464 ANATOMY OF VERTEBRATES. 



of the abdomen as in most Rodentia ; but it has throughout its 

 course an entire investment of peritoneum. It descends in front 

 of the right kidney for 4 inches, and then suddenly returns 

 upon itself, passing behind the ascending colon, and runs along 

 the middle of the spine as high as the stomach, where it becomes 

 a loose intestine, or jejunum. The small intestines are about 8 

 lines in diameter, and present, internally, a series of about 

 twelve small pouches, distant from 3 to 5 inches from each other, 

 about 3 lines in diameter and the same in depth, their orifices 

 pointing toward the caecum. These pouches make no projection 

 externally, being situated wholly beneath the muscular coat. 

 They consist of duplicatures of the mucous membrane, and are 

 surrounded by the agminate follicles, which open into them by 

 numerous orifices. Their use would appear to be to prevent 

 the secretion of these glands being mixed as soon as formed 

 with the chyme, but, by retaining it, to alter its qualities in 

 some degree. 1 The rest of the inner surface of the small in- 

 testines is beset with long and fine villi. For the extent of 

 about a foot from the commencement of the small intestines 

 I found that many of these villi terminated in a black point. 

 The length of the small intestines is 4 feet 6 inches. 



The caecum is sacculated, and in form like that of the Tapir, 

 its magnitude arising more from its breadth than its length. Its 

 length from the orifice of the ileum is 3 inches, its circumfe- 

 rence 8 inches. The colon gradually diminishes as it leaves 

 the caecum, 4 inches from which its diameter is nearly that of 

 the small intestines : the dilated part of the colon is bent in a 

 sigmoid form, and the remainder is convoluted on a broad meso- 

 colon, and at a distance of 2 feet from the dilated part (when 

 unravelled) terminates between two conical caeca in a second 

 dilated intestine. Each of these lower caeca is an inch and a 

 half in diameter at its base, and gradually contracts till it termi- 

 nates in a glandular vermiform appendage about half an inch 

 long, and 2 lines in diameter. The intestine continued from 

 these is 3 inches in diameter, but also gradually contracts, 

 so that at a distance of 6 inches it also becomes as small as the 

 small intestines. The whole length of this intestine, or second 

 colon, is 2 feet 6 inches ; making the length of the whole 

 intestinal canal, exclusive of the caeca, 9 feet 4 inches, or 

 about six times the length of the animal. Notwithstanding the 

 complexity of the intestinal canal, it is suspended from a single 

 continuous duplicature of the peritoneum advancing from the 



1 cliii". p. 203. 



