HAUNTS AND HABITATS 35 



Experiment has shown that the snake when made to fall 

 from a height, descends with the body rigid, and that the line 

 of fall is at an angle from the point of departure to the ground. 

 It seems probable that the concave lower surface buoys the rep- 

 tile up in its fall, since the fall of a split bamboo through the air is 

 perceptibly slower than that of an undivided rod of equal weight. 



Other reptiles have taken to a more or less completely bur- 

 rowing and subterranean life, frequently with loss of the limbs, 

 and sometimes more or less abortion of the eyes ; thus coming 

 under the designation of what many writers are pleased to call 

 degraded animals, which is, of course, merely another term for 

 specialisation and adaptation in a particular direction. Among 

 such burrowing and worm-like creatures are several families of 

 snakes — notably the blind-snakes, or Typhlopidce — and the am- 

 phisbsenas and slow-worms among lizards. Many other rep- 

 tiles, such as the spiny-tailed lizards (Urotnastix) and the tuatera 

 (Sphenodon) are burrowers, but without " degradation " ; while 

 among the skink lizards (Sancidce) almost every gradation from 

 a fully limbed to a limbless burrower may be observed. 



Of the purely terrestrial forms other than burrowers, limit- 

 ations of space preclude anything more than the very briefest 

 mention in regard to haunts. It may be observed, however, 

 that, unlike the smaller mammals, a very large number of forms 

 — and notably the lizards of the genera Agcwia and Lacerta — 

 are diurnal in their habits, and trust to escape from enemies 

 by the lightning speed with which they retreat into the crevices 

 of the rocks they frequent. Desert forms, on the other hand, 

 of which there are many, probably trust largely to resemblance 

 to their surroundings as a means of escaping detection by foes. 

 A large number of lizards living among grass likewise owe their 

 safety to a similar protective resemblance, as is more fully 

 noticed in the sequel. 



Up to a recent date no reptiles were known to have adapted 

 themselves to an existence in caverns; but about 1898 it was 

 discovered that numbers of a species of Coluber frequent caves 

 in the Selangor district of the Malay Peninsula, where they feed 

 on bats by which the cave is tenanted. These snakes grow to 

 eight or nine feet, and are paler-coloured than ordinary, while 

 their colouring presents a remarkable resemblance to that of the 

 w r alls of the cave; at first sight, suggesting that the reptiles are 



