VENOM 237 



in some of the Viperidce these two openings are connected 

 by a fine seam marking the line of closure of the edges 

 of the groove. In some rare cases the fang is not grooved 

 at all. 



In repose the poison-fangs are more or less obliquely 

 recumbent, and are more or less concealed in a sheath 

 of mucous membrane ; in action they are erected by 

 the rotation of the maxillae, which is particularly free in 

 the Viperidce, though quite limited in the Colubrines. In 

 some Elapines and sea-snakes the poison-fangs are small ; 

 in some of the big Viperidce they are over an inch long. 



In rear of the poison-fangs, and in the same mucous 

 sheath, is a bunch of " reserve " fangs ; in the Viperidce 

 there are no teeth in the maxilla, except the fang and its 

 reserves; but in most venomous Colubridce there are 

 additional small teeth, which may either be grooved or, 

 more commonly, simple. It is to be understood that 

 the canal of the poison-fangs has nothing to do with the 

 pulp-cavity, which lies, as usual, in the body of the tooth. 



The venom is forcibly ejected through the fangs by 

 the act of biting. When a snake bites it lays hold like a 

 bulldog, the muscles of its jaws can be seen vigorously 

 working, and in many snakes the venom is effectively 

 injected only in this way. But it is also certain that in 

 some cases particularly, according to Dr. H. E. Arbuckle, 

 in the viper Causus rhombeatus the gland itself is con- 

 tractile, and is capable, when artificially stimulated in the 

 unconscious snake, of ejecting its secretion through the 

 fang. This may explain the accounts of snakes that spit 

 poison; although it is possible that in these " spitting 

 snakes " it may be the secretion of the labial glands that 

 is spurted out. At any rate, it is stated that C. rhombeatus 

 dribbles poison from its fangs, and that some of the 

 Indian and African Colubrines can spit venom. 



The amount of venom spent at one act varies according 

 to species, from two or three drops in some sea-snakes to 

 thirty drops in a large ' king cobra " ; of course in any 

 given species the amount depends upon the size of the 



