Authorities.—The following selection from the extremely extensive ichthyological literature which has appeared during the period 1880-1906 will supplement the bibliographical notice appended to section I. I. The General Subject: A. Günther, Introduction to the Study of Fishes (Edinburgh, 1880); B. Dean, Fishes Living and Fossil (New York, 1895); T. W. Bridge and G. A. Boulenger, “Fishes,” Cambridge Natural History, vii. (1904); D. S. Jordan, Guide to the Study of Fishes (2 vols., New York, 1905). II. Palaeontological: A. Fritsch, Fauna der Gaskohle und der Kalksteine der Permformation Böhmens (vols, i.-iii., Prague, 1879-1894); K. A. von Zittel, Handbuch der Paläontologie, vol. iii. (Munich, 1887); A. Smith Woodward, Catalogue of Fossil Fishes in the British Museum, vols. i.-iii. (London, 1889-1895); A. Smith Woodward, Outlines of Vertebrate Palaeontology for Students of Zoology (Cambridge, 1898); J. S. Newberry, “The Palaeozoic Fishes of North America,” Mon. U.S. Geol. Surv. vol. xvi. (1889); J. V. Rohon, “Die obersilurischen Fische von Ösel, Thyestidae und Tremataspidae,” Mém. Ac. Imp. Sc. St-Pétersb. xxxviii. (1892); O. Jaekel, Die Selachier von Bolca, ein Beitrag zur Morphogenie der Wirbeltiere (Berlin, 1894); B. Dean, “Contributions to the Morphology of Cladoselache,” Journ. Morphol. ix. (1894); R. H. Traquair, “The Asterolepidae,” Mon. Palaeont. Soc. (1894-1904, in progress); “Report on Fossil Fishes collected by the Geological Survey of Scotland in the Silurian Rocks of the South of Scotland,” Trans. Roy. Soc. Edin. xxxix. (1899); L. Dollo, “Sur la phylogénie des Dipneustes,” Bull. Soc. Belge Géol. vol. ix. (1895); E. W. Claypole, “The Ancestry of the Upper Devonian Placoderms of Ohio,” Amer. Geol. xvii. (1896); B. Dean, “Palaeontlogical Notes,” Mem. N.Y. Ac. ii. (1901); A. Stewart and S. W. Williston, “Cretaceous Fishes of Kansas,” Univ. Geol. Surv. Kansas, vi. (Topeka, 1901); A. S. Woodward, “Fossil Fishes of the English Chalk,” Palaeontogr. Soc. (1902-1903, etc.); R. H. Traquair, “The Lower Devonian Fishes of Gemünden.,” Roy. Soc. Edin. Trans. 40 (1903); W. J. and I. B. J. Sollas, “Account of the Devonian Fish Palaeospondylus,” Phil. Trans. 196 (1903); C. T. Regan, “Phylogeny of the Teleostomi,” Ann. & Mag. N.H. (7) 13 (1904); C. R. Eastman, “Fishes of Monte Bolca,” Bull. Mus. C.Z. 46 (1904); “Structure and Relations of Mylostoma,” Op. cit. 2 (1906); O. Abel, “Fossile Flugfische,” Jahrb. Geol. Reichsanst. 56 (Wien, 1906); L. Hussakof. “Studies on the Arthrodira,” Mem. Amer. Mus. N.H. ix. (1906). III. Faunistic (recent fishes): (A) Europe: E. Bade, Die mitteleuropäischen Süsswasserfische (2 vols., Berlin, 1901-1902). Great Britain: F. Day, The Fishes of Great Britain and Ireland (2 vols., London, 1880-1884); J. T. Cunningham, The Natural History of the Marketable Marine Fishes of the British Islands (London, 1896); W. C. M’Intosh and A. T. Masterman, The Life-Histories of the British Marine Food-Fishes (London, 1897); Sir H. Maxwell, British Fresh-water Fish (London, 1904); F. G. Aflalo, British Salt-water Fish (London, 1904). Numerous important researches into the development, life-conditions and distributions, carried out at the Biological Laboratories at Plymouth and St Andrews and during the survey of the fishing grounds of Ireland, have been published by W. L. Calderwood, J. T. Cunningham, E. W. L. Holt, W. C. M’Intosh, J. W. Fulton, W. Garstang and Prince in the Journ. Mar. Biolog. Assoc., The Reports of the Fishery Board of Scotland, Scient. Trans. R. Dublin Soc. and other periodicals. (B) Denmark and Scandinavia: W. Lilljeborg, Sveriges och Norges Fiskar (3 vols., Upsala, 1881-1891); F. A. Smith, A History of Scandinavian Fishes by B. Fries, C. U. Ekström and C. Sundevall, with Plates by W. von Wright (second edition, revised and completed by F. A. S., Stockholm, 1892); A. Stuxberg, Sveriges och Norges Fiskar (Göteborg, 1895); C. G. J. Petersen, Report of the Danish Biological Station (Copenhagen, 1802-1900) (annual reports containing much information on fishes of and fishing in the Danish seas). (C) Finland: G. Sundman and A. J. Mela, Finland’s Fiskar (Helsingfors, 1883-1891). (D) Germany: K. Möbius and F. Heincke, “Die Fische der Ostsee,” Bericht Commiss. Untersuch. deutsch. Meere (Kiel, 1883); F. Heincke, E. Ehrenbaum and G. Duncker have published their investigations into the life-history and development of the fishes of Heligoland in Wissenschaftl. Meeresuntersuchungen (Kiel and Leipzig, 1894-1899); (E) Switzerland: V. Fatio, Faune des vertébrés de la Suisse: Poissons (2 vols., Geneva and Basel, 1882-1890). (F) France: E. Moreau, Histoire naturelle des poissons de la France (3 vols., Paris, 1881); Supplément (Paris, 1891). (G) Pyrenean Peninsula: D. Carlos de Bragança, Resultados das investigações scientificas feitas a bordo do yacht “Amelia.” Pescas maritimas, i. and ii. (Lisbon, 1899-1904). (H) Italy and Mediterranean: P. Döderlein, Manuale ittiologico del Mediterraneo (Palermo, 1881-1891, not completed; interrupted by the death of the author); E. W. L. Holt, “Recherches sur la reproduction des poissons osseux, principalement dans le golfe de Marseille,” Ann. Mus. Mars. v. (Marseilles, 1899); (I) Western and Central Asia: L. Lortet, “Poissons et reptiles du lac de Tibériade,” Arch. Mus. d’Hist. Nat. Lyon, iii. (1883); S. Herzenstein, Wissenschaftliche Resultate der von N. M. Przewalski nach Central Asien unternommenen Reisen: Fische (St Petersburg, 1888-1891); L. Berg, Fishes of Turkestan (Russian text, St Petersburg, 1905); G. Radde, S. Kamensky and F. F. Kawraisky have worked out the Cyprinids and Salmonids of the Caucasus (Tiflis, 1896-1899). (J) Japan: F. Steindachner and L. Döderlein, “Beiträge zur Kenntniss der Fische Japans,” Denkschr. Ak. Wien, (vols. 67 and 68, 1883); K. Otaki, T. Fujita and T. Higurashi, Fishes of Japan (in Japanese) (Tokyo, 1903, in progress). Numerous papers by D. S. Jordan, in collaboration with J. O. Snyder, E. C. Starks, H. W. Fowler and N. Sindo. (K) East Indies: F. Day, The Fauna of British India: Fishes (2 vols., London, 1889) (chiefly an abridgment of the author’s Fishes of India); M. Weber, “Die Süsswasserfische des Indischen Archipels,” Zool. Ergebnisse e. Reise in Niederl. Ostind. iii. (Leiden, 1894). Numerous contributions to the fauna of the Malay Peninsula and Archipelago by G. A. Boulenger, L. Vaillant, F. Steindachner, G. Duncker, W. Volz and C. L. Popta. (L) Africa: G. A. Boulenger, Matériaux pour la faune du Congo: poissons nouveaux (Brussels, 1898-1902, in progress); and Poissons du bassin du Congo (Brussels, 1901); G. Pfeffer, Die Thierwelt Ostafrikas: Fische (Berlin, 1896); A. Günther, G. A. Boulenger, G. Pfeffer, F. Steindachner, D. Vinciguerra, J. Pellegrin and E. Lönnberg have published numerous contributions to the fish-fauna of tropical Africa in various periodicals. The marine fishes of South Africa have received special attention on the part of J. D. F. Gilchrist, Marine Investigations in South Africa, i. and ii. (1898-1904), and new species have been described by G. A. Boulenger and C. T. Regan. (M) North America: D. S. Jordan and B. W. Evermann, The Fishes of North and Middle America (4 vols., Washington, 1896-1900); D. S. Jordan and B. W. Evermann, American Food and Game Fishes (New York, 1902); D. S. Jordan and C. H. Gilbert “The Fishes of Bering Sea,” in Fur-Seals and Fur-Seal Islands (Washington, 1899); The U.S. Bureau of Fisheries (since 1903) has published annually a Report and a Bulletin, containing a vast amount of information on North American fishes and every subject having a bearing on the fisheries of the United States; S. E. Meek, “Fresh-water Fishes of Mexico,” Field Columb. Mus. Zool. v. (1904). (N) South America: C. H. and R. S. Eigenmann, “A Catalogue of the Fresh-water Fishes of South America,” Proc. U.S. Nat. Mus. 14 (Washington, 1891); the same authors, F. Steindachner, G. A. Boulenger, C. Berg and C. T. Regan have published contributions in periodicals on this fauna. (O) Australia: J. E. Tenison-Woods, Fish and Fisheries of New South Wales (Sydney, 1882); J. Douglas Ogilby, Edible Fishes and Crustaceans of New South Wales (Sydney, 1893); J. Douglas Ogilby and E. R. Waite are authors of numerous papers on Australian fishes in Proc. Linn. Soc. N.S. Wales and Rec. Austral. Mus. (P) South Pacific: D S. Jordan and B. W. Evermann, “Shore Fishes of the Hawaiian Islands,” Bull. U.S. Fish. Comm. 23 (1905). (Q) Madagascar: H. E. Sauvage, Histoire physique, naturelle et politique de Madagascar, par A. Grandidier. xvi.; Poissons (Paris, 1891). (R) Oceanic Fishes: G. B. Goode and T. H. Bean, Oceanic Ichthyology (Washington, 1895); A. Günther, Deep-sea Fishes of the “Challenger” Expedition (London, 1887); C. H. Gilbert, “Deep-sea Fishes of the Hawaiian Islands,” Bull. U.S. Fish. Comm. 23 (1905); R. Collett, Norske Nordhavs Expedition: Fiske (Christiania, 1880); C. F. Lütken, Dijmphna-Togtets Zoologisk-botaniske Udbytte: Kara-Havets Fiske (Copenhagen, 1886); L. Vaillant, Expéditions scientifiques du “Travailleur” et du “Talisman”: Poissons (Paris, 1888); A. Agassiz, Three Cruises of the U.S. Coast and Geodetic Survey Steamer “Blake” (Boston and New York, 1888); A. Alcock, Illustrations of the Zoology of H.M.S. “Investigator”: Fishes (Calcutta, 1892-1899, in progress); A. Alcock, Descriptive Catalogue of the Indian Deep-sea Fishes in the Indian Museum (Calcutta, 1899, contains references to all the previous papers of the author on the subject); R. Collett, Résultats des campagnes scientifiques accomplies par Albert Ier prince de Monaco: poissons provenant des campagnes du yacht “l’Hirondelle,” (Monaco, 1896); R. Koehler, Résultats scientifiques de la campagne du “Caudan,” (Paris, 1896); C. H. Gilbert and F. Cramer, “Report on the Fishes dredged in Deep Water near the Hawaiian Islands,” Proc. U.S. Nat. Mus. xix. (Washington, 1896); C. Lütken, “Spolia Atlantica,” Vidensk. Selsk. Skr. vii. and ix. (Copenhagen, 1892-1898); C. Lütken, Danish Ingolf Expedition, ii.: Ichthyological Results (Copenhagen, 1898); S. Garman, “Reports on an Exploration off the West Coast of Mexico, Central and South America, and off the Galapagos Islands in charge of Alexander Agassiz, by the U.S. Fish Commission Steamer “Albatross,” during 1891,” Mem. Mus. Comp. Zool. vol. xxiv. (Cambridge, U.S.A., 1899). (S) Antarctic Fishes: G. A. Boulenger, Report on the Collections made during the voyage of the “Southern Cross”: Fishes (London, 1902); L. Dollo, Expédition Antarctique Belge (S.Y. “Belgica”). Poissons (Antwerp, 1904); E. Lönnberg, Swedish South Polar Expedition: Fishes (Stockholm, 1905); G. A. Boulenger, Fishes of the “Discovery” Antarctic Expedition (London, 1906).
(G. A. B.)
III. Definition of the Class Pisces. Its Principal Divisions
Fishes, constituting the class Pisces, may be defined as Craniate Vertebrata, or Chordata, in which the anterior portion of the central nervous system is expanded into a brain surrounded by an unsegmented portion of the axial skeleton; which are provided with a heart, breathing through gills; and in which the limbs, if present, are in the form of fins, as opposed to the pentadactyle, structure common to the other Vertebrata. With the exception of a few forms in which lungs are present in addition to the gills, thus enabling the animal to breathe atmospheric air for more or less considerable periods (Dipneusti), all fishes are aquatic throughout their existence.
In addition to the paired limbs, median fins are usually present, consisting of dermal rays borne by endoskeletal supports, which in the more primitive forms are strikingly similar in structure to the paired fins that are assumed to have arisen from the breaking up of a lateral fold similar to the vertical folds out of which the dorsal, anal and caudal fins have been evolved. The body is naked, or scaly, or covered with bony shields or hard spines.
Leaving aside the Ostracophori, which are dealt with in a separate article, the fishes may be divided into three subclasses—
I. Cyclostomi or Marsipobranchii, with the skull imperfectly developed, without jaws, with a single nasal aperture, without paired fins, and with an unpaired fin without dermal rays. Lampreys and hag-fishes.
II. Selachii or Chondropterygii, with the skull well developed but without membrane bones, with paired nasal apertures, with median and paired fins, the ventrals bearing prehensile organs (claspers) in the males. Sharks, skates and chimaeras.
III. Teleostomi, with the skull well developed and with membrane bones, with paired nasal apertures, primarily with median and paired fins, including all other fishes.
(G. A. B.)