42 ON THE PHYSIOGNOMY OF SERPENTS. 



to detain their prey, and to assist deglutition. Inde- 

 pendently of these functions, the teeth often conduct into 

 the wounds, which they make a liquor, secreted by glands 

 lodged in the head. These glands are of two kinds : the 

 one, like the salivary glands of mammals and birds, is 

 composed of numerous small grains, Avhich secrete a fluid 

 similar to saliva, intended to prepare nutritious substances 

 for digestion ; the others have a different structure : they 

 form a thick sac, the interior of which is divided into 

 numerous compartments : they distil a liquor which, 

 by the deadly effects it can produce in the animal body, 

 becomes the fatal implement, by means of Avhich ser- 

 pents kill the animals which serve for their support. The 

 salivary glands are the property of all Ophidians ; but 

 scarcely a fourth part of the known species are also pro- 

 vided with the poison glands. The teeth, which conduct 

 the poison into the wounds, are always hollow, and, per- 

 forated at both ends, are called fangs : these are al- 

 ways placed at the anterior end of the maxillary bone, 

 where tliey are fixed, and often are its only occupants : 

 concealed in the gums, which here form a sort of sheath, 

 they are recumbent, while the snake is in a state of re- 

 pose, but are elevated when he intends to bite. The rest 

 of the teeth, and all those of non-venomous serpents, are 

 solid, with the exception of the cavity that contains the nu- 

 tritive organs of the tooth. It is observed, however, that 

 a considerable number of non-venomous serpents of differ- 

 ent genera have jaws provided with one or two teeth 

 larger than the rest, and generally grooved by a canal, ex- 

 tending along theu' anterior face. These channelled teeth 

 always are found at the posterior part of the maxillary 

 bone ; and we but rarely fuid a second in the middle of 

 the jaws : they have no other function than pouring into 

 the wounds they make a more copious saliva, secreted by 

 the posterior salivary glands, w^hich are most voluminous 

 in the region occupied by those channelled teeth.* 



* It is erroneous to class with venomous serpents those snakes which 

 have long and channelled posterior teeth. Vague and contradictory ac- 

 counts of the qualities of Ophidians, furnished by the natives of Java, 

 have probably caused this mistake. In the Indies, as in Brazil, in 



