314 THE I^ATTJEAL HISTOEY EEVIEW. 



them it is necessary to dig for them to a depth of four feet in the 

 ground!" 



The Calamariidae or Dwarf Snakes, which next follow, are likewise 

 a characteristic family of Indian Herpetology. They are all of small 

 size, live on the ground, and feed principally on insects and worms. 

 Moreover, they are very gentle and never attempt to bite ! The 

 Oligodontidae are likewise peculiar to the Indian region — one of the 

 two genera (Simotes) being very numerous in species. The Colubridae, 

 which next follow, are on the other hand very widely diffused, being 

 found all over the world, and being likewise very numerous in India. 

 Sixty-nine species of this family are treated of by Dr. Giinther, who 

 divides them into five sub-families, each of which is well distin- 

 guished by peculiarities of mode of life, as well as of structure. The 

 last of the four sections, the Natricina, in their water- loving pro- 

 pensities, form a transition to the next following family, the Homa- 

 lopsidse, which are thoroughly aquatic in their habits, and only 

 occasionally found on shore. Several of them even enter the sea, and 

 in some points show resemblance to the truly marine Hydrophiidse. 

 Perhaps the most singular of them, and indeed one of the most 

 outre forms in the whole series of Ophidians is the Herpeton tentacu- 

 latum* of Siam, which is remarkable for two flexible, cylindrical, scaly 

 tentacles, which terminate its snout, and are supposed to serve 

 as organs of touch in the water or mud, and to save the necessity of 

 exserting the tongue. Dr. G iinther was formerly inclined to remove 

 this snake from its present position to the neighbourhood of Acro- 

 cTiordus. But he now acknowledges that it was rightly assigned 

 by Prof. Schlegel to the Homalopsidae. 



The Psammophiidse, or Sand-snakes, are an African group, of 

 which two species occur in India. The Dendrophiidse, or Tree- 

 snakes, are generally distributed throughout the tropics, living on 

 trees, as their name imports, and feeding principally on tree-lizards. 

 Eight species of the group are contained in Dr. Giinther' s work, 

 amongst which is Clirysopelea ornata — perhaps the most beautifully 

 coloured species in the whole group of Ophidians. The slender- 

 bodied "Whip-snakes (Dryophiidse) are likewise arboreal in their 

 habits, and bright in their colours, and generally distributed in 

 tropical countries. They are, however, nocturnal in their mode of 

 life as are the next succeeding family, the DipsadidsB, of which 



* See P. Z. S. 1860, p. 113, pi. xxiii. 



