ANATOMY OF THE BEAVER. 



71 



would lead to the conclusion that both longitudinal 

 and lateral motions were concerned in the grinding 

 operations. 



Fia. 6. 



Stomach of beaver, inside view. One-quarter natural size. 



The insalivation of the dry food of the beaver is 

 provided for by the extraordinary development of 

 the salivary glands. The parotid and submaxillary 

 glands, united, are very large, and cover the front 

 and sides of the neck. The oesophageal membrane 

 is white, thick, and loosely attached to the muscular 

 coat. Where it enters the stomach it has a free 

 fringed margin. The stomach is one of the most 

 peculiar organs of the beaver; it is 10" in length and 

 4" in width, and when filled appears constricted in 

 its middle portion. This is not unusual in the ro- 

 dents, but in the beaver the structure is peculiar. At 

 the cardiac orifice is a gland, or aggregation of folli- 

 cles, through the margin of which the oesophagus 

 passes. This gland is half an inch in thickness and 

 3 inches in diameter. It is composed of compound 

 follicles, which open by 15 or 20 orifices in parallel 

 rows. When the stomach is distended with air. 



