130 THE VITAL FUNCTIONS. 



7. Receptacles for retaining Food. 



PROVISION is often made for the retention of the undigest- 

 ed food in reservoirs, situated in different parts of the mouth, 

 or the oesophagus, instead of its being immediately intro- 

 duced into the stomach. These reservoirs are generally em- 

 ployed for laying in stores of provisions for future consump- 

 tion. Many quadrupeds have cheek pouches for this purpose: 

 this is the case with several species of Monkeys and Ba- 

 boons; and, also, with the Mus cricetus,or Hamster. The 

 Mas busarius, or Canada rat, has enormous cheek pouches, 

 which, when distended with food, even exceed the bulk of 

 the head. Small cheek pouches exist in that singular ani- 

 mal, the Ornithorhyncus. The Sciurus palmarum, or 

 palm squirrel, is also provided with a pouch for laying in a 

 store of provisions. A remarkable dilatation, in the lower 

 part of the mouth and throat, answering a similar purpose, 

 takes place in the Pelican; a bird which displays great dex- 

 terity in tossing about the fish with which it has loaded this 

 bag, till it is brought into the proper position for being swal- 

 lowed. The Whale has also a receptacle of enormous size, 

 extending from the mouth to a considerable distance under 

 the trunk of the body. 



Analogous in design to these pouches are the dilatations 

 of the oesophagus of birds, denominated crops. In most birds 

 which feed on grain, the crop is a capacious globular sac, 

 placed in front of the throat, and resting on the furcular bone. 

 The crop of the Parrot is represented at c, Fig. 299; where 

 also, s indicates the cardiac portion of the stomach, and G the 

 gizzard, of that bird. The inner coat of the crop is furnished 

 with numerous glands, which pour out considerable quantities 

 of fluid for macerating and softening the dry and hard texture 

 of the grain, which, for that purpose, remains there for a 

 considerable time. Many birds feed their young from the 

 contents of the crop; and, at those seasons its glands are 



