2 22 FIRST LhSSONS IN ZOOLOGY 



aquatic others are as strictly terrestrial, nc\'er entering the 

 water. The eggs of all arc oblong and arc deposited in 

 hollows, sometimes covered in the sand. 1 he newly 

 hatched young are usuall)' circular in shape, and differ 

 in color and pattern from the adults. 



The group of lizards (fig. i8o) is a very large one, 

 about 1500 species being known in the world, but it 

 is represented in the United States by comparatively 

 few species. Specimens of some species of the com- 



FlG. 180. — A liziird in the yrass. (I'lKjto'^'rapli from life by Ciierry 

 Kearton; permission of Cassel! -X: C<>.) 



mon swift are obtainable almost anj'where in the United 

 .States. They ma}- be looked for in woods, along 

 fences, and especially on -warm rocks. In certain 

 regions the glass-snake or joint-snake is common. 

 This lizard, popularly considered to be a snake, has 

 no external limbs, and its tail is so brittle, the vertcbrx- 

 composing it being ver)' fragile, that part of it may 

 break off at the slightest blow. In time a new tail is 

 regenerated. It li\'cs in the central and northern part 

 of the United States, and burrows in dr}- places. In the 

 western part of the country horned toads are common, 

 about ten different species being known. These are liz- 



