46 ELEMENTARY BIOLOGY. [CHAP. 



e. The large intestine; cf. Sect. B. 2. d. 



f. The lungs ; apparent as sac-like diverticula of the 

 gullet, immediately in front of the liver (leave 

 them in place). 



2. Lay open the interior of the stomach and duodenum. 

 Wash carefully and examine in water under a hand 

 lens. 



a. The stomach: its lining membrane (mucous mem 

 brane) is smooth and thrown (if the viscus be not 

 distended with food) into a number of irregular 

 longitudinal folds or ruga. 



Note the nature of its contents ; consisting of 

 worms, insects, or other small animals in a partially- 

 digested state. 



If. The duodenum. Note the shaggy nature of its 

 lining membrane; it is sharply marked off from 

 that of the stomach at 



c. the pylorus; a valve-like fold, obvious as a con- 

 striction at the point of junction between a. and />. 



d. The ileum; slit it open and examine under a hand 

 lens. 



a. Its contents; food material in a highly emulsified 

 assimilable condition. 



y3. Its lining membrane; beset by numerous semi- 

 lunar folds (intestinal valves} arranged in parallel 

 series. These may be ill defined. 



e. Open up, in like manner, the large intestine. 



a. Its contents; food material in a dry state, little 

 assimilable and green (fceces). Note that the 

 colour of the same is identical with that of the 

 bile seen in the gall-bladder. 



