INDEX. 



583 



CHAPTER XXI. 



Yertebrata ........ 



Distingaishing characters of vertebrate classes 



Comi^lete skeleton, how composed. 



Nervous system of vertebrata .... 



Increased perfection of the senses .... 



Blood of vertebrata ...... 



Variations of its temperature, the cause of important 



differences ........ 



Its efiect upon the instincts and affections of ditierent 



races of vertebrata ...... 



PAGE 



309 

 310 

 311 

 311 

 312 

 312 



313 



314 



CHAPTER XXII. 



