DO THE STORY OF REPTILE LIFE. 



undergone very marked changes in adaptation 

 to burrowing habits, resulting, in extreme cases, 

 not only in the loss of the limbs, but of the limb 

 girdles. In these cases the length of the body 

 becomes enormously lengthened and snake-like. 

 So much, indeed, do they resemble snakes, that 

 only after some experience can the one be dis- 

 tinguished from the other. One of the most 

 interesting features about the loss of the limbs 

 is that every possible gradation from fully 

 functional limbs to mere vestiges thereof may 

 be found. Nowhere is this gradation in the 

 reduction of the limbs so well seen as in the 

 Skink family. 



The Skinks, it should be remarked, are a very 

 numerous family, numbering several hundred 

 species, and distributed nearly all over the world. 

 Australia may perhaps be regarded as their head- 

 quarters, but they occur also in some numbers in 

 Africa and the Oriental region, and, sparingly, 

 in Europe and North and South America. 

 Dwellers in sandy regions, they seek safety 

 from pursuit not in precipitate flight, but by 

 burrowing, which they do with the ease and 

 rapidity of moles, in some cases penetrating to 

 a depth of several feet in a surprisingly short 

 space of time. They, and the burrowing forms 

 of other lizards, however, differ conspicuously 

 from the moles, and similarly modified types 

 of the mammalia, in that the burrowing habit 

 has resulted, in the most extreme cases, in the 

 total loss of the limbs; whilst in the mam- 

 malian forms in question the burrowing habit 

 has resulted in the development of digging-limbs 



