Lahille has promulgated a system based upon modifications of the structure of the pharynx. His arrangement of the fixed ascidians seems to me admirable, but his treatment of the pelagic forms is most unsatisfactory. He follows Herdman in placing Pyrosoma near Calocormus and the Didemnidæ, though upon different and purely speculative grounds. Salpa is divorced from Doliolum through an erroneous interpretation of the ciliated pits on the gill of Salpa. The subjoined scheme is based upon anatomical and embryological facts. The pelagic caducichordate types possess a single row of undivided branchial slits (protostigmata). This condition is recapitulated, as I have elsewhere shown, in the ontogeny of various fixed ascidians, but the protostigmata of the young postlarval form are subsequently subdivided into rows of minute secondary stigmata. The structure of Pyrosoma and its allies is thus more primitive than that of any of the fixed ascidians. The two groups, Thaliacea and Ascidiacea, are distinguished in my scheme upon this basis. My subdivision of the Thaliacea explains itself; that of the Ascidiacea I have adopted, with some modifications, from Lahille. PERENNICHORDATA. TUNICATA. I. Endostylophora.-Pharynx provided with an endostyle. E.g., Oikopleura, Fritillaria. II. Polystylophora. Endostyle absent; pharynx provided with numerous finger-like processes arranged in rows. E.g., Kowalevskia. CADUCICHORDATA. I. Thaliacea.-Protostigmata undivided; cloaca posterior. Pelagic. II. Ascidiacea.-Protostigmata subdivided into rows of secondary stigmata; i. Stolidobranchia.-Pharynx with internal longitudinal bars; bars solid and ribbon-shaped. E.g., Botryllus, Cynthia, Goodsirea. ii. Phlebobranchia.-Pharynx with internal longitudinal bars; bars tubular and vascular. E.g., Perophora, Ascidia, Diazona. iii. Aplousobranchia.-Pharynx without internal longitudinal bars; horizontal membranes present. E.g., Clavelina, Distaplia, Amaræcium, Didemnum. 12. On the Presence of Skeletal Elements between the Mandibular and Hyoid Arches of Hexacanthus and Læmargus. By Dr. PHILIP White. 13. On the Presence of a Sternum in Hexanchus griseus. 14. On the Creodonta. By Professor W. B. SCOTT. Our knowledge of this remarkable group of extinct flesh eaters has been of slow growth, and only lately has sufficiently perfect material been recovered to give us an accurate insight into the structure and relationships of several of the more important genera. The creodonts are almost exclusively Eocene forms, and especially characterise the Lower Eocene, the Wasatch being probably their time of culmination, while only one genus (Hyænodon) is known to pass into the Miocene. The appearance of five distinctly differentiated families in the Puerco indicates that their origin is to be looked for in the Cretaceous formation. North America was eminently the home of the group, having many more genera and families than Europe has yet yielded. So far, none are known from the southern hemisphere. Though including several divergent lines of differentiation, the group is characterised by a fairly uniform structure. The incisors and canines are of the carnivorous type, and rarely are reduced in number; the sectorials are either absent or present in more than one pair (except in the Miacida); the molars generally retain the tritubercular plan more or less distinctly. The milk dentition is of the same character as in the true carnivora. The brain is small and the hemispheres usually little convoluted. The skull has a very long slender cranial part, with deep postorbital constriction, very prominent sagittal and occipital crests, and a short facial region. The vertebræ are remarkable for the complex zygapophyses on the lumbars and posterior thoracics. The limbs are relatively short and light, the humerus retaining the epicondylar foramen, and the femur the third trochanter. The feet are weak and almost invariably plantigrade and pentadactyl, and with only one known exception, the scaphoid, lunar, and central remain separate. The ungual phalanges are very generally cleft at the tip, as in the insectivora. The creodonts fall quite naturally into two sections, one with more or less blunt and tuberculated teeth, and the other with trenchant teeth. The first section, which includes three families, the Arctocyonidæ, Triisodontidæ and Mesonychidæ, is most abundant in the Puerco, and has but a single representative in the Middle and Upper Eocene. No existing forms appear to have been derived from the creodonts with tuberculate teeth. The second section includes five families, the Proviverridæ, Oxyænidæ, Hyænodontidæ, Palæonictidae, and Miacidæ, the last of which is very sharply distinguished from all other creodonts, and forms the connecting link with the true carnivora. The creodonts with trenchant teeth are most important and highly developed in the Wasatch and Bridger, after which they decline, their place being gradually taken by the carnivores. Most of the fissipede carnivora would seem to be clearly derivable from the Miacida, except the cats, the origin of which is still obscure, and which are remarkable for the extremely rapid specialisation which they attain at a very early period. The Pinnipedia, on the other hand, would seem to have been derived from some other creodont family. Wortman has suggested, with considerable probability, that the Oxyanida were the ancestors of the Pinnipedes, but the gap between the two is yet so great as to render this uncertain. 1. On some Results of Scientific Investigation as applied to Fisheries. By Professor W. C. M'INTOSH, F.R.S. My remarks are based on experience mainly, but not altogether, gained in Scotland, but are applicable to the empire, or indeed to European fisheries. The greater responsibility has been felt, since England possesses no public department precisely corresponding to the Fishery Board for Scotland. It may be pointed out that such investigations in regard to the fisheries are of so recent a date that perhaps it is too early to estimate comprehensively the results; but since there are hostile critics it may be well to take a general survey of the results-often gained under considerable difficulty, especially in regard to sea-going ships, for only small steam vessel has been at the service of the Fishery Board, instead of powerful vessel capable of going to distant grounds in rough weather. Previou to 1883 no statistics of a reliable kind, other than those of herrings and salted fishes, were available to guide the Legislature as to whether marine fisheries were diminishing, stationary, or increasing. This anomalous state of things permitted indulgence in exaggerated statements as to the scarcity of fishes, and the decline, or, as it was said, impending ruin of the fisheries. While thus a very great improvement had been made, the returns were far from being complete. They give the greater part of the fishes caught, but left many unreported. If anything is national property it is the sea, and it ought to be comparatively an easy task to give an account of its stewardship. In the scientific report to the Royal Commission of 1884 the closing of certain bays against beam and otter trawling was indicated thus:-The experiment of allowing a bay having a definite boundary and suitable for observation to remain unfished for several years either by line, trawl, or stake-net would perhaps be more satisfactory' (than a close time). Its fish fauna would be carefully examined at closure, and frequently during the period, and the general increase in size, emigration, and immigration of the fishes noted. Advantage might be taken at the same time to increase the number of its valuable food-fishes, e.g., turbot and soles, by artificial means. Such an experiment would give a valuable basis for future legislation, tend to increase our knowledge of the food-fishes in a remarkable degree, and would be worthy of the interests which this country has in the department of sea fisheries.' It was afterwards arranged to leave out the line fishermen, since many of the older men with small boats would have suffered hardship; and, after some years' observations, the Fishery Board decided to close all the water within the three-mile limit, besides certain larger areas. These closures were made, rightly or wrongly, on the faith of the scientific experiments made by the Board. The investigations also showed from 1884 onwards that the three-mile limit was insufficient to protect the spawning fishes, which, as a rule, were beyond that area. Investigation has also cleared up the migrations of fishes. In shallow bays ripe plaice are seldom found, almost all occurring in the deeper water beyond the three-mile limit. Yet the number of young plaice in such areas is prodigious, the eggs and young being wafted into the shallower water. There they grow till they reach a size of 10 to 13 inches, when they seek the outer waters, in which to attain maturity and to grow to full size. This explains the occurrence of the enormous number of these fishes in so limited an area, as, for instance, in St. Andrews Bay, and their survival after the use of the most extensive and persistent means of capture. Similarly, while the cod spawns are in the off-shore waters, the very young forms, ranging from in. to an inch, appear in the in-shore grounds in June, haunt the borders of the tidal rocks for some time, and again return to breed in deep water. On the other hand, the very young haddock is an off-shore fish; and so is the very young ling, the latter, when from three to seven inches, migrating shorewards and returning to deep water for adult life. Scientific investigation has shown the enormous fecundity of foodfishes, as well as the provision by which only a portion of the roe ripens at a given time. With wise regulations, therefore, our waters might always be relied on for supplies. We have largely increased our knowledge of the sizes of the respective sexes of marine fishes at maturity, and the development of the eggs in the roe, and their numerical proportion to each other. In this work no one had done more valuable service than Dr. Fulton, the Scientific Superintendent of the Fishery Board for Scotland, and the subject has been further elucidated by Mr. J. T. Cunningham, Mr. Calderwood, and Mr. Holt. Such knowledge in regard to Scotland made it clear that the legislative proposal of a size-limit of 10 or 12 inches-below which fishes were to be unsaleable-would be no protection, for instance, to a ripe plaice, though it might tend to preserve the species till it reached somewhat deeper waters. No feature, again, has been more prominently brought out by scientific investigation than the fact that the eggs of almost all our food-fishes float, or are pelagic. Their wide distribution is thus provided for, and they are beyond the possibility of injury by net or trawl. In 1884 both the eggs and the young of foodfishes were, as a rule, wrapt in mystery. Now the eggs and larval stages of most have been described and figured, notably by Professor E. Prince, Mr. Cunningham, 1895. 3 A and Mr. Holt, and the growth in many cases followed to the adult condition. This experience, especially at St. Andrews, has demonstrated the comparative ease with which immense numbers of the eggs of valuable food-fishes can be artificially hatched and then placed in the sea. The Fishery Board's Marine Hatchery at Dunbar has done this on a large scale. Last year it was shown at Oxford that about twenty-seven millions of larval plaice, besides cod and flounders, were placed in the sea. This year about 38,615,000 larval plaice, 3,800,000 larval turbot, 2,760,000 larval cod, 2,500,000 larval lemon-dabs (often sold as soles), besides 600,000 larval dabs and flounders, and 450,000 larval haddock and whiting were' planted,' making a total for the year of 48,725,000 fishes. The total for the two years is thus 75,285,000 fry placed in the sea, while the mortality was very small. Comparing this result with the totals and the expenditure on the other side of the Atlantic, it has been found that in two seasons the economically managed Scotch establishment pressed closely on the grand totals of twelve or thirteen years' work. The Americans, moreover, chiefly deal with the cod, a fish more easily manipulated, and which produces a far greater number of eggs than the plaice; and the same might be said of the Norwegians. The turbot and lemon-dab, again, are valuable fishes for the first time artificially hatched on a large scale. Dr. Fulton and the staff under him have thus made great progress. English soles have been successfully transferred to Scottish waters, many having been carried long distances, as from the Lancashire coast, where they were obtained through the courtesy of Professor Herdman. The distribution of the foodfishes has been carefully investigated at various stages, as well as their capture by the different instruments used in fishing, especially in connection with the variously sized meshes and hooks. Experiments on the vitality of the fishes after capture by trawl or by hook have also been made. Our knowledge with regard to the food of fishes has been largely increased and grouped under two heads: (1) food which is the product of the locality, and for the most part developed on the bottom; and (2) food which is floating or pelagic, and which might be brought considerable distances by currents. The food of fishes to a large extent primarily depended on plant-life, a wonderful cycle passing from diatom or algoid through the lower animal forms to fishes. Much information has also been ascertained on the subject of close times, as applied both to the herring and white fishes, and is available for legislative purposes. The majority of the mussel beds of Scotland, and some of those in England, have been surveyed and reported on, and the whole question put on a new footing-founded on an accurate knowledge of the reproductions of the mussel, for which we are mainly indebted to Dr. J. Hardie Wilson. A series of observations have likewise been made on oysters with a view to resuscitate exhausted beds, e.g., those of the Forth, where careless administration has reduced an income of 15,000l. or more a year to 1487., and this within less than a generation. Various cockle and clam beds have been similarly surveyed, and suggestions made for their conservation and improvement. Experiments in regard to the hatchings of lobsters have been made at Brodick, in Arran, and at Dunbar, and their development is being studied by Dr. Fullerton. Other experiments have been made on the preservation of bait after it was placed on the hooks, and also on the preservation of herrings and white fishes. An important series of physical observations has been carried out in the North Sea as to temperatures, currents, and other features of the water, the relations of these to the fishing grounds and the migrations of fishes. Lastly, a commencement has been made in determining the proportional number of the sexes of salmon entering the rivers at various periods, and their external differences, the determination of when and to what extent the muscles undergo changes during the growth of the roe and milt, so as to clear up the subject of the deterioration of the fish as food. The structure of the alimentary canal of the fish in connection with its cessation to feed and other points are also being studied. These complex investigations are in the hands of Mr. T. Tosh at Berwick-on-Tweed, Dr. Noel Paton, and the staff of the College of Physicians' Laboratory, Edinburgh, and in those of Dr. Alex. Brown, Aberdeen. Some persons think that the Universities, and not the Government, shoul dcarry out such investigations; but it need scarcely be said that the Universities have neither the means, the ships, nor the experienced staff distributed along the coast line and in constant touch with the subject, for efficiently dealing with it. A public department alone is capable of undertaking it with success, as the practice of other nations from America to Japan abundantly testifies. 2. On the Royal Dublin Society's Fishery Survey. 3. On the Fishery School at Ringsend, near Dublin. 4. Oyster Cultural Methods, Experiments and New Proposals. The author spoke of the difficulties in spat collecting, and of some recent suggestions as to their obviation; of the lack of definite knowledge as to the most favourable physical conditions of the oyster's set; of questions of aeration, density, temperature, and silt deposit of the water during the spawning season. He referred to the difficulty in retaining the embryos in bassins and in determining the duration of the motile stage. The suggestiveness of the mare piccolo and of the closed lake of Brénéguy; the experiments in spat collecting of Rice, Saint-Sauveur, and more recent culturists, and the possible defects of the cultural methods lately patented in the United States were also discussed. 5. On Oysters and Typhoid: an experimental Inquiry into the effect upon the Oyster of various external conditions, including Pathogenic Organisms. By RUBERT W. BOYCE, M.B., M.R.C.S., Professor of Pathology in University College, Liverpool; and W. A. HERDMAN, D.Sc., F.R.S., Professor of Zoology in University College, Liverpool. Our motives in undertaking this investigation have been- 1. Purely scientific-the elucidation of the life conditions of the oyster, both under normal and abnormal environment. 2. Economic or technological-to trace the causes and effects of diseased conditions, with the view of determining what basis exists for the recent 'Oyster and typhoid ' scare, (a) in the interests of the oyster fisheries, and (b) in the interests of the general public. A. The objects, in detail, we had in view in entering on the investigation were as follows:-- 1. To determine the conditions of life and health and growth of the oyster by keeping samples in sea waters of different composition-e.g. it is a matter of discussion amongst practical ostreiculturists as to what specific gravity or salinity of water, and what amount of lime are best for the due proportionate growth of both shell and body. 2. To determine the effect of feeding oysters on various substances—both natural food such as Diatoms, and artificial food such as oatmeal. Here, again, there is a want of agreement at present as to the benefit or otherwise of feeding oysters in captivity. 3 To determine the effect of adding various impurities to the water in which the oysters are grown, and especially the effect of sewage in various quantities. It is notorious that oysters are sometimes grown or laid down for fattening purposes |