334 YERTEBRATA: REPTILIA OR REPTILES. 



Snakes which have the posterior parts of the body and 

 tail much compressed, and raised vertically, thus adapting 

 them for swimming, are called Sea-snakes or Hydrophidse. 

 They are of small size, and inhabit both the salt and fresh 

 waters in warm climates, and are very venomous. 



PRINCIPAL TOPICS CONSIDERED IN CHAPTER II., SECTION IV. 



SUB-SECTION I. 



Reptiles considered as a Class. How they eat. Blood. Circulatory appa- 

 ratus. Respiration. Skeleton, etc. Nervous system. Eyes. Hearing 



apparatus. Smell. Touch. Classification of Reptiles. 



SUB-SECTION II. 



The Order of Chelonia. Land and Fresh-water Turtles. Sea Turtles. 



Fossil Turtles. 



SUB-SECTION III. 



The Order of Dinosauria. Sanria in general. Structure and size of Dino- 

 saurs. The Geological period to which they belong. 



SUB-SECTION IV. 



The Order of Crocodilia. Living examples. Where found. Crocodilians 



more fully described. Crocodiles and Alligators compared. 



SUB-SECTION V. 



The Order of Lacertia. Living examples briefly noticed. Fossil Lacertians 



or Thecodonts, and when they made their appearance. 



SUB-SECTION VI. 



The Order of Enaliosauria. Ichthyosaurus. Plesiosaurus. Discosaurus.- 



Mosasaurus. 



SUB-SECTION VII. 

 The Order of Pterosanria. Structure and size of Pterosaurs. Where found. 



SUB-SECTION VIII. 



The Order of Ophidia. Serpents more fully described. Boas, Anacondas, 



Pythons. Striped Snakes, etc. Rattlesnakes, etc. Harlequins. Vipers. 



Sea-snakes. 



