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Rh considerable use of anatomical characters in his definitions of larger groups, and may thus be considered as the father of modern zoology Associated with Ray in his work, and more especially occupied with the study of the Worms and Mollusca, was Martin Lister (1638–1712), celebrated also as the author of the first geological map.

After Ray’s death the progress of anatomical knowledge, and of the discovery and illustration of new forms of animal life from distant lands, continued with increasing vigour. We note the names of Vallisnieri (1661–1730) and Alexander Monro (1697–1767); the travellers Tournefort (1656–1708) and Shaw (1692–1751); the collectors Rumphius (1637–1706) and Hans Sloane (1660–1753); the entomologist Réaumur (1683–1757); Lhwyd (1703) and Linck (1674–1734), the students of Star-Fishes; Peyssonel (b. 1694), the investigator of Polyps and the opponent of Marsigli and Réaumur, who held them to be plants; Woodward, the palaeontologist (1665–1722)—not to speak of others of less importance.

Two years after Ray’s death Carl Linnaeus (1707–1778) was born. Unlike Jacob Theodore Klein (1685–1759), whose careful treatises on various groups of plants and animals were published during the period between Ray and Linnaeus, the latter had his career marked out for him in a university, that of Upsala, where he was first professor of medicine and subsequently of natural history. His lectures formed a new departure in the academic treatment of zoology and botany, which, in direct continuity from the middle ages, had hitherto been subjected to the traditions of the medical profession and regarded as mere branches of “materia medica.” Linnaeus taught zoology and botany as branches of knowledge to be studied for their own intrinsic interest. His great work, the Systema naturae, ran through twelve editions during his lifetime (1st ed. 1735, 12th 1768). Apart from his special discoveries in the anatomy of plants and animals, and his descriptions of new species, the great merit of Linnaeus was his introduction of a method of enumeration and classification which may be said to have created systematic zoology and botany in their present form, and establishes his name for ever as the great organizer, the man who recognized a great practical want in the use of language and supplied it. Linnaeus adopted Ray’s conception of species, but he made species a practical reality by insisting that every species shall have a double Latin name—the first half to be the name of the genus common to several species, and the second half to be the specific name. Previously to Linnaeus long many-worded names had been used, sometimes with one additional adjective, sometimes with another, so that no true names were fixed and accepted. Linnaeus by his binomial system made it possible to write and speak with accuracy of any given species of plant or animal. He was, in fact, the Adam of zoological science. He proceeded further to introduce into his enumeration of animals and plants a series of groups, viz. genus, order, class,, which he compared to the subdivisions of an army or the subdivisions of a territory, the greater containing several of the less, as follows:—

Linnaeus himself recognized the purely subjective character of his larger groups; for him species were, however, objective: “there are,” he said, “just so many species as in the beginning the Infinite Being created.” It was reserved for a philosophic zoologist of the 19th century (Agassiz, Essay on Classification, 1859) to maintain that genus, order and class were also objective facts capable of precise estimation and valuation. This climax was reached at the very moment when Darwin was publishing the Origin of Species (1859), by which universal opinion has been brought to the position that species, as well as genera, orders and classes, are the subjective expressions of

a vast ramifying pedigree in which the only objective existences are individuals, the apparent species as well as higher groups being marked out, not by any distributive law, but by the interaction of living matter and its physical environment, causing the persistence of some forms and the destruction of vast series of ancestral intermediate kinds.

The classification of Linnaeus (from Syst. Nat., 12th ed., 1766) should be compared with that of Aristotle. It is as follows—the complete list of Linnaean genera being here reproduced:—