INTRODUCTION xl 



B Amniota. Vertebrates which have an integumentary covering of epi- 

 dermal scales, feathers, or hair ; whose eggs (in the ovipa- 

 rous species) are laid on the land and have the protection 

 of a shell; whose embryos have the additional protection 

 of an amnion and respire by means of an allantois; and 

 which respire after birth by means of lungs. 

 Division i. Scmropsida. Vertebrates which have a covering of epider- 

 mal scales or feathers, which produce a large egg, and 

 which are either oviparous or ovoviviparous. 

 Class 3 or Vertebrates. Reptiles. Cold-blooded vertebrates with 

 a covering of horny scales or plates. 

 Order i. Crocodilia. Crocodiles and alligators. 

 Order 2. Lacertilia. Lizards. 

 Order 3. Serpentes. Snakes. 

 Order 4. Testudinata. Turtles. 

 Class 4 of Vertebrates. Birds. Warm-blooded vertebrates with 



a covering of feathers. 

 Division 2. Mammalia. Vertebrates which have an epidermal cover- 

 ing in the form of hair, produce a minute egg (except the 

 Monotremata), have uterine embryonic development, and 

 suckle their young. 

 Class 5 of Vertebrates. Mammals. 



