276 THE WORLD OF ANIMAL LIFE 



REPTILES 



In former periods of the world's history Reptiles occupied a 

 leading position so far as numbers, and size, and power were con- 

 cerned, and Birds and Mammals an inferior one. Now the posi- 

 tions are reversed. Mammals and birds are much more numerous 

 in the world than reptiles, and are much more imposing and 

 powerful groups of animals. 



We need not therefore be surprised to learn that more groups 

 of reptiles have ceased to exist than are living to-day. It may 

 interest us even to see the names of the groups of the Reptilia 

 which have died out, as well as the names of the orders which still 

 exist. 



ORDERS OF REPTILES STILL REPRESENTED 



1. Crocodiles — Crocodilia. 



2. Tortoises and Turtles — Chelonia. 



3. Lizards and Snakes — Squamata. 



4. Tuateras (Beaked Lizards) — Rhynchocephalia. 



ORDERS OF REPTILES WITH NO LIVING 

 REPRESENTATIVES 



1. Dinosaurs — Dinosauria. 



2. Flying Dragons — Ornithosauria. 



3. Plesiosaurians — Plesiosauria. 



4. Fish-lizards — Ichthyosauria. 



5. Mammal-like Reptiles — Anomodontia. 



The characters of the living reptiles are: — (i) They are all 

 cold-blooded; (2) they all lay eggs, and never suckle their young; 

 (3) they are never covered with hair, or fur, or feathers, but with 

 scutes, or scales, or, as in the turtles, with a bony carapace or 

 external shield. 



We must not forget that they belong to the great kingdom of 

 the VertebratA; all have a spinal column, although all have not 



