14 ORGANIZATION OP REPTILES. 



capacity, not only by expanding the jaws, but by separating the lateral branches 

 of the inferior maxilla, which are only joined by ligaments.* This structure allows 

 some Serpents to swallow other animals of greater size than themselves. In no 

 animal of this class do we find the mouth provided with fleshy or movable lips, 

 as in the Maimnalia; for the thick fleshy covering of the upper jaw in the Trionyx 

 does not seem to perform the ofiice of lips. The shape and arrangement of the 

 jaws, the form and size of the teeth, and the modes in which they are implanted, 

 ofier interminable varieties, differing in almost every tribe. In some, the teeth are 

 entirely wanting, as in many Batrachian animals; in the Chelonia, their place is 

 supplied by a horny covering to the jaws; in the Sauria, as in the Alligator, the teeth 

 are most perfect, the bony part being hard, with a very thin enamel;t in Serpents 

 they are disposed so as to lacerate the food, or to hold it and prevent its escape 

 from the mouth. The poison fangs form a curious part of the organization of 

 some Serpents, which will be fully explained hereafter. Frogs and Hylas have 

 small pointed teeth in the jaws and palate; these are in a rudimental state, and 

 can only be useful in detaining their prey within the mouth. No Reptiles masti- 

 cate their food; not even the Gopher, which lives on grass and plants; and those 

 of the Chelonia that feed on Shell-fish, only break the shell with their horny man- 

 dibles, but do not chew the animal within. As they do not masticate their food, 

 it follows that their salivary organs must be less perfect than in the Mammalia. 

 Instead of single large glands, as in those animals, destined to secrete saliva, we 

 find in Reptiles numerous small follicles disposed about the tongue and mouth, 

 each one pouring out its secretion by its own proper orifice. The secretion is, 

 strictly speaking, rather mucous than salivary; and being very viscid, it is of great 

 use to many in entangling their prey. 



The tongue in this class of animals, offers the greatest variety, not only as to 

 form and structure, but as to its mode of attachment and powers of motion. In 

 the Chelonia it is short and thick, filling up the lower part of the mouth, and cannot 



* Carus, Vergleich. Zoot. Erst. Theil., p. 153. 

 t Cuvier, Lecons d'Anat. Comp., torn. iii. p. 110. 



