INTESTINAL TEACT OF MAMMALS. 471 



Iu Babimssa babirussa (fig. 48, I, p. 520) the structure still more closely resembles 

 that of the Pig. The duodenum is a distinct simple loop. Meckel's tract is enor- 

 mously long and thrown into regular closely-packed folds ; the proximal portion of 

 the hind-gut and the rectum are practically identical with the corresponding regions 

 in the Pig. To the peculiarities of the caecum I refer later (p. 519). In the Pigmy- 

 Hog, Porcula salvania, the pattern is in the main similar to that of the Common Pig, 

 the spiral coil being extremely well marked. 



Excluding the Hippopotamidce, on which I have not sufficient information, it is 

 clear that the gut-pattern of the non-ruminant Artiodactyla is definite, the charac- 

 teristic features being the length and simplicity of Meckel's tract, the short wide 

 caecum, and the expansion of the anterior portion of the hind-gut into a very long and 

 extremely capacious single loop, coiled into an elongated spiral and with the proximal 

 portion of the loop much wider than the distal portion. 



Sub-Order TRAGULOIDEA. 



Family Tragulid^e. Tragulus meminna (fig. 19, p. 472). 



In the Ruminant Artiodactyles the total length of the intestinal tract is relatively 

 great. The increase compared with the groups which I have already considered is 

 almost entirely in the hind-gut, the complications of which are characteristic. The 

 increased length of this region and its mode of folding in the body-cavity has led to 

 considerable alteration of the mesentery, with the result that when the tract is 

 laid out in a fashion to display its pattern the mesentery has been cut or torn in a 

 number of regions. The Chevrotain, of which I have examined several individuals all 

 belonging to the common Indian species, displays the Ruminant Artiodactyle pattern 

 in a simple form. There is no distinct duodenal loop. Meckel's tract is much 

 elongated, and is suspended iu a number of simply-placed folds at the periphery of 

 a semicircular expanse of mesentery ; distally these folds shorten and the recurrent 

 portion of the tract is nearly straight, passing nearly at right angles into the relatively 

 short and wide caecum (fig. 19, C). In the actual figure the width of the caecum and 

 of the portion of the hind-gut with which it is continuous is slightly underestimated. 

 The hind-gut displays three well-marked regions. The most proximal (S.P. in fig. 19) 

 is a short narrow loop coiled into a loose spiral of about two turns. This is the 

 simplest form in which the spiral watchspring-like coil of the hind-gut of Ruminants 

 appears. It lies folded back over the central portion of the mesentery of Meckel's 

 tract ; but in the Chevrotain the connection is very slight, and the loop may be folded 

 back with almost no dissection. Next follows a longer loop (S.F. in fig. 19). In the 

 living animal this is applied closely to Meckel's tract lying just where the minor loops 

 of that start from the mesentery. It corresponds with the similar fold which I have 

 described in other Mammals, and it is in intimate connection with the mesentery and 



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