VENOMS 



rIV 



from 35 — 40 small, backwardly curved teeth ; the other internal, 

 the palatine, which only numbers from 20 — 22 teeth, having the 

 same curvature (fig. 1, a). 



In the poisonous snakes 

 the maxillary bones are 

 shorter, and the outer row 

 is represented by a single 

 long and tubular or 

 grooved tooth (the fang), 

 fused with the maxillary 

 bone, which is itself mov- 

 able (fig. 1, B, c, D, E, f). 



Certain species {Dip- 

 sas) have maxillary teeth 

 which increase in size 

 from front to rear; the 

 longest teeth are grooved 

 and serve for the better 

 retention of prey, and also 

 to impregnate it with 

 saliva; but they are not 

 in communication with the poison-glands. 



The poison-fangs are normally covered 

 with a fold or capsule of mucous membrane, 

 in which they are sheathed. This fold con- 

 ceals a whole series of reserve teeth in 

 different degrees of development, which 

 eventually become attached to the extremity 

 of the maxillary when the principal tooth 

 falls out or is broken (fig. 2). 



Poison Apparatus. — The grooved or fur- 

 rowed teeth in the Proteroglypha and the 

 canaliculate teeth in the Solenoglypha are 

 arranged, not for the purpose of seizing 



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Fig. 2. — a, Maxillary bone and fangs of one of 

 the Yvperiicb ( Yvgera russellii) ; B, maxillary bone 

 and fangs of one of the ColubridcB (Naja tripu- 

 dians) ; c, maxillary bone and fangs of one of 

 the Colubridcs {Bungarus fasciatus) ; d, maxillary 

 bone and teeth of one of the non-poisonous Colu- 

 bridcB (Ptyas mueosus). (After Sir Joseph Fayrer.) 



Fig. 3. — a, Fang of one 

 of the Viperidis {Vipera 

 russellii) ; D, transverse sec- 

 tion of the fang. 



