IIISTORICAL SKETCH OF CLASSIFICATION. The Creeks had considerable knowledge concerning animals, which Aristotle recorded, added to and arranged, for the first time of which we have any knowledge, in an orderly fashion. Aristotle had some conception of genera and species. It is true that his yepor Locuo•) was a rather elas tic term, since it was applied both to small and large groups of animals. Aristotle also conceived a difference be,ween vertebrates and inverte b•ates, although he made the distinction by means of an definition. The following are the eight groups of animals as defined by A ristotle : .1 iiimais with Blood—Vertebrates: (1) Viviparous animals (four-footed), and in a special -yews Igenos) of this the whale was placed. (2) nirds. (3) Oviparous, four-footed animals. (4) Fishes.
A ?anvils without (reel) Blood—Invertebrates: (5) soft animals ( paXcisea, »ialakia. i.e. Cepha lopoda). (6) Animals with soft shells x6arpaKa, nialakostraka, i.e. Cru,tneen ). (7) In sects. (S) Shelled animals (sea-urchins.
The elder Pliny added little to our knowledge of animals. Be was simply a compiler, who copied freely from Aristotle, whom he some times misunderstood, and he admitted much of the error and superstition of his time to rank with fact. It was not until the seventeenth cen tury that any very great addition to our knowl edge of the structure, development, and relations of animals was made.
Linnaus to Curier.—Ilay wrote a Synopsis of Ilainnialia and lleptilia (London, 1693), which was used by the master systematizer, Linna-us (1707-7S). in his Systema turcr, as the foun dation upon which he built that part of his clas sification that had to do with vertebrates. Lin nieus did not add much to our knowledge as an investigator; but lie sifted and sorted, rejected and retained, from the accumulations of his predecessors, and out of this more or less chaotic mass he erected his orderly system—the first great classification of animals. His Systema Naturce went through thirteen editions, twelve of which were published during his lifetime. and five of these were revisions by his own hands. The arrangement by Linna-us was into 'classes,' as follows: (I) ,Nlammalia. (2) Ayes. (3) Amphibia (including reptiles). (4) Pisces. (5) Insects (including insects proper, myria pods, arachnids, and crustaceans). (6) Ferules (radiates, mollusks, worms, eirripeds, and a fish, myxine).
This classification was based mainly on exter nal appearance and some internal anatomy; and, though imperfect and incomplete, it gave a great impulse to the study of zohlogy and to more orderly arrangements of animals, based on ana tomical characters. It was Linnaeus who intro
duced binary nomenclature, since lie first gave every animal a generic and a specific name of Latin origin.
The next great systematist was Cuvier (17('i9 IS32). "Cuvier did not," says Clans, "as most zoiitomists have done, look upon anatomical dis coveries and facts as in themselves the aim of his researches; but he emitemplated them from a comparative point of view, which led him to the establishment of general principles." lore over. Curler appreciated fully the idea of 'corre lation.' "The organism." he declared. "consists of a single and complete whole, in which single parts cannot be changed without causing changes in all the other parts." envier became con vinced, from a study of the nervous system and the arrangement of the systems of organs, that the animal kingdom is divided into four great branches (7'ableau Wineniaire de l'histoirc natu relic des animaux, Paris. l798) as follows: Branch 1..laimaiio Vertcbralu. Classes: (1) Mammalia. (2) Aves. (3) Reptilia. (4) Pisces.
Branch 2. Animulia Mullusca. Classes: (1) Cephalopod:* (not subdivided). (2) Pteropoda not subdivided). (3) Gastropoda. (Orders: Pulnionata, Inferobranehia. branchia, Ilet('ropoda, Pe•tinibratichia. Tuhuli branchia, Seutibran•hia, Cyclobranchia.) (4) Acephala. (Orders: Testaeea, Tunicata.) (5) Brachiopoda (no subdivisions). (() Branch 3. .1 /tint(' ihz Classes: (1) Annelides. (Orders: Tuldeohr, Dorsibrancli i:e. Abranchbe.) (:2) Crustacea. (Section 1: ..Nlalacostraea. Orders: Decapoda. Stomatopoda, .Amphipoda, La•modipoda, Isopoda. Section 2: Entomostraca. Orders: Brachiopoda. Pcecilo Trilobitiv.) (3) _1r:1(111)41es. (Orders: Pulinonari.V.Trachearite.) (4) Insects. (Orders: Myriapoda, Thy sanura, Pa rasit a , Suet oria . ('o leoptera. Orthoptera. Iletnipte•a. Neuroptera, Hymenoptera, lthipiptera. Diptera.) Branch 4. Animalia Radiata. C1as,,es: (1) Echinoderms. (Orders: Pedicellata, Apoda.) (2) Intestinal Worms. (Orders: Nematoidea, Parenchymatosa.) (3) Acalepine. (Orders: Simplices. Ilydrostaticle.) (4) Polypi (Antho zoa, Ilydroida. Bryozoa, Corallime, Spongice). (Orders: C'arnosi, Gelatinosi, Polypiarii.) (5) lnfusoria. (Orders: Rotifera, Iioniogenea.) Lamarck to Lcuckart.-Probably to Lamarck, more than to any other systematist, we are in debted for the term ]nvertebrata and to the ar rangement of groups in an ascending series. In his Hisloirc naturclle des unimans sans rerti. bres (Paris, ISO] ), he classifies the invertebrates as follows (accepting the vertebrates as arranged by Cuvier): 1. Apathetic Animals. Do not feel; no brain, no senses; rarely articulated.