92 



SIR JOSEPH PAYPKP, K.C.S.T.. ETC. 



Deglutition is effected in a peculiar way ; the prey being 



seized, the mouth gapes laterally and vertically, each side of 

 the jaws is called separately into action; the sharp and 

 recurved teeth hold the prey firmly, as each side of the jaw 

 alternately advances or relaxes its grasp, and it is thus 

 gradually but inevitably engulfed. 



The maxillary bones in the venomous snakes are much 

 shorter, and provided with fewer teeth than in the innocent. 

 In the latter, they are elongated slips of bone set with small 

 recurved teeth. In the poisonous colubrine snakes they are 

 less elongated and have a fixed, large poison fang several 

 loose, reserve fangs, and one, two, or more fixed smaller 

 teeth, not directly connected with the poison apparatus. In 

 the Viperidae the maxillary bone is a short, triangular, 

 movable wedge, furnished with a poison fang lying hidden 

 in the mucous sheath. The movements of the fang are due 

 to the rotation of the maxillary bone. This mobility is great 

 in vipers, whilst it is slight in the colubrines. 



When the fang is reclined or erected, the maxillary bone 

 into which it is inserted is pushed by the external pterygoid 

 bone, a movement which is effected by muscular action. 

 The muscular arrangement for opening and closing the mouth 

 at the same time compresses the poison gland, thereby inject- 

 ing the venom through the tubular fang. The fangs are shed 

 at intervals, and to supply the loss, the reserves are pro- 

 vided. These lie in the capsule of mucous membrane which 

 ensheathes the fang. The fang is, during development 



II. 



Cobea di Capello (Naja Tri/pudians) . 



A Poison "land. 

 B Duct. 

 C Fang. 



