230 



VERTEBRATE ZOOLOGY 



The digestive system varies somewhat in carnivorous and her- 

 bivorous forms, but in all turtles is comparatively simple. The tongue 



wr 



pr-m 



*7 



FIG. 131. Skull of turtle. A, lateral; B, ventral view. 6s, basisphenoid; //, 

 frontal; j, jugal; m, maxilla; ob, basioccipital; ol, exoccipital; op, opisthotic; os, 

 supraoccipital; pal, palatine; par, parietal; ph, postfrontal; prfr, prefrontal; pt, 

 pterygoid; prm, premaxilla; q, quadrate; qj, quadrate jugal; , squamosal; v, 

 vomer. (From Parker and Haswell, after Hoffmann.) 



is broad and soft and cannot be protruded. The stomach is a simple 

 U-shaped enlargement of the alimentary tract. The intestine is with- 



