SCALED REPTILES SNAKES. 423 



name of Opisthoglypha from the circumstance that either one or several pairs 

 of teeth in the hinder part of the upper jaw are traversed by a longitudinal 

 groove for the purpose of conveying poison from the secreting gland. 

 Whereas all are more or less noxious, many are deadly. In habits and form 

 many of these curiously simulate the members of the first section of the family. 

 The ^roup is but poorly represented in Europe, but among the Continental 

 species is the so-called cat-snake (Tarbophis vivax), forming a genus by itself. 

 This snake belongs to a sub-family of the section the Dipsadomorphince, in 

 which the nostrils are always situated on the sides of the muzzle. It frequently 

 grows to a yard or so in length, and is grey or brownish-yellow in general 

 colour, with various dark spots and blotches, and a chestnut patch on the 

 head-shields. It is fond of warm sunny spots among rocks, where it feeds 

 chiefly on lizards, which it kills by the injection of poison. The typical repre- 

 seiitalivesof the sub-family are the arboreal snakes of the genus Dipsadomorphus 

 which are widely spread through the warmer regions of the Old World, where 

 they have precisely the same mode of life as the arboreal forms included in 

 the section Aglypha. In colour they incline to black and brown, while in 

 length they may exceed a couple of yards. Many of them, at least, are 

 purely nocturnal snakes, and whereas some feed on birds, others prey almost 

 or quite exclusively on the smaller kinds of mammals. Occasionally they 

 descend from their leafy haunts to wander on the ground. Of similar habits 

 arc the Indian whip-snakes (Dryophis), in which the somewhat compressed 

 body and tall are remarkable for their extreme length and slenderness. This 

 ha bit of body enables these snakes to curl their tail tightly round a bough, 

 whence they strike to a long distance at any passing prey. Here, too, 

 belongs the Tropical American and West Indian genus Philodryas, which in- 

 cludes a considerable number of arboreal species, characterised by the green 

 tone of their coloration. This genus is also represented in Madagascar. The 

 number and arrangement of the teeth 

 form important features in the distinc- 

 tion of these genera of tree-snakes. In 

 the present section the place of the 

 water-snakes among the section Agly- 

 pha is taken by the fresh-water snakes 

 of the genera Homalopsis and Cantoria, 

 which range from India to New Guinea 

 and the North of Australia. These 

 snakes, few of which grow to more than 

 a yard in length, are far more aquatic 

 in their habits than the species of 

 Tropidonotus, and but seldom leave 

 the water at all ; and some of them 



even descend rivers to enter the sea. Fig> 2 ^T THE CORAL-SNAKE 



Their food consists of fish and other (Elaps corallinus). 



aquatic creatures ; and they give birth 



to living young while in the water. A considerable number lie in wait for 

 their prey by anchoring themselves to roots or sunken branches by means of 

 the prehensile tail. 



In snakes, beauty and venom frequently go together, and an excellent 

 instance of this association is afforded by the coral-snake (Elaps corallinus} of 

 South America and the West Indies. Together with the remaining members 

 pf the colubrine family here noticed, the coral-snake belongs to the section 



