OCR Text |
Show 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. The caecum of Erethizon dorsatus. Interior of tbe caecum, showing :-ic, the ileo-CEecal valve ; c, tbe valvular constriction at the commencement of the large intestine; and gl, the line of glands extending between these two apertures. The colic pouch is the rounded 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 1"*5. That of the colon at its first curve (just beyond the pouch of which its proximal end consists) is 3"*3; but 17"*8 (7 inches) nearer the anus it is only 1"*8. The lower portion of the large intestine, however, is smaller in calibre than in the so-called small intestine. The villi 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 |