THE HORNED VIPER. 



171 



are a certain conformity of habits, and a nearly equal aptitude for 

 leaping. 



Otherwise, their organization rather resembles that of the rat, 

 along with which it is classed by zoologists. Their hind-legs are 

 much shorter than those of the jerboa, and their tail is garnished 

 with but a few short, stiff hairs. Like the jerboas, they inhabit the 

 sandy wildernesses of Africa, Asia, and eastern Europe. 



These small animals, exclusively frugivorous and graminivorous, 



^*nrm*jg! 



JERBOAS ATTACKED BY A HORSED VIPER. 



seem able, in the solitary places where they make their retreats, to 

 multiply themselves ad infinitum ; but, while a great number perish 

 through famine, they are also decimated by a host of enemies in the 

 reptiles of the Desert, and especially by the terrible horned viper, or 

 cerastes, and a great saurian, intermediate between the lizard and 

 crocodile the " varan of the Desert." 



The horned viper (vipera cerastes) is thus named on account of 

 the two horns or protuberances on its forehead, which give it a 



