GENEIiAL CLASSIFICATION OF POISONOUS SNAKES 



15 



resistant substances rapidly takes place. The very bones are dis- 

 solved, and the faeces, which are voided some days later, contain 

 only a few osseous remains and a felt-like material composed of 

 hair or feathers. 



Scales. — The skin of snakes, which is very elastic and extensile, 

 is covered with scales, small on the back, and in great transverse 

 plates on the entire ventral surface. 



Fig. li. — Arrangement of the Scales of the Head in one of the Poisonous 

 Colubridce {Naja tripudians, or Cobra-di-Capello). (After Sir Joseph Fayrer.) 



The shape and dimensions of the scales of the head are highly 

 characteristic in each species. It is therefore necessary to know 

 their names and the arrangement that they exhibit : these details 

 are shown with sufficient clearness in figs. 13 and 14. 



Coloration. — The colouring exhibited by the scales of snakes 

 is governed generally by the biological laws of mimlcnj. It is 

 therefore not a character of specific value, and may be modified 

 several times in the course of the existence of the same reptile, 

 according to the surroundings in which it is obliged to live. 



