Chap. IX.] 



TKEE-SNAKES. 



307 



nized from its bright colour and from the pointed move- 

 able appendage, into which the snout is prolonged. The 

 snakes of this genus being active chiefly during the 

 night, the pupil of the eye is linear and horizontal. 

 They never willingly descend from trees, but iprey 

 there upon nocturnal Saurians, geckoes, small birds and 

 their young ; and they are perfectly harmless, although 

 they often try to bite. It is strange that none of the 

 numerous specimens which it has been attempted to 

 bring to Europe have ever fed in captivity ; whilst in 

 South America they take their food freely in confine- 

 ment, provided that some green plants are placed in 

 their cage. 



In Ceylon I have never seen any specimen of a 

 larger size than three feet ; whilst they are known to 

 attain to more than five on the Indian Continent. 



The inference is obvious, that the green coloration 

 of the majority of tree-snakes has more or less con- 

 nection with their habits and mode of life. Indeed, 

 whenever a green-coloured snake is observed, it may at 

 once be pronounced, if slender or provided with a pre- 

 hensile tail, to be of the kind which passes its life on 

 trees; but if it be short-bodied then it lives on the 

 prairies. There are nevertheless tree-snakes which have 

 a very different coloration; and one of the most re- 

 markable species is the Passerita fusca or Dryinus 

 fuscus, of which a figure is annexed. It closely re- 

 sembles the green Passerita in form, so that natu- 

 ralists have considered it to be a mere variety. It is 

 entirely of a shining brown, shot with purple, and 

 the yellow longitudinal stripe which runs along the 

 side of the belly of the green species, is absent in this 

 one. It is much more rare than the green one, and 



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