SEVENTEENTH AND EIGHTEENTH CENTURIES 2.0I 

 cidental character. Trees are also divided according to the number of cotyle- 

 dons, and then again into sub-groups. The actual genera are mentioned by 

 one name and are described with a short diagnosis; the species into which 

 they are divided are characterized in a few words, followed by a more de- 

 tailed description. Ray was thus the first to describe both genus and species 

 at the same time. 



Ray's zoological system 

 As a zoologist Ray left no comprehensive work corresponding to the bo- 

 tanical work above mentioned. During his period of coUabc ration with 

 Willughby the latter took over the zoological side, and after his premature 

 death Ray published in his name a couple of works on birds and fishes; how 

 much in th .se works originated from the one or from the other of the two 

 friends it is not easy to decide. In his own name, on the other hand, Ray 

 promulgated two zoological works: a survey of the quadrupeds and reptiles, 

 and a work on insects. The former of these, a small cctavo vclume, is his 

 most important contribution to the knowledge of the animal kingdom. He 

 begins with some general reflections on the characteristics of animals; he 

 defines the animal as a body having life and powers of perception and of 

 independent motion, and he then discusses Descartes's assertion that animals 

 lack sensibility, the incorrectness of which is proved. As regards the repro- 

 duction of animals, he denies spontaneous generation and then deals with 

 the theories of epigenesis and preformation, ovism and animalculism, with- 

 out making any very important contributions in that connexion. The theory 

 of fabulous creatures, which had always up to then been included on the 

 authority of classical authors, is examined and entirely exploded. In regard 

 to systematic classification, which comprises the greater part of the work, 

 Ray follows Aristotle in essentials, and this for good reasons, since the lat- 

 ter' s division of the quadrupeds is on the w^hole both natural and well 

 founded. Ray, however, did not venture to follow up the consequences of 

 the comparative anatomical method which Aristotle founded; like the latter 

 he refers whales to the fishes, although he is quite well aware of their closer 

 anatomical affinity with the mammals. On the other hand, in certain respects 

 Ray goes deeper into the characteristics of the individual animal groups 

 which he adopted; above all, he takes account of the structure of the circula- 

 tory organs and on this basis divides animals first of all into sanguiferous 

 and bloodless — he quite realized that the last-mentioned group possesses 

 blood of a kind, though colourless, but he prefers to retain the Aristotelean 

 nomenclature. The sanguiferous animals are divided into those that breathe 

 wit'i lungs and those that breathe with gills; those provided with lungs are 

 again divided into animals having two heart- ventricles and animals with only 

 one To the last belong oviparous quadrupeds and reptiles; the first is divided 

 into oviparous (birds) and viviparous (partly land animals — mammals — 



