THE MAIN GROUPS OF ANIMALS. xxxiii 



sexual, Turbinata at the top, and the ^ sedentary and asexual Bivalves at 

 the bottom, while the Univalves or limpets, usually fixed but capable of 

 locomotipii, would have held the middle place. Xlje greater or less 

 power of^'ocomotion, the presence or absence of the^'Xiigher senses, the 

 degrees of vital '^en.trali2ation, of which the number of legs formed a 

 criterion, and the^ position of.the bady in regard to its elevation above_ 

 the ground, would have given to the subdivisions of his Insecta the 

 following order : Intestinal worms ; Myriapoda ; Spiders ; Hexapodous 

 Insects. So we might go on with the other groups. But it is hardly 

 worth while to do so, seeing what space the necessary collection of 

 passages would occupy, and how much conjecture after all would have 

 to be allowed. It will be as well therefore to limit ourselves to the 

 main groups ; and these may now be presented in the following 

 tabular form : — 



i. Sanguineous Animals [Vertebrata\. 



A. Vivipara {Mammalia]. i. Man. 



2. Quadrupeds. 



3. Cetacea. 



B. Ovipara. 



a. With perfect ovum. 4. Birds. 



5 . Quadrupeds and Apoda {Reptiles and 

 Amphibia.'] 

 ^. With imperfect ovum. 6. Fishes, 

 ii. Bloodless Animals [Invertebrata]. 



a. With imperfect ovum. 7. Malacia \Cephalopodf]. 



8. Malacostraca {Crustacea]. 

 ^. With scolex. 9. Insecta {Remaining Arthropoda and 



some Vermes^] 

 7. With generative \ 



slime ; buds ; f 10. Ostracoderma or Testacea {Mol- 

 or spontaneous i lusca excepting Cephalopods]. 



generation. j 



S. With spontaneous) r-T- ^i ^ t 



generation only.) ^'- l^oophytes.] 



^ Or rather "the usually sedentary Bivalves" ; for Aristotle was acquainted with the 

 peculiar motion of the Scallop, cf. H. A. iv. 4, 8. 



