STOMACHS OF MAMMALIA. 171 



The stomach of the Water Rat is composed of 

 two distinct cavities, having a narrow passage of 

 communication : the first cavity is lined with cu- 

 ticle, and is evidently intended for the maceration 

 of the food before it is submitted to the agents 

 which are to effect its digestion ; a process which 

 is completed in the second cavity, provided, for that 

 purpose, with a glandular surface. 



In proportion as nature allows of greater latitude 

 in diet, we find her providing greater complication 

 in the digestive apparatus, and subdividing the 

 stomach into a greater numbsr of cavities, each 

 having probably a separate office assigned to it, 

 though concurring in one general effect. A grada- 

 tion in this respect may be traced through a long 

 line of quadrupeds, such as the Hog, the Peccari, 

 the Porcupine (Fig. ,308), and the Hippopotamus, 

 where we find the number of separate pouches for 

 digestion amounting to four or five. Next to these 

 we may rank the very irregular stomach of the 

 Kavgvroo (Fig. .'309), composed of a multitude of 

 cells, in which the food probably goes through 

 several preparatory processes ; and still greater 

 complication is exhibited by the stomachs of the 

 Cetacea, as, for example, in that of the Porpus 

 (Fig. 310). As the fishes upon which this animal 

 feeds are swallowed whole, and have large sharp 

 bones, which would injure any surface not defended 

 by cuticle, receptacles are provided, in which they 

 may be softened and dissolved, and even converted 

 into nourishment by themselves, and without inter- 

 fering with the digestion of the soft parts. The 

 narrow communications between these several sto- 

 machs of the Cetacea are probably intended to 



