Page:The Zoologist, 4th series, vol 2 (1898).djvu/475

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volume, written by a well-known Cambridge zoologist, appeared opportunely a little before the meeting of the Zoological Congress at that University town. It is a classification of the Vertebrata based on the sound foundation of that which preceded as well as that which exists. It of course naturally follows that the osseous structure is all that we certainly know of the past vertebral life, though Dr. Gadow argues "it would be pedantic to exclude all soft perishable parts on the plea that they are unknown in the fossil forms. Here discretion is to be used. We do not 'know' that the palæozoic Fishes did possess an entirely venous heart, nor has it yet been shown that the embryos of Dinosaurs were surrounded by an amnion; but we feel nevertheless certain, because of the laws of correlation which comparative anatomy allows us to deduce from the study of recent creatures." This proposition will be generally accepted, and is distinct from the question of antecedent colouration, a subject still in the domain of probabilities. This method will perhaps be best exemplified by reference to our own relationships, which Dr. Gadow thus arranges:—
 * ".—Caudal vertebræ transformed into a coccyx. Walk erect or semi-erect.
 * Hylobates.—S.E. Asia. 'Gibbon.'
 * Pliopithecus.—Miocene of Europe.
 * Simia satyrus.—'Orang Utan.' Sumatra and Borneo.
 * Troglodytes gorilla and T. niger.—West Equatorial Africa.
 * T. sivalensis.—Pliocene, Punjab.
 * Dryopithecus.—Miocene, France.
 * Pithecanthropus erectus.—Plistocene, Java.
 * Homo sapiens.—Cosmopolitan."