REPTILES GENERALLY. 



19 



which are extremely elongated, 

 and covered with the extended 

 skin of its sides. 



The most active among rep- 

 tiles, and possessing the most 

 varied movements, are lizards 

 and snakes, which latter, strange 

 to say, though without legs, wings, 

 fins, or any other appendages to 

 assist locomotion, can do all and 

 much more than all the rest can 

 do. They can even let themselves 

 down from a tree, or spring from 

 branch to branch as easily as the 

 flying frogs and lizards, swinging 

 like an acrobat, springing, leaping, 

 and climbing like a monkey, and 

 when on the ground vanishing 

 like a flash in their swift gliding. 

 Without hands the constricting 

 snakes can grasp their prey with 

 the coils of their body ; without 

 fins they can swim like a fish ; 

 and they can even do two or 

 three things at once through the 

 wonderful adaptation of their 

 spine to meet emergencies. It 

 is the peculiar construction of 

 the spine which enables them 

 to accomplish all this. Owen, 

 Huxley, and other distinguished 

 anatomists write enthusiastically 

 of the beautiful adaptation of a 

 snake's spine to its needs. Each 

 vertebra is elaborately articulated to the next and to the ribs by 

 eight joints ; and each interlocks 

 with the one next to it by a cup and 

 ball-shaped process. Here (fig. 5) 

 you see a front and a back view 

 of one single vertebra, and cin 

 imagine the pliancy of movement 

 all these cup and ball arrange- 

 ments would give to a long spine, 

 and why they are justly called vertebra, from verto, to turn. 



Fig. 4. — Flying Lizard. 



. Fi S-5-- 

 a, posterior view. b, anterior view. 



The 



