280 REPTILES OF THE WORLD 



a lizard quicker than an Elapine or Viperine snake of 

 the same bulk. 



The Opisthoglypha is a cosmopolitan division. In 

 the New World the members are confined to the warmer 

 latitudes — from the extreme southern part of the United 

 States through the tropics. In the Old World they 

 range farther into the temperate regions. 



Poisonous River Snakes; Homalopsince: In rela- 

 tion to the Opisthoglypha, this subfamily occupies the 

 same position as the Aglyphous Acrochordince. The 

 species are entirely aquatic, with valvular nostrils on 

 the upper surface of the snout, and small eyes — the pupil 

 vertical. The greater number have very narrow ab- 

 dominal plates. All are viviparous. Their aspect is 

 as ugly as their temper. Rivers and bays of the East 

 Indies from Bengal throughout Malaysia to North 

 Australia are inhabited by representatives of the twenty- 

 three species. In the harbors of Cochin China and 

 Siam is found the most interesting of these serpents, 

 Herpeton tentaciilum, having two tentacles on the snout. 

 Occasional members of the Homalopsince are seen well 

 out to sea. They may be told from the deadly repre- 

 sentatives of the Hydrophiinai by the rounded tail — not 

 broadly-compressed or paddle-like. The various spe- 

 cies feed upon fishes. When the prey is seized, the jaws 

 grip it in chewing fashion until the fangs have been 

 well imbedded. Thus holding the prey, the reptile sinks 

 leisurely to the bottom. Within a few minutes the fish 

 is helplessly benumbed by the poison. Even though it 

 be provided with long, spiny fins, the muscles of these 

 become perfectly inert. Seizing it by the head, the 

 snake swallows it without difficulty, as the bristling fins 

 fold against the body of the prey as deglutition goes 

 on. 



