‘ hy be Tue ie 1a Ue pry aval Ws TWENTY-SIXTH ANNUAL REPORT OF THE FISHERY BOARD FOR SCOTLAND, Being for the Year 19077, IN THREE PARTS. Part JI.—GENERAL REPORT. Part II.—REPORT ON SALMON FISHERIES, Part II].—SCIENTIFIC INVESTIGATIONS. PART II].—SCIENTIFIC INVESTIGATIONS. Presented to both thouses of Parliament by Command of his Majesty. ae : QoS % TIRPaey os RAL LS 3 \/4 AY ne O° ! No = ig rae i, (2 f WS ~O ok yi qo) pow wos ) HOLE Me A dae GLASGOW: PRINTED FOR HIS MAJESTY’S STATIONERY OFFICE By JAMES HEDDERWICK & SONS LIMITED, At “Tur Citizen” Press, St. Vincent PLACE. And to be purchased, either directly or through any bookseller, from OLIVER & BOYD, TwrppaLr Court, EDINBURGH; or WYMAN & SONS, Lrp., Ferrer Lane, E.C., and 32 ABINGDON STREET, WestMinsTER, §.W. : or EK. PONSONBY, 116 Grarron Stremt, DUBLIN. 1909. [Cd. 4454.] Price 2s. 6d. CONTENTS. GENERAL STATEMENT, , The Hatching of Plaice, . ; The Loch Fyne Experiments vith pinice Bryer Investigations on the Herring Fishery of Loch Fyne, The Decomposition of Fish, 5 The Specific Characters of the Gadide, . The Parasites of Fishes, . : Scientific and Technical Instruction to Hishet men, SCIENTIFIC REPORTS. J. On the Decomposition of Fish. By Dr. A. G. Anderson, M.A., M.D., B.Sc., D.P.H., Assistant to the Medical Officer of Health, Aberdeen. (PI. 13); Introduction : General Review and peas, Criteria to be Considered, : General Appearance : Handling a Fish, The Firmness, Softness, &e.. Or the Fish when Handled, Appearance of Surface and Scales, Appearance of the Hyes, Appearance of the Gills, Smell. . Reddish Discoloration of Ventral Aspeet of Backbone, Rigor Mortis, Detection of Rigor Mortis, : Trawled Fish compared with Line Fish, Manner in which Flesh strips away from Backbone or Bone away from Flesh, . The Appearance of Abdominal Walls as affected by the Gut, Distribution of Bacillus Coli in 1 Fish, ‘with Tables of Experimental Data, Bacteriological Examination ‘of Fresh Peritoneal i Fluid in Fish, chiefly for Bacillus Coli, . The Bearing of the Distribution of Bacillus Coli in Fish and other Lower Animals on Public Health Questions, . Summary regarding Detection of Decomposition in Fish, 4 : : Explanation of Plate, Contents. PAGE II. On Sea-Fish Hatching. The Loch Fyne Experiments with Plaice. By Dr. T. Wemyss Fulton, Scientific seta tendent. (Plate IT.), : 40 Introduction, . : 40 The Sea-Fish Hatchery of the Fishery Board, : 41 The Principles of Sea-Fish Hatching, . : ; 42 Proofs of Results, : 46 The Acclimatisation of the Shad in the Pacific, : 48 Special Statistics, , : . ; ¢ 49 Special Investigations, . ; : 51 The Experiments with Plaice in 1 Lochfyne, : P 52 The Results, . : : ; 56 Discussion of Results, . : : : 3 59 III. Some Notes on Fish Parasites. By Thomas Scott, LL.D., F.LS. (Plates III.-VII.), . 2 F 73 IV. Report on the Operations at the Marine Fish Hatchery, Bay of Nigg, Aberdeen, in 1907. By Dr. T. Wemyss Fulton, F.R.S.E., Scientific Superintendent, : ; ‘ 93 ~¥5-On the Specific Characters of the Haddock (Gadus Aiglefinus, Linn.), Whiting (Gadus Merlangus, Linn.); Gadus Poutassou, Risso ; Gadus Argenteus, Guichenot ; Gadus Saida, Lepechin; Gadus Ogac, Richardson; Gadus ‘Navaga, Kolreuter ; with a Key to the Species of Gadus found in Northern Waters. By H. Chas. Williamson, M.A., D.Sce., F.R.S.E., Marine Habenaley, Aberdeen. (Plates VIIL- XIII), 3 ‘ , ‘ 97 Introduction, . : : ‘ ; 97 The Fishes Examined, : ‘ 97 External Characters—Body-Dimensions, ; : 98 Enumeration Characters, : 99 Table showing the Measurements as ‘Percentages of the Length of the Fish, . 100 Table showing the numbers of Vertebre, Fin- -~vays, and Pyloric Czeca in the different species, . ite Key, : 2 : : «DE The ‘Skulls, etc., Ha : : . 120 Diagnostic Value of certain Bones, : : « VhZs The Diagnosis of Isolated Bones, : ; ay LS The Rib -(Pleurapophysis), : : : . 124 Notes on the Species, . : 3 : wi £26 Literature, . 4 Ms : peels (3\0) Letters used in the Plates, é : ; > et Explanation of the Plates. : Y : . fez “2h TWENTY-SIXTH ANNUAL REPORT. TO THE RIGHT HONOURABLE JOR ENS ENC Dek FR My P., His Majesty's Secretary for Scotland. OrFice oF THe FisHery Boarn FOR SCOTLAND, EpinspureH, 11th December, 1908. SIR, In continuation of our Twenty-sixth Annual Report, we have the honour to submit— PART II1.—SCIENTIFIC INVESTIGATIONS. GENERAL STATEMENT. This part of the Twenty-sixth Annual Report deals with the scientific investigations which have been conducted by the Board in 1907 in connection with the sea fisheries of Scotland, so far as they have been completed, by means of the Parliamentary Vote granted for the purpose. The scientific work has, as usual, been carried out under the supervision of Dr. T. Wemyss Fulton, the Scientific Superintendent under the Board, the researches having been for the most part undertaken at the Board’s Marine Laboratory, Bay of Nigg, Aberdeen, and partly in the Firth of Clyde. The hatchery for sea fishes is also situated at Aberdeen, and a statement of the work done at it during the year will be found below. As was explained in previous Reports, the investigations into the condition of the fishing-grounds in the Moray Firth and Aberdeen Bay by means of commercial trawlers specially employed far that purpose was discontinued at the end of 1905, but the statistics of the catches of line tishermen within the Moray Firth continue to be collected. In the Firth of Clyde, and in Loch Fyne in particular, the investigation into the herring fishery which has been in progress during the last few years was continued, and it is intended to 6 Part [1T.—Twenty-sixth Annual Report pursue the observations on the temperature of the water and the abundance of plankton or floating herring-food until the fishery improves, so as to bridge over the period of depression, which unfortunately still continues, and to ascertain whether the scarcity of herrings was related to one or other of these conditions. A fuller statement on this investigation is given below. THE HATCHING OF PLAICE. In the season of 1907 the hatching of the eggs of the plaice at the Bay of Nigg Hatchery was continued as in previous years, but owing to the fact that the supply of the spawning adults was the lowest since the work was commenced, the number of the fertilised | egos collected from the spawning pond, and consequently the number of fry obtained and planted in the sea, was the lowest for any year. Although the capacity of the spawning pond allows of much more than a ‘thousand plaice being retained in it with ease, only 87 fishes, including males and females, were available for the supply of fertilised spawn. The cause of the decrease was the difficulty of obtaining supplies of adult fishes. Hitherto the stock was obtained by the use of a trawler which was permitted to fish in the bays of the Moray Firth and in Aberdeen Bay for the purpose of securing a supply, all the plaice which were suitable for the hatchery being brought ashore in tubs, the remainder of the fishes taken becoming the property of the owner of the trawler as recompense for the use of the vessel. This arrangement was interrupted at the end of 1905, as explained in last Report, the plaice since obtained for the hatchery being brought ashore by the “ Goldseeker,” the vessel employed in the international fishery investigations. Plaice of the kind required are only to be caught in any quantity on the inshore grounds where trawling, except for scientific purposes, is prohibited. Under present circumstances it is not possible to get sufficient supplies from the ordinary com- mercial trawlers working on the offshore grounds. The quantity of plaice obtained by them on any single voyage is, as a rule, small, and it would require many expeditions of the kind to procure an adequate stock, and, as the fish would require to be purchased at their market value, the cost would be very consider- able. ‘The total number of the eggs of the plaice collected from the pond in the course of the season of 1907 was estimated at about 1,627,000, as compared with 7,486,000 in 1906 and over 40,000,000 in 1905. The estimated number of place larvee, or fry, obtained from them and “ planted” in the sea on the neighbouring parts of the coast of Aberdeenshire was 1,282,000, the loss in incubation amounting to about 21 per cent. Owing to the small numbers of fry that were at any one time available, it was not thought to be desirable to incur the expense of transporting them to the northern parts of the coast as in former years, as was requested by the fishermen of the localities. The number of eggs and fry dealt with since the work was begun at the Bay of Nigg is shown in the following Table :— of the Fishery Board for Scotland. Year. Eggs Collected. Fry Liberated, 1900 43,290,000 31,305,000 1901 63,377,000 51,800,000 1902 72,410,000 55,700,000 1905 65,940,000 53,600,000 1904 39,600,000 34,780,000 1905 40,110,000 24,500,000 1906 7,486,000 4,406,000 1907 1,627,000 1,282,000 Owing to the fact that the hatching work is carried on in conjunc- tion with the work of the Marine Laboratory, its cost is relatively small, the extra expenditure on coals, food for the fishes, &c., being estimated at about £80. | Tar Locu Fyne EXPERIMENTS WITH PLAICE Fry. To the present Report Dr. Fulton contributes a paper descriptive of the problems and principles of the artificial propagation of sea fishes, dealing especially with the proofs of the results of the work which have been brought forward, and in particular with the experiments on the effects of the liberation of large numbers of plaice fry in Loch Fyne, which were begun thirteen years ago and have been carried on since then in each year. Hatcheries for the propagation of sea fishes now exist in America, Norway, New Zealand, New South Wales, Scotland, and England, where there are two, one at Piel and the other at Port Erin, in the Isle of Man. In the United States, where the amount of money voted by Congress for piscicultural work in the year 1906-1907 amounted to 454,180 dollars, or about £94,600, there are three permanent hatcheries and several temporary hatcheries devoted to the artificial propagation of marine fishes, the output of fry from them in the year aggregating over 503,000,000 and 168,000,000 lobsters. In Canada the amount appropriated for pisciculture was nearly £33,000, five hatcheries being engaged in lobster culture, the output of young lobsters amounting to 501,000,000. With regard io the benefits accruing from these operations, the Fish Com- missioner of the United States reports that encouraging results of the efforts of the Government to maintain the fish supply by artificial means appear in reports from fishermen and fish culturists in all parts of the country; and that, although it is difficult to establish definitely the extent to which the hatcheries have affected the condition of the commercial fisheries of the coastal waters and the Great Lakes, the renewed productiveness of old and abandoned fishing grounds and the abundance of fish on entirely new areas are strongly indicative. Proof of the amount of benefit derived from the artificial propa- gation of sea fishes is very difficult to obtain, since in almost all cases the fry which were added to any area of water are simply an addition to the fry which naturally exist there; and there is no system of statistics in use which would enable the effect of the liberation of fry on the quantity of fishes subsequently caught to 8 Part IIT.—Twenty-sixth Annual Report be measured or to be separated from the fluctuations due to other causes, whether natural or artificial. An exception was the case of the introduction of the shad to the waters of the Pacific by the United States Commission. Fry of this fish, which did not exist there, were brought from the Atlanric coast between 1873 and 1880, the total number being comparatively small, viz., 619,000. From these colonies the shad increased to such an extent that in 1895 it was reported to be one of the most abundant fishes of California, and had extended along 2700 miles of coast line. With the view of ascertaining the effect of the liberation of the fry of plaice, considerable numbers of them were transferred to Loch Fyne from the hatchery of the Fishery Beard in the years 1896- 1901, and a few months later the abundance of the young plaice to be found in certain localities in the loch was tested by fishing with a push-net on the beach. In the six years 1902-1908 no fry were placed in the loch, and the push-nettings were continued at the same places and at corresponding times in order to determine the abundance of the young fish in the same way. The total number of the year’s plaice which were obtained was 13,068, the collective results in the two periods being as follows :— No. of Fry No.of Hours No. of Average No. Liberated. Fishing. Plaice. per Hour. 1896-1901, 142,880,000 74 6,491 Sf 1902-1908, None. 1654 6,577 39°7 Thus, in the first period, when plaice fry were being put into the loch, the average number of young plaice taken was 87°7 per hour, whereas in the second period, when no plaice fry were added, the average number taken per hour was 39:7, or less than half. The average at each of the five stations where collections were made was less in the second period than in the first, the decrease per hour ranging from 19-2 to 1047. The collections were made in the months of June, July, August, and September, and the mean number of young plaice taken per hour was less in each month in the second period than in the first, and, with one or two exceptions, this was true of each of the stations considered separately. As shown in the accompanying Table, the fluctuations from year to year were very considerable, the mean aunual average ranging in the first period from 24 to 174, and in the second period from 8 to 112. When the average was high at one station or in one month it was also, with few exceptions, high at the other stations and in the other months, and so when it was low, and thus the numbers represent approximately an actual abundance or scarcity of the young plaice in Loch Fyne in the particular years. of the Fishery Board for Scotland. 9 Vidae No. of Fry | Duration of |No.of Plaice|Average No. Liberated. Fishing. taken. per Hour, Hrs. Mins. 1896 4,100,000 10246 1,114 Lahl-4: 1897 21,170,000 2 30 60 24:0 1898 19,200,000 12 ..30 1,195 95:6 1899 16,470,000 Tiger a B 488 28°7 1900 30,590,000 16 O 850 531 1901 51,350,000 LOO 2,784 1740 1903 None. Soo 1,231 373 1904 None. Fh ga) | 253 8-0 1905. None. OH? ae: 2 ae Doge 112:0 1906 None. 30 25 | 505 16:6 1907 None. 8 50 294 Bow 1908 None. 31 45 961 30:3 The period of thirteen years over which those experiments have extended is a considerable one, and Dr. Fulton thinks it is reason- able to believe that the greatly increased average abundance of the young plaice in the first six years was mainly due to the liberation of the 142,880,000 fry in those years; and that, on the other hand, the decrease in the abundance in the last six years was mainly owing to the fact that no plaice fry were added to the loch in these years. These conclusions are supported by a mathematical investigation of the fluctuations in the averages by Miss Lee, of the Marine Biological Laboratory, Lowestoft, to whom the figures were submitted, but a further series of observations would be very valuable, especially to determine more precisely the natural fluctuations. INVESTIGATIONS ON THE HERRING FISHERY OF LOCH FYNE. Since the latter part of 1904, as mentioned in previous Reports of the Board, investigations have been pursued with regard to the herring fishery in Loch Fyne, as far as the means at disposal have admitted. The enquiry was commenced owing to the failure of this important fishery for a series of years, as the following figures, showing the quantity of herrings (in crans), make evident :— Year se Yen ee 1895, - =. 17,853 1901, - - 29,117 1896, - - 18,406 1902, - - 26,339 1397, - - 56,820 1903, - - 21,198 1898, - - 40,801 1904, - =) 1f;820 1899, - - $2,113 1905, - - 4872 1900,.. - - 24,743 1906, - - 8,258 1907, - - 93,914 10 Part ITI].—Twenty-siath Annual Report There has thus been an almost continuous decline since the year 1897, which, however, represented the largest quantity which has been recorded as taken from the loch, and the decrease during the last four years has been very marked, and cnfortunately still continues. The object of the enquiry was to ascertain, as far as possible, the nature and extent of the annual fluctuations in the abundance of the herrings, their causes, and the movements of the shoals into and out of Loch Fyne. In last year’s Report a paper was published dealing with all the available statistics for the period from 1854 to 1906, and showing the annual fluetuations which had taken place in that period. It was brought out that about thirty- three years ago a very similar time of depression and poor fishing occurred, the yield gradually falling from 39,795 crans in 1868 to 3648 crans in 1873 and 4806 crans in 1874, after which it rose, at first with some irregularity, to 55,754 crans in 1882, the second largest quantity recorded from the loch, and fell again to 1886 and 1887, when it was considerably below the average. There is no good reason to suppose that the present poor yield will not be followed by corresponding years of abundance as in the past, or that it is in the main, at all events, anything but the trough of one of the waves of scarcity and plenty which have characterised the fishing during the last half-century. The investigations to which reference has been made comprise the determination of the temperature of the water, the abundance of the planktonic food of the herring, and the examination of samples of fish from various parts of the Clyde in relstion especially to the condition of the reproductive organs. Variations in the temperature of the sea and in the quantity of food upon which the herrings live are believed by many to be causes producing fluctuations in the herring fishery, and when observations are completed, that is, when the herrings return in something like their normal numbers, they will probably show to what extent this explanation is correct. In addition to the regular serial observations of the temperatures in Loch Fyne made by means of a smail yacht, other observations have been made in the Clyde by the fishery cruiser “ Vigilant.” . THE DECOMPOSITION OF FISH. In the present Report will be found a paper by Dr. A. G. Anderson giving the results of an investigation undertaken by him on the processes involved in the decomposition of fish, including a bacteriological study of the subject, the observations and experi- ments having been made partly at the Board’s Marine Laboratory and partly in the laboratories of Marischal College, Aberdeen. Fresh fish, from its essential nature, readily undergoes decomposi- tion, the process being associated with and chiefly caused by micro- organisms which are universally present, the three chief factors which facilitate or inhibit their action being the supply of nourishment, the temperature, and the degree of moisture. Compared with the red muscles of mammals the pale muscles, or edible portion, of fishes have usually less fat and much more water, are slightly less vascular and looser in texture, and are thus more susceptible to the attack of putrefactive micro-organisms. of the Fishery Board for Scotland. 11 Excluding the gut, micro-organisms do not exist to any appreciable extent in the tissues or body fluids of fish under normal conditions, but after death the tissues offer comparatively little resistance to the invasion of putrefactive organisms, which are soon found multiplying in great numbers in the gut and all the body fluids, eradually penetrating amongst the surrounding tissues. Among the products of their activity are some substances of an alkaloidal nature which are very poisonous and have recently been isolated from decomposing fish; one class, mytilotoxin, acts chiefly on the nervous system, paralysing motor nerves like curara, while another class affect the digestive-organs, causing acute gastritis and enteritis. It is thus a matter of importance to be able to detect the earlier stages of decomposition in fish, which are sometimes disguised. The criteria which Dr. Anderson considers in detail are the general appearance of the fish, the firmness or softness of the flesh, the appearance of the surface and scales of the eyes and gills, the smell, the discolouration on the ventral aspect of the backbone, rigor mortis, the manner in which the flesh strips away from the backbone, and the appearance of the abdominal walls as affected by the gut. Since it is possible to inhibit the action of most bacteria of putrefaction by maintaining a low temperature of from 0° C. to —s° C., while at the same time maintaining the fish in a condition of rigor, fish may be preserved in a comparatively fresh condition for a considerable time with very little deterioration in their tissues, but at temperatures below —3° C. they sutfer considerably, the muscles on thawing being very soft and limp, and such fish are difficult to cure, have lost much of their natural flavour, and readily undergo decomposition. Asa result of experiments to determine the auesticn as to the best time to ice fish, as on board trawlers, whether before, after, or during rigor, Dr. Anderson found that those which had been iced when rigor was completed were dis- tinctly superior to those iced before rigor had set in or after it had disappeared, the next best being those dealt with before rigor supervened. The experiments were made on haddocks and whitings, ungutted and gutted. It was found that rigor generally set in earlier and disappeared earlier in trawled fish than in fish caught by line, and since this allows of the earlier onset of decomposition, it is concluded that the former are not equal to the latter either in general condition, curing properties or keeping properties. The author describes with technical detail the bacteriological part of the investigation. THE SPECIFIC CHARACTERS OF THE GADID. In continnation of two previous papers on this subject, Dr. Williamson contributes to the present Report a paper on the specific characters of the haddock, whiting, and some other less known members of the genus Gadus, together with a key to the species of that genus which are found in northern waters. Ina group of fishes, as that of this genus, it is not possible to separate the different members by a simple scheme, because the character which may be of value for separating two species may be quite neutral in the other members. It is therefore necessary to take 12 Part I11—Twenty-sizth Annual Report. — the characters of the fish seriatim, making each one a basis of classilication. It has usually been thought necessary to subdivide the genus by the test of a single character—for example, by the question of whether the upper or the lower jaw forms the most anterior point of the fish when the mouth is closed. Then in each sub-group the individual members were separated by other characters. Theoretically this is a convenient arrangement, but in practice it is of little value in some cases, for the first selected character may not be readily recognisable in some specimens, and in that case the diagnosis may not be obtained. The specific characters of the various forms dealt with are described in detail, and are illustrated by numerous tables and six plates. THE PARASITES OF I[ISHES. A paper, illustrated by five plates, descriptive of certain parasites’ infesting fish is contributed to this Repert by Dr. Thomas Scott, in continuation of other papers on the same subject which have appeared in former Reports. They include both ectoparasites and endoparasites, three species of the former being new to science, while some rare and curious forms are comprised among those belonging to the latter group. Dr. Scott states that in the many cases of parasitism in fish that have come under his notice, he has usually been unable to observe any very serious results produced by the presence of the parasites; and in cases where the fish were much emaciated it was a moot point whether the emaciation was caused by the parasites or due to other causes. SCIENTIFIC AND TECHNICAL INSTRUCTION To FISHERMEN. For some years past, as mentioned in previous Reports, repre- sentative fishermen selected by the Technical Committees of © various counties have visited the Marine Laboratory and Hatchery to receive demonstrations and instruction relating to the life- history and habits of the food fishes, such as might be of interest and use to them, and to see the processes of fish-hatching. Owing to a misunderstanding as to the scope of the invitation formerly issued by the Board, no delegates attended in the spring of 1907, but in the spring of this year representatives came from the Counties of Elgin and Caithness. We have the honour to be, SIR, Your most obedient Servants, ANGUS SUTHERLAND, Chairman. D. CRAWFORD, Deputy-Chairman. DARCY W. THOMPSON. W. R. DUGUID. L. MILLOY. D. MEARNS. H. WATSON. WM. C. ROBERTSON, Secretary. SCIENTIFIC REPORTS. I.—_ON THE DECOMPOSITION OF FISH. By Dr. A. G. ANDERson, M.A., M.D., B.Sc., D.P.H., Assistant to the Medical Officer of Health, Anentca (Plsik) TABLE OF CONTENTS. PAGE 1. Introduction: General Review and Discussion, . ; 13 2. Criteria to be Considered, . : : i 17 3. General Appearance : Handling a Fish, : 17 4. The Firmness, Softness, &c., of the Fish when Handled, 18 5. Appearance of Surface and Scales, : 18 6. Appearance of the Eyes, . : ; ; : 18 7. pec mente of Gills, : : : : . 18 8. Smell, ; 19 9. Reddish Discoloration of Ventral Aspect of Backbone, é 20 10. Rigor Mortis, : : 21 11. Detection of Rigor Mortis, : : 25 12. Trawled Fish compared with Line Fish, . 25 13. Manner in which Flesh strips away from Backbone or Bone away from Flesh, 26 14, The Appearance of Abdominal Walls as affected by the Gut, e 26 15. Distribution of Bacillus Coli in Fish, with Tables of Experimental Data, 30 16. Bacteriological Examination of Fresh Peritoneal Fluid, in Fish, chiefly for Bacillus Coli, 35 Mie ihe Bearing of the Distribution of Bacillus Coli in Fish and other Lower Animals on Public Health Questions, 35 18. Summary regarding Detection of Decomposition in Fish, 37 19. Explanation of Plate, : - : : ‘ 39 1. IntRopUCTION: GENERAL REVIEW AND DISCUSSION, During the past two years, in my capacity as Assistant to the Medical Officer of Health in Aberdeen, I have had frequently to deal with hygienic problems relating to trawling, fishcuring, and the examination of fish. In many cases T have been unfavourably impressed with the lack of knowledge of the elementary scientific principles underlying the various processes in the different departments of the fishing indusiry, and with the absence of a spirit of scientific enquiry which is so essential in any progressive business. It was with the aim of stimulating this spirit of enquiry that I commenced some practical studies—the results of some of which are included in this paper—and in the hope that fishermen, fishcurers, and meat inspectors might gain a more intelligent acquaint- ance with their business, and that thereby the fish-consuming public might also be benefited. I was, moreover, asked by the Fishery Board for Scotland to undertake an investigation on the processes involved in B 14 Part I1I.—Twenty-siath Annual Report the putrefaction of fish, including a bacteriological study of the subject, and the observations and experiments referred to below were in part made at the Fishery Board’s Marine Laboratory at the Bay of Nigg and partly in the laboratories of Marischal Coilege. The subject of the putrefaction of fish, it need scarcely be said, concerns not only one of the chief sources of our food supply, but also the interests of a great industry. Fish as a foodstuff has in recent years been gradually gaining in favour, and by the great development of trawling inereased supplies have been made available both for use in the fresh condition and for curing purposes. Cause of Decomposition.—Fresh fish from its essential nature is a. foodstuff which very readily undergoes decomposition and putrefaction ; and it is now well understood, and capable of easy demonstration, that these processes are associated with, and chiefly caused by, micro- organisms which are universally present. It is also well known that the three chief factors which facilitate or inhibit the action of the micro- organisms are (1) the supply of nourishment, (2) the temperature, and (3) the degree of moisture. Structure and Chemical Composition of Flesh of Fish.—Further, the structure and chemical composition of the muscular tissue in fish are such as to facilitate the easy invasion of bacteria and the early onset of decomposition. With regard to the structure we find that in mammals the red variety of segee muscle predominates, whereas in fishes it is the pale ay that is general, and she latter exhibits a lower erade of differentiation than the former. In pale muscle the striations we less vegular aud the fibres much more readily break up into smaller Ronis, and these again into discs. The fibres are not so much bound into separate and strong bundles as in the red muscle in mammals, those which subserve locomotion being simply separated from each other by delicate connective tissue septa. It may also be noted that pale muscle is slightly less vascular than the red. When we consider the chemical composition of fish we find that the various edible fishes differ less amongst themselves in composition than do the meat foods. But it has to be noted that there is considerably more refuse matter, such as skin and bones, in fish than in other flesh foods, and that this refuse matter contains considerably less water, proteids, fats, and salts than are found in the edible parts of fish. The following table showing the composition of edible fish, beef, mutton, and pork is compiled chiefly from the excellent works of Kénig, Voit, and from the Reports of the Massachusetts State Board of Health :— Approximate Percentage Composition of Edible Fish. Beef. Mutton. Pork. yee pee Fat. ee Lean. | Fat. | Lean.| Fat. | Lean. Water, .. | 72 | 82 | 58 °| 72 | 76-/ 53 | 76 | 47 | 72 Proteids, .| 19 17 17 2) 21 17 17 15 20 Fats, 4 Fi 8 3} 29 6 2 29 6 37 7 Inorganic Salts, 1°5 1°5 1 ] 1 1 1 1 1 ioe of the Fishery Board for Scotland. 15 Wacer.— From this table we see that the percentage of water found in fish is greater than in beef, mutton, and pork. In the mackerel group the average is 72, in the haddock group it is between 80 and 85 per cent. Proteids.— With regard to proteids the total quantity present under the various headings is fairly constant, and varies little in the different meat foodstuffs. But there is some difference as regards the variety of the proteids present. In fish, from 4 to 5 per cent. of the proteids consist of the albuminoid gelatine-yielding collagen, which is convertible by boiling with water or treatment with acids into gelatine. There is also much less hemoglobin or allied colouriug matter in the flesh and blood of fish than in meat, which accounts for the white colour usually characteristic of the former. The distinctive colour of the salmon and some other varieties of fish is usually due to fatty animal pigments of the lipochrome series, which are not of a proteid nature. Fish are also poorer in extractives, the chief of which are creatin, creatinin, and xauthin. To the presence of these amido-bodies in meat is due the well-known stimulating effect of meat extracts and beef-tea, which, possessing little actual food value, act as a stimulant through the nervous system in a somewhat analogous manner to tea and coffee. Hence fish, through its gelatine-yielding collagen, is excellently suited for soup-making, but because of the absence of extractives does not make good fish-tea. Fat.—The amount of fat present sharply divides the mackerel group from the haddock group. The former are spoken of as fatty or oily fish, the latter as lean fish. Halibut and mackerel contain about 5 per cent., herring 8 per cent., salmon and turbot 12 per cent., and eel 18 per cent., whereas none of the fish in the haddock group have more than 2 per cent. of fat. Hence the constituents fat and water appear to form a sort of inverse ratio—the more of the one present the less of the other. This also holds for the other flesh foods, The fish in the haddock group are compara- tively free of fat, but contain a much larger proportion of water. In the mackerel group the proportions of fat and water are not so materially different from those which exist in other flesh foods. It has been supposed that not only is the characteristic flavour of different kinds of fish due to the presence of certain constituents in the fat, but that also the proneness of fish to early decomposition may be attributable to the same cause. The former statement may be true, but it has to be admitted that the higher members of the fatty acid series, such as palmitic and stearic acid, have very little smell. The latter supposition is hardly in accord with known facts. The fat of fish is of a soft oily nature, because it contains more triolein, which is liquid at ordiuary temperatures, and less tripalmitin and tristearin, which are solid at ordinary temperatures, than the fat of mammals. But the fatty acids, such as palmitic and stearic, which are saturated compounds, and oleic acid, which is an unsaturated compound, are both alike very stable com- pounds, and are not readily broken up except by strong physical and chemical agents. Inorganic Constituents.—The inorganic salts in fish exceed that found in mammalian foodstuffs and contain more phosphate salts. If the average quantity found in the latter be taken as 1, that found in fish averages from 1:5 to 2 per cent. Hence when we compare the edible portion or pale muscle of fishes with the red muscle of mammals, and find that the former has usually fess fat and much more water, that the tissues are slightly less vascular and have a looser texture, we are led to conclude that these characters 16 Part III—Twenty-siath Annual Report have some intimate relation with the fact that the susceptibility of fish muscle to the attack of putrefactive micro-organisms and to the consequent decomposition is greater than that shown by mammalian muscle. Bacteria in Fish.—The question of the presence or absence of bacteria in the blood and tissues of living healthy animals in a normal condition is a subject which has received a good deal of consideration, and regarding which there is some diversity of opinion. Regarding fishes it has been frequently stated that micro-organisms can exist in their blood and tissues, just in the same way as many well-known parasites which make the blood and tissues of fish their habitat. Concerning the parasites of fish there is no ground for contention. They are numerous, and, so far as discovered, their life-histories and habitats are generally well known. During the past ten years the working out of the sporozoan parasites—especially the causal relationship of the myxosporidia to disease in fishes and that of the hemosporidia to disease in man—constitutes a brilliant chapter in zoological science. Regarding bacteria, during the past year I have frequently made microscopic examinations of the blood of different varieties of fish, and although I have occasionally observed rod-like and coccus-like bodies, which were suggestive of bacteria, I have to state that as yet I have not been able to isolate in culture any micro-organisms. I have also frequently examined, both microscopically and by cultures, the fresh peritoneal fluid of fishes, when removed immediately after death with aseptic precautions. "When due care was taken it was very seldom that I found any micro-organisms present, and in such cases one often finds that the fish are not in good condition, or have the appearance of suffering from some disease or injury. Neither in the fresh, healthy, living muscular tissue have I ever found any micro-organisms, when examined in the same way with due precautions. Consequently, I am persuaded that, excluding the gut, micro-organisms do not exist to any appreciable extent in the tissues or body fluids of fish under normal conditions, although it may be possible that, under any abnormal conditions, the tissues may be unable to destroy some of the bacteria which reach them during life; or, since the tissues of these animals have great powers of adaptation, they may become tolerant to some. After death, on the other hand, the tissues of fish offer comparatively little resistance to the invasion of putrefactive organisms. For these are soon found multiply- ing in great numbers in the gut and in all the body fluids, and gradually penetrate in amongst the surrounding tissues. Products of Bacterial Activity—-Among the products of bacterial activity are some substances of an alkaloidal nature which are very. poisonous and have recently been isolated from decomposing fish. Jt is found that one class of these alkaloids, to which the name mytilotoxin has been given, acts chiefly on the nervous system, paralysing motor nerves like curara, while another class of these acts chiefly on the digestive organs, causing acute gastritis and enteritis. Hence when one has regard not only to the increasing quantity of fish used as food but also to the susceptibility of fish to decomposition, and to the common arrangements on trawlers whereby the fish caught may remain in an iced condition for from one to two weeks or longer, the detection of the earlier stages of decomposition in fish is a matter of the highest importance. Bearing on Public Health.—This appeals most to public health authorities, whose concern is the public health, and especially to the inspector of meat. His task of examining fish, for the purpose of determining their condition and estimating their position between the of the Fishery Board for Scotland. 17 extremes of perfect freshness and putridity, must often impress him with the truth of the adage, ‘‘ Appearances are deceptive.” When fish are seen newly caught, or when putrefaction is pronounced, the appearances in each case are sufficiently characteristic and definite. But between these extremes, and especially in the incipient stages of decomposition, the question is often one of great difficulty and doubt. Here the usual tests employed are very arbitrary, and it is impossible to fix any standard to which all would agree. When a fish has reached the stage of putridity, any ground for contention disappears. it was in consideration of the above-mentioned difficulties that the following observations and experiments were made, with the view of determining the value of the more common tests applied in examining fish, and, if possible, to find any others more readily applicable and reliable. The fish experimented with were haddocks, whitings, lemon soles, plaice, dabs, cod, and herrings. The method adopted was to procure both line-caught and trawl- -caught fish by pre-arrangement with reliable fishermen, who carefully noted the time and place of capture. The fish on landing were laid out on trays. Some were washed daily with sea water and kept covered with a damp cloth, in such conditions as might prevail in a fishmonger’s shop, while others were subjected to different methods of treatment. The tempera- ture was carefully noted from day to day, as the fish were always kept at the ordinary atmospheric temperature. 2. CRITERIA TO BE CONSIDERED. I will now discuss sertatim the various points as usually alluded to in the examination of fish :— I. General appearance of fish. Il. The firmness, softness, etc., of the fish when handled. III. Appearance of surface and ‘scales. IV. Appearance of eyes. V. Appearance of gills. VI. Smell. VII. Discoloration on ventral aspect of backbone. VIII. Rigor mortis, TX. Manner in which the flesh strips away from the backbone, or the bone away from the flesh. X. The appearance of the abdominal walls, as affected by the gut. 3. GENERAL APPEARANCE: HANDLING a FISH. Experience soon teaches one that in many cases it is extremely difficult, or even impossible, to determine by appearance alone whether any given fish is or is not fresh and fit for human food, and in this respect there are many possibilities of error. This is often the case with trawled fish which may have been dragged for some time in the trawl net over a muddy or rough sea-floor, subjected to great pressure in hauling the net, or that have been imperfectly iced. The body region of such fish usually presents a very battered and limp appearance, while the head shows more or less extravasation of blood. They may look unsaleable and quite unfit for human food, though, if they are examined more closely, they may be found quite fresh and wholesome. On the other hand, one finds not infrequently in the case of flat-fish that their tougher skin and firmer texture give them the deceptive appearance of being quite 18 Part I1I—Twenty-siath Annual Report firm and fresh, while closer examination shows that the tissues are saturated with sour-smelling ferments and in the earlier stages of decomposition, 4. THe Frrmyzss, SOFTNESS, BTC., OF THE FISH WHEN HANDLED. One carefully notes the presence or absence of rigidity—especially towards the tail region, where it geuerally persists longest. If # is present, it stamps the fish as perfectly fresh, and they will be found to be firm and elastic to touch and to slight pressure between finger and thumb. If it is absent, then the fish are not quite fresh. Instead of being firm and elastic they become soft and inelastic, and very soon pit readily and deeply on moderate pressure, Their fitness or unfitness for human food has to be decided by other considerations. There are also certain very definite chemical changes, which take place as muscle passes from the fresh to the putrid condition, and which can be readily detected by litrrus paper. But this subject will be discussed in detail subsequently under the heading of “ Rigor Mortis.” 5, APPEARANCE OF SURFACE AND SCALES. One readily observes the imbricated arrangement and disposition of the scales, with their silvery, iridescent, and golden sheen below the lateral line, and paler olive colour towards the dorsum, when a fish is seen newly caught and perfectly fresh. This appearance is, however, only of hourly duration, and the lustre disappears long before decomposition ensues. But more important is the general firmness or looseness of the scales. In the fresh state the scales have a certain degree of firmness, and hence when one finds that they rub off readily, it certainly indicates that the fish are not quite fresh. If, on the other hand, the surface presents a patchy appearance, it often indicates that the fish have been trawled or roughly handled. This appearance, combined with a good deal of blood extravasation about the head region, is very characteristic of trawled fish. 6, APPEARANCE OF THE EYEs. This readily appeals to most people in examining fish, but it has a very limited value. In the newly-caught and fresh fish, the full and prominent eye, with jet black pupil in most fish, and transparent cornea, 1S a very prominent feature. In whatever condition the fish is kept these appearances are very brief. For in 24 hours, in most cases, one can detect commencing opalescence in the cornea, with a lack- lustre appearance of the pupil, and usually in 48 hours slight hollowing of the eyeball is seen. These changes gradually become more inteusified, and by the third or fourth day the eyes are grey and shrunken. 7. APPEARANCE OF GILLS. This is a time-honoured criterion, and although a good one, yet it is — not an absolutely safe guide regarding the condition of a fish. In fresh fish the colour of the gills is described as bright red. This may be a good generic term; but in haddocks and whitings, although the ground colour is red, it is not a deep red. There is present a quite , characteristic pale reddish tint, whereas in the herring it is a darker red or brownish-red tint. Thus different varieties exhibit different tints, with red as a ground colour. Now, in every case, in about 24 to 36 of the Fishery Board for Scotland. 19 hours, the gills in all varieties of fish begin to lose their reddish tint and gradually become grey and slimy. This always occurs by the third or fourth day. There are, however, certain points which have to be kept in view. In examining quantities of fresh fish, one meets frequently with some which have paler gills than their neighbours, and yet are perfectly fresh, and it is remarkable that in many cases the gills retain with little diminution— especially if washed daily with fresh water or salt water— their characteristic tints, even when the fish has become putrid. It should also be noted that the gills of trawled fish at time of capture, more especially if they have been dragged in the trawl net for some time, are usually of a paler colour than line fish at time of capture. 8. SMELL. So long as fish are fresh they retain their characteristic but not dis- agreeable odour; but when fish begin to decompose through bacteria activity new substances are formed which are often characterised by disagreeable penetrating odours, and often the escape of these volatile bye-products is the first warning that decomposition has set in. There are two stages in the history ofa fish on the highway to decom- position concerning which all will agree. First, when the odour is perfectly fresh and natural, and, secondly, when the odour is putrid. In the former condition the fish are fit for human food; in the second condition they should be unhesitatingly condemned. But there is an intervening period between these extremes, and here it is the daily experience of those engaged in the examination of fish, that it is often very difficult to interpret these odours correctly as regards the indications which they may give concerning the condition of a fish and its subsequent fitness or unfitness for human food. It is in this intermediate stage that there is room for contention and disagreement. Regarding this subject I have made the following observations :— (1) That in every case unwashed fish give off an offensive odour sooner than washed fish. Hence, in smelling an unwashed fish an offensive odour might be derived from decomposing slime lying on the surface, although the fish itself may be quite fresh. (2) If fish are washed daily with sea water, or even tap water, the development of an offensive odour is considerably retarded. (3) Ungutted fish soon develope a very disagreeable odour from the decomposition which rapidly ensues, especially in the gut, and to a less extent in the liver. (4) If fish (gutted or ungutted) in the incipient stage of decomposition, and giving off a slightly-tainted odour, are thoroughly washed in sea water it is remarkable how they are freshened. The tainted odour is expelled and for a time they may again smell quite fresh. (5) Trawled fish are comparatively free from slime when taken on board, because they have been dragged along for some distance through the water at a considerable speed and most of the slime washed off. But such fish when removed from ice soon begin to give off a tainted odour, because decomposition generally sets in earlier than in line fish. (6) To test a fish fairly it is always necessary to find out whether the smell is due to the flesh, or to the skin, or to the slime, or to all com- bined. Regarding the odour given off as a criterion for purposes of meat inspection, one has always to keep in view that the sense of smell is differently developed in different individuals, and that it is impossible to 20 ‘Part IIT —-Twenty-sivth Annual Report set up any exact standard of smell. The different terms used, such as fresh, tainted, putrid, etc., can only have a relative value, although a general standard is always understood. Still, it appears to me that it is possible to place the more common edible fishes into two groups, the one containing the haddock, whiting, turbot, halibut, plaice, and dabs, ete., the other containing such as the salmon, eel, herring, etc. The members of these two groups possess a very characteristic odour when removed from sea water. The former may be described as fresh, fishy, and sea- weedy ; the latter as fresh, fishy, but oily. The time taken before the fresh, fishy odour becomes tainted, stale, and finally putrid depends, as already stated, on the degree in which the media, the moisture, and the temperature are suited for the multiplication of the bacteria of putrefaction. The processes follow along perfectly definite lines, and are the same for all fish. In the case of washed, ungutted haddocks and whitings, experimented with during last July and August, I invariably found the fresh, fishy odour beginning to be tainted after 48 hours. With washed, gutted haddocks and whitings a longer time elapses before the tainted odour begins to be appreciable, but on an average it is marked at about 60 to 72 hours, and by 84 hours it is distinctly putrid. As regards herrings, the time of appearance of tainted odour appears to be more variable ; in some cases after 33 hours, in others not until about 50 hours, but, on the whole, it is earlier than in the case of most white fish. 9. ReppisH DIscOLORATION OF VENTRAL ASPECT OF BACKBONE. In all the fish examined, there appeared with striking regularity a reddish-brown discoloration on the ventral aspect of the backbone, usually between the second and third day in the case of line fish, and, on the whole, earlier in the case of trawled fish. It is best seen in the region extending from the kidney to the tail. The kidney itself isa diffuse reddish organ, lying on the ventral aspect of the anterior region of the backbone, It is very friable, and after death readily disintegrates to form reddish debris in this region, but it is not to be confused with the reddish discoloration round the vertebral column, which has a different origin and a different significance. The earliest appearance of this thin red line in line-caught fish was about 48 hours after capture. It gradually increases in size from 3-inch to z-inch in diameter during the following 12 hours, and is usually well seen after 60 to 72 hours. Occasionally it was observed in trawled fish before 48 hours after landing, and, on the whole, it appears earlier and develops quicker than in line fish. _ The regularity of this appearance suggested a daily microscopic examination of the blood in order to ascertain if there were any changes taking place in it which in any way might be correlated with, and which might be considered explanatory of, the reddish discoloration. Taken from the fresh fish, the red corpuscles are seen to be flat, slightly bi-convex, oval bodies, with a reddish-yellow colour, showing prominent nuclei and nucleoli. The white corpuscles show no special feature. Occasionally a body will be seen which appears to contain encysted sporozoa, and occasionally a slender, sometimes a thick, rod- shaped bacillus-like body, or a few coccus-like bodies may be seen lying in the serum. On the second day the red cells generally show a breaking- up of their contents. The cell-wall in many cases shows dimpling and creases, while in others the cell contents shrink away from the cell-wall, leaving clear spaces, and a few bacilli may be seen in each field. On the of the Fishery Board for Scotland. 21 third day—that is after 60 hours-—the blood presents the appearance of an amber-coloured field. The corpuscles have nearly all broken down and their contents have escaped. In each field there will now be seen many micro-organisms, some of which are motile, and a few fragmentary corpuscles. The blood for examination was always taken from the cardinal vein in the caudal region, but on the third day the fluid in this vessel was very scanty. The discoloration of the tissues, which produces the appearance of a reddish-brown ventral line, will be observed to commence circumjacent to the caudal vein, and inferior to the vertebrel column. It then spreads outwards and round the vertebral column, staining the adjacent muscle, until there is a column of tissue from }-inch to 3-inch in diameter dis- coloured. If the muscular tissue round the vein be examined from day to day the commencement and progress of the staining of the muscle fibres is readily seen, and by the third day (60 -72 hours) micro-organisms are readily detected amongst the tissues, although none will be found in the tissues immediately after death, when examined with proper precautions. These examinations were made by both wet, dried. and stained micro- scopic preparations, and by ordinary culture media. An account of the extended bacteriological examination of the nature and properties of these micro-organisms will be given elsewhere. From these investigations it appears that the micro-organisms present in the blood before death, as also those that gain entrance after death, multiply rapidly in the blood, which forms a suitable nutrient medium, while at the same time the red blood cells disintegrate, and their colour- ing matter or hemoglobin is set free. Both micro-organisms and colouring matter soon make their way through the wall of the blood vessel. The former can be detected among the tissues, while the latter causes the reddish-brown staining of the tissues and forms the red streak along the ventral aspect of the backbone. It will be noticed that this staining does not increase beyond certain limits as putrefaction proceeds, the reason being that the blood is limited in quantity, and therefore in its staining powers. These changes occurred in all the fish examined, such as haddocks, whitings, cod, herring, plaice, etc., and they occur in gutted and ungutted fish alike. The chief value of observing the presence, degree of development, or absence of this sub-vertebral red streak is that it indicates fairly accu- rately the length of time since the fish were captured or landed. Recently in some fishing districts it has been attempted to remove the sub-vertebral blood vessel along with the gut at the time of capture. In the fish trade, haddocks with well-marked red discoloration will not readily sell as fresh fish, and are usually cured. When cured, the red discoloration is still present, and such a fish will be slightly sour to taste and smell, and its keeping properties are impaired. 10. Rigor Mortis. The study of rigor mortis in fish is a subject of no less importance to those engaged in the inspection of fish in the interests of public health than to trawl fishermen and fishcurers, who are so often concerned in the preservation of fish as long as possible in the fresh state. Physiology teaches, and it is a matter of simple experiment, that muscular tissue retains its property of irritability, and will therefore respond to stimuli for some time after the death or destruction of the brain and the cessation of all voluntary movements. The stimuli may be 22 Part I1].—Twenty-siath Annual Report mechanical, as pinching, cutting, ete, or electrical, such as may be pro- duced by a galvanic cell. This is well seen in the lower vertebrates, such as fish and amphibia. Since the muscles of cold-blooded animals such as fishes are not so closely under, nor so dependent on, cerebral control as those of warm-blooded animals, and since in them metabolic changes are not so active, they exhibit a greater vitality after death as a whole, and retain their property of irritability longer than in higher animals. ‘ As rigor mortis can only supervene after the complete cessation of irritability, it is consequently later of appearing and longer of dis- appearing in these animals than in mammals and birds. As the due appreciation of these facts would be invaluable to trawl fishermen, fish- curers, aud meat inspectors, and since such knowledge could be utilised on the one hand for the better preservation of fish, and on the other for the inspection of fish, the following simple experiments may be readily carried out, and by doing so, an intelligent and practical acquaintance with this subject may be readily obtained. When a newly-caught fish is taken out of the water, as in rod or line fishing, it leaps and struggles about, often with fins erect, and attempts to get back to its natural habitat. These movements gradually diminish, and usually in from 15 to 30 minutes have ceased, and in five minutes more there is usually no response on handling. The fish is now practi- cally dead, but the muscles still retain their power of irritability for a varying length of time, which may extend from 10 to 15 hours according to circumstances, and still respond in the form of contraction to electrical and mechanical stimuli, which may be produced, on the one hand, by a very simple electrical apparatus, and on the other by simply tapping, pinching, cutting, etc. This property of irritability will be found to disappear first in the muscles of the head region, then in those of the trunk, and lastly in those of the tail region. ‘Then, just in the same order from before backwards, the gradual disappearance of irritability is succeeded by rigidity of the muscles or rigor mortis. It is first seen in the muscles of the low2r jaw and gill covers, when the mouth and gill covers are firmly closed. The stiffening then travels backwards until the whole fish is rigid, and, when complete, the mouth is often gaping widely open. After an interval of time, varying from hours to days, the rigor begins to disappear precisely inthe same order as 1t appeared—first the muscles of the jaws and gill covers, then those of the trunk, and lastly those of the tail region, until the whole fish becomes quite soft and limp, just as it was when removed from the water. Such, in general outline, is the sequence of events; but there are many important factors which exercise a determining influence as regards time of onset, length of duration, and disappearance of rigor in fishes. ‘The most important of these I will state briefly. They are from observations made on a large number of fish, probably several thousands. The cause of rigor mortis—the coagulation of the soluble myosinogens of the muscle plasma—is not for the present under consideration. it will be found that rigor is later in appearing and lasts longer in the following conditions :— . Fish in season. Fish in a healthy and vigorous condition. Fish which are at once killed on capture. . Fish which are not only killed but are pithed at the same time —that is, have the brain and spinal chord destroyed. . Fish gutted immediately on capture. . Fish handled as little as possible after capture. . Fish kept at low temperatures, as when iced or kept in cold storage. Qa DOW of the Fishery Board for Scotland. 23 On the other haud, rigor appears earlier and disappears sooner in the following conditions :— A?, Fish not in season. B}!. Fish in an exhausted condition. C1. Fish not killed at time of capture. D!. Fish neither killed nor pithed at time of capture. K1. Fish ungutted. F!, Fish roughly handled. G1. Fish not iced and not kept at low temperature. It is also to be observed that rigor tends to persist longer in those varieties of fish, such as salmon, whose muscular tissue is firmer in texture and contain a smaller percentage of water than in most varieties of white fish, such as whitings and haddocks, where the tissues are not so firm and contain more water. From these observations we must conclude that the degree and duration of rigor in fish depends chiefly on the condition of the muscular tissues at time of death. The more the conditions at time of death approximate A, B, ©, D, E, F, G the later will rigor set in—sometimes not for 10-30 hours—and it may persist 1-3 days. whereas the more exhausted the fish is, when conditions A1, B1, C1, D1, E1, F1, G! obtain, the sooner rigor appears and disappears. Sometimes it is even difficult to detect. The cause of the disappearance of rigor in muscle is a question regard- ‘ing which all are not agreed. True it is that, in muscle in condition of rigor, the conditions for pepsin-digestion are present. The muscle is avid, and pepsin ferment, although in a very small quantity, is also present. Still it appears that although pepsin-digestion may play some part in the initial stage, it is a small one, and that the chief and final cause is due to bacterial invasion. It is very rare to find any micro-organisms in musele during rigor, but as rigor passes off they increase rapidly. As already stated, to preserve fish as long as possible in rigor, condi- tions A, B, C, D, E, F, G have to be observed, and in practice the most important is G—the maintenance of low temperature. Since it is possible to inhibit the action of most bacteria of putre- faction by maintaining a low temperature from 0°C. to -3°C., while at the same time maintaining the fish in-a condition of rigor, it thus becomes possible to preserve fish in a comparatively fresh condition for a con- siderable time with very little deterioration in their tissues. At temperatures below —3° C. the fish suffer considerably. When such fish are thawed they are usually found to be very soft and limp, and pit deeply on pressure. The lower the temperature the deeper and more extensive the freezing of the water in the tissues, which must cause at the same time a proportionately greater amount of mechanical disintegration. Such fish are more difficult to cure; when cooked they are found to have lost much of their natural flavour, and they very readily undergo decom- position. By maintaining the temperature about —4° C. to 5° C. fish appear to remain in a condition of rigor indefinitely. If the temperature is kept at -5° C., or lower, fish do not appear to pass into rigor, but may be observed to do so on raising the temperature above —4° C. It has so happened that on some occasions the fish I was experimenting with were kept in a mixture of sawdust and ice. This combination impressed me favourably, and it appears to be more effective in maintain- ing rigor and inhibiting the onset of decomposition than ice alone The best mixture appears to consist of small lumps of ice, with the interven- ing spaces filled up with sawdust. Although I have not been able as 24 Part I11—Twenty-siath Annual Report yet to experiment very far in this direction, yet I am convinced that this matter deserves consideration and a fair trial by those engaged in the trawling industry, Further, there is the very important question—What is the best time to ice fish ? A. When rigor is completed ? B. Before rigor has set in? C. After rigor has disappeared ? In the trawling industry the process of icing is so extensively practised that the degree of freshness when put on the market, the suitability for successful curing, and the palatable qualities of the fish in general, may be said to depend on proper icing. Consequently, this is a subject which deserves more consideration than it has hitherto received. But as this part of the investigation is not yet complete, and as many enquiries are in hand as to the conditions of icing observed in trawling, I will only note a few more or less provisional conclusions. The observations which I have made during the past few months have been chiefly on haddocks and whitings. Some were gutted and some left ungutted and immediately placed in ice, under conditions A, B, C. The fish were selected from line boat catches, and three sets of experiments were made, as in following Table :— A. Rigor B. Before C. Rigor completed. rigor set in. | disappeared. Fish used. Ist. | Qnd.|3rd.} Ist. | 2nd.| 3rd. | 1st. | 2nd. 3rd. Haddocks, gutted, -| 6 |5/]}4{]6),6{]31]6)] 6) 38 Haddocks, ungutted,- | 6 | 5 | 47]6/6/31]6 {| 6 (| 3 Whitings, gutted, - {| 4|5|,4]61!]5 |3]4 1] 6) 8 Whitings, ungutted, - | 4 5 | 4 7 6 5 3] 4 6 3 Some of each variety were placed in ice when rigor was completed (condition A), others were iced immediately after death before rigor had set in (condition B), and those of a third lot were iced at various periods (1-10 hours) after rigor had passed off (condition C). Then some of each lot, A, B, C, were removed at intervening periods of 5, 10, 15 days afterwards, examined and treated so as to ascertain their qualities as regards keeping, curing, and palatability. In each respect those preserved under condition A were found to be distinctly the best; in the second degree came those preserved in condition B; while those preserved under condition C were poorest. In regard to those iced under condition C (1-10 hours after rigor had passed off), it was found that in proportion to the number of hours before icing was the rapidity of decomposition when removed from the ice. of the Fishery Board for Scotland. 25 11. Detection oF Ricor Mortis. When rigor is strongly and fully developed its presence is easily detected. ‘The fish is quite rigid or nearly so according to the degree of rigor, which again depends on conditions already discussed. When one balances such a fish on the finger it may remain quite rigid, but when rigor is beginning to pass off it may begin to droop at head or tail or both. Here it is often difficult to be certain about the condition, and especially when rigor has not been well developed. But when rigor is passing away one will observe that the fish, from being firm and elastic to the touch, becomes softer and inelastic and pits readily on pressure, The chemical changes are always fairly definite during these transitions. Preceding rigor, while the muscles are irritable and respond to stimuli, their reaction is neutral or faintly alkaline. During rigor they are strongly acid. As rigor passes off they become neutral. Then as decomposition ensues they become strongly alkaline when tested with litmus paper. This part of the subject has been discussed in considerable detail, and the reasons for this must be stated. We have found, on the one hand, that those who have to do with the preservation of fish in the fresh state have not given the subject due consideration, nor recognised the great commercial value, and yet it is the initial and most important stage in the process of fish preservation ; and we have found, on the other hand, that this subject is often inadequately understood by those whose duties are to examine fish in the interests of public health. They likewise fail to take advantage of an invaluable criterion, which, when present, stamps fish as absolutely fresh, or, if absent, points to ensuing putre- faction and decomposition, _ 12. Trawnt FisH coMPARED WITH LINE FISH. Since the advent of the great trawling industry the question has often been discussed as regards the general condition, curing properties, and keeping properties of trawl fish as against line-caught fish. But, at the present time, opinion is very much divided. Professor MacIntosh, in an Appendix to the Report of the Trawling Commission, 1885, states that the general condition of trawl fish is excellent and that they become rigid like line-caught fish, whereas, on the other hand, it is the experience of many fishcurers that it is often difficult to cure such fish, especially as findon haddocks. I have examined many lots of fish taken from the trawl net after being a certain number of hours at work and treated under different conditions, Some were killed when taken out on board, some not killed, some gvtted, and some ungutted. When such fish are compared with line fish under similar conditions, it will be found generally that rigor sets in earlier and disappears earlier in the trawl fish. The reason for this is evident when one considers the conditions under which fish are trawled. The longer the fish remain in the trawl net the more do they become crowded together, while the motion of the net through the water maintains a certain degree of compression. Respira- tion is consequently impeded while the fish are struggling to respire and to get freedom. Trawled fish are also subjected to considerable pressure while the net is being brought on board. The result is that the tissues are not sufficiently oxygenated, waste products accumulate, and the fish become more and more exhausted the longer they remain in the trawl net. Fishcurers frequently observe this condition in herrings which have been 26 Part ITI —Twenty-sixth Annual Report caught under similar conditions and speak of them as “ drowned herrings,” since many of them are found dead when taken on board. These are always difficult to cure. It will be frequently found, however, that in examining a catch of trawl fish many of them pass into a condition of rigor and behave under treatment just like line fish. These may have been only a very short time in the trawl net, and some may have been captured when the net was being hauled on board. From these investigations we must conclude that trawl fish, since rigor sets in earlier and disappears earlier, which fact allows the earlier onset of decomposition, are neither equal to line fish in general conditions, nor in curing properties, nor in keeping properties, except when the fish have only been a short time in the trawl net. The above statement compares trawl with line fishing only so far as they are comparable, and takes no account of the process of icing fish. 13. MANNER IN WHICH FLESH STRIPS AWAY FROM BackBONE, OR BoNE AWAY FROM FLESH. When iresh fish are examined from day to day it will be found that during the first day it requires considerable pressure by finger and thumb to separate flesh from bone, or to strip bone from flesh, and in doing so many tags of flesh are left adhering to. the bone. By, the second day, although rigor mortis will generally have disappeared and softening commenced, due to early stage of decomposition, yet there may not be much difference as compared with the first day. But from many observations made, it was generally found that by the third day the flesh is much more friable and soft, and separates from the bone with moderate pressure. By the fourth day the flesh will generally be found to be soft and pulpy and to strip off readily and cleanly, leaving very few tags adhering to the bone. On the fifth day the flesh and bone separate from each other readily and cleanly. When gutted and ungutted fish are compared together in this respect, it will be found that the difference in time when the fish in both strips off alike is not so great as one might expect, although it is certainly longer on the whole in the case of the former. This is a very valuable test, but for its due appreciation some care and practice is required. It is difficult, however, to attempt to set any precise time limit beyond which the fish should be condemned by this test. The times stated above are an average, but will be found fairly accurate in practice. One must judge by the degree of pressure required, and the degree of clean- ness of separation. When the flesh comes away readily and cleanly with little pressure, one usually finds other confirmatory signs and has no hesitation in at once condemning such fish. 14. THz APPEARANCE OF THE ABDOMINAL WALLS AS AFFRCTED BY THE GUT. « The part played by the gut is one of the chief factors in initiating decomposition in fish and possesses considerable interest. If ordinary white fish, such as haddock or whiting, line-caught and ungutted, be laid’ out and kept moist for experimental purposes and examined from hour to hour, it will be found that the wall of the gut in almost every case is the first part to undergo post-mortem changes and solution. This will some- times be observed to take place before rigor mortis has set in, and very frequently before rigor has passed off. It is a question round which of the Fishery Board for Scotland. 27 there has been much discussion, whether this solution of the wall of the gut is due to the digestive action of intestinal ferments or to putrefactive processes. But when one has due regard to the rapidity in many cases with which solution of the gut wall takes place, it appears to be at least initiated by post-mortem digestion, although this process may be accompanied by, and is certainly scon superseded by, the action of the bacteria of putrefaction which abound in the gut. There are, however, certain factors which appear to hasten or retard this process. It will always be found to take place sooner in fish which have been feeding immediately before capture. Amongst the fish under examination, one frequently finds, especially in dealing with herring or cod, some whose stomachs were evidently packed with crustaceans or small fish at time of capture, and in these cases digestion and solution of wall of gut may take place in a few hours, whereas if the gut is compara- tively empty the digestion may be considerably delayed. This certainly takes place very rapidly in herring in the above condition, and I have frequently observed it in herring in the spent condition. It has frequently been observed by fishermen that herring with stomachs packed full at time of capture very rapidly undergo putrefactive changes, and often have been useless for curing purposes before being landed. It occurred to me that possibly the kind of food might exercise some influence in determining the earlier or later onset of decomposition in fish. Accordingly I examined the stomach contents of a considerable number of fish, as well as consulted the excellent papers that have appeared in the reports of the Fishery Board for Scotland by Dr. W. Fulton, Director of Scientific Investigations, Dr. T. Scott, and those of other writers. But it appears to me that many fish, although they may have some predilections for certain kinds of food, are on the whole indiscrim- inate feeders, and that the kind of food partaken of is determined chiefly by the habits and disposition of the individual fish and the condition of hunger at time of feeding. One generally finds the principal food in the stomach of the haddock is crustaceans. Whitings, on the other hand, are rapid and agile swimmers, with keener eyesight. ‘They hunt their food, and one finds that it consists chiefly of young herrings, sand cels, and small flat fish. Cod are voracious eaters and appear to feed on crustacea and smaller fish. But, on the whole, more of the former were found in their stomachs than the latter, and it is possible that they prefer the former to the latter when it is readily accessible. As regards saithe, I found that in the adult fish the stomach contents consisted of mixtures of herrings and many varieties of smaller fish, But the younger the saithe the more they seem to prefer crustacea. Herrings appear to feed largely on crustacea and sand eels. I also examined the stomach contents of a few other varieties of fish, but it appeared evident that no very definite conclusions could be formed from this line of enquiry, since fish do not adhere to any one class of food, and that what they eat depends chiefly on the exigencies of circumstances as stated above. However, in order to control the conditions of feeding and make this enquiry more precise, I obtained a small cargo of haddocks freshly caught, brought ashore in sea water and transferred at once to tanks, where they were kept in conditions approaching to their natural habitat. After a few weeks, when acclimatised and feeding readily, separate lots were fed for a few days on such foods as bread crumbs, pieces of fish, and crustaceans. Then, on a certain day, so many were taken from each tank at different times after feeding and killed, some at 15 minutes, one hour, two hours, etc. These were laid out in plates and kept moist, and observations were made from hour to hour. 28 Part IIIl.—Twenty-siath Annual Report From a large number of observations I came to the conclusion that the kind of food in the stomach exercises some, but not an important, influence on the time when decomposition sets in and the rate of its progress. In the fish fed on carbo-hydrates, digestion of the wall of the gut, when it did take place, was slower than in those fed on proteid foods, and on the average decomposition was slower in appearing. Still, it has to be kept in view that very few edible fish in their natural habitat feed on carbo-hydrates, so that this observation does not possess much practical value. Far more important, however, as regards the onset of decomposition, is the time after feeding when the fish are killed. Invariably, in those killed from 15 to 45 minutes after feeding, post-mortem digestion appeared to be more active. Consequently, in a greater number of these, digestion and solution of gut wall took place sooner than in those killed at a later period of from one to two hours after feeding. This obser- vation is in accordance with Pawlow’s experimental work on gastric secretion and digestion—that increase in quantity of food, and especially proteid food, causes a more active secretion of gastric juice, and that the secretion is more abundant in the earlier stage of digestion, or soon after the ingestion of food. This part of the enquiry, however, must be studied in a wider and more natural field than within the confines of the laboratory. Here the environment is so different to that which obtains in nature, and to which fish do not become readily acclimatised. I have often discussed this question with intelligent aud observant fisher people, who assure me that the keeping, curing, and edible qualities of fish vary greatly with the nature of the ground on which they have been living and feeding. So much so is this the case that they associate soft ground with soft fish and hard ground with hard fish, and map out large areas of fishing ground accordingly. ‘They are of opinion that the foodstuff obtained on the soft ground consists chiefly of worms and small fish, while that obtained on the hard ground consists largely of crustacea, and this to a certain extent agrees with my own observations. This statement is also in agreement with the experience of many fishcurers, who tell us that soft fish do not keep so long fresh and are more difficult to cure. Then there are what is known as ‘‘spawny haddocks.” These have been feeding for some time on herring spawn at certain seasons of the year. Now, fishermen and curers inform me that such fish are very difficult to keep fresh, and show early signs of decomposition. Hence it is possible that the food of fishes differs in kind and quality in different parts of the sea and at different seasons of the year in such a way that it has some influence in determining not only the earlier or slower onset of decomposition, but also the quality of the flesh of the fish and its curing and edible properties. As one would expect, temperature plays a very important part in all processes of putrefaction and decomposition in fish. At freezing point, it is supposed, these processes are, if not destroyed, at least inhibited. But J find that fish ungutted and packed in ice, when removed from the iced condition, always begin to exhibit commencing signs of decom- position earlier than fish which have been gutted immediately on capture and then packed in ice. Hence it is quite possible that the degree of cold produced by icing fish, as it is generally carried out on board trawlers, may not altogether inhibit fermentative changes taking place in the gut. From these observations I conclude that the chief factors concerned in determining the rapidity of post-mortem digestion and solution of the of the Fishery Board for Scotland. 29 wall of the gut, and the rate of progress of ensuing putrefactive changes in the gut and the adjacent abdorninal walls, are :— (1) The quantity of food in the stomach at the time of capture. (2) The quality or kind of food in the stomach at time of capture. (3) The temperature at which the fish are kept. After solution of the gut wall the intestinal ferments and bacteria pass out at once into the peritoneal cavity. But even if the fermentative pro- | cesses are inactive and solution of gut is delayed, the intestinal juices and bacteria gradually pass out through the dead membrane into the peritoneal cavity, and the ultimate result is the same in both cases. This process is readily follewed by making cultures and microscopic examination of the peritoneal fluid. Occasionally, in making microscopic preparations of fresh peritoneal fluid, I observed what appeared to be possibly rod-shaped bacilli. But on further examination of this fluid cbtained immediately after death with aseptic precautions by searing the abdomen and with- drawing it by sterile platinum wire, then inoculating bile-salt glucose peptone litmus solution, and plating out on Conradi and Digralski media and making subcultures when necessary on appropriate media, I found that in most cases the cultures gave negative results for the bacillus coli. In over 100 such experiments there were only in the case of six fish pre- sumptive evidence by the MacConkey media of the presence of the colon bacillus. But on plating out, and by subcultures, it was found that two of these cases gave negative results. In three of them atypical coli-like organisms were present, and in two cases strepto-cocci were present. In consideration of these results, as well as those obtained by others regarding man and the higher animals, we must conclude that the peritoneal fluid in healthy living animals is normally sterile. That when otherwise and micro-organisms are present there is probably always some causal condition of disease or traumatism. However, it is remarkable how soon after death one will find micro-organisms in it. In examining the peritoneal fluid by the above method, I have frequently found bacillus coli in about 45 to 60 minutes after death, and in a very few cases even 30 minutes after death. After one hour they will be found readily in greatly increasing numbers. The functions of the peritoneum are subjects around which there has been much discussion. But bacteriologists are now agreed that during life the peritoneum exercises a strong protective influence against intruding bacteria. After death, the power being lost, the intestinal ferments and bacteria pass through it very rapidly and come into close contact with the muscular tissue of the abdominal walls, which usually in a few hours thereafter begin to exhibit a series of changes which are very marked and definite. First, the surface of the muscles, and especially those near the neck, which form the “lugs,” begin to show a delicate pinkish tint which gradually deepens to a reddish brown, and finally to a dark yellowish amber or apple-jelly colour. Simultaneously, as rigor mortis passes off, the muscles begin to soften, and this softening of the inner surface of the thinner parts of the atdominal walls, combined with the above-mentioned discoloration, is spoken of in the fishcuring trade, in the case of the haddock, as “jelly lugs.” If this condition is well advanced the fishcurer knows that such fish are not fresh, and often they are difficult to cure, especially as findon haddocks. If this pulpy, apple-jelly-like material be examined microscopically, it will be found to consist chiefly of muscle fibres considerably swollen, breaking up into discs, and in process of disintegration. Of the numerous c 30 Part 17. —Twenty-sixth Annual Report bacteria always present, the bacteria coli is not infrequent, and is readily detected in cultures, especially on the Conradi and Digralski media. In some cases these processes go on so rapidly that there may be com- plete digestion of a part of the abdominal wall in 36 hours, or even less, after death. In 48 to 72 hours it may occur in about one-half, and in very few will the abdominal wall remain intact after 96 hours. Undoubtedly, as rigor mortis passes off, this process of auto-digestion in the gut and in the surface of the adjacent abdominal walls is early accompanied by, and soon finally superseded by, putrefactive processes, the presence of which is readily detected by :— (1) The softening and apple-jelly appearance of the abdominal walls. (2) The increasing stale odour, becoming offensive and finally putrid. (3) The reaction of the muscles, becoming alkaline to litmus paper. (4) Sometimes in ungutted fish the presence of hydrogen sulphide can be detected. At this stage bacteria are always present and can be detected either by direct microscopic examination or very readily by making cultures from the tissues. The above statement has reference chiefly to ungutted fish. The removal of the gut immediately after capture, or at least soon after capture, will to a considerable extent preclude the, process of auto- digestion. Consequently, the abdominal muscles remain longer firm, and discoloration, with its accompanying softening and putrefaction, are delayed. The micro-organisms present in cultures from the softening abdominal muscles will also differ from those in ungutted fish, inasmuch as the bacillus coli will usually be absent. Ungutted fish during the cold season may keep sufficiently fresh for one or even three days, but if kept longer, whether iced or not iced, the flesh becomes saturated with acrid ferments and exhibit a sour smell. When such fish are cooked they are found to have lost much of their natural flavour. If cured, it will be found that they have lost much of their flavour, and that they do not keep well. 15. Tur DistrRipuTion oF THE Bacinutus Cont In FIsu. For some time it has been well known that, in man, this bacillus is the chief inhabitant of the small intestine, and also in the large intestine it finds a habitat associated with many other micro-organisms. Recently, with the development and more extensive application of sanitary and bacteriological science—especially in the consideration of food and water supplies—this bacillus has been studied more widely in nature, and has now been proved to be present in the dejecta of most, if not of all, mammals; and that, with the exception of some slight difference in culture, in pathogenicity, and as regards fermentaton of the different sugars, there is no essential biological difference between the bacillus coli found in man and in the lower mammals. It has frequently been attempted to formulate these differences as a basis for differentiation and classification of the bacillus coli found in the intestine of man and those found in lower animals, and to extend its application to the consideration of sewage pollution, water supplies, etc. But, however desirable this may be, in considering many public health questions, in practice it fails, and at the present moment there is no reliable means of distinguishing between bacillus coli derived from animal excreta and those derived from human excreta. of the Fishery Board for Scotland. ol During the past few years this enquiry has been extended to the lower sub-kingdoms—birds, amphibians, and fishes—and of these, fishes have probably received the most consideration on account of their extensive and valuable use as a foodstuff, and because they ave the inhabitants of waters from which water supplies are derived. Houston, in his report to the Royal Commission on Sewage Disposal, with special reference to the contamination of shell fish, states, as regards oysters, and in a later report (1903-04) on the bacteriological examina- tion of the excreta of fish——both oysters and fish derived from deep-sea water remote from sewage pollutiou—that typical bacillus coli, or even atypical bacillus coli, are seldom detectable in the former, and are absent, or only present in small numbers, in the intestines of fish. At the same time, the Commissioners had to regret the paucity of our knowledge as to the distribution of the bacillus coli in nature. Recently Eyre, MacConkey, and Johnson have done a considerable amount of work in this direction. Their results differ from those of Houston in this respect, that they find the bacillus coli almost universally present in the intestinal canal of fish. During the past nine months, in the intervals of other work, and as opportunity afforded, I have examined the intestinal contents obtained from a large number of different kinds of fish with the view of ascertain- ing the extent of the distribution of the bacillus coli in fish. The media used :— ((«) MacConkey’s bile-salt glucose peptone litmus solu- tion. General media< (0) Digralski and Conradi’s nutrose litmus agar, and, to less extent, neutral-red bile-salt agar and lactose { litmus agar. (a) MacConkey’s bile-salt glucose peptone litmus solution. Sodium taurocholate, - 5 grams. Glucose, - - - 5 grams. Peptone, - - = 20 grams. Water, - - - 1000 cc. The constituents are heated until dissolved, then filtered and sufficient neutral litmus solution added. The medium is, then distributed into Durham’s fermentation tubes and sterilised by steaming for 20 minutes for three successive days, (b) Conradi-Digralski agar medium. This medium is rather tedious to prepare. (1) Agar Preparation.—To 3 lbs. finely minced horse flesh or minced ox beef, add 2 litres of water, and let stand for 24 hours. Then boil one hour and filter. To filtrate, add peptone sicca and nutrose, 20 grams of each, and 10 grams sodium chloride. Boil one hour and filter. Then add 70 grams bar agar, boil for three hours in koch or one hour in auto- clave, render slightly alkaline (using litmus paper), filter, boil for half an hour. (2) Litmus Solution —Kubel and Tiemann’s, got from Grubler, Leipsig, is the best. Take 260 c.c., boil for ten minutes, then add 30 grams pure milk-sugar and boil 15 minutes. 32 Part ITI.—Twenty-sixth Annual Report (3) Take solution (2) and add to solution (1) when cooled to 60°C. Shake, render faintly alkaline. Then add 4 c.c. hot sterile solution of 10 per cent. water-free soda and 20 c.c. of freshly-prepared solution of 0°1 gram crystal violet (Hochst) in 100 c.c. warm sterile distilled water. Particular media for subculture :— (1) Gelatine slope, stab and shake cultures. (2) Litmus milk. (3) Lactose-peptone litmus solution. (4) Peptone water. (5) Glucose neutral-red broth. In this way I followed Houston’s ‘‘ flaginac ” basis of classification for bacillus coli :— Fl.—Greenish fluorescence in neutral-red cultures. A.G.—Acid and gas in lactose-peptone cultures. In.—Indol formation in peptone cultures. A.C.—Acid and clotting of litmus milk. A microbe which presents these characters in subcultural tests is indistinguishable, as regards the tests employed, from the typical bacillus coli of the human intestine. Method of Procedure.—The fish examined were obtained at different times and from different sources at the Aberdeen fish market during my visitations—some line-caught, some from trawlers. But the great majority of the fish were not caught at any great distance from the shore, although some were obtained from trawlers from the Iceland fishing grounds. Each fish was washed in tap water, then in sterile water, and tacked out on a board. The skin on the ventral aspect of the abdomen was thoroughly seared with a red-hot cautery iron, and the stomach and intestines dissected out by sterile instruments. Some of the intestinal contents were then aspirated up into a pasteur pipette or removed by sterile platinum wire to bile-salt glucose peptone litmus in a Durham’s fermentation tube and incubated for 48 hours at 37° C., 1-5 tubes inoculated for each fish. Sometimes the whole gut was removed, washed in tap water, then in sterile water, and the whole contents well mixed with bile-salt glucose broth. From this emulsion other bile-salt glucose peptone tubes were inocu- lated with varying quantities. None of the fish were cut up and mixed with the intestinal conteats. A positive reaction is shown by the pro- duction of acid and gas. The acid turns the medium red, and gas is seen in the inner small tube. But as this reaction is only presumptive evi- dence of the presence of a member of the coli group, I always plated out on one or other of the solid media—chiefly Digralski and Conradi— and from the colonies on this media, when present, subcultures were made in accordance with the “ flaginac” basis. The following Tables exhibit my recorded results :— of the Fishery Board for Scotland. 33 Table I.—Showing the Biological Characters of the Bacillus Coli and Coli-like Microbes isolated from Fish. a ee Salle e 3 4 Sully n as So 3 3 Pe} a ! Ds | =o S an “Ag || oO So | on SS/s5/F8/25/o8/s5/58/s5/°8) vs Se/ OM] oe) om) ss] ot) os) 54) 68) ot Abe) 4g IAM |g |A ag |e ag Ae ag Qy or 2 Qy 2 | | | | | | | | | Ist Period, 1896-1901, | 336 | 56:0 |2178 |101°4/1079 |166:0|1132 | 58-1 |1766 | 8671 2nd Period, 1903-1908, | 962 | 36°8 |2221 | 57-6 |1840 | 61-3} 938 | 26:1] 616 | 17°7 Decrease perm Hour,.|) Soi 1 19°2) |. 3.2 AS Sie OT Me, 9] B20" <8} 684 The figures show that the average number of plaice per hour at each of the five stations was less in the second period than in the first, that is when the collective results in all the months are considered together. The months in which the collections dealt with in the tables were made were June, July, August, and September, but for various reasons the amount of fishing in these months in the two periods was not always equal. In June only one series of collections were obtained in the first period, whereas in the second period five collections were made; a circumstance which very much reduces the value of the comparison for that month. The detailed averages are given in Table III., and the means are as follow :— 58 Part III —Twenty-siath Annual Report Lochgilp- Big head. Harbour. Salen. Strachur. Inveraray. Mean. 1st Period, 1899, 26:0 39°2 60:0 28:0 23°2 316 2nd Period, 1903,1904, 1906-1908, 29°7 28:25 31:0 28°O es TAD 26:0 In July, however, the number of collections was not only large but there was in each period five collections in this month, in all the years of the first period except 1899 and in all those of the second period except 1907, and it was in this month that the largest number of fish were taken, amounting to over 60 per cent. of the whole. The mean number of plaice taken per hour at each station in the two periods is shown as follows :— Lochgilp- _ Big head. Harbour, Salen. Strachur. Inveraray. Mean. lst Period, 70:2 146°0 208-0 87:1 150°5 130-2 2nd Period, 30:1 96-4 99°8 29-4 28:0 56°1 There was thus a very considerable reduction of the average number per hour’s fishing at each of the stations, and the mean reduction amounted to 74 fish per hour. The detailed averages are given in the table, page 64, and are discussed below. In August, collections were obtained in seven of the years, namely, in 1899 and 1901 in the first period, and in all the years of the second period except 1907. About 20 per cent. of the total number of plaice obtained were taken in this month, and the mean number per hour’s fishing at each station is as follows :— Lochgilp- Big head. Harbour. Salen. Strachur. Inveraray. Mean. 1st Period, 1899, 1901, ; 36-0 75'8 75:0 27°8 27°6 45-9 2nd Period, 34°6 40-0 74:9 25°9 12°9 36°6 The reduction in the average number in this month was much less, and at one station—Salen—the averages were practically identical. The details are given in Table I[I., but the comparison is of less value than in August, for the reason stated, there being nine collections in the two years of the first period as compared with twenty-three collections in the five years of the second period. In September there were two collections in each period, in 1898 and 1900 in the first, and in 1903 and 1905 in the second. The average number of plaice taken at each station in the two periods is as follows :— * Lochgilp- Big head. Harbour. Salen. Strachur. Inveraray, Mean, 1898,1900, 24:0 60:2 1420 27:2 21°7 47:0 1903,1905, 99-0 65:1 137 13°6 13:0 35°9 The reduction is small here also, and at two of the stations the average in the last period is higher than in the first. It may be noted, however, that in the second period there was only one collection made in this month at Lochgilphead and that was in the most productive year of the period —1905. of the Fishery Board for Scotland. 59 We may now consider the averages resulting from a combination of the months, bearing in mind the remarks above made as to the pro- portion in the two periods. In June and July, representing about 71 per cent, of the total fish, the averages in the two periods were as follow :— Lochgilp- _ Big head. Harbour. Salen. Strachur. Inveraray. Mean. lst Period, 65°3 124-6 191°5 fork 125-0 112°2 2nd Period, 29°9 64°3 65°4 28°9 21:1 42°] In July and August together, representing about 80 per cent. of the total number of fish taken, the averages for the various stations were :— Lochgilp- _ Big head. Harbour. Salen. Strachur. Inveraray. Mean. Ist Period, 66°4 122°6 181°4 68°6 109°5 = =105-2 2nd Period, 32:5 69°3 87:2 27:7 20°9 46°6 In August and September, representing about 29 per cent. of the total quantity of fish taken, the various averages were as follow :— Lochgilp- Big ~ | head. Harbour. Salen. Strachur. Inveraray. Mean. Ist Period, 28-0 68-9." 1085 27°6 25°4 46:7 2nd Period, 46°6 48:2 55:9 22°71 12°8 36°4 10. Discussion oF RESULTS. From the consideration of the averages as above discussed it is clear that the number of young plaice of the year which were taken per hour’s fishing by the push-net in the first period of six years, when plaice fry were being added to the waters of Lochfyne, was much higher than in the second period of six years, when no fry were added. When the mean of all the collections made in the first six years is compared with the mean of all those taken in the second six years, the decrease was by more than half, amounting to 48 plaice per hour’s fishing. The decrease was, moreover, common to all the five stations where collections were made, though it differed in degree, varying from 19:2 per hour to. 104°7 per hour. When the collections in the same month throughout the two periods are studied, the same thing is brought out—a decrease in the mean number of plaice taken in the two periods, and, with a few exceptions, a decrease also at each of the stations. In July, in which the number of collections in the two periods were almost the same, in which the same number of years are included, and in which over 60 per cent. of the total number of plaice were obtained, the value of the comparison is greatest. The mean number per hour in that month for all the stations combined was 130°2 in the first period and 56°1 in the second period, a reduction of 74 fish per hour; and there was a notable diminution at each of the stations, varying from 40:1 to 122°5 fish per hour. In August, when two collections were made in the first period and five in the second, the fish obtained representing about 20 per cent. of the total, the mean reduction for all stations was a little under 10 plaice per hour’s fishi2g, and there was a diminution at all stations except one, where the numbers were practically the same. In September the 60 Part ITI —Twenty-sixth Annual Report basis of comparison is less extensive; the mean reduction was 11 plaice per hour, and two of the stations showed an increase in the second period. It will be observed from the tables giving the detailed averages for each of the collections that the fluctuations at any station from month to month and year to year were considerable. The mean annual average number of plaice per hour’s fishing varied in the first period from 24 to 174, and in the second period from 8 to 112. In the month of June the mean, for all the stations combined, fluctuated in different years from 10°2 to 33-4; in July the mean varied from 24 to 266°8 in the first period and from 8-7 to 172 in the second period ; in August it varied from 5 to 112, and in September from 22 tv 54. At the individual stations the fluctuations were still greater, as shown in the tables. Fluctuations in quantity in this way are, of course, prominent in all fish- ing operations. Thus, in the trawling experiments of the “ Garland,” in the Firth of Forth, the fluctuations in the average catch per hour’s trawl- ing at the same station in the same month of different years varied for plaice from | to 44, for dabs from 0 to 112, for haddocks from 0 to 296, and for whitings from 0 to 50. But the means for all the observations in a year were much less, namely, for plaice from 5:9 to 9, for dabs from 4'4 to 8°6, for haddocks from 3°3 to 26°9, and for whitings from 2°2 to 14:4. It would be of importance to determine, if possible, whether the fluctuations in the take per hour were representative of the fluctuations in the natural abundance of the young plaice at the stations on the various occasions when fishing was carried on. A study of the parti- culars as tc the physical conditions prevailing when the collections were made does not appear to show that they had much influence on the averages. It might be expected that when the water was clear the average would be reduced, because of the visibility of the approaching push-net to many of the young plaice, but many of the best catches were taken under such. conditions, and the work was not prosecuted if the weather was rough. It is to be noted that, as a rule, when the average was high at one station or in one month it was also high at the other stations and in the succeeding month. Thus the most productive year in the first period was 1901, and the average in each month and for each station was very high, higher than in any other year of the period, except at Lochgilphead in July. In the second period the most productive year was 1905, and here again the averages at each of the stations and in each month were very high—the highest for any year in the period except at Big Harbour in August. So also in the years of low means, the averages at each of the stations and in each of the months were asa rule low. This may be illustrated by contrasting the averages for 1904 and 1905 as follows :— Lochgilp- _— Big head. Harbour. Salen. Strachur. Inveraray. Mean. 1904—J une, — 21°6 56 10-0 2:0 10°24 July, 3-0 108 = =12°8 9°8 8-4 9-2 August, 1:6 55 8:8 3°3 4°4 4-9 1905—July, 83:0 3320 230°9 104°5 90:7 ra August, 1181 54:5 252-0 64:5 456 112-0 September, 99:0 97°5 18°5 18°5 14°5 49°6 From this general uniformity at the various stations and in the different months of a year, it may be concluded that the averages repre- sent approximately an actual abundance or scarcity of the young plaice on the beaches in Lochfyne in that year, and that they are not due to accidental or temporary circumstances. of the Fishery Board for Scotland. 61 Owing to the great natural fluctuations that occur, as shown, for example, in the means for the second period, when no plaice fry were added, one would not expect that the fluctuations in abundance in the years when plaice fry were added would be closely related to the number of fry liberated in any particular year, for the increase due to this cause is liable to be masked by the extent of this natural fluctuation. Iu the twelve years for which annual averages exist, four of the six highest were in the first period of six years and two in the last six. The highest of all was in the year when the greatest number of plaice fry were added, viz., 1901, when the average was 174 per hour and when 51,350,000 fry were liberated. The second highest was in 1905, when no fry were added, the average being 112 per hour. The third highest was in 1896, viz., 111°4 per hour, when 4,100,900 fry were added ; the fourth highest was in 1898, viz., 95°6 per hour, when 19,200,000 fry were placed in the loch; the fifth highest, 53:1, per hour, was in 1900, when the number of fry liberated was 30,590,000 ; the sixth highest, 37:3 per hour, was in 1903, when no fry were added. The period of thirteen years over which these experiments have extended is considerable, and ought to go far to equalise the natural fluctuations; and I think it is reasonable to conclude that the greatly increased average abundance of the young plaice in the first six years was mainly due to the liberation of the 142,880,000 fry of the plaice in those years, and that, on the other hand, the decrease in the abundance of young plaice in the last six years was mainly owing to the fact that no plaice fry were added to the waters of the loch in that period. On theoretical grounds alone it would be an astonishing thing if the addition of the immense number of plaice larve mentioned to the waters of a long, narrow, and confined loch like Lochfyne should produce no increase in the numbers of young plaice a few months older than the larve added. And if that is the effect in Lochfyne, it will also be the effect elsewhere, though the natural fluctuations may conceal it. With regard to the extent of the influence of the liberation of the fry on the abundance of the young plaice during these experiments, the difference in the averages in the two periods shows that the plaice were more than doubled in number.* There is one consideration, however, that ought not to be lost sight of. On the East Coast, and in the North Sea generally, there have been complaints of the diminution of plaice in recent years, and this was proved to have occurred in the Firth of Forti from the trawling experiments of the “Garland.” There is not sufficient information with regard to the Clyde area to show whether the same change is oceurring there, but if it is—if the adult plaice are decreasing and have been for some years decreasing—it might account, in part at least, for the reduction in the average catch of the young plaice in Lochfyne in the second period of the experiments. It would therefore be desirable to have a third period in the experiments, namely, a series of years during which large numbers of plaice fry were added to the waters of the loch, as in the first period, and to ascertain the effect of this on the abundance of the young plaice on the beaches. * The above conclusion with regard to the result of the experiments in Loch- fyne—that the number of plaice on the beaches was more than doubled by the addition of the artificially-hatched fry—has been confirmed by an elaborate mathematical investigation of the fluctuations in the different years, which was kindly made by Miss R. M. Lee, of the Marine Biological Laboratory, Lowestoft, after my paper had gone to the printer.—T.W.F. E 62 Part [11.—Twenty-siath Annual Report Taste I.—Showing the Time of Fishing and the Number of the Season’s Plaice caught at each Station. i Total. — Mins.| Fish. eee Pe are Salen. Strachur. Inveraray. Date. Bio ge | toe ee Mins.| Fish.|Mins.| Fish.|Mins.| Fish’|Mins.| Fish.{Mins.! Fish. 1896. July 120 | 41 | 120 | 336 | 120 | 421 | 120 | 166 | 120 | 150 1897. July 30} 16| 30; 21] 30 6 | 30 7 1.30%) /0 1898. July 30 | 138 | 150 | 356 | 30] 58 | 150 | 53 | 150 | 374 Sept. 30 | 14/120} 83| 30] 86/ 30 Z|) BO" hoe 1899. June 30 | 13/150} 98] 30] 30) 150) 70| 150] 58 Aug. 30 | 18 | 150 | 127 | 30) 23) 150| 46 | 150 5) 1900. July 30 | 29 | 150 | 220 | 30 | 102 | 150 | 104 | 150) 71 Sept. 30 | 10 | 120} 158} 30| 56/120) 66 | 150] 34 1901. July 30 | 57 | 150 | 527 | 30 | 245 | 150 | 539 | 150 | 900 Aug. a. | 50.) 252). 300)! BB) 120e . oe oO i liens 360 | 336 |1290 |2178 | 390 |1079 |1170 {1132 |1230 |1766 1903. June BON LS) | E20 T eae a. . |.220) 93 120). 86 July Eee ene ees| ALSO Melee Rene Ae cc 160 | 49 | 210 | 105 Aug. Z| 150260") ESO) |) As | PoOR eae Sept. 200 | 152 | 120] i8 | 150 | 24 | 120). 23 1904. June ed spe) AbOg) D452 25O 14 20 fF 20R ta 4 July 120 6 | 150) 27 | 150| 32 | 1385| 22) 150; 21 Aug. 159} 4{]120}] 11] 150] 22/| 90 5 | ASO) paaat 1905. July 120 | 166 | 135 | 747 | 125 | 481 | 120 | 209 | 125 | 189 Aug. 125 | 246 | 120 | 109 | 120 | 504 | 120 | 129 75) 57 Sept. | 120 | 198 | 120 | 195 | 120) 37 | 120] 37) 120) 29 1906. June 130 | 97 | 120] 73 | 120 | 110 | 120 4 | 120 3 July 120 | 33]; 1290] 11 |) 120) 24) 135) 18, 120 3 Aug. 120 | 16 | 120] 25) 120] 31] 120} 54 120 3 1907. June 140 | 41 | 120 | 127 | 1385 | 69] 185 | 57 1908. June 135 |: 64 | 180: |. 29) | 110 1:'73)) 1105) TS 140) July 130 | 41 | 120] 57 | 120 | 320 | 120) 29/ 120) 20 Aug. | 130] 37 | 140] 28 | 140 | 105 | 130} 32) 180) 18 1570 | 962 |2315 |2221 |1800 |1840 [2155 | 938 [2090 | 616 9930 |6577 600 {1114 150 | 60° 510 240 979 216 510 510 269 219 510 450 526 324 510 |2268 450 | 516 4440 |6491 of the Fishery Board for Scotland. 65 Taste [I.—Showing the Average Number of the Season’s Plaice per Hour of Fishing at each Station. Loch- Big Inver- Date. gilphead. Elecbane: Salen. |Strachur. ve, Mean. 1896. July - - - 20°5 | 168:0 | 210°5 83:0 75:0 | 111°4 1897. duly =" '- - 32°0 | _42°0 12:0 14:0 20:0 24:0 1898. July - - - | 276°0 | 142°4 | 1160 | # 21:2 | 149°6 | 115-2 September - - 28-0 41:5 | 172:0 4:0 62°0 54:0 1899. June - - - 26°0 39°2 60-0 28°0 23°2 31°6 August - - 36°0 50°8 46:0 18-4 2°0 25°8 1900. July - - - 580 88:0 | 204:0 41°6 28°4 61'9 September - 20:0 79:0 | 112°0 33°0 13°6 43°2 1901. July - - - | 114°0 | 210°8 | 490°0 | 215°6 | 360°0 | 266°8 August - - as 100°8 | 104:0 39°5 53°2 68°8 Average - 56°0 | 101°4 | 166-0 58°1 86:1 Sit 1903. June - - : 26°0 12°5 a 46:5 43:0 33°4 July - : - ae 97:0 tase 18-4 30:0 48°5 August - - ans 104°0 oc 17-2 19°6 46°9 September - - bus 45°6 9-0 9°6 11°5 22°1 1904. June - - - ae 21-6 56 10:0 2°0 10:2 July - - - 30 10°8 12°8 9°8 8:4 9°2 August - - 16 a5 8°8 3°3 4°4 4°9 1905. July - - - 83°0 | 332°0 | 230°9 | | 104-5 90°7 | 172-0 August - -| 1181 54°5 252°0 64°5 45°6 | 112°0 September - - 99-0 97°5 18°5 18°5 14°5 49°6 1906. June - - - 44°8 36°5 55°0 2°0 15 28°2 July - - - 16°5 5D 12:0 8:0 1°5 8:7 August - - 8-0 12°5 15°5 27°0 15 12-9 1907. June - : - 17°6 63°5 30°7 25°3 ts 33°3 1908. June - - - 28°4 13°4 39°8 61°6 0-0 26°8 July - - - 18-9 28°5 | 160°0 14:5 10-0 45°9 August - - 171 12:0 45:0 14°8 6-0 19°3 Average - 368 57°6 61:3 26:1 Awiere 39°7 | 04 Taste III.—Showin Hour in June, J and 1903-1908. Date. June. July. Part III —Twenty-siath Annual Report g the Average Number of Season’s Plaice taken per uly, August, and September in the two periods 1896-1901 Loch- Big Stra- | Inver- September. 1898 1900 1903 1904 1906 1907 1908 1903 1904 1905 1906 1908 1903 1904 1905 1906 1908 September. 1903 1905 gilphead.| Harbour. Salen, chur. aray. Mean. 26-0 | 392] 60:0! 28:0 | 23:2] 31-6 20:5 | 168-0 | 2105 | 83-0] 75-0 | 111-4 300 | 42:0 | 120) 140 | 90-0umueD 276-0 | 149-4 | 116-0 | 21-2 | 1496 | 115-2 53-0 | 88-0 | 2040 |. 41-6 | 28-41 lel 114-0 | 210-3 | 4900 | 215-6 | 360-0 | 266-8 70-2 | 1460 | 208-0 | 87-11 1505 | 130-2. 36-0 60:8 Ih) 46-01) ee 2-0 | 25-8 100'8 | 104-0 | 39:5 | 53-2 | 68-8 36-0 | 758] 750] 278] 276] 45-9 28:0 Ibs 41-5 |) ol72-0 40! 62:0 | eae 20:0 | 79-0 | 112-0] 33:0] 1361 43-2 e490 | 60-2 | 14290 | a2 | ate | aro 26-0 | 12-5 465 | 43:0 | 83-4 ti 21-6 56 | 10-0 2-0 | 10:2 HES |e SGce, | Sa 2:0 15 | 28-2 176 | 63 | - (30:71 a5-aul) oe 33-3 03-4 | 13:3] 39:3 | 616 0-0 | 26-8 297 | 282! 31:0] 285 | 1121 26-0 ks O70 Ieee 18-4} 30:0 |) aes 30 | 108] 12:8 9:8 84 9:2 83-0 | 332-0 | 230-9 | 1045 | 90-7 | 172-0 16°5 Bap iene 7-55 15 8:7 189 | 2351 1600| 1451] 10:01 460 “30-1 | 96-4 | “99-8 | 'a9-4 || 98:0) geen ie 104-0 oe 1721 19 | 46:9 16 55 8:8 3:3 Ve 4:9 1181 | 54-6 | 259-0 | 64-5 | 45-60) me 80 | 12-5 | 1B | 7-0 15 | ie 17-1 | 190 |) -45:0°| ais 6-0 | 19:2 346] 400 | 7491 2959 | 1291 366 45°6 9:0 961 115 | gem 99:0 | 975 | 185°) 18:5 | 14-B0 eens 99:0 | 66-1 |. 137 | ase | 13:0 eee of the Fishery Board for Scotland. 65 xs 0 “YZ ee ee il a Oc as fe er | |= WO ‘YZ Aine w3¢—co6r Pierre |) OT TTRANREsAReRA eno ee eran See a eae he cg nel Prine CRE SEE TIRSGE ER accion ase Rg RY Eas Races her ranma ar nl ean CT Sr! eh eth Ti Get WD tnt Vad irene EATS ISS Seasons te ane a ene ee RON Eee ahs hor SARS AF emi imatiilOe Wen Pee ame a fiag or Gner| 411 111 PRBSREABERSO Nien MHS OCOGI CIE Or © ANANTH mst 106 | Li oie eel Vo Jaa AL es a ae aa a Tt ee) ed eipiale gh US St te I OSU be RCO ih aim Meir Cen eseee ult ' ‘WL OS “YZ | S| -8nVv U81—F08T | qd i qo OSONG Da iO Oe eT Sa eto ied Uae nS TO Pe PO DS 0h i ale Sa ie Tien ae Fi UU teen toile UUme We Tie hee per ofl. Share cae shot “oun 4996 — S06T | Us ae BG ing Cor ae et . | Ane pug—To6t RUSS Re ait einen 1 “Ur 08 "U0 DA brs oS cat EAE mtr eplg hand a ae wt Vel eM io? Viegas hy ete ( LIS LU he SRRE WR at Yee CAD oe Aviat eed baal Veet etieatih eC a re etic cys Myon ty av engin ian Meat a 3 = os aes rane cena an een er yc Me eek in are mes cue ceumemeLanv ena lid Ai Ree g a ae a dee TO Sa a teen a mr ee me tL ton he S mowermer| | ORR é ee a0 | “‘peinsvat you gt 2 EERO OS AE inne Tee Goes anne rare nin nae Cn i meget i ore Chr i Fein ear PrRIAT i aTie yale hie) le ee SS ae aise nC RNa Rane foc. |, ES EE re ae ey oer Sete ssses ey, th PO Cee NONee hey ht nen De ES nets ith ey Rime eh be alee REN Gi ica ees ee eh ee ers pee h ereorery apen rey Meat eee Titel. 8 teers ainan uw enti iv cosy ee 1 MOE ‘TO >| OR Pop pp S288 SO 02 01a HEI co ~ | ‘Aine a39g—g968T eee a OD g ee Ly COC) Ec oe CICS Te) aay ee Ie SHCAONBMONHROM eleo er = PE a bal ia ache Seater VS Or SUSE 0 TSS aT ra heh laa el een eee LOSS Liga mn OR oT CET) SCG Fa et APN ATE eh Tina oS Sees DMAOANNMOODHAHROMOANNDARAHEOMOD ARIBDOCOHNAHAAANA 000 HHH Oe SSS ASS SS DMOrt-OMOANN HAAR ONDANNOON Hr ri CIN OI 09 20 O93 OD SH SH SHO 10 10 o> ion Taste LV. si a Bie Harpour. Part IIL. —Twenty-sinth Annual Report Pe a er Pa | Ul 0S “UZ TMG CRC inmi nin toon 20 Sey EES ‘ul * ta TTP LP heanNnmmoowo rrr bt iret tt tata at 2 OD Oe “Ane maT a06T Teer E ] “WU OT "US Isa ie IEOwoANAA! Prt tp red tt bt ed 8 1 ee es ‘oun UIE I—S806L i ria | «=, 12 1. LO J cv ioomregege raat srr tr tetera ttt tata tem count US 22 1061 I 3 : J m0 UG PUD 1D Ph Ped c00e ett 60 1 Mo fe ty A) dy de ai, 01) th rn I =v aan | |: Tec CCCRCRECIRERRERREE RRR ini.) ). “mp ae | urg ‘UZ lxXiocoMtomron rt dt i tit be bab Pd bo Pet 8 tot 1 ee ‘aun plgZ—906T similis: au ‘UO “US Toate i) it) heaven SROMMAHAAIMOAGIies Ip rt trite bp eta ta ‘gdag 4IST—cO6T tat B. —h. Ce OMe ty ae Soar eg Pe Py ee eet eh Ae nN ‘TO “US tll iaaaae “sn¥ WIST—SO6T ‘UST “UG | cIcb com “A[DE W99—SOBT rales mW) US iP i ene a “snY W4LI—F061 SS mn ge t00 PEL TT Ceemo eg eteteor | deen td A Alot a. Catal tei a “Ul 0§ * ‘oune T1982 $06 TH 0Z “US Prrrrrtimae ‘das 41¢c—s06T a US AT 1h bP Deen ony WI¢c—s06T PU HOOM ONO reve T 1 Ne Me ft re WS SS Homme (ert brady tt tt Pon UN ft Vo I Sivstetea see oioMdeacoce § Pook fob bob td ee ete) Wet OS Te = UO) ‘UE 1 | 1 Minminon “Ane wWeT— S061 HAE OWT i | i | : |. | |. s |. s |. s |. | | E | | | | | | 7 | m0 “YE | E | a |. a | i | | sale | | | | E Al Ent 3 | | | LL ee a ee Mii te fe ok dc ul ‘meuiec—eoet | | TO a a a oa mM 0S “UZ Perens ‘Sny_W16Z—T06T ‘eet ater “UL OE “YS 1Ooxwe “AINE PAS—TOGT ee) M0 "US eer a 29d 439—0061 WO UZ 4deg Y3TI—006r 9 1D on Inde LD AY SS Se Se San Ee Meo eis Nol os NT SH eat ae RL ST a Laat a Pee bP tort tb ee Pb oP We bh to ob 1) Dobe oP st OL i 2 1 2 i i 2 1 i Ue OPT i eis) Qa rVe VET V Tn SS ‘UW OF “US ll moarnnooonn be Bl oe re “AME y99%—006T Bien Foie PEEP T PPE PPP pie IM RANT Pt ttt baa ad a ie EA 5 ek RINE ‘UL 0§ “UG } a HiT O68 “pornseoul 4Ou JZT + UG I 1 Pani n Spook ee ieee teret Wim i) i fl. i ume pis valli) re 19. | 20. | ‘on. 22. | 28. | 24. | 25. | 26. | 27. | 28. | 29. | 30. | 31. | 32. | 33. | 34. | 35. | 36. | 37. | 38. | 39. | 40. | 41. | 42. a i Ot i ee To i fh i Wo) 1 | qmady een | a 0g “UO Vue ‘wee UITI—668T UU cF “OT 11 me ae Le i Tie i i uh yy | Perr yrrrtrrtrrringawa +r teoenar st tpt tt beat ta ta a ee PUTED TULL Pam mwOomMOMA a 1a i rt bt) bo) 0 tee ado roo | “UL OE “US SUM GE—SERT LN OS BS SRA usSwocce 1 rt Pt ef Phd 1 et ea) 0) eee “Ut Og “4 0 Renter ' dy wooo Po ee Se Tete hee Delete tad Rte | i en ee ee i PPR TT ih i eS ea eam LaLa ae a a TMP Mih en i oo to dy Gna ano he 9. a0, ‘un. 12. | 13. | 14. | 15. | 16. | 17. | 18. ul og * oy cence et. z den ueecasep | these etre doe ee ea : “UL OS “US oF oan Perr rrr rr rr tpt tt tet mae PHA INNA Aa i tt de Pe Tr rr ne: : ‘wm Og “TO : is Mme wz—zeat | | | TP Aes wonos rer ee is or) 0 ; ai m0 “UZ Pree r rrr err ttt itengot a tow PIA PONNA IA! Ia ttt tea SW ae 3 Peri rr rt tl tee RomannOoOnHtAAN! rat tba tt tt bed 0} puze~ 9681 | a PETE PT PI 1 11 emma mm MAOH A LINHA HOH IAI dd AON toe | % Pil ey RONre Hina N ae Ghee Ae RAI aaa pene mele ieee erie ial Ney 0 oon) | | [. | | é ‘tila {.. 0s az ay sn 061 ; | Aine ¢ vee | 4 | woe "Ut *aune Y9¢T-—S06T i “Ww CT GZ “aun Y92Z—L06T m0 US _ |sny PUZE—9O6T Zz aa UG ‘aun PUZZ—906T "OO wa BHR OMDANMDOANAHRONMOANOODET toa AARKSASISIGSSESESSLALSSSSSRSSSSAATAAAAARS AAAS SSS SE eee ee oe eee ee eee eee ere ae ih OOIeel Goths COlGA Ra Cs Cd 1a OO rat eid SOO HrOMOANWMWODHAHEROMOSCANNDHAHErOMORAAND OO rr ‘UL Og “US SUS OGY ro GOR SS ial “Aine uyZI—868T | | i Lary ta Ya Oa te MiQwtwtonNomoan reolpeai | eo uo Ga Ope oe Cr ine) Cal cle) i ie tet lee Tt hay Baer tah ee eg fey tae Da ie Pee 8 VOR Uae an, Rie the a ei Ce 2 et Gy akg . Lien Cie we o amy ee ry . 1 ORC ta Pind devant aps Sen ep aguaaene hgh py aera ‘[ady 496T—8681 : n | “WOE “US | BA FM AAAS “qa, PASZ—S6T | Che URES Cre poe Joie Ose CPS ae icy Mar} “UL 0g “US Ne CRP ia) cca Ch TET eae POL athe: Alero OR ee IK arial Macc See Si owe “AON PUZZ—LOST “UL 0g “HO qo” 6. “ut 08 ‘"O 0 ' ' ' ' . ' ' CO LICS ' ' . ' ' rh ’ ' ' ' ' ‘ ’ ' ' ' ' ' ' ' lamp aycg—16sT ‘ur 0g “U0 n ce ‘judy puz—L6st Cr) “AON UIE1—968T . U9 YS | ; 9 ci ' “Aine WIFI—968T_ ae : a a he Pris eSpaltie: rin et he ao Tr Oo Dea Dn ‘WO ‘UZ | a a a4 4 aon WOL US Sny_WISI—SO6T SSO : | Ame W9T—8061 | | wo Us | :Sny Peet ao “Y Ane nice | : “wO -U “oul T396—906T _ m0 Us | adog U96T—SO06T 2 . cl UT eo | sny WI6T—SO6T meu o “Ws sine 4 ae | “ut 0S * ‘sny W967 F06T : | wm 0s “US sny Pug—Fo6r m0 WZ ameter of the Fishery Board for Scotland. rt ke et ANN AONAN 0.0) CRDi dea eo aire CAUCE Te velvet ON NG) elon wr (eh (Cletehelg of (eonse OO Over mW COL a! eee lieheie sk Ce O80 Sd OC TsO Ree Oe re CIRM Tao) BOK A ee eek CI URC de ne SCAT IN (AMMO AHWO © Cy aK ne aCe aaa SR Cone Cm a reese OMe INL ON Oe (Chr 8 TNA AA eH NA se eee he ek ee lk ek kk lle a T 203 eae 208; | wos “UZ I sind aes qj “amr UOT S061 | O 0 te 6 ORIN PUA 2 IN rl 8 eet 8 rome ae ke ete we ieee a hk ek eA N AN OWMNI eR On ANN srt tt ek kl ll ll ll lee _ Oe “4S Ame YIF—LO6L m0 4S Vv a [CS AGS ON CO OAiGueoi Gel Geertenna se 8 a © og ‘seep ye, WO) Gap a Bi ata, elie 8 ts eh ewe APO Reic eye) 8 nl ve mAnAT Cian Kor aes fle Bap oly— h— Nati Penn Lina) OLE, Dam Gale Cota ran met Lams ayer Che The pai amen MRC CoQ iu] aC) MUL aU) male an SO ce COC Se ROP Oh, Oe eh er otal oh Ko No ole ofniest Ore te lias Ue Den Dito ft) 0 ween i Deno ted ANNA ps REA Ee ee 2 a a a ee ee eee ' pol COCR EB HOC ea oD mai Pre TSO. CR t Clie OV GAC IG LG) At aan bm Lb Ma aC Cs Sa AS US ga ae ta nae CC dee SI WON IPT aD iC CP IG MTCE ie Arm Paar Te eee aa a) ab ake” eh ele Laue sia) fe) Ko wie ea etn Se) Wh WA ie) eee eri | “ICL eius—t05 Ci emUee UM oat Golem — nce — tec — mcrae I a Sey Oe “WO 09d UIT —006T MOE UZ 9deg 430I—006T “WOs "TS ‘ANC 438Z—006T “Wr 0g “US ¥_PI1SZ—O06T 0g 4S 20 UIFZ—668T _ MOF UG ny. U3LT— 6681 494—868T CA TC CT Oe EON Oia fame aT WA SiR PID SCs OT Tie) ime Coe Pee A CMC AA UC, Oe | ee eee eas 6 le yee iW) le Misra Meee ue eum (ANIMA IOIOE AM + te 8 tt Gy aa alten Rear Ye Reh es Cao) AND (o> GEES OE CCN LCs Up CeCe Ona ear Mae 0 at bk 2G Po Ueace) Lee C CnC eUieen Cate UME CEn — MO Peien | Brig -}c eek Dis te Paes Steere Mt) i) AU Cit) 0 ‘paisa you sored ¢ VU aC SUC a ny RCD AC ie that) Gea 1G Cer bet at ott ark WM ny a Or DMINMCWricds + oor , Ope 0) Tee TOG ek ee ola eed, 0) le ay we er 8 ee we ow Dio So 0.50 0) 0 70s Ge CORON SO Cache “Cees CA MAS RCs a US BC ay Oe nay WT FO Mit Laas th ume It Tae te tT eet Js Tae Tat AS a 7? IC eae TL Th) LT a St), af Say WE wm 8 ecm 8) eae) se lel AES HICSS GOS av UNE eed 8) GA a is eee Pie ee ee ee aw lee ee ay ee EO COR Ne SY SEARS} ola rll soo sire Dtetee Gene atin Lot SOMO SCY MR) mUne cies: sCemci tie Te Sti tt a7 yah a 0 OD 6 Date. ‘g Wind. Weather. Sea. Bottom. Air. |Water fa Nov. 18, 1897} —|483| — = — — — Octa wa. — |50°3) — — — — — Feb. 15,1898 | — | 451) — — — — _ April: 22, ,, — |496|) — — — smooth, clear — Uinlbyg dla be — |54:7] — | — — clear = Sept. 20, ,, — |569| — — — dull _ Dec. 19, , —|471) — — snow showers, clear — overcast April 25,1899; — | 486] — N.W. 4 heavy rain smooth — Aug. 10, ,, — {59°77} — N.H. 2 — clear, smooth — Octaaeonme. — |50°4} — S.W. 2 cloudy smooth = April 18,1900 | — | 475) — — overcast calm, clear — Ontliv 205" 5 —|561}) — N.W. 3 cloudy smooth, clear — Sept. 12, ,, | 53°8| 53-4) 26:0) N.W. 4 clear smooth, clear | some weeds July 2, 1901 | — | 58°6 | 25-4 calm clear smooth, clear weedy July 30, 1904 | 61°5 | 61:0 ; 23°6| S.E., mod.| cloudy, fine brownish — Aug. 18, ,, | 59°7) 58°6|22°8| S.W., very | fine bright | clear, smooth | very weedy light sun July -5,1905 | — | 56°5 | 25:8) S8.W., light dull, rain | clear, smooth weedy Aye. sy — | 57-2 | 25:2| S.E., mod. | verv dull, rain jrough nr. shore weedy Satin GRE — | 52°3! 26:0 | N.W., mod. | dull, showery | clear, smooth clean June 22, 1906 | 60°8 | 59°7 | 24:0) S.W., light — quite clear weedy July 23, ,, | 58°8| 56°5 | 24°3 S.W. dull, showery | fairly clear few weeds Aug. 21, ,, | 59:0) 57-2) 26:0 | 5.W., light — very brown — July 1, 1907 | 52°5 | 51:1 | 256 N. = dark weedy June 18, 1908 | 49°3 | 46-4 | 25-6 8.E. heavy rain dirty few weeds July 13, ,, | 68:0} 60°8 | 26-0 Seve showers clear weedy Aug. 14, ,, | 46°4 | 44:6 | 26:0 N.W. — clear few weeds Ti. Bre Harpour. Oct. 12,1897 | — |50°9} — — — — Nov. 20) 5; — |50'5) — = — — Feb. 25, 1898 | — |446}) — — == — — Wlar@e We a. — |44-2) — — clear _ onl IER. — |50'2} — — = very clear —_ April 205) — |47:2| — — — nice and dull — dune) 295" 5, —|fe5| — — — clear _ Sept. 29, ,, — |52:2| — |8.E., stvong| heavy rain thick = iueje, “2h — |45:5| — — showers quite clear - Jan. 11,1899 | —|44:9) — — rain and sleet clear — April 14, ,, — |446] —]| H., strong cloudy clear, smooth — June 23, ,, — 154-7) — — cloudy, rain clear = iSivrere INOS 5 — |56:38| — calm = very clear, — smooth Oct. w Li; —| —| — S. 4 — dull -— July 26, 1900 554) — | W.N.W. 1 |cloudy,showers| clear, smooth — Sept. 11, GEZA 0:20 /t20251)) aN Wea dull clear, smooth good July 38,1901 58:3 | 24:9 calm clear clear, smooth — Aug. 29, ,, — | 57°7 | 25:3] N.W., light dull, rain clear -- June 25, 1903 | 55:4 54:9; — calm oo clear, smooth a July 13, ,, |57°2)55:2) — — = smooth — Aug. .25, ,,. | 55°0}54°7}. — — cloudy clear, smooth — Sept. 25, 55°4 | 55:0 | 25:2 — dull clear, smooth — June 28, 1904 | 58:3 | 57°6 | 25°3 | S.E., mod. bright sun | clear, smooth weedy July 28, ,, | 61:2) 69:4 | 24:1 |S., very light] fine, sunny {| clear, smooth clean Aug. 17, ,, | 61°5| 59°5| 25:0! S., gentle fine clear, smooth clean July 6, 1905 | — | 55:0) 26:2} N., mod. dull very clear clean LAT ee US ae — | 59:0 | 25°8 — dull clear, smooth clean Sept. 15, ,, — | 52°2 | 25:9; S.W., mod. dull, rain clear, rough clean June 23, 1906 | 58°6 | 52°7 | 265 /S.W., light — clear, smooth | very weedy July 24, ,, | 58°3 | 56°5 | 22:0 S.W. — clear very weedy Aug. » 99 | 07°21) 57:2] 24:0) W., light — dark — Jne 27, 1907 | 50:0 | 48-2 | 20:0 We showery clear — June 13, 1908 | 51:8 | 49°6 | 26-0|S.E., strong raining very clear very weedy July 15, ,, | 60°6 | 59-4 | 25°6 S.E. showery dark — Aug, 11, %, | 67:7))/54:0)) 26°38) NNW. — clear weedy of the Fishery Board for Scotland. 71 III. SAven Bay. Temp. °F.| & Date. ra Wind. Weather. Sea. Bottom. Air. |Water fast July 10,1896; —]} —]|] — —_ _ very clear clean Nov. 21, 1897 | — |498| — — _— - = Feb. 28,1898) —|] —] — — _ clear — April 14, ,, — |464) — — — rough, dull _ June 28, ,, — |56°8} — — very clear — Sept. 30, ,, — |53°2} — =] northerly, | cloudy, rain | thick, muddy — light Mec; 225. a5 — |45°5]; — SW breeze = — — Jan. 11, 1899 | — | 43-8}; — — cloudy, showers calm — PAtoritl os UO Fae — |43:5} — N.3 clear, sunny clear — June 20, ,, — 151-2) — — dull, rain clear weedy Ames cOh 5, — |554) — S.E. 2 — very clear, — smooth Octia eoilsces —| — W.S.W. 4 overcast choppy, dull _ April 18,1900 | — | 46:0) — W. 4 rain dull, smooth — July 253, 55 — |568} — N.3 rain clear, smooth — Sept. 13, ,, | 49:1] 51:3 | 26-2 calm clear clear, smooth good July 2,1901 | — | 52:9 | 25-4 — calm clear, smooth — Aus. 295) 7 — |57:7|25:4|N.W., med.| favourable clear — Sept. 25, 1903 | 54:1 | 54:0 | 25-0 — very dull dirty, choppy weedy June 29, 1904 | 56°5 | 54:3 | 25:2 |S., veryli +] fine, sunny clear, calm clean July 29, ,, | 60°8| 60-4) 25-0] S.E., light | very dull, rain| clear, rough clean PANGS is.) | OOFO TEDSLaullaore W., ligt fine, cloudy | clear, smooth | little weedy July 4,1905 | — | 55:4] 26°2|S.W., light dull, rain clear, smooth weedy Aes Gs), — | 57:0 | 25-7 calm dull clear, smooth clean Sepsis .; — |52:2) 26-2] S., light dull very clear dirty June 22, 1906 | 61:9 | 56°7 | 22°5 calm — clear, smooth weedy July 24, ,, | 56°5 | 53°6 | 22:8/5.W., light showery dark weedy Aug. 22, ,, | 601 | 55:4 | 23:6 S.E. — very dark — June 27, 1907 | 49°6 | 47:8 | 22°8 W. — dark very weedy June 15, 1908 | 51°8 | 48-2 | 25:8 |S.W., strong — muddy very weedy July 15, ,, | 64:4 | 59-0 | 26°8 W. — dark very weedy Aug: 11,5, |57°9: |) 54:0} 26°8 |) N.N.OW. — clear weedy IV. Srracuvur. duly 14,1896 | —j} —j| — — clear — Oct. 8, 1897 | — ]51:8) — = = = — Nov: 225. ;, ==) (49:2) = = = — Feb. 23,1898 | — | 42°38} — — — dull — Apri sl9y -;; — |49°3) — — — very clear = Siilys 2s, -,, — |58:8| — — = rough on beach — Sept. 23, ,, — |57:2) — — — quite clear = Jan. 10,1899} —/|456] — — calm, fine little dirty = April 24, ,, — |466| — | S.E., light | heavy rain | clear, smooth = wine e21- ,, — |564|) — _ cloudy clear, smooth = ue ell, — 1583} — spe bright sun clear, smooth = Oct; — 30)—%, = || AR ANSE Mic overcast dull weedy July 27,1900} — |55°8| — calm sunshine clear, smooth == Sept. Log 59:0 | 56°5 | 226 N.W. 4 overcast clear, choppy | very weedy July 4,1901 | — | 54:1 | 24:9 — misty smooth = Aug. oF — | 57°7 | 22-2 |against shore rainy dull = July 13,1908 | — |556) — _ dull smooth = Aug. 26, ,, |54:7|54:0| — — rainy clear, smooth = Sept. 24, ,, | 56:1 | 55:2 | 23-0 light very dull clear, smooth = July 1, 1904 | 55:2) 55-8/ 26:0] S. strong | rain and very clear clean breeze dull Aug. 1, ,, | 601|59-0|25°8/S.W., mod.| dull, rain | clear, smooth | very clean Aug. 20, ,, | 57°7| 55:4 | 23°6|N.W., light | fine, sunny very clear weedy July 7, 1905 | — | 57:2] 26:1) W., mod. dull clear clean Aug, 18. .;, — | 55°2| 25:2) W., strong dull, rain jrough nr. shore muddy Sepia Usa, — | 55-6 | 15°6 calm very dull | clear, smooth weedy June 26, 1906 | 565 | 57:6 | 24:0 W. showery dark, choppy weedy July 26, ,, | 72:3] 63-0 | 20°6 5.S.E. — little muddy | slight weeds Aug. 24, ,, | 583] 57-2 | 22°6 none — dark weedy June 28, 1907 | 50°7 | 48°6 | 23-0 N.W. — clear weedy June 16, 1908 | 50:0 | 46°8 | 25-0 Ss. showers clear weedy duly | LZ, 55 ole Sad-2 127-0 Ss. W. —_— - clear _ weedy Aug. 138, ,, | 60-0 | 53°6 | 26:8 W. — dark little weeds Part III.—Twenty-sixth Annual Report V. INVERARAY, Temp. °F.| = Date. eae Wind. Weather. Sea. - Bottom. Aix. |Water fat 14, 1896 | — — — — clear — 27,1897 | — | 42:2) — — —= = = 18, 1898 | —/41°5) — = = dull — A iter —|410) — — — _— — Sin — |488) — = — very clear _— iy sets — |563}; — — — smooth, thick — PA mie — |565] — — — thick, muddy — 8, 1899 | — | 424} — — — clear, calm — DON. — |46°8) — W. 2 cloudy dull, smooth — Day — |547| — — showery dull — — |61:9} — W.7 bright sun |} clear, smooth — — |500; — calm overcast smooth weedy — |52:9) — S8.W. 1 cloudy very clear — — |562) — N.E. 3 dull, cloudy | dull, choppy — 56°3 | 55°6 | 22°2| N.W. 0:2 dull, rainy | clear, smooth good — | 46-2 | 20-9 W. heavy rain dull — — | 41°7} 115 calm sunny clear clean — | 58-8 | 24°9 calm dull yellow-brown | fairly clean — |56°3|] 8-4 light heavy rain smooth _ 56°21] 55:38) — = heavy rain | clear, smooth — 55°6 | 54:3) — _— rainy clear, smooth -- 57°4 | 50:7 | 21°2 light dull, rain | clear, smooth — 55:4 | 66°5 | 25°6| S., strong showery brownish clean 60°8 | 60-4 | 26°1|8.W., gentle} dull, rain clear, smooth clean 60°8 | 60-1 | 24:2 calm fine, cloudy | clear, smooth muddy — | 57-7 | 25:9! W., mod. dull clear, smooth clean — |54°7 | 25:0 |N.W., strong} dull, rain rough near | dirty, weedy shore — | 53°6| 22°8) S., light dull, rain clear, smooth |mud and leaves 56°1 | 56°8 | 25°5 W. rain, thunder broken — 65°8 | 57-2 | 10°4 8.5. W. light showers clear weedy 58°3 | 55:8 | 22:0 8.8. E. — brown — 50:0 | 471 | 25°2 |S.,verystrong] heavy rain | dark, choppy | very weedy 68:0 | 60°8 | 23:6 S.W. rain clear weedy 59:0 | 50°7 | 25:2 W. rain clear very weedy uaduroyMog WOAINg eUBUPIC) te 68 1f 69 & oe FL Gy. YTIVM ‘yooune * you 6E€ ‘Id premor 7 ~ “PF pveysun yoo, fi eedang~ Spee i — serusyeg SUS yes 2 ea ae ee ey he | on . barypaly ‘TT aivqd ot the Fishery Board for Scotland. 73 III.—SOME NO'VES ON FISH PARASITES. By Tomas Scort, LL.D., F.LS. (Plates III.—VIT.) Papers containing records and descriptions of parasites more or less peculiar to fishes have been contributed at various times to Part III. of the Annual Reports published during previous years by the Fishery Board for Scotland. In the present paper there are notes on several additional species, some of which are interesting because of their strange and unusual forms. These notes have been prepared from specimens obtained at various times chiefly in connection with research work undertaken on behalf of the Board, but a few have reached me from other sources. Some of the specimens have been in my possession for several years, while others have only recently been obtained. z am indebted to my colleague, Dr. Williamson, for some of the species recorded, and to my son, Andrew Scott, A.L.S., for the drawings and photographs with which the paper is illustrated. The species to be described comprise examples both of the Ectoparasites and the Endoparasites of fishes. Three species belonging to the former group appear to be new to science, while some rare and curious forms are included among those belonging to the second group. The various species mentioned in the sequel are arranged and described in the following order :— (1) Eetozoa. CRUSTACEA. CopEPoDa. Pandarus bicolor, Leach, var. Hatschekia cornigera, sp. n. Chondracanthus Williamsoni, sp. n. PLATYHELMINTHA. TREMATODA-ECTOPARASITICA. Octobothrium Sybille, sp. n. (2) Entozoa. TREMATODA ENDOPARASITICA. Distoma cestoides, Ed. van Beneden. CEsToDA. Bothriocephalus proboscideus, Rudolphi. punctatus (Rudolphi). Ancistr ocephalus microcephalus (Rudolphi). 74 Part III.—Twenty-siath Annual Report Schistocephalus solidus, Creplin. Tetrarhynchus minutus, P. J. van Beneden 3 tetrabothrius, P. J. van Beneden. megacephalus, Rudolphi. Ph yllobothr wm thridax, P. J. van Beneden. hs lactuca, P. J. van Beneden. Acanthobothrium coronatum, P. J. van Beneden. Dinobothrium septaria, P. J. van Beneden. Diplobothrium simile, P. J. van Beneden. Abothrium rugosum, Goeze. Taema sp. NEMATHELMINTHA ACANTHOCEPHALA. Echinorhynchus proteas, Westrumb. 3 acus, Rudolphi. cs sath earuureuice 33 agilis, Rudolphi. ADDITIONAL NOTES. (1) On a large Cestode from the intestines of a Common Porpoise. 2) On Nematodes observed in the viscera of a Common Porpoise. (3) On the injurious effects of parasites on fishes. The following are descriptions of the various species mentioned above :— CRUSTACEA. CoPpEPODA-CALIGOIDA. Genus Pandarus, Leach (1816). In a previous paper* J gave a description and figures of Pandarus bicolor, Leach. These specimens had been obtained from the Tope, Galeus canis, Rondel. I have now to record the same kind of parasite from the Picked Dog-fish, Squalus acanthias, Linn. A considerable number of these fishes, captured off the West of Scotland and landed at the Fish Market at Aberdeen in March of this year (1908), were examined at the Laboratory at the Bay of Nigg. On these Dog-fishes quite a number of Pandarus bicolor were observed; they resembled those previously described in form and colour. Figure 19, Plate III., represents one of the specimens. The cephalon is ornamented by deep chocolate-brown pigment, as shown in the drawing ; the middle plates are also coloured, but not so deeply. The body seen from above is elongated and somewhat eliptical in outline, but flat when seen from the side. Among the specimens of normal form and colour was one that differed from the others in both characters, but especially in culour. This specimen is represented by figure 18 on the same plate. This form resembles in some respects a species described in 1888 by Lay under the name of Pandarus sinuatus, and to that species I was at first inclined to ascribe it. Probably, however, it * Highteenth Annual Report of the Fishery Board for Scotland, Part III., p. 157, Pl. VLI., figs. 33-38 (1900). of the Fishery Board for Scotland. 75 may only be a somewhat abnormal variety of the more common P. bicolor. This form has scarcely any trace of the brown colouration so conspicuous in P. bicolor ; it is also rather broader in proportion to the length. The second dorsal plate is as wide as the posterior part of the cephalic shield, and the posterior margins of each of the two lobes is obliquely truncated instead of being rounded as in the normal form. The lobes of the next plate, which have their posterior margins somewhat evenly rounded, are Separated by a semicircular hollow and are not spread so widely apart as in the normal P. bicolor. The anal lamina are also more prominent than in the normal form. Till further specimens of this pale-esloured form are obtained, I prefer to regard it as only an accidental variety of P. bicolor. Genus Hatschekia, Poche (1902). (syn. Clavella, Oken, nec. Cuvier). Hatschekia cornigera, sp. n. Pl. IIL., figs. 1-7. I found this Copepod moderately frequent on the gills of several specimens of Sea Bream, Pagellus centrodontus, De la Roche, sent to the Laboratory from the Fish Market at Aberdeen. The species, however, does not appear to be generally common, for a considerable proportion of the fishes examined had their gills apparently free from the parasites. Hatschekia cornigera is a small species, and measures only about 2-4 millimeters in length exclusive of the ovisacs, which are moderately elongated. It is, like some other species of the same genus, of a narrow elongated form (fig. 1), but may be distinguished from them by the cephalon being produced backwards in the form of a short blunt-pointed, spur-like process on the median dorsal aspect, as in the drawing (fig. 2), which shows a profile view of the head and part of the thorax. The antennules are short, stout, and five-jointed, and sparingly setiferous, the third and last joints being shorter than the others (fig. 3). The antennz are small, but being armed with stout terminal hooked spines they form effective grasping organs (fig. 4). The mandibles, maxillz, and maxillipeds do not appear to differ greatly from the corresponding appendages of other members of the genus. Figure 5 represents one of the second pair of maxillipeds ; they are each three-jointed, moderately elongated, and armed with a stout terminal claw which is bifurcated at the extremity; the second joint bears also a small curved spine near its proximal end ; there is also a small seta at the base of the terminal claw. The thoracic limbs comprise apparently only two pairs, as in other members of the genus. Both pairs are somewhat alike in structure, but the first are considerably smaller than the second pair. One of the first pair is represented by figure 6; it consists of a moderately stc ut, two-jointed basal part and two, two-jointed branches. The inner branch is rather shorter than the outer, and the first joint is shorter than the end one; in the outer branch the joints are nearly of equal length. Both branches are furnished with several stout spines. In the second pair, one of which is represented by figure 7, the inner branches are stouter and rather longer than the outer, and the end joint is about twice the length of the first. In the outer branch the end joint is the smallest. Both branches are furnished with a few terminal spines, one cf which is considerably stouter _ and rather more elongate than the others. The colour of the parasites resembles that of the gills of the fish. 76 Part III —Twenty-siath Annual Report Genus Chondracanthus, De la Roche. Chondracanthus Williamsoni,* sp.n. Pl. IIL, figs. 8-17. In this species the body is depressed, and of an ovate form when seen fromabove. Length about 7-5 millimeters, greatest width equal to about half the length. The head, which is articulated to the thorax, is subquad- rangular in “its general outline, but has a shallow rounded projection on each side, as shown in the figure (fig. 8). There is only a slight con- striction between the cephalon and the thorax, and the neck is very short. The thorax, which is considerably depressed, has the lateral margins coarsely crenulated, or lobate; there are about six rounded but somewhat irregular projections or lobes on each side, the second and the last three being more prominent than the others. The posterior end of the thorax also terminates in a narrowly rounded median lobe, as shown in the ficure (fig 8). The abdomen is much reduced in size and of a rounded form. The antennules are small, uniarticulated, and rather rudimentary in structure (fig 10). The antenne are moderately large, and each consists of a stout basal part, to which is articulated a strong terminal hooked spine, the vi appendage thus forming a powerful grasping organ (fig. Il). The mandibles are similar to those observed in other species of Chondracanthus ; they consist each of a very short basal joint, and a terminal and broadly falciform masticatory part, both edges of which are finely serrated (fig. 12). The dilated appendage, armed with two short stout spines, situated at the base of the mandible, represents the maxilla (see fig. 12). Both pairs of maxillipeds are very small. ‘The first pair are very similar in structure to those of Chondracanthus cornutus ; each consists of a moderately stout base and terminating in astraight claw-like spine, finely setose on the inner edge (fig. 13). The second pair are rather larger than the first ; they each consist of two joints of nearly equal width, but differing slightly in length, and armed at the apex with a short and claw-like spine and a small rounded process, as shown in the drawing (fig. 14). There are only two pairs of thoracic limbs ; both pairs are rudimentary, and are also similar in structure. Each limb consists of a short and hroad basal part, gibbous on each side, which bears a small oblong process, separated from the basal part by a narrow constriction (figs. 15-16). The ovisacs were not very slender, and appeared to be of moderate leneth, but they were more or less incomplete. Figure 9 represents a young female which, though resembling the adult in having the lateral margins coarsely crenulated, differs in being pro- portionally narrower, The male of this species is somewhat similar in form and structure to that of Chondracanthus cornutus (O. F. Miiller), It is considerably dilated in front, but tapers towards the posterior end (fig. 17). The male is very small, being rather less than the 4, of an inch iu length. The colour of this form is opaque white with a slight trace of red. Host Sebastes norvegicus (Ascan.), from Aberdeen Fish Market, February 1908. Several specimens were found in the angles formed by the gill cover and gill-arches, with the claw-like antenne of the specimens firmly fixed in the tissues of the host. * After my colleague, Dr. H. C. Williamson, to whom I am indebted for this and several other species. of the Fishery Board for Scotland. 77 Sebastes norvegicus does not appear to be a very rare fish in the waters round the more northerly parts of the Scottish coasts, but the examples from which the specimens of Chondiacanthus here recorded were obtained were captured in the vicinity of Iceland. PLATYHELMINTHA. TREMATODA. Genus Octobothrium, Leuckart (1828). Octobothrium Sybille,* sp.n. Pl. IV., fig. 12. This is a small species, being only about two and a half millimeters in leneth. Like some others of the same genus, it is flat, elongated, and narrow. The anterior extremity is about half the width of the middle portion of the body, and is narrowly rounded in front. There are two small submarginal suckers on the ventral aspect, one being on each side and a little in front of the mouth, which is in the median line. From the anterior end the width gradually increases towards the middle, then tapers slightly posteriorly. The posterior end expands and assumes a fan-like outline, but with the apex truncated. Round each of the two lateral margins of the fan-like expansion are four prominent “ suckers.” Each sucker appears to be divided into two subequal portions, as shown in the drawing (fig. 12). A single specimen of this species of Trematode was obtained on the gills of a Trout, Salmo fario, Linn., captured by Dr. H. C. Williamson in Loch Tay, Perthshire, in August 1901. Genus Distomum. Distomum cestoides, Ed. van Beneden. PI. V., fig. 12; Pl. VII., figs. 3-5. 1870. Distoma cestoides, P. J. van Ben. Les Poissons des cotes de Belgique, p. 17, Pl. IV., fig. 9. P. J. van Beneden, in the work referred to above, mentions the occur- rence of a large trematode in the esophagus of Raza batis captured on the coast of Belgium, which he records under the name of Distoma cestoides. A few specimens, comprising adults and young, of what appear to be the same species of the Trematoda have been observed in large Rava batis brought to the Fish Market at Aberdeen. One of the adult specimens is represented by the Photograph Plate VIL, fig. 3. It measures nearly two inches in length and between five and six millimeters in diameter. The specimen is cylindrical in form, and the ventral sucker is situated near the terminal one. One or two of the other specimens were even longer than that photographed, the largest measuring about two and three-quarter inches in length. It was observed that one or two of the larger specimens were deeply pigmented immediately posterior to the ventral sucker; these when dissected were found to contain ova in abundance; the ova were of a dark chocolate-brown colour, oval in form, and measured about 1147 x :0806 mm. (Pl. V., fig. 12). Besides the mature specimens, others varying in size and evidently immature were also observed, the ays of which being only six to eight millimeters long (Pl. VIL, g. 4). * Sybilla, Queen of Alexander I. of Scotland and daughter of Henry I. of England, is buried in a small island near the east end of Loch Tay. The Highland Tay, by Hugh Macmillan, p. 80. F 78 Part [1I.—Twenty-sixth Annual Report Several young specimens of a Distomum, which closely resemble the immature D. cestoides from the Skate, were found encysted on the walls of the stomach of a Witch Sole, Plewronectes microcephalus, captured in the Moray Firth. There were several cysts observed, and all those examined contained only young Distomids—in some cases one, in others two examples. Two of the young forms and one of the cysts are shown on Plate VIL., figs. 5 and 6; the figures are about twice the natural size. Fishes form a considerable proportion of the food of large Skates, and probably the Witch Sole, which lives in moderately deep water, some- times becomes the prey of these large Plagiostomes, Should this happen, the encysted Distomids will be liberated and reach maturity in the alimentary passages of their new host. < Several other large Distomids besides the one here referred to have been recorded as the parasites of various fishes. One of the largest, perhaps, was that obtained by Nardo in 1827, from a fish captured in the Gulf of Venice. Two specimens of this parasite were obtained, one of which measured five inches in length.* This species was named by Nardo Distoma gigas, but Dr. Cobbold, the English authority on Entozoa, considered that Nardo’s Distoma belonged to the same species as that described by Rudolphi in his history of Entozoa published in 1808, under the name of Distoma clavatum.* The species described by Creplin as Distomum veliporum is also a moderately large one. It, is said to attain a length of three inches, and as it has been recorded from the same species of Skate as those described above,r I was at first under the impression that those found by me might belong to that species. Our specimens, however, agree better with van Beneden’s figure in his work Les Poissons des cotes de Belgique, p. 17, Pl. IV., fig. 9., than with the description of D. veliporum in Diesing’s Systema Helminthum. I have therefore provisionally ascribed our specimens to van Beneden’s species Distomum cestoides, It may be noted here that D. veliporwm is apparently a widely-dis- tributed species. Prof. E. Linton, of Washington and Jefferson College, U.S.A., has described in the proceedings of the U.S. National Museum (vol. xx., p. 521) a large Distomum from the stomach of a “ Barndoor Skate,” Rata levis, captured at Wood’s Hole, Massachusetts, which he ascribes to this species. This specimen, however, like that of D. cestoides recorded by van Beneden, was incomplete. The specimen recorded here is in fairly perfect condition. CrEsToDA. Genus Bothriocephalus, Rudolphi (1808), Bothriocephalus proboscideus, Rudolphi. PI. V., fig. 4. 1808. Bothriocephalus proboscideus, Rud., Entoz. Hist. Nat., vol. iii, p. 39. 1850. Dibothrium proboscideum, .Dies., Syst. Helminth., vol. i, p. 590. This Cestode was obtained in the intestine of a Trout captured in Loch Tay, in August 1901, by my colleague, Dr. H. C. Williamson. The *See “Parasites,” by T. Spencer Cobbold, M.D., p. 460; and ‘Systema Helminthum,” Diesing, voi. 1i., p. 366. + Catalogue des Poissons des cotes de la Manche dans les environs de Saint- Vaast, par M. A.-E. Malard. Bull. Soc. Philomathique de Paris, 8 ed., Ser. t. II., p-.70 (1890). of the Fishery Board for Scotland. v9 drawing shows the anterior portion, including the head, of the specimen. The entire worm may reach a length of one or even two feet. B. probos- cideus is one of the most common species of the genus, and is of frequent occurrence in Trout and Salmon, and, as Dr. Cobbold remarks, when the parasite is present in large numbers it cannot fail to prove injurious to the bearer,* Bothriocephalus punctatus, Rudolphi. Pl. V., fig. 3. 1808. Bothriocephalus punctatus, Rud., Entoz. Hist. Nat., vol. ili., p. 50. 1858. Dibothrium punctatum, Dies., Syst. Helminth., vol. i., p. 593, The specimen of B. punctatus represented by the drawing was obtained in the intestine of a common Eel, Angwilla vulgaris, Leach, captured at the mouth of the River Dee at Aberdeen in July 1905. The whole specimen measured 235 millimeters in length, or fully nine inches, but specimens double that length have been recorded. Only the head and anterior part of the body are represented by the drawing. In this species the head is elongated and narrow, and the articulations (proglottides) are also long and narrow. This parasite appears to be widely distributed, and common to a number of fishes. Professor Linton also records what he regards as the same species from several of the fishes frequenting the Atlantic coast of America, but the Eel does not appear among the various hosts mentioned by Diesing, van Beneden, or Linton. B. punctatus is found sometimes abundant in the Turbot, Rhombus maximus. I found the stomach of a large and fine Turbot crowded with them ; they formed a living mass, so inextricably mixed up together, that it was almost impossible to separate one of the specimens without break- ing. They extended from the stomach down into the intestines. J. P van Beneden records this parasite as abundant in the Turbot, and states that it “est tout aussi abondant dans le Turbot de la Méditerranée.” Linton records the parasite from the Sand Flounder, Bothus maculatus, from Woods Holl, Massachusetts ; one of the longest specimens, preserved in alcohol, measured 223 millimeters ; a considerable number of specimens were also found in the stomachs of Sea Raven, Hemitripterus americanus, the largest of which measured about 300 millimeters. In report No. XIV. on the Lancashire Sea-Fisheries Laboratory, Mr. J. J. Johnston describes two forms of B. punctatus, one of which he finds in Turbot captured in the Irish Sea, and the other, which is more slender, in the Brill. He has counted over sixty specimens in a single Turbot.§ Genus Ancistrocephalus, Monticelli (1890). Ancistrocephalus microcephalus (Rudolphi). Pl. V., fig. 5; Plate VI., fig. 2. 1819. Bothriocephalus microcephalus, Rud. Entozoorum Synopsis, pp. 138, 473. 1850. Dibothrium microcephalum, Dies., loc. cit., vol. iii., p. 592. This species was obtained from a Short Sunfish, Orthagoriscus mola, landed at the Aberdeen Fish Market in September 1899. The worms * Parasites, a Treatise on the Entozoa of man and animals, p. 468. + Les Poissons des cotes de Belgique, p. 73. = Notes on Cestode parasites of fishes, Proc. U. S. National Museum, vol. xx., p. 430. § Report for 1905 on the Lancashire Sea-Fisheries Laboratory (1906), p. 152. 80 Part III.—Twenty-siath Annual Report were still alive when observed, and appeared to be endeavouring to leave the fish, and making their exit by the mouth. In this species the head is comparatively small and compressed and provided with two nearly circular suckers placed opposite each other on the flattened sides, as shown in the drawing (Plate V., fig 5). Each of the suckers measure about 5 mm. in diameter, and they are surmounted by aslightly projecting ledge armed on the under side with numerous minute hook-like denticles. One incomplete specimen measured about 26 inches in length, and another about half that length, (Pl. VI., fig. 2). According to Diesing, this Cestode may attain a length of six feet. It has been recorded by Rudolphi from Orthagoriscus mola, captured in the Mediterranean. Prof. Linton also records this species, and mentions one of the specimens as being 150 centimetres long (nearly sixty inches). Van Beneden records the same worm from the coast of Belgium, and states that he has seen a score of individuals in a single fish,* while Malard also records it from the coast of La Manche, and apparently all from the same species of Sunfish. Genus Schistocephalus, Creplin (1829). Schistocephalus solidus (O. F. Miller). Pl. VIL, figs. 7-8. 1776, Tenia solida, O. F. Miiller, Zool. Danicee Prodromus, pp. 26-37. 1808. Bothriocephalus solidus, Rud., Entozoorum, Hist. Nat., p. o4. 1829. Schistocephalus dimorphus, Crep., Nov. obs. de Entoz., . 95. 1850" Schistocephalus dimorphus, Dies., Syst. Helminth., vol. 1., p. 584. 1893. Schistocephalus dimorphus, Olsson, Bidrag till Skand Helmiuth fauna, ii, p. 15. 1896. Schistocephalus solidus, F. W. Gamble, in the Camb. Nat. Hist., vol. i, p. 84. The three-spined Stickleback, Gasterosteus aculeatus, is a little fish not uncommon in the Loch of Loirston, near the village of Cove, Kincardine- shire. On visiting this loch towards the end of May 1901, my colleague, Dr. H. C. Williamson, found a large proportion of the Sticklebacks infested with worms, so much so that many of the little fishes had their abdomens distended with the parasites, causing them to assume an abnormal appear- ance. Many of the fishes examined had the entire abdominal cavity occupied by the parasites. In some cases there was only a single worm of large size, folded upon itself two or three times, and which, when straightened out, was much longer than the fish. In other cases two, and sometimes several, specimens were present, but these were generally of smaller size. The loch is frequented by a number of water-birds such as Sea-gulls and Terns, and the Heron is also occasionally observed about the loch. These birds are liable to be infested with the tape-worm, Schistocephalus solidus, Rudolphi, in its sexually-mature stage, and the Stickleback parasite mentioned above is the same worm in its sexually-immature condition. It is thus evident that some of the birds frequenting the loch had been giving shelter to the Schistocephalus, and that larvee hatched from the * Les Poissons des cotes de Belgique, 87. of the Fishery Board for Scotland. 81 eggs produced by the mature worm had found their way by some round- about road to the abdomen of the fish, there to continue the cycle of their curious and highly interesting life-history. Figure 7, Plate VII., is a photograph of one of the little fishes infested with the parasite showing the distended abdomen, and figure 8 is the photograph of another fish showing the worms in situ. This Cestode is apparently widely distributed ; not only has it been recorded under one or other of its different names by European writers on Helminthology, but Prof. Edwin Linton mentions its occurrence in the abdominal cavity of the Blob, Cottus bairdiz, captured in Swan River, Montana, August 3rd, 1891. (Proc. U.S. National Museum, Volt Xu, p. 427, pl. xxviii., figs. 4-5.) Genus Tetrarhynchus, Rudolphi (1808). Tetrarhynchus megacephalus, Rudolphi. Pl. IV., figs. 9-10; Pl. VL., fig. 3. 1819. Tetrarhynchus megacenhalus, Rud. Entozoorum Synopsis, p 129 et 447. Tab. II., fig. 7-8. 1878. Tetrarhynchus megacephalus, Van Ben., Pois. d. cotes. d. Belgique, p. 12, Pl. VI., figs. 8, 9-15. This Yetrarhynchus is one of the largest of this curious group of parasites; the specimen represented by the photograph (Pl. VL, fig. 3) measured about eighteen inches in length, and nearly half an inch in width. It was obtained by my son in the intestine of a Greenland Shark, Scimnus borealis, Flem., captured at the mouth of the Forth estuary many years ago. This parasite has also been found, but in a sexually-immature state, in the Blue Shark, Carcharias glaucus, and some other species of the shark family ;* -but though it appears to be limited in its distribution chiefly to that group of Selachians, it has also been recorded as occurring in other fishes, one of which is Scorpaena porcus, a Mediterranean fish, Van Beneden remarks that the same worm, or a near ally, has been found on the gills of a Sparoide, as well as in the mouth of a turbot; but, he adds, “ Dans cette situation le ver est errant.” f Tetrarhynchus tetrabothrius, P. J. van Beneden. PI. IV., fig. 11. 1850. Tetrurhynchus tetrabothrium, van Ben., Les Vers Cestodes, Acad. Roy. de Belgique, Tom. XXV., p. 154, PE OXEV ILE, This was obtained in the intestine of Picked Dog-fishes, Squalis acanthias, Linn., examined at the Laboratory in March 1902. The fishes had been captured in the North Sea and landed at the Fish Market at Aberdeen. In these Dog-fishes this parasite was of frequent occurrence, being observed in nearly all the specimens examined. Van Beneden also records the ocurrence of this Cestode in the same species of Dog-fish, as well as in Mustelus vulgaris, taken off the coast of Belgium. Olsson has recorded T.. tetrabothrius from Picked Dog-fishes captured in the Skagar- *This Tetrarhynchus, in Dr. Baird’s catalogue of Entozoa in the British Museum, is recorded from a large Spotted Dog-fish, Sculliwm catulus (p. 68). + Les Poissons des cotes de Belgique, p. 5. = Les Poissons des cotes de Belgique, pp. 6-10. 82 Part III —Twenty-siath Annual Report rack and Oresund * and Johnston from similar Dog-fishes and from Thorn- back Skates, trawled in the Irish Sea.t Tetrarhynchus minutus, P. J. van Beneden. PI. V., figs. 7-8. 1850. Tetrarhynchus minutus, van Ben., Les Vers Cestodes, Ds LOL Mex? This Cestode was obtained in the intestine of an Angel-fish, Squatina angelus, captured in the Firth of Clyde in May 1904; it is a smal! species and easily overlooked. As indicated above, this species was described by van Beneden in 1850, amd the characters by which he distinguishes it are as follows :—“ Les bothridies ne sont pas complétement séparées les unes des autres ; les trompes sont couvertes de crochets recourbés ; les gaines des trompes forment des tours de spire; les segments sont trés-longs et peu nombreux,” and he adds that the species may be recognised from closely- allied forms by its small size, the length of the seements, which are several times longer than broad, and the number of articulations, which seldom exceed six, the last segment being already mature when five or six rings can be counted, whereas in other species mature segments do not usually occur till a larger number of rings have beea formed. Van Beneden’s specimens of 7’. mautus were also obtained from Sguatina angelus, which appears to be the only kind of fish this Cestode has been recorded from. | : Another species of Tetrarhynchus—T. erinaceus, P. J. Van Beneden, described in 1858,+ has been noticed in fishes examined at the Labora- tory, usually in small cysts on the walls of the stomach, and pyloric caca of Gadoids (Cod-fishes and Saithe). 7. erinaceus, in this encysted state, according to van Beneden, is unable to attain sexual maturity, and is therefore placed by him among the zenosites or strangers—parasites that have not yet reached their ultimate destination, or, as that author remarks, “Ce sont des parasites en transit.” The encysted Tetrarhynchus can only reach the sexually mature stage after it has been transferred to the stomach of some Plagiostome, and the fish belonging to that group in which the parasite has been most frequently observed in a sexuaily mature condition is the Thornback Skate, Raia clavata. The proboscides do not appear to be exserted while the parasite remains within its cyst, but when removed from it and placed in a little sea-water the Cestode, apparently recognising the change in its environment, soon begins to push out its formidably armed proboscides. So far as I have observed, the thrusting out of these armed appendages is not completed by a continuous movement, but intermittently, as if the operation were a work of some difficulty, and that a pause was necessary for further effort. I have also observed that, though the fish may have been dead for a good while, the encysted parasite would be still alive, and on being removed from its prison would in a short time begin to thrust out its proboscides. T. erinaceus is a widely-distributed species, either in its encysted state or in its state of sexual-maturity, for it has been recorded not only by van: Beneden, Olsson, and other European Helminthologists, but also by Linton in his papers on the Entozoa of American fishes. Two of the species of Tetrarhynchus mentioned here—T. tetrabothrius and T. minutus—have also been assigned to the genus Rhynchobothrium, Rudolphi, but meanwhile I leave them where van Beneden placed them. *Bidrag till Scandinaviens fauna, Kongl. Sv. vet. Akad. Handl., Bd. 25, No. 12, p. 25 (1893). + Rept. for 1905 of the Lancashire Sea Fisheries Laboratory, p. 174 (1906). +t Mem. sur les Vers intestineaux, p. 128, Pl. XVIII. of the Fishery Board jor Scotland. 83 Genus Phyllobothrium, P. J. van Beneden (1850). Phyjllobothrium thridax, van Beneden. PI. V., fig. 9. 1850. Phyllobothrium thridax, Les Vers Cestodes, p. 122, BLY 1906. " Phyllobothrium thridax, Johnston, Report for 1905 of the Lancashire Sea Fisheries Laboratory, p. 161. This Cestode was obtained in the intestine of the same. fish in which the Tetrarhynchus minutus was observed, viz., in Sguatina angelus, captured in the Clyde near Girvan in May 1904. The specimen was small and appeared to be immature, though possessing the characters of the species. Van Benden obtained P. thridax also in the Angel-fish, as well as in Raia batis, and Johnston recurds it from Raia clavata captured in the Trish Sea. Olsson has recorded the same Cestode from Raia batis captured in the Oresund, and Lénnberg and Monticelli have also recorded it, but it does not appear to be so common as some of the others mentioned here. Phyllobothrium lactuca, P. J. van Beneden. PI. V., fig. 1. 1850. Phyllobothrium lactuca, van Ben., op. cit., 120, Pl. IV. 1906. Phyllobothrium lactuca, Johnston, op. cit., p. 159. This was also observed in the Angel-fish from the Clyde mentioned above. Johnston records it from Raia batis, Raia clavata, and Raia ctrcularis captured in the Irish Sea. Van Beneden states that it is com- mon in the Smooth Hound, Mustelus vulgaris, and records it also from the Picked Dog-fish, the Grey Skate, and the Thornback, and Malard records it from Zrygon vulgaris and one or two of the Plagiostomes already referred to. Genus Acanthobothrium, P. J. van Beneden (1849). Acanthobothrium coronatum (Rudolphi). Pl. V., fig. 2. 1819. Bothriocephalus coronatus, Rud., Entozoorum Synopsis, p. 141. 1850. Acanthobothrium coronatum, van Ben., op. cit., p. 129, Pl. VIII. and IX. 1906. Acanthobothrium coronatum, Johnston, op. cit., p. 155. I obtained this species in specimens of Grey Skate, Raia batis, from the Fish Market, Aberdeen, in March 1901. The specimen, of which only the head (or scolex) is represented by the drawing (fig 2), measured sixty-five millimeters in length. One of the more important characters by which A. coronatum is distinguished seems to be the presence of a group of three suckers above each of the four bothria. These accessory groups of suckers form a sort of crown on the apex of the scolex, while immediately beneath each group two moderately strong bifid hooks may be seen, as indicated in the drawing. This species is found in the sexually-mature stage in various sharks and rays, and is apparently widely distributed. The following European fishes are mentioned among the hosts of this Cestode :—Scylliwm canc ula, the lesser Spotted Dog-fish; Mustelus vulgaris, the Smooth Hound; Squatina angelus, Trygon pastinaca, Torpedo marmorata, Raia batts, 84 Part III—Twenty-siath Annual Report and ftaia clavata ; while Linton records the same parasite from the Barn- door Skate, Rava laevis, captured at Woods Hole, Massachusetts, Genus Dinobothrium, P. J. van Beneden (1889). Dinobothrium septaria, van Beneden. Pl. VI., fig. 4. 1889. Dinobothrium septaria, van Ben., Bull. Acad. Roy. de Belgique, 3me. série., tom. 17, p. 69, Pl. L., figs. 1-3. The specimen represented by the photograph Plate VL, figure 4, is from the intestine of a Porbeagle Shark, Lamna cornubica, captured in the North Sea in May 1901. The specimen measures about forty-five millimetres in length. Each pair of bothria measure about nine milli- inetres across by about seven millimetres in length. This Cestode is readily distinguished by the peculiar form and arrangement of the bothria from all other species belonging to this group of parasites. As the species does not appear to have been previously recorded from Scottish waters, it may be of interest to give the following extract from Prof. van. Beneden’s description. The scolex, he says, is surrounded with four bothria, as in the majority of the Cestodes of Sharks and Rays; these bothria are placed back to back, and possess no appearance of hooks. The worms having been preserved in alcohol had become somewhat contracted, and the form of the bothria was not unlike a shell of the genus Septaria. These bothria are large, of an oval form, and attached by the whole length of their base ; the external face is concave and crowned above by a projection which in some respects resembles the hinge of certain bivalve shells.* The specimens recorded by van Beneden measured twenty-five to thirty millimeters, and were thus considerably smaller than the specimen recorded here, Genus Diplobothrium, P. J. van Beneden (1889). Diplobothrium simile, van Beneden. PI. VIL, fig. 2. 1889. Diplobothriwm simile, van Ben., op. cit., p.’ (0; “Biwle figs. 4-8. A specimen of a Cestode that appears to belong to this species is represented by the photograph, Plate VIL, figure 2. This, like the species just described, was obtained in the intestine of the same Porbeagle Shark in which the other was found. The specimen measured fully 70 millimeters in length—nearly three inches. This Cestode was described by van Beneden at the same time as the Dinobothrium, and was also found in a Porbeagle Shark. The Scolex or ‘‘head” does not at first sight present so remarkable a form as the Dinobothrium, but its structure suggests a more or less near relationship with species already known to science. A closer examination, however, “Le scolex est entouré de quatre bothridies, comme dans la plupart des Cestodes de poissons Plagiostomes ; ces bothridies sont placées dos 4 dos et ne possedent aucune apparence de crochets. Dans |’ état de conservation actuelle des vers, contractés par I’ alcool, elles ressemblent, 4 une coquille du genre Septaria. Les bothridies sont larges, de forme ovale, attachées par toute la largeur de la base, la face externe concave et couronnées en haut par une saillie qui rappelle jusqu’d un certain point, la charniére de certaines coquilles bivalves. Van Beneden, op. cit., p. 69. ee of the Fishery Board for Scotland. 85 reveals certain interesting differences, which are fully described by Professor van Beneden in the paper referred to, published in the Bulletin of the Royal Academy of Belgium for 1889. In this paper he remarks that at first sight it suggested to him a likeness to Z'etrabothrium maculatum, Olsson, a form previously recorded from the same kind of fish, and therefore he gave the species the name of Diplobothrium simile—the generic uame Liplobothrium referring to the peculiar arrangement of the bothria. He states further that ‘“‘ce qui caractérise surtout ce genre, c’est quil a, comme le précédent, une cloison complete entire les deux couples of bothridies ; cette cloison présente a son sommet quatre pieces qui semblent fournir des points d’appui 4 la couche musculaire ; sous certains aspects, ce Cestode resemble beaucoup au Cestode, dont nous venons de parler, et qui a été décrit par Olsson ; mais les organes qui lui ont fait donner le nom de Tetrabothrium sont complétement isolés, tandis que dans le Diplobothrium ils sont réunis deux par deux ; a l’extérieur on croirait voir par moments quatre orifices parfaitement séparés, tandis qu’en réalité il y’a, de chaque coté, une séparation qui ne s’étend pas jusqu’au bord des orifices.” Genus Abothrium, P. J. van Beneden (1870). Abothrium rugosum (Goeze). 1782. Taenia rugosa, T. A. 8. Goeze, Versuch siner Naturg. der EKingeweiderviirmer thierscher Korper, p. 41]. Tab. xxxiii., figs. 1-5. 1808. Bothriocephalus rugosus, Rudolphi, Entoz. Hist. Nat., Wel, BI, po 42. 1850. Dibothrium rugosum, Diesing, Syst. Helminth, Vol. L., p. 591. : 1870. Abothrium gadi, van Beneden, Poissons des cotes de Belgique p. 56, Pl. V., fig. 14. This Cestode appears to be common in the sexually-mature stage in the larger gadoids. Its head is invariably inserted in one of the cecal tubes and so intimately incorporated with its tissues as to have the appearance of forming an: integral part of the tube. For this reason, the attempts made to remove the head of the worm from the tissues of the pyloric czeca have usually ended in failure, and no satisfactory description of this part of the worm has yet been published. The piercing of the wall of the pyloric ceca by the head of the Cestode produces certain curious results ; the cecal tube becomes distorted some- times to a considerable extent, nodular processes are formed, and frequently, as remarked by Linton, a yellowish waxy deposit is formed consisting of the degenerated tissue of the ceca. The worm, which extends from the cecal tube to the intestine, is often in the larger fishes - of considerable length; specimens from such fishes sometimes reach to twenty-five and thirty inches, but as, like most other Cestodes, they are very contractile, the specimen that may, while living, stretch to thirty inches will be found to be little more than half that length when preserved, especially if the preservative be alcohol. Linton records a specimen 65:5 millimeters in length, while Johnston obtained one that measured 85 centimeters,* equal to about 34 inches. * Report for 1906 on the Lancashire Sea Fisheries Laboratory, p. 171. 86 Part III.—Twenty-siath Annual Report Genus Taenia, Linné. Taenia sp. Pl. V., figs. 10-11. A specimen of a Cestode that appears to belong to the genus 7'aenia was obtained in the intestine of an Kel captured in the Loch of Loirston, near Cove, Kincardineshire, in 1901. The specimen measured about 75 mm. in length, and was moderately slender. The head seen in front is obscurely quadrangular, with the bothria occupying the bluntly-rounded corners, and nearly equidistant. In the centre is a minute stellate disk, somewhat difficult to make out. ‘The bothria are circular, surrounded by a muscular ring, and with a membrane extending over the inner half, The head appears to be unarmed. This specimen has some resemblance to a form mentioned by Linton found in the intestine of “‘ Anguilla chrysypa (Anguilla vulgaris),” and named by him TYaenia dilatata.* The Loch of Loirston specimen may belong to this species, but I scarcely think so; the 7. dilatata Linton, shows the front aspect of the head made uneven by shallow “dilatations” which is not the case with the specimen recorded here. I therefore prefer for the present to leave the species unnamed. NEMATHELMINTHA. Sub-Order AcanTHocEPHALA, Rudolphi. Genus Echinorhynchus. Lichinorhynchus proteus, Westrumb. PI. IV., figs. 3-4; Pl. VL, fig. I. | 1821. Hcehinorhynchus proteus, Westrumb, De Helminth. Acanth., p. 37, tab. 1, figs. 11-12. 1850. . Echinorhynchus proteus, Diesing, Syst. Helminth., Vol. TL, p.257. This curious species was observed in the intestine of an Eel, Anguzlla vulgaris, Cuv., captured near the mouth of the River Dee at Aberdeen in July 1905. In this species the proboscis is short and feebly armed ; it is also sub-clavate in form, rather linear or cylindrical. Immediately posterior to the proboscis is a large bulb-like expansion (or bulla), which the parasite seems to have the power to compress or dilate at will, for it can insert not only the proboscis but the bulla also into the tissues of the muscus mem- brane of the intestine, as shown by the photograph (PI. VI., fig. 1). This figure represents a small portion of the inner surface of the intestine of of the Kel with two Hchinorhynchi in situ ; the proboscis and bulla of the parasites are entirely immersed in the substance of the intestinal wall. A careful examination of the fish revealed the fact that in a few instances the proboscis of the parasite had pierced right through the intestine so that the apex of the proboscis could be easily seen projecting slightly on ° the outside surface of the wali of the intestine. Between the bulla and the body of the Cestode there is a long slender neck, and both the bulla and the neck are unarmed. The length of the specimen represented by the drawing (PI. IV., fig. 3), is sixteen millimeters, or fully half an inch. * Parasites of Fishes of the Woods Hole region, U.S. Fish Commission Bull. for 1899, p. 435, Pl. XXV., figs. 272-273. ’ ; of the Fishery Board for Scotland. 87 Echinorhynchus proteus, being a widely distributed and apparently a somewhat variable form, has been described under many different names. It has also been recorded from many kinds of fishes, both marine and freshwater ; at least over forty different kinds are mentioned as being the _ hosts of this worm.* Echinorhynchus acus, Rudolphi. Pl. IV., figs. 7-8. 1&08. chinorhynchus acus, Rudolphi, Entoz. Hist. Nat., Vol. Il. p. 279. 1850. Echinorhynchus acus, Dies., Syst. Helminth., Vol. II., Dou. Many examples of this Hchinorhynchus were observed in the intestine of a large cod-fish captured in the Moray Firth in June 1897, and though frequently observed at other times and places, the species has not been represented so numerously as on that occasion. They were found fairly numerous in the intestine of a saith captured recently in the nets of the salmon fishers working near the Laboratory. Although the hosts of Hchinorhynchus acus are said to include a number of different kinds of fishes such as Cottus scorpius, the Conger, the Angler- fish, and one or two kinds of flat-fishes, this parasite seems to be more frequently met with in Gadoids than in any other fishes captured off the coasts of Scotland. In this species the hooks with which the proboscis is armed are numerous and large ; they are arranged in close set and slightly oblique rows. There are about twenty hooks in a complete series extending once round the circumference, but scarcely half that number are in view at one time. Hach hook is bent backwards at a sharp angle, as shown in the drawings (figs. 7 and 8). The length of this species, as given by Diesing, is from one to three inches; the largest I have noticed, however, scarcely exceeded 50 millimeters in length. The Echinorhynchus represented by the drawings, figures 5 and 6 on Plate IV., was obtained in the intestine of a common Trout captured in Loch Tay in August 1901. The number of hooks in the series is rather less than in the specimen from the Gadoid—the number in view at one time being eight. Butit so closely resembles Echinorhynchus acus that it is probably only a variety or a slightly immature form of that species. Echinorhynchus agilis, Rudolphi. Pl. IV., figs. 1-2. 1819. Hchinorhynchus agilis, Rud., Entozoorum, Synopsis 67 et 316. 1850. Echinorhynchus agilis, Diesing, Syst. Helminth., Vol. II., p. 35. Diesing’s definition of this species is as follows :—“ Proboscis clavata, uncinorum seriebus 3. Collum brevissimum inerme. Corpus utrinque attenuatum, densissime transversim striatum. Longit. 2-3.” And he mentions as the hosts of this entozoon Mugil cephalus, captured at Spezia (Gulf of Genoa), and Mugil labeo, captured at Remi. This description by Diesing applys fairly well to an Hchinorhynchus observed in the intestine of a Grey Mullet, Mugil chelo, captured in the nets of the salmon fishers near the Laboratory in June 1900. One of the specimens is repre- * Linton has also observed Z. proteus in a number of American fishes. 88 Part III —Twenty-sixth Annual Report sented by the drawings (figs. 1 and 2, Pl. IV.). The body tapers slightly towards both ends, and is marked by numerous transverse striz, and thus far it agrees with the definition of #. agzlis of Diesing ; there seems, how- ever, to be aslight difference in the number of hooks on the proboscis, of which there are apparently six in the series instead of three. The hooks as shown in the drawing are of moderate size; those surrounding the summit of the short truncated proboscis extend more or less outwards, while the others, which spring from about the middle and have stout gibbous bases, are turned downwards. I was at first inclined to ascribe this form to Hcehinorhynchus gracilis, van Beneden, as the proboscis and its armature resemble somewhat closely that author's figure in Plate V. of his work on the Fishes of the Coasts of Belgium,* which species he also obtained in the intestine of Mugil chelo, but I scarcely think that van Beneden’s Z. gracilis can be the species of that name which Diesing ascribes to Rudolphi, for Diesing’s definition of Rudolphi’s Hehinorhynchus gracilis, is as follows :—“ Proboscis cylindrica, uneinorum minutorum seriebus, 10-12. Collum nullum. Corpus cylindricum retrorsum attenuatwm,” ~ and there is no reference to transverse striz. Moreover, the Hchinorhynchus gracilis, Rudolphi, is, according to Diesing, found in the intestine of a bird, Coracias garrula, Linn. et Gmel. I have, therefore, for the several reasons stated, referred our specimens to Hchinorhynchus agilis, Rudolphi, SOME ADDITIONAL NOTES. (1) ON A LARGE CESTODE FROM THE INTESTINES OF A Common PorPOISE. Diphyllobothrium — stenvmacephalum, Cobbold, Pl. V Platine. ln ‘ 1858. Diphyllobothrium stemmacephalum, Cobbold, Trans. Linn. Soe., vol. xvii., p. 167. 1879. Diphyllobothrium stemmacephalum, idem, Entozoa of Man and Animals, p. 422. *5 Me oe 5 This large Cestode was obtained in the intestines of a Common Porpoise, Delphinus phocceena, cast ashore in front of the Laboratory at the Bay of Nigg. The porpoise had become entangled in the nets belonging to the salmon fishers, and being unable to extricate itself had been drowned. Dr. Cobbold, who described the Cestode in 1855, and who also obtained it in the same species of Cetacean, states that ‘the small intestine of the Porpoise was completely choked for the space of eight or nine feet by fine tapeworms so closely packed together that the gut presented the appearance of a solid cylinder.” These tapeworms, he remarks, were of various sizes ; four of them measured respectively from seven to ten feet in length, while a fifth was only eighteen inches. : The Porpoise cast ashore near the Laboratory, and which I had the privilege to examine, had the small intestine also crowded with the same kind of parasites, and so much so that it seemed to be impossible that any matter could pass, yet the Cetacean had the appearance of being in perfect health. The removal of the parasites in anything like a complete con- dition was very difficult owing to their great length, their being so crowded together, the extreme attenuation of the anterior end with its * Les Poissons des cotes de Belgique, p. 28, Pl. V., fig. 7 (1870). + Systema Helminthum, vol. ii., p. 37 (1850). of the Fishery Board for Scotland. 89 minute head, and the readiness with which the lower “joints ” (proglottis), separated from each other. The longest example I obtained measured fully niue feet, and appeared to be fairly complete. Another specimen reached to about seven feet in length, and there were a number of smaller pieces. The proglottides or “joints” near the middle and towards the posterior end of the larger specimens measured from ten to twelve millimeters in width and nearly the same in length. The head or scoJex seen in profile is very compressed, but viewed in front its outline is somewhat triangular, and the suekers—two in number—occupy the two sides of the triangle, as shown in the drawing (fig. 6, Plate V.}. The neck is extremely slender, measuring only about ‘08 mm. in width. There appears to be very little known concerning the life-history of this Cestode, but probably in its larval stage it lives encysted in the body of some species of fish such as the whiting, considerable numbers of which are sometimes captured by this Cetacean for food ; the Cestode being in this way introduced into the stomach of the Porpoise would obtain its freedom and be able ere long to attain to sexual maturity in the intestine of its new host. Figure 1, Plate VII., is from a photograph, about natural size, of the largest of the specimens of the Diphyllobothrium, from the Porpoise referred to. The Cetacean was obtained in May 1900. (2) On Nematopes orn THREADWORMS OBSERVED IN THE STOMACH AND OTHER VISCERA OF A Common PORPOISE. In another Porpoise obtained on June 18th, 1902, under much the same ~ conditions as the one mentioned above, no Cestodes of any kind were observed, but in the stomach and some of the other internal organs many small threadworms were noticed. The length of some of these measured between forty-five and fifty millimeters, but the majority were considerably smaller. The worms occurred in abundance in the stomach and other portions of the viscera, and were of a dull reddish-brown colour. Strongyloid Nematodes, known as Lung-worms, are found parasitic in the Common Porpoise; they are all viviparus. ‘Three species have been recorded, Prosthecosacter inflexus, Diesing, measuring 6 to 9 inches in length ; P. minor, Diesing, the length of which is about an inch; and P. convolutus, Diesing, the length of which may extend to a little over one and a half inches (18—20"). Dr. Cobbold, referring to these worms, states that when “they are examined in a fresh state the young may occasionally be seen escaping from the Vvaeina, .°..’. : that Professor van Beneden noticed this phenomenon in Prosthecosacter infleaus, and the same was observed by Busk in P. convolutus.” * The Entozoa from the Porpoise examined at the Laboratory in 1902, like those mentioned above, are apparently also viviparous, and they agree fairly well with the species last named—P. convolutus, Diesing. Though the specimens when removed from the Porpoise were still alive, they had to be put into preservative fluid straight away, and therefore I had not the good fortune to observe the phenomenon referred to by Cobbold. Afterwards, however, when a few of them were dissected, fully formed larve were obtained in considerable numbers. Figure 13, Plate V., represents the posterior portion of a female specimen showing the larve in situ. Figures 13 a., b., and c. represent three * Entozoa of Man and Animals, p, 423. 90 Part II.—Twenty-sixth Annual Report of the larvee greatly enlarged, while figure 6, Plate VI., represents a small portion of the viscera crowded with the parasites and figure 7 on the same plate shows a few of them separated out; both of these figures are from photographs enlarged about twice the natural size. Like most of the Entozoa mentioned in the preceding notes, these parasites of the Porpoise are in their early stages probably migrants, but little or nothing appears to be known concerning their life-history. In Dr. Cobbold’s opinion “it is highly probable that the embryos enter the bodies of various fishes before they acauire sexual maturity. Thence they will be passively transferred to the stomachs of cetacea, whence they bore their way through the tissues to the bronchi and pulmonary vessels,” and thus reach the goal of all their wanderings—an environment where they can accomplish the purpose of their life, viz., the development of young, on which in their turn will devolve the responsibility for their continuance of the species. (3) On tHE InsuRtous EFrects oF Parasites ON FISHES INFESTED BY THEM. In the many cases of parasitism that have come under my observation, I have usually been unable to notice any very serious results produced by the presence of such unbidden and, perchance, unwelcome guests. Occasionally evidence of injury apparently caused by them has been obtained. Whitings and other Gadoids have been captured reduced almost to skin and bone, having one or more large worm-like Lernwa hanging at their _ gills full of the red bleod they had extracted therefrom. Yet, even in cases like these, it may be a moot point whether the emaciation is caused by the Lernea, or that their presence is simply owing to the emaciated condition of the fish—the emaciation itself being due to other causes—which by reducing the fishes’ vitality has left it more exposed to the attacks of these parasites. But though there may be no direct proof that the emaciated condition referred to was caused by these crustacean parasites, their presence doubtless tended to aggravate the trouble, and the same may be said about the attacks of parasites in other directions. The next example of parasitism to which I have to refer shows how these vermin (fishermen have a more suggestive name for them) may be injurious to fishes in other ways. Figure 5, Plate VI., reproduced from a photograph, represents the pectoral fins of a flounder infested with crustacean parasites, Lepeophtheirus pectoralis. They are so numerous that a large portion of | both fins is covered by them. The soft tissues of the fins, more especially round the edges and between the spiny rays, was extensively lacerated, and this with the added encumbrance of so many beasts hanging on to them must have interfered greatly with their movements. These parasites are usually found adhering to the underside of the fins, and in this position they are more sheltered and less likely to be rubbed off, and the irritation they may produce will be the more exasperating. A careful scrutiny of the photograph shows considerably over a hundred specimens of the Lepeophtheirus adhering to the pair of fins ; they are so crowded towards the outer edges of the fins that they overlap each other two or three deep, and the delicate margin of the fins has been destroyed. of the Fishery Board for Scotland. EXPLANATION OF THE PLATES. PLATE III. Hatschekia cornigera, sp. n. Fig, 1. Female, dorsal view, - - - Fig. 2. Female, side view of cephalothorax, - - Fig, 3, One of the antennules, - - Fig. 4. One of the antenne, - - - - Fig. 5. One of the maxillipeds, - - - Fig. 6. Foot of first pair, - - - - 2 Fig. 7. Foot of second pair, - - - - Chondracanthus Williamsont, sp. 0. Fig. 8. Female, dorsal view (adult specimen), - - Fig. 9. Female, dorsal view (specimen peance mature), = Fig. 10. One of the antennules, 7 Fig. 11. One of the antenne, Fig. 12. Mandible and maxilla, Fig. 13, First maxilliped, - - Fig. 14. Second maxilliped, Fig. 15. One of the first pair of thoracic appendages, Fig. 16. One of the second pair, - - = Fig. 17. Male, side view, - - - . - - Pandarus bicolor, (?) var. Fig. 18. Fémale, dorsal view, - - - - - Pandarus bicolor. Fig. 19. Female, dorsal view, - - - - - PLATE IV. Fig. 1. Hchinorhynchus agilis, Rudolphi, - - - Fig. 2. Proboscis of the same, - - - - - Fig. 3. Hchinorhynchus proteus, Westrumb, - - Fig. 4. Proboscis of the same, - - - - - Wig. 5. Hchinorhynchus, sp. from a common trout, - - Fig. 6. Proboscis of the same (6a a spine more enlar ged), - Fig. 7. Echinorhynchus acus, Rudolphi, - - - Fig. 8. Proboscis of the same, - Fig. 9. Tetrarhynchus megacephalus, Rudolphi (Scolex), - Fig. 10. A proboscis of the same, - - - Fig. 11. Vetrarhynchus tetrabothrius, van Beneden, : - Fig. 12. Octobothrium Sybille, n. sp., - - - - PLATE V. Fig. 1. Phyllobothrium lactuca, van Beneden,_ - > = Fig. 2. Acanthobothrium coronatum, van Beneden, - Fig. 3. Bothriocephalus punctatus, Rudolphi, — - - : Fig. 4. Bothriocephalus proboscideus, Rudolphi, - - - Fig. 5. Ancistrocephalus microcephalus, Rudolphi, < - Vig. 6, Diphyllobothrium stemmacephalum, Cobbold, - - Fig. 7. Tetrarhynchus minutus, van Beneden, - - Fig. 8. Portion of a proboscis of the game, near proximal ond, - Fig. 9. Pyllobothrium thridax, van Beneden,~ - - Fig. 10. Tenia sp. from «common Eel, - - - - Fig. 11. Head of the same seen from above, - - Fig. 12. An ovum of Distomum cestoides, van Beneden, - Fig. 13. (?) Prosthecosacter sp., posterior end of 0 with larvee in situ, Fig. 13. a. b. c., Three larve of the same removed, - ~ SOK CERN an tok INA OK ORIEN Ia SOK. (ON SE Er oe coe ox XX XX XK K KK XK XK PRIS OR) ER OK OG IR Oe OR HaN 91 12 12 92 — CONT OD orp CO DD oP WNre onro Part IIT.— Twenty-siath Annual Report PLATE VI. Echinorhynchus proteus with their heads embedded in Eel intestine, - - - slightly enlarged. . Ancistrocephalus microcephalus (Str obile), - slightly enlarged. . Tetrarhynchus megacephalus, (Strobile), - - SHently cole . Dinobothrium septaria, van Beneden, (Strobile), xe . Lepeophtheirus pectoralis, adhering to pectoral fins of flat fish, - (2) Prosthecosacter in viscera of Porpoise, - - =) ok Se . Specimens of the same shown separately, - Kine . Echinorhynchus acus, with their heads embedded i in intestine of Coal-fish, - - - - - : =? eta PLATE VII. . Diphyllobothrium stemmacephalum, Cobbold, - about the natural size. . Diplobothriwm simile, van Beneden, - slightly enlarged. . Distomum cestoides, van Beneden, - about twice natural size. . The same, young examples, - about twice natural size. . (?) The same, young Epa les from cysts on the stomach of a Witch Sole, E E twice natural size. . One of the cysts contaidine young Distomides, - twice natural size. . Three-spined Stickleback infested with Cestode worms, - natural size. . A Stickleback, showing the worms 2n sztu, - - natural size. ee litle Se i eth LS EE eo eS Pe PLATE Ill. a 2 = a & i 6 n = = n < B Cy PLATE IV. PARASITES OF FISHES. ee r Me SS F. B. REPORT, 1908. A. Scott, del. ad. nat. A. Scort, del. ad. nat. Fics. 1-5 and 7-12 ParasITEs OF FISHEs. Fics. 6 and 13 a.b.c. PARASITES OF PORPOISE. PLATE Vi. F, B. REPORT, 1908. A. Scort, Fics. 1-5 Parasites oF Fisuzs. Fics. 6 and 7 PARASITES OF PORPOISE. Reproduced from Photographs. F, B. REPORT, 1908. ee catia 6 SSL Fics. 2-7 PARASITES OF FISHES. Fic. 1 PARASITE OF PoRPOISE. A. Scort, Reproduced from Photographs. 7 ie > a Seip = Les. TR sara ae of the Fishery Board for Scotland. 93 IV.—REPORT ON THE OPERATIONS AT THE MARINE FISH HATCHERY, BAY OF NIGG, ABERDEEN, IN 1907. By Dr. T. Wemyss Futton, F.R.S.E., Scientific Superintendent. In the season of 1907 the hatching of the eggs of the plaice was con- tinued as in previous years, but owing to the fact that the supply of spawning adults was the lowest since the hatching work was commenced, the number of fertilised eggs collected from the spawning pond and the number of fry obtained and planted in the sea were the lowest for any year. Although the capacity of the pond would allow of considerably over a thousand plaice being retained in it, the number which was available for the supply of fertilised eggs was only 87. The reasons for this are referred to below. The first eggs were collected on 25th February, and the last collection of a measurable quantity was made on 19th April, although a few eggs were netted at intervals until 16th May. In ordinary seasons, when there was a fairly large number of spawning adults in the pond, the first collections of eggs were obtained usually in the latter part of January and the last in the early part of May, the dates varying a little owing to the temperature and other circumstances. The total number of eggs obtained from the pond in 1907 was estimated at about 1,626,000, whereas in 1906—when the supply of adult plaice was also much below what is necessary—the number was 7,486,000. Of the total, about 40,000 were collected in February, 1,213,000 in March, and 373,000 in April; the largest number were obtained between 16th and 26th March, when about 660,000 were collected. The estimated number of dead eggs which were removed from the hatching apparatus during the season was 345,000, showing a death rate of about 21 per cent., or about half of what it was in the previous year, when the filtering and water supply arrangements were defective. Included in the measure- ments of dead eggs are the shells of those which hatched out, so that the number is in reality less than that stated. The estimated number of fry of plaice which were “planted” in the sea was 1,282,000. They were all liberated in the neighbourhood of the hatchery, mostly on 1st April, 12th April, and 25th April, in from 104 to 114 fathoms, the surface temperature ranging from 42°8 to 43°5 F. The fishermen of the northern part of the coast of aonecneetanie’ requested that plaice fry from the hatchery should be liberated in their localities as in some former seasons, but owing to the small numbers that were at any one time available it was not thought desirable to incur the expense required in doing so. During the season there were considerable fluctuations in the temperature of the water in the spawning pond, as may be seen from the table appended. On the 30th December the temperature fell to 29°5 F., and on the next day it was still lower, viz., 29'1 F. In the early part of January it rose, reaching 41 and 42 F. in the period from 12th to 16th, but later in the month and in the first part of February it was very low, falling to 31:3 F. on 6th February and being under 33°4 F. from the 26th January to February 11th. The frost was so severe in the first days of February that the supply of sea water to the tank- house was frozen up. The temperature of the water in the pond fell G 94 Part III —Twenty-siath Annual Report again to near the freezing point on 22nd and 23rd February. The temperature of the water in the hatching apparatus between 25th February, when eggs were first obtained, till the close of the season, varied between 33:1 F. (on March 9th) to 52 F. on 15th May. The specific gravity of the water in the spawning pond remained tolerably aie throughout the hatching season, varying between 27°0 and 27°8, The number of the eggs of the plaice collected from the spawning pond and the number of fry hatched out and placed in the sea in the various years since the hatchery was established at the Bay of Nigg are as follows :— Eggs Collected. Fry Produced. 1900, i 43,290,000 31,305,000 1901, * 65,377,000 51,800,000 1902, 72,410,000 55,700,000 1903, 65,940,000 53,600,000 1904, 39,600,000 34,780,000 1905, 40,110,000 24,500,000 1906, 7,486,000 4,406,000 1907, 1,627,000 1,282,000 335,840,000 257,373,000 The reason for the decline in the hatching work in the last two years was referred to in the last Annual Report, when the operations in 1906 were described. The quantity of fertilised eggs depends upon the number of adult fishes in the spawning pond, and hitherto the stock of spawners was obtained by the use of a trawler which was permitted to fish in the bays of the Moray Firth and in Aberdeen Bay for the purpose of procuring a supply, all the plaice which were suitable for the hatchery being brought ashore in tubs, the remainder of the catch becoming the property of the owner of the trawler as recompense for the use of his vessel. This arrangement was interrupted at the end of 1905, as explained in last Report, and such plaice as have been since obtained for the hatchery have been brought ashore from the Moray Firth by the ‘“ Goldseeker,” the vessel employed in the international fishery investigations, but the supply has not been adequate for the work. Plaice of the kind required are only to be caught in any quantity on the inshore grounds, where trawling, except for scientific purposes, is prohibited. Under present circumstances it is not possible to get sufficient supplies from the ordinary commercial trawlers working on the offshore grounds in the North Sea. Asa rule, the quantity of plaice obtained by them on any single voyage is small, and it would require many expeditions to obtain a sufficient number for the hatchery. The fish obtained in this way would, moreover, have to be purchased at their market value, and the cost could scarcely be borne by the present vote for scientific investigations. The expense incurred in dealing with a small quantity of.eggs is very little less than that of dealing with a large number. At present the cost of the hatching work is very moderate, and is estimated not to exceed about £80 per annum. This is owing to the fact that the work is carried on in conjungtion with that of the Marine Laboratory, no addi- tional staff being required, the attendant (Mr. George Walker) being also able to undertake the care of the hatchery, the expenditure on the hatchery representing mainly extra coals, food for the fishes, ete. —_—er ee of the Fishery Board for Scotland. 95 Taste I.—Showing the Daily Progress at the Hatchery, and the Temperature and Specific Gravity of the Water. In Pond. In Hatchery. Eggs | Dead Date. Col- ue Temperature. Temperature. lected. | moved. Sp. Gr. | — Cent. | Fahr. Cent. | Fahr. 1907. January 21 3'0 37°4 27°8 22 2°8 37°0 27°8 t, 23 3°0 37°4 27:7 5, 24 1°6 34°9 27°6 . 25 1:4 34°5 27°6 = 26 0°6 33'1 27°6 oe 28 0°8 33°4 27°8 Ha 29 0:2 82°4 27°8 * 30 0:4 32:7 27°6 A 31 0:0 32°0 27°8 February 1 0:0 -| 32:0 27°8 Se as Pe 2 0:4 32°77 27°8 ee a — 4 0:2 32°4 27:6 See ae “A 5 0:2 32°4 27°6 ae Abe a 6 0:4 oles 27°6 ye: ih % Fi 0:0 320 27°6 ee pA? - 8 0:8 33°4 27-6 ae ee ‘ 9 0°8 30°4 27°6 ie ee bes 11 16 34°9 205 *, me i, 12 2:0 35°6 27°6 £ . - 13 2°0 35°6 27°6 Sn nA a 14 1°4 34°5 27°6 oe Se 15 3 378 27°6 AS ae * 16 2°6 36°9 PALS Le + ks 18 3°6 38°5 27°4 aw 28 - 19 32 37°8 2ie2 a, ne = 20 2°6 36°7 27°6 a nae he 21 1°8 35'2 27°6 ee sae a 22 0°6 301 27°4 ae ae k 23 071 32°2 27°2 8. ety . 24 i 1°4 34°5 2/2 ik as _ 25 | A few. 3°71 37°6 27°4 i: o 7 26 ee 3°4 38'1 27°4 3°6 38'5 ¥ 27 13,300 % 3°9 39:0 27:2 5:4 41°7 4 5 28 26,700 | quantity 40 39°2 27:6 5:2 41:4 March J 20,000 42 39°6 27°6 5:2, 41-4 Ks 2 Fes Ry 5-0 41°0 27°6 5:2 41°4 5 4 20,000 | 20,000 4:6 40:1 27°4 5°8 42-4 35 5 ae M0 4°8 40°6 27°2 5°5 41°9 5 6 26,700 |quantity 4-2 39°6 27°4 4°4 39°9 FA 7 26,700 | 10,000 4°6 40°3 27°6 | 5:2 41-4 ke 8 40,000 ade 4-0 39°2 27°4 44 39°9 a 9 40,000 2°6 36°7 27°6 0°6 Baal % il 40,000 2°8 37°0 27°4 ne?) 34:2 35 12 60,000 2:0 35°6 27°4 2°4 36°3 bs 13 40,000 2:0 35°6 27°6 2°8 37°0 e 14 26,700 2°6 36°7 27°6 30 37°4 5 15 20,000 48 40°6 27°6 56 42-1 es 16 60,000 ae 4°8 40°6 27°6 42 39°6 ie 17 ae 3 5:0 41:0 27°6 5'8 42°4 ne 18 | 100,000} 20,000 5:0 41:0 27°4 56 421 in 19 {120,000 a 4°6 40°3 27°4 4°6 4071 3 20 53,300 2: 46 40°3 27°6 5:0 41:0 " 21 26,600 | 80,000 By. 41:4 27°6 6:0 42°8 i 22 80,000 ois 5:0 41:0 27°6 5:4 41°7 oF 23 80,000 5:0 41:0 27°4 4°8 40°6 5 24 bis Ria 41°7 27°4 56 421 ee _— 0 00.0 96 Part 1II—Twenty-siath Annual Report TABLE 1.—continued. Tn Pond. In Hatchery. Dead Bess | Hogs Date. Col- ae Temperature. Temperature. lected moved. | ————————es | ey Thee Crates Cent. | Fahr. Cent. | Fahr. 1907. March 25 | 140,000 6°6 43°9 27°4 7:0 44°6 a 26 60,000 Hae 7:0 44°6 27°4 6:2 43°2 Ka 27 26,600 | 20,000 7°4 45°3 27°4 fa 45°3 55 28 40,000 ay 76 45°7 74 if? 45:0 fn 29 26,700 72 44:9 27°4 GL 45:0 3 30 40,000 76 45°7 276 6:8 44:2 ie 3l Eh 7°4 45'3 27:2 7°6 45'7 April 1 Aon aS 78 46:0 24D) 74 45:3 ». 2 80,000 ae 7:0 44°6 27:2 74 45:3 Be 3 at 100,000 7:2 45:0 27°4 ae 45:0 a 4 | 100,000 a 7:0 44-6 27°4 Wee 45:0 4 5 ae 6°38 44°2 27°2 7:0 44°6 5% 6 80,000 6°8 44°2 27°6 6°4 435 50 if aay 70 44°6 27:4 6°8 44:2 a 8 40,000 6°8 44:2 27°4 6:0 42°8 3p 9 bs 6'8 44-2 27°4 6°6 43°9 5 10 26,700 7:0 44°6 27°4 6°4 43°5 Ne 11 oot + 7:0 44°6 27°6 6°4 435 59 12 20,00) | 40,000 7:0 44-6 27:2 6°4 43°5 » 13 eat a 74 45°3 27:0 6°8 44:2 s 14 a 8'6 47°5 Dicer 76 45:7 a 15 6,700 ENS 76 45°7 27°4 78 46-0 a 16 al Be: 78 46:0 27°4 8°4 47°1 5 17 138,300 | 40,000 76 45°7 27°4 74 45°3 5 18 on Eh 6°8 44:9 27:0 6:4 43°5 3 19 6,600 66 43°9 212 6:2 43°2 is 20 ce 6°6 43°99 | 27:2 6°6 43°9 ‘5 21 6°8 44:9 27:2 6°6 43°9 3, 22 7:0 44°6 27:2 6°4 43°5 ” 23 7°8 46:0 27°4 7'6 45°7 of 24 at: 7:0 44:6 27°4 72 45:0 3 25 | A few. 6:0 42:8 27°4 2 45:0 9 26 ae 8:4 47-1 27°4 76 45°7 0 a ws 8:2 46'8 27°4 6°8 44:2 - 29 | A few. 74 45°3 27°4 74 45°3 “si 30 sa) 7:0 44°6 27°4 7:0 44°6 May 1 78 46:0 27°4 74 45:3 ‘cs 2 76 45‘7 27°4 74 45°3 A 3 8:0 46°4 27°4 8:2 46°8 a 5 84 47°1 27°4 8-4 471 ” 7 a: 86 47°5 27°4 8°4 47-1 An 8 | A few. 10:0 50:0 27:0 10:2 50°4 ” 9 bs 10:0 50°0 27:2 10°2 50:4 ss 10 10:0 50°0 Dee 10°4 50°7 ~ 11 ra 10:2 50:4 272 10:0 50:0 A 13 | A few. 11:0 51:8 27°0 11:0 51°8 fe 15 ; 11:0 51:8 27:0 11:2 52:2 _ 16 | A few. 11:2 52:2 27:0 9°6 49:3 Totals, - {1,626,600} 345,000 — of the Fishery Board for Scotland. 97 V.—ON THE SPECIFIC CHARACTERS OF THE HADDOCK (GADUS ZGLEFINUS, LINN.), WHITING (GADUS MERLANGUS, LINN.); GADUS POUTASSOU, RISSO ; GADUS ARGENTEUS, GUICHENOT; GADUS SAIDA, LEPECHIN; GADUS OGAC, RICHARDSON ; GADUS NAVAGA, KOLREUTER; wits a Key to THe SPECIES OF Gapus rFounp IN NorrHern Waters. By 4H. Cuas. Wiuuramson, M.A., D.Sc, F.R.S.E., Marine Laboratory, Aberdeen. (Plates VIII.-XIII.) CONTENTS. PAGE Introduction, ‘ : : 3 ; : : 97 The Fishes Examined, ; : : : : 97 External Characters—Body- Dimensions, : : : . : 98 Enumeration Characters, . 99 Table showing the Measurements as Percentages ‘of the Length of the Fish, . 100 Tables showing the numbers of Vertebra, Fin- ays; and Pyloric ‘Ceca in the different oe : é : : 105 Key : ; - : ; : : ill Tho ‘Skulls, ete, se : : : ; : 120 Diagnostic Value of certain Bones, , ; F : ; 123 The Diagnosis of Isolated Bones, . . ‘ : : ; 123 The Rib (Pleurapophysis), . : : . : : : 124 Notes on the Species, s : é 3 : : s 125 Literature, . : 3 : : : : : 130 Letters used in the Plates, : : : ; : ‘ : 131 Explanation of the Plates, . ; : : : é ; 132 INTRODUCTION. This paper continues the research on the classification of the Gadide. The two preceding parts were published in the Twentieth and T'wenty- fourth Annual Reports of the Fishery Board for Scotland, Part III., in 1902 and 1906. They dealt with six species, and in the present con- tribution the remaining seven species are discussed. I have been indebted to several zoologists for the courteous supply of specimens of the rarer species, and my thanks are specially due to Mr. E. W. L. Holt, Dublin, Drs. Job. Schmidt and A. C. Johansen, Copenhagen, for examples of G. poutassou and argenteus ; to Professor Brandt, Kiel, Dr. Pappenheim, Berlin, and Professor Vanhoffen, Charlottenburg, for specimens of G. saitda and the loan of examples of G. ogae; and to Dr. Breitfuss, St. Petersburg, fora specimen of G’. sazda. Dr. Hector Jungersen, Copenhagen, also kindly favoured me with the loan of G. ogac and G. navaga. The Fishes Examined. The sizes of the fishes (in cm.) and the localities from which they were obtained were as follows: 98 Part III—Twenty-sixzth Annual Report G. ceglefinus.—The haddocks were obtained from Scottish waters, and also from Iceland. The Scottish specimens, some of which were fresh, the others preserved in formaline or alcohol, measured—5 at 13, 6 at 14, 6 at 15, 16, 17, 4 at 20, 21, 21, 23, 25, 30, 36, 37, 37, 56, 56, 60, 61. The haddocks from Iceland, which are known in the Aberdeen Fish Market as ‘‘ Jumbo Haddocks,” were examined fresh ; they measured 72, 72, 73, 75, 76, 77, 77, 84 cm. G. merlangus (Diagram).—The whitings were from Scottish waters. Some were fresh, the others preserved. They measured 5, 6, 6, 7, 7, 10, 11, 11, 12, 12, 16, 17, 4 at 18, 20, 20, 21, 21, 22, 23, 23, 24, 24, 36, 36, 46, 48 cm. G. poutassou (Fig. 4).—Most of the specimens examined had been got by Dr. Fulton during his trawling experiments in the North Sea. One large specimen, 37 cm. long, lent by Mr. Holt, was captured on the West of Ireland, and the poutassou sent by Drs. Schmidt and Johansen were got at 63°21'N. : 21°48'W. in the young-fish trawl, with 100 metres of wire. All were preserved in alcohol or formaline. Their lengths were as follows :—9, 7 at 10, 7 at 11,6 at 12, 8 at 13, 4 at 14, 6 at 15, S166, 17, 17,37 cn G. argenteus (Fig. 2).—Some sent by Mr. Holt were got 80 miles W.N.W. of Cleggan, Co. Galway, Ireland, 11th May, 1905; the others, from Drs. Schmidt and Johansen, came from 57°32‘N.: 7°E., 31st May, 1907. Two had been captured by Dr. Fulton. All were preserved in alcohol or formaline. They measured 6, 7, 7, 8, 8, 9, 10, 10, 11, 12, 13, 14, 15, 17 cm. G. saida (Fig. 3).—The specimens of this species were preserved in alcohol. Three were obtained by Professor Vanhéffen at Karajak Greenland ; the fourth, from Dr. Breitfuss, was got in the Barents Sea They measured 16, 16, 17, 19 cm. G. ogac (Fig. 1).—Two specimens, measuring 63 cm. aud 33°5 em, in length, had been obtained in Greenland. The former was captured by Professor Vanhéffen, The latter was lent by Dr. Jungersen. G. navaga (Fig. 84).—One specimen of this species measuring 17:9 cm. was lent by Dr. Jungersen. The characters by which the fishes were tested consisted, as in the former portions of the research, of measurements on the fish— Body-Dimensions— aud the enumeration of the Vertebre, Fin-rays, etc.—Enumeration- characters. These characters numbered in all 36. In addition, the the species were compared by the shape of the skuli, abdominal cavity, aud ovary—lInternal characters. The work has been carried on by the same methods throughout, and with identical characters. Some characters which were adopted in the first two papers have been dropped, and a few characters connected with the abdomen have been introduced. This has necessitated a further examination of certain of the species already treated. External Characters—The Body-Dimensions. The body-dimensions which were recorded were of two classes—(qa) distances of certain points on the body from the anterior end of the fish, and (d) girth at three points, and the dimensions of various organs, e.g., the eye and fins. (a) The distances were all measured from the anterior end of the fish when the mouth was closed. In some species this point was the premaxilla, in others the mandible. The distance from the anterior end to each point on the body was taken along the lateral axis. The lateral axis is the line joining the anterior tip of the fish to the middle of tail—Y Z in diagram. "981 “POAT “snsuDjpaayy Snpoy ‘M‘H'V nae ere apne eee of ‘WYYOVIG of the Fishery Board for Scotland. Sis The measuring board described in “On the Mackerel of the East and West Coasts of Scotland,” Eighteenth Annual Report of the Fishery Board for Scotland, p. 295, 1900, was used for this part of the research. The accompanying diagram shows the points on the fish to which the distances were measured. The point a represents the anterior end of the fish (mouth closed). Distance from the tip of mandible to premaxilla, ... @ to 0. Anterior edge of the orbit (for the length of the snout), ... -o @-to | Base of first ray of ventral fin, 1 C © a@to 2 Opercular cleft, , wee he coo BUCO 29 Base of first ou of pectoral fin, Ee ee . ato 4 Anus, a ass We GHGS 1G Base of first ray of first dorsal Lee te ae Bs) Ment toll 5% ”? ”? last y? 9 9 9? 37 bcd oe a to rf Wee igs) SAT Shas} ys)ii Iss SBR COMGL / 53 5 ato 8 53 last Er 3 i a to 10 End of bend of lateral line, . ato ® Base of first ray of third dorsal fin, a to Ll. » 9» last 5) wy ” ” a to 14. Shes oa) an tations rst anal * se ion wen tO eo. pm TITSb es. 44 SCCONG, Alia - “ik sale (nes GOR. Sie LSE oe ay ee 5 ra cae 5s Lor LO, Ventral base of tail fin, : ven GP bon. TG: End of middle rays of tail = -Length of Fish), wont On £08 LG, Tip of ventral ramus of tail, s«- | & to. ls; (0) The Girth at the Pectoral Region, at the Anus, and at Root of Tail. —A thread was passed round the fish at the position and the two ends crossed. A sharp knife was then drawn across the euds, cutting the thread to the size of the girth. Lengths of the Pectoral, Ventral, and Lirst Dorsal Fins.—In each case the fin was measured from the base of the first ray to the farthest edge of the fin. Diameter of the Eye.—For this the horizontal diameter of the orbit was taken. The interorbital space was measured on the top of the head. The length of the ventral ramus of the tail was measured from ‘the base of the first fin-ray of the caudal fin on the ventral edge to the extreme tip of the ramus. For the spread of the tail, ze. the breadth, dorso-ventrally, the tail was not distended to its fullest length ; it was simply flattened out. Length of Barbel.—For the measurement of the lengths of the bartel, fins, and iuterorbital space, and diameter of the eye, a pair of compasses was employed, Enumeration-Characters. Number of rays in each of the dorsal and anal fins. Internal Characters. Number of vertebree. The ural and hypural elements are together counted as one vertebra. Number of the vertebra bearing the first hemal arch. Distance of the first hemal arch (crown of the arch) from the anterior end of the fish. Shape of the skull and clavicle. 100 The colour of the peritoneum. Part I11.—Twenty-sixth Annual Report The number of the lobes of the urinary bladder. Position of the ureter with respect to the swim-bladder. Number of pyloric ceca. Shape of the ovary. Shape of the abdominal cavity. Standard—the Length of the Fish. All the measurements have been represented as percentages of the length of the fish. The length is measured from the anterior end of the fish, mouth closed, to the end of the middle rays of the tail fin. These have been summarised, and the range of variation with the number of variants for each species is shown in the following table. There are also included the ranges of variation for the Gadids treated in the two previous papers. From the latter the number of variants is omitted, but these can be found in the papers just mentioned. Certain new measurements have been made on the species already treated. MEASUREMENTS REPRESENTED AS PERCENTAGES OF THE LENGTH OF THE FisH. RANGE OF VARIATION. GIRTH. LENGTH OF FINs. TAIL. Bye. Length Horiz. L th of i i Diam. eng Pectoral eee Tail. {Pectoral| Ventral. ee Ventral | Spread. Ramus. G. callarias ae 48°3-54°4144°5-50°2| 12-15 ]11°2-14°2| 9°9-11°3| 16°5-19 } 3°3-4°6 9 5°5-6°6 915°3-18°2| 14-174 G. ogac .. 46:4 |86°3,48°3| 10°3, 14 12°6,14°3]18'2,18° 77,8 116, 17°3| 13°3 (2)* (2) (2) (2) (2) G. navaga 45°8 40°2 13°4 10°6 12°8t G. eglefinus (Scotland) |45°5-54°5|/44°3-53°4/12°4-14'8 13°4-16°1|11 4-156) 16-23°3 6°3-7°6 |18°4-21°3 13-37 em. (31) (31) (31) (81) (29) (31) G. eglefinus (Scotland) 13-14°2 14° rF 15°4| 9°5-10°8 |15°9-18°29 5°3. 6°2 | 6°6-7°1 56-61 cm. (4) (4) (4) G. exglefinus (Iceland) 14°3-16°2414-4-17-4] 9°8-11°6 | 16°6-20 6'5-8°2 }119°3-19-9}12'9-16'34 1-2-1: 72-84 cm. (4) (8) (8) (4) (4) (8) —_—_ | — ee G. merlangus .. . 188°9-48°4] 40-49°6 |11°9-17°9j11°9-16°4] 88-13 |12°7-17°98 4:9-8-1 17°3-21°8) 6°8-12°9f 4-9 (25) (25) (25) (28) (21) (25) (25) G. luscus 55-68 | 55-69 | 13-15 | 16-19 | 14-17 | 18-24 9-10 | G. minutus 46-55 48-58 11-14 12-16 16-19 5-8 G. virens . 143°9-50°7/47°3-56°7|12°8-156110°9-14°3] 5°7-8°6 |11°9-14°3} 3°3-6 5°5-7°5 916°6-19°3}14°2-19 G. pollachius .. 42°9-51°9]45°4-59°3| 14-17°2 }9°9-14°7 | 4:2-6°6 |11°6-14'8] 3°5-6°7 | 4°7-7°3 }14°8-19°9/10°5 17°9 G. esmarki 87°50 | 36-52 9-12 10-16 /15'2-16°3 8-12 G. argenteus . |43°3-56°4137°4-52°6/11°7-15 6} 9°1-11°9 15°1 (13) (18) (18) () G. saida.. . |35°1-43°1130°5-35°5| 8-10 4#17°8-19°7 17°4-20°2'14°9-15'4 6-6'6 18°9-20 | 9°5-16'6 4 | ® | ® 4 | @ (4) | @) G. poutassou 80-38°3 |27°4-37°6| 9°6-13 [113°2-16°3] 3°7-6°9 | 11-11°9 } 5°4-7°5 | 4°5-6°5 | 16°2-19| 6-82 (31) (29) (80) (88) (36) (3) (28) (20) described have been published in the previous papers. + The first dorsal fin was a little frayed. * The figures within brackets are the numbers of variants. The numbers of the variants for the species already t The barbel was found equal to 1 per cent, of the length of the fish in a virens measuring 9°4 cm. in wp of the Fishery Board for Scotland. 101 MEASUREMENTS REPRESENTED AS PERCENTAGES OF THE LENGTH OF FISH. RANGE OF VARIATION—continued. DISTANCE FROM THE ANTERIOR END OF THE FISH—MovuTH OLOSED. = A First DorsaL. | SECOND DORSAL. Tip of | Tip of Oper- : End of Man- | Pre- | Orbit. Neutral cular rece Anus dible. |maxilla. ‘ | Cleft. 3 Begin- End Begin- ning. a ning. G. callarias Se *5-1°2 is as 7°5-8°9 | 22-24°6 |23°7-26°3] 26-284 |43°9-47°3]28°6-30°9) 42-44°2 | 44-45°8 G. ogac ies SEO bake: ea Bo ae 6°9, 7°4| 17°9, 21) 23°2 |25°3,27°3 3 30°4, 32 | 44°7, 46 946°8,48°3 (2) (2) (2) (2) (2) (2) (2) (2) G. navaga.. . 1°4 ar 67 18°7 21°2 22°3 29 40°7 43 G. zglefinus 12:6] .. | 6-2-8°7 |18-6-24:6| 23-26-9 |24-7-27-8|38-4-42 3)23-9-28-9/37-4-41-7[40°3-44-3 (Scot.) 13-37em. | (28) (30) (30) (30) (30) (30) (30) (30) G. eglefinus 5-1-4 =3 i 7-4-8 nae 23°7-24°6 = 41°2,41°6]26°1-27°6|38°2-40°4]41°6-43°1 (Scot.)56-6lem. | (4) (3) (4) (4) 4 (4) G. eglefinus (Ice- | -8-2°2 a m 6°6-8 | 20-21°9 |22°4-24-9/24°2-26°4/35 "8-43-9124 °5-27 °3/36°6-40°3} 40-43°9 land) 72-84cem. | (8) (8) (4) (8) (8) (7) (8) (8) G. merlangus .. *3-'9 ue mm 6-9 20°5-26 |22°5-26°9] 24-28°5 |29°7-35°8] 27°9-31 | 38°9-43 [41°2-46'6| (13) (25) | (4) | (@5) | (25) | (4) | (5) | (5) G.luseus .. .. 5) ts za 5-6 16-18 20-22 21-24 22-29 24-27 36-39 G. minutus ee *4-"5 Bn 3-6 17-23 18-21 21-24 30-35 24-27 35-38 G.virens .... =n 4-9 | 6°7-8°4 |21°2-23°3) 22°4-24 |23°5-25°5/36°4-42°4) 30-32°3 |41°3-43°7143°3-46°5 G. pollachius .. sd *7-2:7 |7°9-10°8 | 21°6-25 | 22-25°7 |23°4-27 4/33 3-37°3] 31°5-35 |41°9-45°O} 44°3-49 G. esmarki.. .. sf *B-1 5-8 18-23 15-22 21-25 32-38 23-29 35-40 G. argenteus .. an *9-3°3 | 5°8-O°1 |22°4-29°9/24°4-27°3) 25-31°5 |38°6-43°3}28°6-33 2/39 °8-44°8) (12) (13) (12) (2) (12) (12) (13) (18) a. SAGA woes) ce Ae *6-1'2 | 6°5-7°4 | 21°3-23 | 21°4-23 | 25-26°3 |41°7-44°7] 28-30°7 | 38°7-42 (44°6-46°3] 57°7- (4) (4) (4) (4) (4) (4) (4) (4) (4) G. poutassou .. aye *6-2°6 | 6°7-8°7 | 21°2-25 |21°9-24°9/23°9-28-4| 29-33°3 132°8-35°5/39-9-45 -8]44°3-50'5/52°5-59°262 8-67 °6 (19) (83) (34) (28) (36) (34) (36) (36) (86) (36) (36) 102 Part II.—Twenty-sixth Annual Report MEASUREMENTS REPRESENTED AS PERCENTAGES OF THE LENGTH OF THE FISH. RANGE OF VARIATION—continued. THIRD DORSAL. DISTANCE FROM THE SeconD ANAL, ANTERIOR END OF FisH—MovutTH CLOSED. TAIL. First a Pe é eens ip. A rch Beginning] End. {Beginning| End. ee oD ous G. callarias 65°8-68°3 | 78°9-81°7 | 67-69°7 | 79°4-81°7 | 81-9-84-2 | 97-2-100°5| 57-7-64-8 | 51-529 @youae ; .. | 68:2, 69°2 | 80°5, 80-9 | 68-8, 70:9 | 80'S, 81-7 } 83-7, 84-1 | 100-4, 101] 53-7, 56-9 (2) Qe 2) (2) (2) (2) (2) “G. navaga .| os | 792 | 653 | 803 83-7 | 1016 48 : G. wglefinus (Scotland) _ | 63-2-66°8 | 77°5-81°6 | 63°8-68-2 | 78-2-82-4 | 91-8-85 | 102-1044 | @7-7-74-4 0 51 13-37 cm. (30) (30) } (0) (30) (29) (31) (19) G. eglefinus (Scotland) 65°8-68°1 | 80-2-81°6 | 66-4-68°6 | 81-4-82°7 | $3-9-84°5 | 101-103'5 56-61 cm. (4) (ayy PR) (4) (4) (4) G. wglefinus (Iceland) 64°5-66°9 | 79°5-82°2 | 66-69°3 | 90-82-9 | 82-4-84-9 |101°9-104-4 72-84 cm. (8) (8) (8) (8) (8) (8) G. merlangus _ 60°5-67°7 | 77°7-81°5 | 62°3-69 | 77-8-82°8 | 80°6-84-9 | 100-3-102 } 61-4-70°7 (25) (25) (25) (25) (25) (27) G. luscus 64-68 | 77-79 fEndof1A| 79-84 | 81-84 | 100-101 G. minutus 62-67 | 79-82 | 63-68 | 80-86 | 83-85 | 101-106 G. virens 67-9-72'8 | 81°2-85-4 | 67-3-73 | 80°6-85-4 | 84-6-88-4 | 102-106-4 56°5-61-2 G. pollachius. . 67°4-71°6 | 79°3-84°7 | 66-723 | 78-2-83°9 | 83-6-86'S | 100-104'3 53°3-55 G. esmarki 62-70 | 78-84 | 62-67 | 79-84 | 84-86 102 G. argenteus .. 61-6-69°7 | 74-9-84°7 | 63°2-66-4 | 76-86°3 | 80-7-89°6 | 102-103'3 (13) a3) | a3) (12) (13) @) G. saida 63°7-65°7 | 80-9-82 | 63°7-66'8 | 81°5-8°3 | 83-9-85-7 | 104-104-5 | 46-2-49°6 (4) (4) (4) (4) (4) 61°9-69°4 G. poutassou .. 63°7-70°7 | 80-85°5 | 64°3-68°9 | .86-87-4 | 82°9-88-4 | 101-1065 | 53-2-85-9 (86) (36) § (36) (36) (81) (40) The data set out in these tables are not of direct value from the point of view of specific discrimination. But a detailed examination of them will reveal wherein lie diagnostic characters. One species may be readily separated on the first examination of the fish by some prominent distinguishing mark, as, for example, the black area on the side of eglefinus. But in another the formulation of a specific description is difficult, not always because the fish resembles its neighbours closely, but owing to the difficulty of expressing the difference. And that obtains, even although the two species may be quite easily separated, when compared side by side. An accurate and detailed description of a single fish will not serve for a specific description in every case. In some instances it might do so, but not in the genus Gadus. A perfect specific description would be sufficient to enable one to diagnose a fish by itself, without having recourse to direct comparison with another fish. But that is not altogether necessary, since it is usually possible to make use of pictures of some or all of the species. It must, however, be comprehensive enough to admit of the diagnosis of a damaged fish. This can only be assured when the scheme of ¢lassification is an extended one, working along various lines, by each of which the species may be reached, or at least found in a reduced group. quite normal although deprived of some of its so-called specific characters. A fish may be re of the Fishery Board for Scotland. 103 A callarias, 69 cm. in length, was caught near Aberdeen. It had been mutilated. All its fins had been trimmed. The pectoral and ventral fins had been cut off short, movable stumps only being left. All the dorsal and anal fins and the tail fin had been partly cut away. One eye had been destroyed. All the fins had healed and the fish was well nourished. The stomach contained crabs. The tables given above are useful in showing characters which are hidden when the fish is examined; but they are mainly of service in estimating the exact value of the characters which have otherwise attracted attention. Ina group of fishes, as that of the genns Gadus, it is not possible to separate the different members by a simple scheme, because the character which may be of value for separating two species may be quite neutral in the other eleven members of the genus. It is therefore necessary to take the characters of the fish seriatim, making each. one a basis for classification. It has usually been thought necessary to sub- divide the genus by the test of a single character—for example, by the question of whether the upper or the lower jaw forms the more anterior point of the fish when the mouth is closed. ‘Then in each sub-group the individual members were separated by other characters. Theoretically this is a convenient arrangement, but in practice it is of little value in some cases. For the first selected character may not be readily recognisable in some specimens, and in that case the diagnosis may not be obtained. A character which is very noticeable in examining different members of the genus Gadus is the varying size of the eye. The size of the eye has been compared by previous authors to the length of the snout and to the length of the barbel. The species may then be grouped according as the eye is less than, equal to, or greater than the snout. An examination of the tables given above will reveal how the species will range them- selves under this classification. But while in one species the result will be at once apparent, in another the relationship may be doubtful. That is due to the range of variation in each character. For example, in callarias the diameter of the eye equals 3°3-4°6, while the length of the snout is 7°5-8°9. In this fish the eye is always less than the snout. But in merlangus the relationship is more obscure, the eye measuring 4-9-8-1, while the snout equals 6-9. In such a case it is necessary to ‘refer to the measurements* of each fish, and find out the relationship of the eye and snout in each individual specimen. The result of that enquiry is to show that in merlangus the eye was, in the majority of eases, less than the snout, but it may be equal with it, or it may exceed the snout by a very little. In those fishes in which the lower jaw projects in front of the upper the tables do not show the size of the snout. They give the position of the orbit with reference to the tip of the mandible. The distance between the mandible and the premaxilla must be subtracted from the orbit distance in order to get the length of the snout. In all cases the corroboration of the character must be made on the fishes. This character, the relation of the snout and eye, is a good one for certain fishes, and of less value for others. There is probably hardly a single character or comparison between two characters but may be of more or less value for diagnosis. There is a certain amount of evidence to indicate a change in the size of certain characters with an increase in the length of the fish. Thus the eye was found to be larger in small eglefinus, virens, pollachius, and toa certain extent merlangus, than in big fishes of these species. In the com- parison in length between the pectoral fin and the first dorsal fin of * The measurements made on the fish are not published here. 104 Part FII.—Twenty-siath Annual Report pollachius, in one fish measuring 30 cm. in length the former was slightly the greater, while in four speoimens measuring 36-93 cm. in length the first dorsal fin was the greater. The comparative lengths of the paired fins form a specific character of some value. In each species there is a more or less extensive range of variation. In some, eg., virens, the range is short; in the majority it is much greater than in that species. During the research it was noticed that there might be in a species a character that was specially variable, what might be termed an unstable character. Thus in esmarki the relation between the lengths of the pectoral and first dorsal fins was much more subject to variation than in the other species, Fin-rays. The other external characters which have been adopted for classification are the numbers of rays in the unpaired fins. The rays of the paired fins have not been counted except in three species. The number of rays in the ventral fin was found constant at 6. The rays of the pectoral fin varied in luscus and minutus from 18-20, and in esmarki from 19-20. The number of specimens examined were respectively 4, 8, and 5. In the caudal fin 38 and 40 rays were found in luscus, 38 and 39 in minutus, and 40 in esmarki. In this character, 2, 3, and 1 specimens respectively were counted. : The number of rays in each fin is shown for each fish in the following tables :— [ TABLES, of the Fishery Board for Scotland. 105 THe Number oF VERTEBR& AND FIN-RAYS IN GADUS AIGLEFINUS. . ed sol 3S Fs 22% FIN-RAYS. oO 4 a8 BE a Lb De 2 De, See) ACG 2A. C4 . 4 . . . . CM. Ab Peo 13 54 23 16 22 21 24 23 13 53 22 16 21 Pi 24 22 Ts 55 Me 14 22, 20 25 21 te 54 23 16 29 21 24 22 13 53 ai 13 20 22 24 22 14 53 21 15 22, Ae 24 25 14 54 + 16 21 21 24 ) 22 14 54 22 14 us) 22 24 23 14 54 Pil yf PA 22 24 22, 14 53 2, 15 DAl| 22 25 22 14 54 23 15 22 21 24 22 15 54 22 16 22 21 | 25 22 15 53 i} 15 22 20 26 22 15 56 23 15 22, 22 25 23 TS 53 WY 15 20 21 25 235 | 15 54 22 15 Ban 19 23 21 15 53 Mie 14 20 22 24 94 16 53 23 16 ae 23 26 23 ali 54 21 15 a 2ik 26 23 20 53 Dil 16 23 22 23 23 20 ka 16 25 20 25 22 20 54 21 16 29 20 23 22 20 22 14 a, 21 24 ail 21 54 21 16 23 22 25 ao 21 54 22 14 22 20 24 22 23 52 Blt 15 | 20 | 26 22 25 aes 21 16 22 21 24 25 30 54 22 14 23 22 24 23 36 54 vil 16 22 22 24 24 37 54 21 15 25 22 27 24 37 53 22 16 21 21 25 a) 56 53 22 16 19 Di 24 24 56 55 WY, Lyi 22 21 26 ae 60 54 Pa 18 23 21 26 23 61 53 20 14 21 20 25 22 "72 55 22 15 20 21 26 23 *72 54 Re 16 22 22 26 22 *73 53 21 15 25 20 27 23 *75 53 21 15 vat | 21 26 22 *76 54 22 16 21 22 25 iN *77 54 22 15 22 23 24 24 *T7 a Pil: 14 22 20 aT 21 ¥84 a5 22 14 22, “il 26 24 * Iceland Aiglefinus. 106 Part I11.—Twenty-siath Annual Report Tort NuMBER OF VERTEBRE AND FIN-RAYS IN Gapus MERLANGUS. 1D ew : Qc a 3 =e FIN-RAYS. = ne | BES ra ® 2 > on eS ae aaa 5 oe 223 5 1D 2 D 3D. |-i Al 2A Cm a Hs 2 = 5 54 21 13 21 DAML 33 24 6 5b 14 23 21 34 22 6 54 12 20 as 31 23 if 54 1.3} 19 19 33 22 i 55 21 14 20 il 35 22 10 54 20 13 Dil 23 35 23 11 54 2 14 21 19 33 21 iil 54 22, 14 20 21 33 23 12 55 DAL 14 19 19 34 22, 12 55 oil 13} Alt 20 34 22 16 54 20 15 23 ai 34 24 17 5D 21 its 20 Dit ae 22 18 54 20 12 20 Mail 30 23 18 54 OR} 14 21 21 30 23 18 54 20 13 23 20 34 22 18 55 20 14 20 21 30 23 20 53 20 1 19 20 33 23 20 55 2 15 21 21 35 23 21 55 21 14 22 18 34 20 21 5D 2ill 2 23 19 a2 22 22 54 21 We 19 20 29 22 23 55 Dil 13 23 20 35 24 23 53 22 14 19 19 29 20 24 54 PALI 15 23 22 Vp 25 24 54 20 14 23 20 35 24 35 57 23 16 21 DB. av 24 36 56 21 14 20 24 37 26 of the Fishery Board for Scotland. 107 THe NuMBER oF VERTEBR&, FIN-RAYS, AND PyLoric Caca In GaDus PoutTassou. ae S Be ® 2 2 4 ae Oo . ob Cm. Z 10 57 10 57 10 56 10 57 11 58 LE 57 et 58 lbh 57 11 57 11 58 12 57 12 58 12 58 12 58 12 58 13 58 13 55 13 57 Ka 57 13 58 tS 57 13 57 13 58 14 58 14 ah 14 BE 14 58 15 57 15 57 15 58 15 57 15 57 16 57 16 57 16 57 17 56 iy 58 bearing First Hemal Arch. Vertebra rr. FIN-RAYS. 8 1 Joa ae al Jl gl ae 2 13 24. 36 12 24. 37 12 23 38 Mii 24 34 14 23 40 13 25 37 13 26 ae 12 24 39 a! 23 oh 12 25 36 12 25 oll 1] 26 35 13 ae oT 14 26 37 13 26 40 15 26 42 11 24 33 12 25 36 12 27 39 13 25 4] iu 24 35 11 24 36 Life) 24 35 qe 25 39 12 26 39 13 26 37 1% 25 38 11 24 37 10 23 39 13 26 38 13 24 39 13 25 39 ii 25 39 12 25 40 12 25 37 Number of Pyloric Ceca. 108 THe NuMBER Length. a 16 16 17 MS) 33°5 63 17°9 Number of | Vertebree. Part I1.—Twenty-siath Annual Report 56 5D 57 oF VERTEBRA, FIN-RAYS, AND PyLoric CCA IN Gapbus ARGENTEUS. bearing First Heemal Arch. Vertebra ee Hy er =: 20 —_——— | —_— | | | FIN-RAYS. Gapbwus SAIDA. IM 12 15 14 14 15 16 15 Gapus OGAc. 17 i 22 ay. 18 18 Gapus NAVAGA. 14 20 21 17 20 22 16 21 21 25 21 22 22 19 20 Number of Pyloric Czeca. 10 30 31 24 of the Fishery Board for Scotland. 109 In the next table are shown the ranges of variation in the numbers of vertebre and fin-rays that have been found during this research. The particulars, with the numbers of variants, have been already shown in this and the two previous papers. This table may be used for the specific discrimination by means of the fin-rays. NuMBER OF VERTEBRA AND FE'IN-RAYS. RANGE OF VARIATION. S38 eee S FIN-RAYS. BB | oe SPECIES. 2e |\204 jae z 3 S 3-2 | First | Second] Third | First | Second Zr 5 = Dorsal. | Dorsal. | Dorsal. | Anal. Anal. . callarias 51-53 | 19(8) | 12-15 | 17-22 | 18-20 | 19-24 | 17-19 ogac * : : ne us 13-17 | 17-20 | 17-20 |! 20-23 |. 17-20 veglefinus, Scot- land . | 52-56 | 20-23 | 13-18 | 19-25 | 19-23 | 23-27 | 21-25 veglefinus, Ice- land 53-55 |2Zland 22) 14-16 | 20-25 | 20-23 | 24-27 | 21-24 nayaga t about 58)... 12-14 | 16-20 | 20-25 | 21-24 | 22-25 merlangus. 53-57 | 20-23 | 12-16 | 19-23 | 18-24 | 29-37 | 20-26 luscus 48-49 | 16-17 | 12-15 | 21-26 | 18-22 | 31-36 | 18-22 minutus 48-51 15-18 | 11-15 | 20-26 | 19-23 | 26-31 | 20-24 virens 54-55 | 24,25 | 12-15 | 19-24 | 19-24 | 25-32 | 20-24 ‘pollachius . 90-55 | 22,23 | 12-14 | 17-22 | 17-20 | 25-34 | 17-21 poutassou . 55-58 | 24-27 | 12-14 | 10-15 | 23-27 | 33-42 | 24-28 esmarki 52-55 | 18-19 | 14-18 | 21-29 | 23-29 | 24-32 | 24-30 argenteus . 39-42 | 13-14 9-12 | 12-15 | 15-18 | 15-18 | 16-18 saida { 55-57 19-20 | 10-14 | 12-18 | 18-24 | 15-22 | 17-25 * The data furnished for this species by Vanhéffen and Smitt have been included. + The data furnished by Kolreuter and Smitt for this species have been included. +The data furnished for this species by Giinther, Vanhéffen, Smitt, and Jensen have been included. It is not necessary to discuss the external characters individually, although it may be well to append notes on certain of them. The results of my enquiry into the varied relationship are set out in the key. The intention has been to express the characters on broad lines. Very accurate measurements cannot be adopted in a diagnosis, owing to the fish being liable to damage or distortion. Distortion or injury may render some of the test-characters inapplicable. GirtH.—The girth is of considerable importance as indicating the shape of the fish. It is, however, a character that should be measured on fishes in good condition. Where preserved fishes are used only approximate values can be got, and even in fresh material the soft tissues may yield more in one specimen than in another. It would be an advantage to have some characters which would give a definition of the body of the fish, since each species has a general form distinctly different from its neighbours. In this connection a comparison between the species in the dorsal aspect would be of value. Tu SPACE BETWEEN THE SECOND AND THIRD Dorsau Fins.—The wide gap on the dorsal edge between the second and third dorsal fins is a prominent character in poutassou. It is a character that varies H 110 Part [11.—Twenty-siath Annual Report much in the genus. In poutassou it reaches its maximum, and in minutus and luscus it sometimes vanishes through the meeting of the two fins. A useful standard with which to compare this space is the length of the base of the second dorsal fin. THe Position oF THE First Dorsau Fin.—In some species this fin begins nearer the snout than in others. In eglefinus, luscus, minutus, and esmarki, the first dorsal fin is placed farther forward than in the other members of the genus, while in poutassou it occupies the furthest posterior position. It is an advantage to have the position Pad by comparison with other points on the fish, Thus the beginning of the pectoral fin may be associated with the first dorsal, and the “extent of the distance between made a distinguishing character. In some species this character seems to be fairly well fixed, e.g., in eglefinus, while in others, e.g., esmarki and argenteus, it is subject to a considerable range of variation. In several instances, moreover, it has been found that this distance is relatively greater in large fish than in the small specimens of the same species. This distance has been compared to the length of the snout. Largrat Lins.—The lateral line is of specific value, both in its shape and in the form of its scutes. The arctic species saida has a very characteristic lateral line ; in it the line forms a bend below the lateral ~ axis, as well as the usual bend above. The line formed by the meeting of the ventral and dorsal muscle segments of the trunk is taken as the lateral axis in this connection. In several species the scutes are noticeable from their wide separation. Numser or Fin-raygs —In some cases it would be possible to fix the species by the number of the fin-rays, but there are cases where the fin- ray formule of a certain fish might fit into two species. Nevertheless © the number of fin-rays forms a very important character. InTeERNAL CHaRacTEeRS.—These do not call for special discussion here. They are included in the key. DISCRIMINATION-CHARACTERS. The characters which I have selected, upon which to found a key for the discrimination of the species, are the following :— The more anteriorly projected jaw, upper or lower. The position of the anus with reference to the dorsal fins. The form of the lateral line. The shape of the tail fin. The diameter of the orbit compared with the length of the snout. The presence and size of the barbel. Comparison in length between the pectoral and ventral fins. Comparison in length between the pectoral and first dorsal fins. The position of the first dorsal fin with reference to the pectoral fin. The relation of the second and third dorsal fins to one another.,. The relation of the anal fins to one another. The relation of the girths at the pectoral and anal regions. Prominent colour marks. Separation of the species by length. The deciduous character of the scales. The number of rays in the unpaired fins. The number of vertebre, The number of the vertebra bearing the first hemal arch. The colour of the inside of the mouth. of the Fishery Board for Scotland. 111 The abdominal cavity—the colour of the peritoneum ; the first hemal arch; the form of the abdominal cavity ; the shape of the swim-bladder. The form of the urinary bladder. The position of the ureter with respect to the swim-bladder. The shape of the ovary. The pyloric ceca. The skeleton. Comparison between the skulls and certain bones of the different species. KEY. In cases where measurements are adopted in the key, they are made on similar lines to the measurements described on pages 98 and 99. A pair of compasses will be suitable for this purpose. Distauces are measured along the lateral axis. In the key the eglefinus from Scotland and Iceland are combined. I. Lower Jaw :— a. shorter than upper jaw.. .....callarias, ogac, glefinus, navaga, merlangus, luscus, minutus. b. of same length as upper jaw ..virens (sometimes in young), minutus (sometimes). ce. projects in front of ,, ,, ...virens, pollachius, poutassou, argen- teus, esmarki, saida. II. Anus :-— a. in front of the first dorsal fin...poutassou. b. kelow the beginning of the first dorsal fin............ ..luscus. c. below the first half of the igi. 22 ..luscus, pollachius, merlangus. d. about the middle of the first dorsal Mirees oxen: <.- ..metlangus, minutus. e. beiow the second Balk) oe the first dorsal fin ...............minutus, virens, esmarki. f. below the end a oe first GGESAN DM! cco wenecs eon tye .....zeglefinus, argenteus, saida, navaga. g. below the interval between the first and second dorsal fins...eglefinus, argenteus, saida, callarias, ogac. h. below the first half of the second dorsal fin............ callarias, ogac, eglefinus (in two specimens from Iceland the anus was immediately below the be- ginning of the second dorsal fin). III, Latzrat Line :— a. straight, white... ..............virens (white not always prominent in small specimens). uf » indistinct ............poutassou. BO CURVED. ccm... ..+ sceoe soe}... callarias, ogac, navaga, pollachius, minutus. ep 2 SHB ss... s .o...eglefinus, merlangus, esmarki, argen- teus, saida (see below). » curve double............salda. ec lateral line black k (usually a black) . ue . eclefinus. 112 Part [I1.——Twenty-sixth Annual Report c. lateral line, posterior part, White: ,. x vs white in callarias, merlangus, poutassou, eglefinus, luscus, minutus, argenteus, esmarki, saida (dull colour in spirit), navaga (yellowish in spirit). XX. Toe AspominaL Cavity :— The Colour of the Peritoneum : Peritoneum steel-grey colour....callarias. 55 black..................eglefinus, argenteus, poutassou, saida, esmarki. fe darken nks ao ieee. merlangus, saida, ogac. 3 AVINTGC asc tesa tee tes pollachius, virens. Tue First Hauat ArcH. The number of the vertebra bearing the first heemal arch varies with the species, as will be seen on reference to the table on page 109. _ There is a marked difference in the shape of the first hemal arch in different species. This is exhibited both in the size of the arch and also in its shape. Drawings of this bone for all the species, with the exception of G. ogac and G. navaga, are shown in Plate [V. ‘The posterior side of the arch is represented, the vertebra resting on its anterior disc. The arch may be round as in pollachius, fig. 39, or nearly round, the condition found in merlangus, fig. 65. The most common shape is that of a broad oval, and that form is found in callarias, fig. 61; virens, fig. 66 ; minutus, fig. 63; luscus, fig. 67; saida, fig. 59; and esmarki, fig. 64. f&glefinus, fig. 68; poutassou, fig. 57; and argenteus, fig. 58, have a narrow, oval arch. féglefinus is readily distinguished from the other species by its characteristic first hemal arch. It bears two lateral wing-like expan- sions, fig. 68, which have no counterpart in the other species. This wing-like expansion is repeated on the second arch, but it has disappeared on the third, a thickened ridge alone representing it. These lateral plates receive the ends of the swim-bladder. Sometimes the expansions are found on three of the 20-23 vertebrae. The first hemal arch in this species is most commonly found on the 22nd vertebra, but it is also found on the 21st. It may happen that the arch is not complete, one side being short, although the other side may be continued downwards into the hemal spine. If the hemal spine is present on an imperfect arch, this is regarded as the first hemal arch; but if the spine is absent and the arch incomplete, it has been neglected. Facultative Hemal Arch.—Occasionally a facultative hemal arch is formed by the union of the ribs of the vertebra immediately preceding the first hemal arch. In these cases there is no hemal spine. Such an seme i of the Fishery Board for Scotland. 1 Y arch may be formed also by the transverse processes being united inferiorly by cartilage in the aponeurosis that lines the bottom of the abdominal cavity. More than one case (zglefinus) was noted where one side only of such an arch was formed: the transverse process on the opposite side did not reach the floor of the abdomen. In minutus the three vertebre in front of the first hemal arch formed three facultative arches by means of their ribs, which met inferiorly in the tough fascia. In luscus, two of the ribs from the corresponding region formed almost complete arches. As a rule the ribs cease on the anterior side of the first heemal arch, and they are represented behind that point by a film of ligamentous tissue connecting the hzemal arches. In virens, however, a rib was found running obliquely downward from the first to the second hemal arch. The first arch is the largest, the succeeding arches becoming smaller, rapidly in some species, more gradually in others. The arches all slope more or less backwards. The arch bears at its lower end a spine. It is shortest on the first arch, and gradually increases in size in succeeding vertebre. The hemal spines are long in eglefinus ; in merlangus, poutassou, and saida they are markedly bent backwards from the arches. The first hemal spine is usually attached to the aponeurosis that lines the end of the abdominal cavity, and which binds the ends of the inter- spinous bones. This ligamentous tissue is continued posteriorly, forming the upper edge of the interspinous region. Some of the hemal spines pass through it into the interspinous region, and are attached directly to the interspinous bones. The hemal arch always lodges the caudal artery and the caudal vein. It lodges these alone in saida, fig. 60. The kidney accompanies the blood vessels into the arches in all the other species which I have dissected. The conditions in ogac and navaga were not examined. The swim-bladder enters the hemal arches in most of the species, e.g., virens, fig. 74; pollachius, fig. 72; merlangus, fig. 62; luscus, fig. 71 ; minutus, fiz. 80; poutassou, fig. 70; esmarki, fig. 75. In callarias, fig. 91, and eclefinus, fig. 81, the end of the swim-bladder reaches to the second hemal arch. The swim-bladder does not enter the hemal arches in argenteus, fig. 69, and saida, fig. 60. The extent to which the swim-bladder and the kidney enter the heemal arches may be here summarised :— 5 Callarias—-The swim-bladder is continued back to the second and third hzemal arch. It is bound tightly to the first and second arches ; it is constricted much by the first arch. Aj glefinus—The swim-bladder ends at the second hzmal arch, to which it is bound firmly below. Merlangus.—The swim-bladder is continued backwards to the 8th or 9th heemal arch. Virens.—The swim-bladder extends back to the 4th, 5th, or 6th heemal arch, tapering to a fine point. It is bound to the first heemal arch. Pollachius.—The swim-bladder extends posteriorly to the 10th or 11th hemal arch. Luscus.—The swim-bladder goes back to the 13th arch; the kidney seems to end at the 6th arch. Minutus.——The swim-bladder ends at the 10th arch; the kidney was very small and not noticeable on the outside of the arches. Poutassou.—The swim-bladder extends to the 6th arch. Esmarki.—The swim-bladder ends at the 9th arch. 118 Part IIl—Twenty-siath Annual Report Argenteus.—The swim-bladder ends at the vertebra in front of the - first heemal arch. The first and second arches are filled with the kidney, which ends at the 3rd arch. Saida.-—The swim-bladder ends a little in front of the first hemal arch ; the kidney ends at the first he nal arch, The Form of the Abdominal Cavity.—In some cases the first haemal spine ends the abdominal cavity, ¢.g., callarias, fig. 91 ; eglefinus, fig. 81 ; virens, fig. 74; poutassou, fig. 70. In other species the cavity is con- tinued posterior to that point, either above it, that is, into the hemal arches, or below, into a sub-hemal cavity formed between the hemal spines and the interspinous bones of the first anal fin. Of the former condition the following species are examples : —Pollachius, fig. 72; luscus, fig. 71; minutus, fig. 80; esmarki, fig. 75; argenteus, fiz. 69. In these fishes the liver, ovary, and gut may extend into the hemal arches. The fishes which have the sub-hemal extension of the abdominal cavity are merlangus, fig. 62, and saida, fig. 60. None of the movable abdominal organs enter the hemal arches, but they have room below for expansion. Poutassou, in which the hemal spines are markedly bent backwards, fig. 70, might be regarded as having a slight sub-hemal extension. In many of these fishes the interspinous region of the first anal has a long stretch which is not directly supported by the vertebral column. The peritoneum is loosely attached to the hind end of the abdominal cavity. In esmarki a white matter of a soft and fatty appearance was found in the hemal arches. In saida the abdominal cavity is lofty, the vertebral column coming very near the dorsal edge. The Shape of the Swim-bladder.—In the Gadids the swim-bladder is usually large. The anterior eud is sometimes furnished with horn-like prolongations. In callarias these are long and they have a spiral form. They pass round the head kidney and lie on top of it, between the branches of the vagus nerve and the muscles at the top of the clavicle. Pollachius, fig. 85; merlangus, fig. 95; and virens, have two short horns. In one virens the horns were absent. According to Kélreuter, the swim-bladder in navaga has two horns. XXI. Urinary BuappDER :— The urinary bladder has two IGWES A. '\ a . Part I[1. —Twenty-siath Annual Report thin verticle ]Jamina on the parietal in saida; on the frontal it is merely a ridge. It rises, but is very low, on the frontal in callarias. The hind end of the squamosal is very broad, its upper and lower edges are almost parallel, in eglefinus. The two edges approach one another rapidly as they proceed posteriorly in callarias, virens, pollachius, merlangus. Vigw FROM ABOVE. The shape of the frontal is of some importance. It tapers rauch at its anterior extremity in callarias, virens. It is rounded in front in eglefinus (fig. 9), pollachius, merlangus (fig. 16), luscus, minutus, esmarki. The middle foramina of the frontal are well separated from the anterior opening of the supra-orbital groove in callarias, ogac (fig. 19), > 49. dorsal view. Nat. size. nea: Half of a caudal fin-ray, showing the surface that is in contact with the other half-ray. Nat. size. w—unsegmented strip; s—segmented intermediate portion. », Ol. Base of caudal fin-rays. Ventral view. Nat. size. », D2. Basi-branchials, seen from above. », 93. One of the ribs attached to the seventh to twenty-first vertebre. Nat. size. », 954, Eleventh vertebra, seen from above. Nat. size. The neurapophysis is formed in part of cancellous tissue. The pores are large and perforate the bone. », 90. Interspinous bones of the first dorsal fin. » 96. Otolith of G. minutus, 23 cm. lorg. Nat. size. » Ov. First hemal arch of G. poutassou, 13°7 cm. long. Nat. size. BEI say eae A » G.argenteus. Nat size. er Os » G. saida. Nat. size. >, 60. Hind abdominal cavity of G. satda. Nat. size. , 61. First hemal arch of G. callarias, 38‘8 cm. Nat. size. ,, 62. Hind abdominal cavity of G. merlangus, 38°5 cm. , 63. First hemal arch of G. minutus, 21°7 cm. Nat. size. soe Gas As >» G. esmarki, 19°5 cm. a Gs Mia a » G.merlangus, 38°5cm. re OO | 53 - >» G. virens, 53 cm. na PGI. 93 35 Sen Ga luscuss| 275) em: Be 3, GS aOss at » G. eglefinus, 36 cm. st PLATE XII. Fig. 69. Hind abdominal cavity of G. argenteus. About nat. size. we AO! G'. poutassou, 13°7 cm. long. Reduced. Be pls Abdominal cavity of ‘a. luscus, 27°5 cm. long. Reduced. Be Aaa 5 He G. pollachius, 93 cm. long. Reduced. The dotted line indicates the course of the ureter on the right side of the body. Part III.—Twenty-siath Annual Report . Ovary of @. luscus, 27°5 cm. long. Reduced. . Abdominal cavity of G. virens, 55-4 cm. long. Reduced. G. esmarki, 15°7 cm. long. i 39 oe} G. ogac. x 4. 99 99 . Ovary of G. minutus. Reduced. G. saida, 17°5 cm. long. Nat. size. ee Ok merlangus. Reduced. ’ Hind abdominal cavity of G. minutus, 26°5cem. Nat, size. G. eglefinus, 36 cm. : Ovary of @ merlangus, 36°4 cm. long. Side view. . Junction of first and second anal fins of G‘. merlangus, 36:4 cm. long. PLATE XIII. . G. navaga. Nat. size. Anterior end of swim-bladder of G. pollachius, 50°5 em. long. . Abdomen opened to show ovary, etc., of G. esmarki. . Ovary of G. eglefinus. View from above. . Abdomen of G. saida, opened to show large testis—t. Nat. size. . Loop of gut at end of abdomen of G. pollachius, 76 cm. long. . Ovary of G. callarias. x 4. . Hind abdominal cavity of G. callarias, 69 cm. long. Reduced. . Ovary of G. argenteus, 17-4 cm. long. About nat. size. . Anterior end of the swim-bladder of G. callarzas. . Ovary of G. pollachius, 80 cm. long. Side view. x about 4. . Anterior end of the swim-bladder of G. merlangus. . Ovary of G. pollachius. Same as Fig. 94. View from below. . Ovary of G. esmarki, 19°5 cm. long. About nat. size. ‘dS snpoy ‘M'OH “ ‘€ G ‘sory ‘AIAIVM “H 'V ‘TOT ¥ = = Se —— Oa ae —— ~ ii Ae = =a = <... —aneene. : = = - = + cea 2 ban ee JE “UOSPADY 2 DN 4 ‘ono sn /p 9) qT MIA ALWid A. H. WALKER. Gadus aglefinus. Haddock A. H. WALKER. H.C.W., Fics. 13, 18a, 14, 21, 24, Fic. 23, after Vanhoffen ; 29, 30, 31; i cern Fics. 16, 17, 18, 22, 27, 28, Gadus Merlangus; Fics. 12, 15, 19, 23, G. ogae ; Fics. 13, 25, 30, G, satda; Fics. 14, 21, 24, 31, G. Poutassou; Fics. 20, 26, 29, C. argenteus. > = * 7 a =e a. i _ PLATE Xi. H.C.W. Fics. 82-65, Gadus Pollachius, 87°8 cm.; Fics. 56-68, Gadus Sp. H.C.W. aes Argenteus \ = \G) uN i SS CRs ac 5 = we jean AUS Se ) ) > rem: KN Sy Wee : Gadus Sp. ens al « PLATE Xi, ie ee. lag, = {oa a rae F . — a i : st Pi ante ol a SE Na ly, Nati = A 4x2 om * : , ND AAT POPSET, - Si RI RR OR SE te PLATE Xiil. 8 ae ie as 4 ae Pes GOLEL SAPP, va ; oe Esmarki Pollachius = ——__ 9V ne fp ye Argenteus taf co a SSP og ae 92 sw. bl. Callarias ———<$—$— ee Se, ; a ee ‘ ; 93 —— 7 te Left Ovary Pollachius Gadus Sp. of the Fishery Board for Scotland. 135 INDEX. Abothrium gadi, 85. —— rugosum, 85. Acanthobothrium coronatum, 83. Ancistrocephalus microcephalus, 79. Angel-fish, parasite of, 82, 83. Bacillus coli, bearing of, on public health questions, 35. distribution of, in fish, 30. Bacteria, action of temperature on, 23. Blue shark, parasite of, 81. Bothriocephalus coronatus, 83. —— microcephalus, 79. proboscideus, 78. —— punctatus, 79. —— rugosus, 85. — solidus, 80. CHEMICAL composition of flesh of fish, 14. Chondracanthus Williamsoni, 76. Coal-fish, notes on specific characters of, 126. Cod-fish, parasite of, 87. Cod, notes on specific characters of, 125. —— special investigations in Norwegian fiords, regarding hatching of, 51. Common eel, parasite of, 79, 86. Decomposition of fish, 10, 13. —— —— action of temperature on, 28. appearance of abdominal walls as affected by the gut, 26. bacteria in fish, 16, 29. best time to ice fish, 24. causes of, 14, criteria to be considered, 17. detection of rigor mortis, 25. influence of food on, 28. reddish discoloration of ventral aspect of backbone, 20. rigor mortis, 21. summary regarding, 37. test of smell, 19. Destruction of eggs and larve, 42, Dibothriun: microcephalum, 79. proboscideum, 78. —— punctatum, 79. rugosum, 85. Dinobothrium septaria, 84. Diphyllobothrium stemmacephalus, 88. Diplobothrium simile, 84. Distomum cestoides, 77. Echinorhynchus acus, 87. — agilis, 87. gracilis, 88. proteus, 86. Kel, parasite of, 79, 86. Effects of parasites on fishes infested by them, 90. Eggs and larve, destruction of, 42. — investigations in Norwegian fiords, 43. Expense of fish hatchery, Bay of Nigg, 94, FisH, chemical composition of flesh of, 14 —— decomposition of, 10, 13. structure of flesh of, 14. Fishermen, scientific and instruction to, 12. Fishes, effects of parasites on, 90. parasites of, 12. Fish hatching, expense of fish hatchery, Bay of Nigg, 94. acclimatisation of shad in the Pacific, 48. —— —- experiments with plaice in Lochfyne, 52. ——— —— in Canada, 40, 46. in England, 41. in Norway, 41. —— —— in U.S.A., 40, 46. —— —— opinion of fishermen on, 47. —— —— output, 41. —— —— proofs of results, 46. report on operations at fish hatchery, Bay of Nigg, 93. special statistics of, 49. —— —— statistics of, 47. statistics of experiments in Norwegian fiords, 49. Food, influence on decomposition of fish, technical =O- Gadus eglefinus, see Haddock. argenteus, specific characters of, 97, —— merlangus, see Whiting. navaga, specific characters of, 97. ogac, specific characters of, 97, 127. ovac, see G. ogac. — poutassou, specific characters of, 97, 27. saida, specific characters of, 97, Greenland shark, parasite of, 81. Grey skate, parasite of, 77, 83. Havpvock, specific characters of, 97, 125. Hatching of plaice, 6. Hatschekia cornigera, 75. Herring, investigations in Lochfyne on, 2 136 Investigations in Norwegian fiords on eggs and larvee, 43. Knot Dahl, investigations in Norwegian fiords, 43. LocHryNE, experiments on hatched plaice in, 7, 52. investigations on herring, 5, 9. statistics of herrings caught in, 9. MULLET, gre arasite of, 87. » grey, Norway haddock, 76. Norwegian fiords, statistics regarding fish hatching in, 49. Octobothrium sybille, 77. Opinion of fishermen on fish hatching, 47. Parasites of fishes, 12. Parasite of angle-fish, 82, 83. of blue shark, 81. of cod-fish, 87. of common eel, 79, 86. —— of common porpoise, 88, 89. — of Greenland shark, 81. of grey mullet, 87. —— of grey skate, 77, 83. of picked dog-fish, 74, 81. of Porbeagle shark, 84. —— of sea bream, 75. — of sunfish, 79. —— of three-spined stickleback, 80. ON DEOULS STAN oe == of turbot, 79: Parasites, effects of, on fishes infested by them, 90. Phyllobothrium lactuca, 83. thridax, 83. Picked dog-fish, parasite of, 74, 81. Plaice, hatching of, 6. value of pretection of, in the early stages, 45. fry, experiments with, in Lochfyne, ~ 7. Pollack, notes on specific characters of, 126. Porbeagle shark, parasite of, 84. Porpoise, common, parasite of, 88, 89. Products of bacterial activity, 16. Part I1T.—Twenty-siath Annual Report. Protection of plaice in the early stages, 45. Public health questions, as affected by bacillus coli in fish, 35. > Ricor mortis in fish, 21. Schistocephalus dimorphus, 80. solidus, 80. Scientific and technical instruction to fishermen, 12. "5 Sea bream, parasite of, 75. fish hatchery of the Fishery Board, 41. —— —— hatching, 40. principles of, 42. Sebastes norvegicus, 76. Sewage pollution in relation to bacillus coli, 36. : Shad, acclimatisation of, in the Pacific 48 Special investigations in Norwegian fiords, regarding hatching of cod, 51. Specific characters of Gadus argenteus, navaga, 97. — —— —— ogac, 97. —— —— —— poutasson, 97. saida, 97. of haddock, 97. of whiting, 97. Statistics of fish hatching, 47. of herrings caught in Lochfyne, 9. Stickleback, three-spined, parasite of, 80. Structure of flesh of fish, 14. Summary regarding detection of decom- position in fish, 37. Sunfish, parasite of, 79. Tanta, 86. rugosa, 8d. solida, 80. Temperature, action of, on bacteria, 23. action on decomposition of fish, 28. Tetrarhynchus megacephalus, 81. minutus, 82. tetrabothrius, 81. Trawl fish compared with line fish, 25. Trout, parasite of, 77, 78. Turbot, parasite of, 79. WHITING, specific characters of, 97, 126. » i iki wu eae aes Rit PAL Maat ity Baa . a re a ihe, fare ice eg ¥ < 4