor even should we complain if among our geological students we have many who decline to submit to the yoke of examination, and are consequently unknown to the list of those bearing our University 504 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. degrees, but are content to be numbered among that heterogeneous crowd of geologists popularly known as amateurs. ‘'hey and their teachers and their companions may comfort themselves in the fact that all the most famous geologists of the past have been in their day amateurs in the science—Hutton, Murchison, Lyell, Sedgwick, Ramsay, De la Beche, and in modern times Heim and the great Suess. This is surely a great and a goodly company. ven if we ourselves never rise higher than the amateur stage in one or more of the many branches of the science, and get merely an occasional geological outing in the country, and collect only now and again a new fossil or make an original observation— what more glorious and exhilarating than a summer geological excursion in the field! From the sunny morn to the dewy eve, the entire land we traverse is all our own. There is the charm of freedom, there is the keen joy of the chase. The hunt for discovery is as exciting as the hunt for game, and moreover, it is all unstained by the horror of bringing death to a helpless creature. Rather, on the other hand, have we often the delight of restoring to life and light some grand geological phenomenon hitherto dead to science for want of its true interpreta- tion; or we have the pleasure of discovering some fossil relic of the extinct creatures of the lost geological past, and in the words of the great historian—‘ He who ealls what has vanished back again into being, enjoys a bliss like that of creating.” , ys (oi 900° % vi py A — aT: Dt 2 7 | wr, A vi) a : i Mahed a ait ; ae a i) Say Ph iy = q a 4 i | Ny é A = ee y, > > 7 x 4 i ‘ ' on i 7 7 i i fi é 4 i f t o i m7 : i = Wah ee rhe ai (Ky ae dt hast we tet, ht Lh iG fhe ] i |