150 SNAKES. 



expands, so do some others ; but all these movements are, 

 no doubt, connected with respiration in some way, just as 

 in human beings, sighing, sobbing, panting, etc., in which 

 the ribs take part, are only modifications of the ordinary 

 movements of respiration, and chiefly emotional. 



Very similar also to the manner of the puff adder is that 

 of Vipera rhinosceros, one of the largest African poisonous 

 serpents, known as the * River Jack,' being fond of water. 

 One of these was in the London collection for several years, 

 and I observed that whenever disturbed, its body swelled 

 considerably, while the 'hissing,' or expulsion of breath, 

 alternated with this expansion. 



Snakes, like other animals, probably differ in temper or 

 in nervousness ; for while some are noted hissers, others 

 hiss only on great provocation, and others, again, not at 

 all. One remarkable example of a non -hissing snake, 

 though from no amiability of temper, is the little carpet 

 viper of India {Echis carinafa). Unless you were positively 

 assured by learned authorities that this exceedingly irritable 

 little viper never hisses, you would scarcely believe your 

 ears, so sibilant is the sound it causes by rustling its scales 

 together. 



Sir Joseph Fayrer, in the Thanatophidia, describes this as a 

 very fierce and aggressive little viper, always ready to attack 

 and be on the defensive. It throws itself into a double coil, 

 and its agitated motion causes the rough, carinated scales 

 to rub against each other, and make a sound like hissing, 

 but ' it does not hissj 



This rustling is very much like the sound of the crotalus 

 rattle, and the dry scales must be raised in a sort of way, or 



