572 



CERASTES; PUFF-ADDERS; RATTLE-SNAKES. 



very unpleasant consequences follow the insertion of the poison- 

 fangs into his body, it is very seldom (if ever) that fatal results 

 occur to persons previously healthy. The Viper is ovo-vivipa- 

 rous, the eggs being hatched within the body ; and the female, 

 when loaded with them, may often be seen basking in the sun, 

 and thus taking advantage of its warmth for the development of 

 her offspring. The Viperidse of tropical regions are much more 

 venomous ; their bite being commonly fatal to man. Amongst 

 them we may mention the Cerastes, or Horned Viper, so called 

 from a small pointed horn which arises from above each eye, 

 which is celebrated from its being regarded as the Asp by whose 

 bite Cleopatra died. When moving on the ground, its body 

 always forms a series of parallel bends, and from this arrange- 

 ment it is always prepared to spring forward and inflict its 

 wound ; in fact, under these circumstances its activity is said to 

 be great, as it will spring to a distance of three feet, or about 

 double its own usual length. The Puff Adders of Africa also 

 belong to this family, and some of them attain to a considerable 

 size ; the common at least reaches a length of more than five feet. 



513. Of the family CROTA- 

 LIDJS, the true Rattle- Snakes, 

 distinguished by the peculiar ap- 

 pendage to their tails, from 

 which their name is derived, 

 are confined to America ; but 

 there are other species belong- 

 ing to this family, some of 

 which are found in the Eastern 

 Hemisphere, in Asia and its 

 islands. The Rattle consists of 

 a number of thin horny cells, 

 which are articulated loosely to 

 each other, and which produce a 

 rustling noise when shaken. The 

 number of joints increases, up 

 FIG. 331.-KATTLKSNAKE. to & certain amount at least, 



with each casting of the skin. The Rattle- Snake vibrates this 



