100 VERTEBRATES: REPTILES. 



The Great Auk of the 

 Arctic regions is as large as 

 the Penguin. Other kinds 

 are much smaller, and those 

 called Puffins are not larger 

 than a dove. Puffins make 

 their nests in burrows in 

 the ground, and each bird 



lays but one egg in a sea- 

 Fig, 166. Puffin. 



REPTILES. 



Reptiles are vertebrates which have cold blood, and 

 are covered with hard plates, called scales, and which 

 lay eggs in holes that they dig in the ground ; these 

 eggs hatch without being brooded by the parent, and 

 the young, as soon as hatched, look just like the par- 

 ents, only smaller. Reptiles are such as Turtles or 

 Tortoises, Lizards, and Serpents or Snakes. 



TURTLES. 



Turtles, or Tortoises, are reptiles which have a shell 

 into which they can more or less completely withdraw 

 their head, legs, and tail. Some of them live wholly 

 upon the land, like those called Gophers in the South- 

 ern States, which dig burrows in the ground that are 

 dangerous pitfalls for horsemen, and the Box Turtles, 

 which live in the woods, and which can shut their shell 

 so tightly as to entirely hide their extremities, as seen 

 in Figure 169. Others, like the Painted Turtle, with 

 its colors of black, yellow, and red, the Wood Tortoise, 

 with its beautifully carved scales, the Speckled Tortoise, 



