388 



ORGANS OF DIGESTION. 



sions more distinctly marked, as seen in the annexed view of 

 the digestive organs of the mature frog, (125. D.) At the 

 base of the broad bifid, reverted tongue, (125. D. b, e,) is the 

 short wide pharynx, (D. c,) and simple larynx leading to 

 complicated cellular lungs, (D./, /,) and the capacious mus- 

 cular oesophagus and stomach, (D. g,) adapted to receive un- 

 divided prey, are bounded below by a constricted thick 

 pylorus, (D. h,) beyond which the duodenum, (D. n,) is pli- 

 cated internall y with several transverse circular folds of the 



FIG 



...4 



mucous coat, like the valvulae conniventes of mammalia. The 

 form of the stomach is similar in the toads, salamanders, 

 arid tritons, and has the narrow elongated spleen loosely 

 attached to its left side by cellular substance and vessels. A 

 slight pyloric valve is seen in the toad and pipa. The two 

 lobes of the liver overhang the stomach above and before ; 

 the intestine now forms but a few convolutions of inconsider- 

 able width, supported by a distinct and vascular mesentery, 

 (D. m) ; the pancreas, lengthened like the spleen, is situated 

 behind the pylorus, and the short, wide, straight colon, (D. 



