EPIDERMAL APPENDAGES. 325 



to South Africa {Lophophrys) has a bunch of irregular and 

 much shorter horns standing erect and apparently unpaired. 

 Incipient horny scales often accompany the regular pairs, 

 making it difficult to decide exactly which was Pliny's of the 

 * four horns/ and which is the Hcxacornis of Shaw. Varieties 

 exist and add to the perplexity ; probably also hybrids occur 

 among these as among non-viperine snakes. 



A curious variety of the nasal appendages appears in the 

 Langaha with the crete de ccq ; only the crest is on the 

 snout instead of on the head. 



These spurs are merely 

 modifications of the epidermis 

 like the rest ; but are, no 

 doubt, endowed with peculiar Vxo^\& oi Langaha. 



sensitiveness, so that possibly they act as a sort of herald 

 in the dark, like a cat's whiskers. 



There are the pointed-nosed Dryophidians also, with 

 scaly protuberances, and others with variously-elongated 

 snouts terminating in long, scaly, horn-like appendages, all, 

 no doubt, more or less sensitive, to enable the owners to 

 feel their way, or ascertain the nature of their surroundings, 

 especially if they are of nocturnal habits. 



In some of the tree snakes, 

 notably Passerita, there is 

 no appendage, but the long 

 snout is itself endowed with vrofiic oi Passerita. 



mobility. This is a nocturnal snake ; a harmless and 

 exceedingly slender, graceful creature. 



But of these curious developments or prolongations, one 

 of the Indian fresh -water snakes presents a remarkable 



