332 



ZOOLOGY 



SECT. 



T 



constitute its food. The tongue in Snakes is slender and bifid, 

 capable of being retracted into a basal sheath, and is highly sensi- 

 tive, being used chiefly as a tactile 

 organ. The tongue of the Croco- 

 dilia (C) is a thick immobile mass 

 extending between the rami of the 

 mandible. In some of the Chelonia 

 (B) the tongue is immobile ; in 

 others it is protrusible, sometimes 

 bifid. 



In the enteric canal of the 

 Reptiles the principal special 

 features to be noticed are the 

 muscular gizzard-like stomach of 

 the Crocodilia, the presence of a 

 rudimentary coecum at the junc- 

 tion of small and large intestines 

 in most Lacertilia and in the 

 Ophidia, and the presence of 

 numerous large cornified papilloe 

 in the oesophagus of the Turtles. 



Organs of Respiration. The 

 Reptiles have all an elongated 

 trachea, the wall of which is sup- 

 ported by numerous cartilaginous 

 rings. The anterior part of this is 

 dilated to form the larynx, the 

 wall of which is supported by 

 certain special cartilages the 

 cricoid and the arytenoids. The 

 trachea bifurcates posteriorly to 

 form two bronchi, right and left, 

 one passing to each lung. In some 

 of the Chelonia its lumen is divided 

 internally by a vertical septum. 

 The lungs of the Lacertilia and 

 . Ophidia are of the simple sac-like 

 character already described in the 

 case of the Lizard. In .some the 

 lung is incompletely divided in- 

 ternally into two portions an an- 

 terior respiratory part with saccu- 

 lated walls, and a posterior part 

 with smooth, not highly vascular 

 walls, having mainly the function 

 of a reservoir. The only additional complication to be specially 

 noted is the presence in the Chamaeleons (Fig. 943) of a 



FIG. 943. Lungs of Chamaeleon. 

 trachea. (From Wiedersheim.) 



