THE HISTORY or The earliest zo ologist was Aristotle (u.e. 354-322). Down to the period of Ray and Linnams he was the only naturalist worthy of the name. His works, The History of Animals, The Generation of Animals, and The PariR of Animals, eontain, besides er rors of fact or opinion, many singularly correct statements. He recogniZed some of the more im portant groups, which lie called 'genera.' Such were the Malakia or cephalopods, Malacostraca or soft animals with shells (the higher crustacea), Entoma (insects, arachnids, myriapods, and the higher worms), etc. He also dissected the cuttle fish, octopus, and other animals.
Zoiilogy as a descriptive science dates from the lime of Linnums (q.v.), but it was not until the rise of comparative anatomy, embryology, mor phology, paleontology, and the evolution theory lint it became well-grounded science. 'H, predecessors of Linnams were Malpighi, Leeuwen Swannnerdam. liedi, and W. Harvey (q.v.). Harvey in 1616 discovered the use of the heart and the mode of the circulation of the blood in arteries and veins, and from his observa tions on the development of the chick declared that all living things arise from an egg by a gradual process of growth and differentiation (epigenesis). The invention of Om microscope by the Janssens (1590-1600) and its improve ment during the sevent(entli century enabled Malphigi to discover the organs named after him. Leeuwenlmek the blood corpuscles, striated muscle-fibres, dentinal canals, epidermal cells, and described certain infusoria, rotifers, and hydra. Swammerdam dissected in sects and snails, and worked out the metamor phosis of certain insects. Eedi was the first to combat the notion of spontaneous generation (q.v.), while Hansen (1677) discovered the sperms of animals. The history of zoiilogy may be roughly divided into four periods: (1) Toward the end of the seventeenth cen tury Ray, basing his ideas of the classification of animals mainly on the work of Aristotle, was the first to arrive at some conception of species and of specific characters. lint it is Linniens to whom we are indebted for Id:to:Mal nomenclatu're; and the first genuine though very imperfect classification of animals (q.v.) dates
back to the Systcrna Natur(e, the tenth edition of which appeared in 1758. He recognized genera, orders, and classes, dividing the animal kingdom into six of the latter. As the result of his influ ence, his own pupils, and also Pallas, did much to advance zoiilogy, while the anatomists and physiologists of this period were Camper, Wolff, Spallanzani. Hunter. and Vicq d'Azyr, the latter of whom proposed the term 'comparative anat omy,' also previously used by Leibnitz. Lamarck (1744-1829) divided animals into 'vertebrate' and 'invertebrate,' and reorganized the latter di vision, founding the classes of Tnfusoria, Eadiata (Echinodermata), Annelida, Arachnida, and Crustacea. He was far in advance of any other zoologist from the time of LiBlITUS to that of Cuvier. Geoffroy Saint-Hilaire also advanced our knowledge of the vertebrates by establishing the orders Monotremata and Marsupialia, the latter forms having been distributed among the rodents and primates.
(2) Cuvier (q.v.) was the founder of compara tive anatomy and vertebrate paleontology, while Lamarck founded invertebrate paleontology. Cu vier's work as a comparative anatomist, show ing the importance of structure as the basis of all classifications. was most important. In di viding the animal kingdom into four branches, he led the way for the recognition of the more numerous phyla constituting the animal world. Early in the nineteenth century Geoffroy Saint Hilaire advanced embryology, and founded the doctrines of the unity of organization and of homologies, which paved the way for the theory of descent. Vieq d'Azyr established the principle of serial homology. Biehat was one of the found ers of histology. France at this time led the scientific world, though Germany had her Blu m-alma, who founded anthropology, her Hol linger, the teacher of later embryologists, Tiede mann, Rojanus, and Carus. Meekel, in his time the leading German anatomist, studied at Paris with Cuvier, as did :Milne-Edwards, while Owen felt his influence.