450 



ANATOMY OF VERTEBRATES. 



folds of the mucous membrane at the beginning of the colon, 

 and not extending round the circumference of the gut : but the 

 boundary of the ileuin is not defined by any ileo-colic valve nor 

 by any appreciable alteration in the vascularity or other structure 

 of the mucous membrane in the two divisions of the intestinal 

 canal. The inner surface of the colon is smooth, finely reticulate, 

 with a few very narrow transverse folds, from 1 inch to half 

 an inch apart, subsiding for the most part before reaching the 

 attached line of the gut-; these folds are not obliterated when 

 the canal is fully distended ; they commence about 18 inches 

 from the ileum, gradually become shorter and narrower, and 

 disappear about a foot from the rectum. The longitudinal 

 folds of the rectum extend to the margin of the anus, where a 

 little dark pigment is developed under the epithelium. The soft 

 epithelial-covered integument extends from the fore part of the 

 anus to the vulva, which is distant about half an inch. The 

 longitudinal muscular fasciculi of the rectum and rectal end of 



C 1 



the cloaca are strongly marked, and are from one line to one 

 line and a half in breadth. The specimen dissected 1 measured 

 4 feet 7 inches from the snout to the vent : the intestinal canal 

 was 34 feet in length, the large intestines being but 4 feet of that 



extent. 



In the little two-toed Anteater the double caecum reappears : 2 but 

 each is relatively rather longer than in the six-banded Armadillo. 



In the two-toed Sloth ( Cho- 

 loepus) the oesophagus is 

 lined by a dense epithelium 

 disposed in longitudinal 

 folds: it communicates with 

 both the first and the second 

 compartments of the cardiac 

 division of the stomach, fig. 

 354. The first compartment 

 is the largest, and is subdi- 

 vided into a left and right 

 portion ; the left, b, termi- 

 nating below in a short ca3cal appendage, c : its inner sur- 

 face is minutely villous and vascular. The right compartment 

 of the paunch is partially subdivided into a larger left and a 

 smaller right cavity, d, both of which are lined by a continuation 

 of the thick epithelium of the oesophagus, the inner surface of 



1 vni". p. 121, pis. li, lii, and liii. 



2 ' There are two cseca, as in birds,' ccxxxvi. vol. ii. p. 181. 



354 



Stomach of two-toed Sloth, cxxii' 



