370 



LOWER VERTEBRATES. 



seized, without first waiting for it to die. This habit has often resulted in considerable 

 interest to those unfamiliar with it. Not infrequently the snake can be induced, on 

 irritation, to disgorge a well-secured meal, which often appears as a lively frog, that 

 hops away with all the experience, if without the understanding, of Jonah. The habit 

 may also explain the almost universal belief, of which more has been said in the intro- 

 duction, that certain snakes swallow their young in time of danger. Since a serpent, 

 that had been made a meal of would live for some little time after being swallowed, 

 and if, in the meantime, the feasting snake were killed, the imprisoned animal would, if 

 liberated, crawl away with all the experience of the frog. 



We will first treat one of the largest genera, and the one that is the most typical 

 of the family ; its members are recognized by their keeled scales, regular arrangement 

 of the cervical plates, and by the numerous teeth of the jaws and palate, of which the 



rM^r \ 



Fig. 216. — Tropidonotus natrix, ' common snake ' of Europe. 



anterior are shortest. The Tropidonoti are found in the neighborhood of water, as a 

 general rule, and, though not aquatic, are excellent swimmers, and, on being surprised, 

 will often choose this means of escape. Members of the genus are abundant in North 

 America, Europe, Asia, and a portion of Australia, as well as some of the islands of the 

 Eastern Archipelago, though rare in Africa and South America. 



The illustration which has been selected to represent this large genus is that of 

 Tropidonotus natrix, a form which is abundant throughout Europe, being particularly 

 fond of the neighborhood of ponds and streams, into which it often voluntarily plunges, 

 sometimes coiling itself up and remaining at the bottom for hours at a time. With 

 the common people it is known as the ringed or grass-snake, and is often tamed, soon 

 learning to distinguish its friends. In confinement it will eat beetles, grasshoppers, 

 frogs, and even bread and milk. Of the dozen or more American representatives of this 

 genus, Tropidonotus sipedon is, perhaps, the most familiar. This snake is found in 



