COLUBRIDM 



245 



mice, and guinea-pigs. Thus hypodermic injections of the saliva of 

 the two last-named snakes will cause convulsions and death from 

 failure of respiration in rats and mice. 



Therefore the saliva, though it may not be known to have affected 

 even a child, must be looked upon as poisonous, and the Aglypha 

 must be grouped with the 

 other Colubridae and the 

 Viperidae under the head 

 Thanatophidia. 



The Aglypha are divi- 

 ded into three sub- 

 families : Acrochordinse, 

 Colubrinae frat-snakes), 

 and Dasypeltinae (African 

 egg-eating snakes). 



Some of the important 

 species are Tropidonotus 

 natrix, the common British 

 •' snake, and Coronella aus- 

 triaca, a rare snake found 

 in South England. 



Tropidonotus fasciatus 

 IS the North American water moccasin, Zamenis mucosus the Indian 

 rat-snake, and Dasypeltis scabra is the African egg-eating snake. 



2. Opisthoglypha — Poisonous Colubridae with one or more of 

 the hinder teeth of the upper jaw grooved.— Early last century 

 there was a great controversy as to whether these snakes were 

 poisonous or not, and it is generally stated nowadays that, though 



poisonous, their venom is 

 weak, and that the posi- 

 tion of the poison-fangs 

 at the back of the mouth 

 prevents the bite from 

 hurting man. Quelch has, 

 however, recorded cases 

 in which bites on the 

 fingers from Erythrolam- 

 prus cBsculapii L. and 

 Xenodon severus have 

 caused severe inflamma- 

 tion. 



The following list is given by Faust of those known to be poisonous 

 to animals: Ccelopeltis monspessulans Herm., Trimorphodonhiscutatus 

 D. and B., Tarbophis savignyi Descr., Dryophis prasinus Russl., and 

 Leptodira annulata L. 



The Opisthoglypha are divided into three subfamilies: — 

 (i) DipsadomorphincB — Opisthoglyphida with well-developed mouth, 

 and nostrils situated at the side of the head. — ^They include the Indian 

 tree-snakes. 



Fig. 31. — Skull of Tropidonotus natrix 



LlNN^US. 



All the teeth are solid, there are no grooved 

 or perforated fangs, hence the name Aglypha, 

 but the saliva may be poisonous. Note the • 

 length of the maxilla. 



Fig. 32. — -Skull of Ccelopeltis monspessulans 

 Hermann. 



Note the fangs in the rear of the upper jaw; 

 hence the name Opisthoglypha. These fangs 

 are grooved. 



