128 REPTILES AND BATRACHIANS 



This species feeds probably exclusively on fish, as my 

 captive specimens refused frogs and all other food ; these 

 snakes vi^ere at all times very ill-tempered, literally throwing 

 themselves, when out of the water, at the intruder. They 

 shed at intervals of about three months, the " skin " 

 coming off, unlike many other purely aquatic snakes, 

 entire. Cantor, who has compared its physiognomy to 

 that of a bulldog, observed a female in his possession to 

 bring forth twenty-seven young ones. In Siam the 

 Elephant Trunk Snake is highly valued for its skin, 

 which is used by the natives for making drum-heads. 



In dealing with the sub-family Colubrina we shall begin 

 with the genus Tropidonotus, of which the Grass Snake 

 is the well-known British representative. The head is dis- 

 tinct from the neck ; the eye, which varies much in size, 

 according to the species, is provided with a round pupil. 

 The cylindrical body is rather elongate ; the scales are 

 mostly keeled. In the upper jaw the posterior teeth are the 

 longest, while in the lower jaw they are all sub-equal in size. 



Tropidonotus is distributed over Europe, Asia, Africa, 

 North Australia, and North and Central America. 



All the Old World species, so far as we know, lay eggs, 

 while, without exception, those of the New World bring 

 forth their young alive. 



The Common Grass Snake, T. natrix, of Europe, 

 Algeria, West and Central Asia, is very abundant in many 

 parts of the South of England ; it is rare in the North of 

 England, while in Scotland it is, as in Ireland, entirely 

 absent. In form it is moderately slender, with a blunt 

 and not very prominent snout. The scales round the 



