390 



LOWER VERTEBRATES. 



given, that the weak action of the heart may be kejjt up, and finally, but as soon as 

 possible, there should be injected directly into the wound a one per cent solution, in 

 water, of potassa perraanganas, a chemical antidote discovered by Dr. Lacerda, of Rio de 

 Janeiro, and found to be ^-ery effective. 



The first representative of the sub-order of which we treat is the Actractas^ns 

 irrer/idaris, of southern Africa, a form the habits of which are little known. Though 

 a small serpent, seldom exceeding two feet in length, it has the fangs developed in a 

 most extraordinary degree, being so long as to reach back to the angle of the jaw. 

 That this snake can strike as do other members of the sub-order is much doubted by 



Fig. 225. — Vipera cerastes, horned-viper. 



some, as the fangs seem to fill the mouth in such a way as to prevent their apices from 

 being protruded. 



The vipers have the body robust, the tail short and not prehensile; the head 

 triangular and generally covered with scales, or at least incompletely shielded ; the 

 eye is of moderate size, and is provided with a vertical pupil, and in front of it there- 

 is no depression or pit so universally characteristic of the Bothrophera. The viper.s, 

 some of which grow to a considerable size, are inhabitants of Africa, and from their 

 virulent nature have been known since time immemorial ; the most common is the 

 Vipera cerastes, or horned-viper. This animal, though not so poisonous as the cobra, 

 is extremely dangerous. In its appearance it is a most re]ingnant animal, of a pale 

 brownish-white color above, witJi spots and blotches of a darker shade. Over each 



