92 REPTILES OF THE WORLD 



small they fold these useless members against the side 

 of the body in times of fright, when, with the aid of a 

 sharpened snout, they plow their way, literally swim into 

 the desert sands. 



Structure of Lizards. 



Lizards may be fairly well separated for popular 

 study, according to the structure of their scales. Some 

 have very coarse, overlapping scales, each terminating 

 in a sharp point and having a strong keel; species thus 

 coated are rough, lusterless and bristling with sharp 

 points. Others have smooth, rounded scales as polished 

 as glass. While a number of lizards have the scales 

 arranged in oblique rows, many display a ringed ar- 

 rangement on both the body and the tail. A good pro- 

 portion of the larger (as well as the smaller) lizards 

 have such a fine, granular scalation they appear to be 

 covered merely with a bare, rough skin unless closely 

 examined. Some of the degenerate, worm-like species 

 have lost their scales, in place of which are hardened, 

 polished and movable rings of skin, encircling the body ; 

 these are used in precisely the same fashion as the seg- 

 ments of an earthworm — to assist in locomotion. 



The general form, as has been previously mentioned, 

 greatly varies. Yet the vast majority of lizards have 

 four well-developed limbs. Among several of the fam- 

 ilies — and these by no means nearly allied — we find 

 startling illustrations of degeneracy; and all along sim- 

 ilar lines. In adopting subterraneous habits certain 

 species have ultimately lost their limbs while their eyes 

 have become small and nearly useless. Such degenera- 

 tive tendencies are always marked with decided elonga- 

 tion of the body — into a snake-like or worm-like form. 

 We find all stages of development. Most striking are 



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