1882.] 



ANATOMY OF ERETHIZON DORSATUS. 



275 



of the liver ; a conspicuous fold of small intestine lay towards 

 the right side of the hinder part of the abdominal cavity, while 

 the voluminous caecum occupied its middle and part of its hindmost 

 portions. 



The small intestine measured 13 feet 3 inches. The large intestine 

 measured 10 feet 9 inches — the whole intestine thus measuring 24 

 feet. 



The diameter of the duodenum at its commencement is 3"'3 ; but 

 at 2""5 (1 inch) from the pyloric valve it contracts to 2". 



Fig. 4. 



■ 'r>m, 



The caecum of Erethizon dorsatus. 



Interior of the caecum, showing : — ia, the ileo-csecal valve ; c, the valvular con- 

 striction at the commencement of the large intestine ; and gl, the line of 

 glands extending between these two apertures. The colic pouch is the 

 roimded prominence just beneath the letter c. The glands enlarged are 

 figured separately. 



The diameter of the ileum about 2"-.5 (1 inch) from the ileo-caecal 

 valve is l"-5. That of the colon at its first curve (just beyond the 

 pouch of which its proximal end consists) is 3"*3 ; but I7""8 (7 

 inches) nearer the anus it is only 1"'8. 



Tbe lower portion of the large intestine, however, is smaller in 

 calibre than in the so-called small intestine. 



Tiie vilU of the small intestine are short, but delicate and close- 

 set. There are a few solitary glands in the large intestine. 



In the small intestine there are seventeen Peyer's patches — nine 

 large and oval, and eight exceedingly small. 



In the first five feet of the large intestine there is a series of 

 glands, from 1"'2 to 3"-8 apart, situated along the free margin of 



