INTESTINAL TRACT OF MAMMALS. 501 



of irregular scattered loops, by no means closely set together, and a straighter recurrent 

 portion suspended on an irregularly circular expanse of mesentery. The caecum varies 

 considerably, and shows evidence of being degenerate. In Herpestes griseus (fig. 37, C), 

 for instance, it tapers to a point and is slightly twisted. In H. albicauda it is short 

 and rather wide ; in II. ichneumon relatively longer and very slender. In Suricata it 

 is of moderate length and of even calibre. In Cynictis it is much as in Suricata. In 

 Nandinia it is absent. In Arctitis I found it present, but in a vestigial form, consisting 

 of a minute globular sac, joined to the gut by a hollow narrow stem, whilst, according 

 to Weber and Beddard, it is sometimes absent. In Cryptoprocta it is small and tapers 

 towards the extremity. The hind-gut is usually rather short and shows only traces, 

 which vary in the different genera, of differentiation into colic and rectal portions. The 

 anterior mesenteric vein curves round the Meckelian mesentery, receiving irregularly 

 placed tributaries from the wall of the gut; it is joined by a posterior mesenteric vein 

 from the whole of the hind-gut. 



Family Felidjs. Felis caracal (fig. 38, p. 502), Felis serval. 



In the Felidae the duodenal loop (the figure of the Caracal was drawn after the 

 duodenum had been partly dissected out) is distinct. Meckel's tract is relatively 

 short and is composed of a few very irregular well-separated minor loops, and a 

 straight recurrent portion suspended at the periphery of a nearly circular expanse 

 of mesentery. The caecum is present, but is obviously degenerate. It is always 

 short, and in the Caracal is slightly curved ; in the Serval it is still shorter and is 

 bluntly rounded. The hind-gut is relatively very short indeed, and shows practically 

 no trace of differentiation into colic and rectal regions. The anterior mesenteric vein 

 curves round the Meckelian mesentery, receiving irregularly placed tributaries, and is 

 joined by a posterior mesenteric vein from the hind-gut. 



The general features of the Carnivora, as a whole, are the great preponderance of the 

 fore-gut over the hind-gut, and the reduction of the latter region and of the caecum. 

 The Finnipedia are clearly marked off by changes, probably adaptive, in the Meckelian 

 tract. Between the Arctoid and Herpestoid divisions it is difficult to discriminate so 

 far as the characters of the intestines are concerned. The caecum, which is obviously 

 degenerating in the whole group, cannot be taken as a useful character from this point 

 of view. It is absent, it is true, in all the Arctoids except the Canidae, but in the 

 latter it is larger than in any other Carnivora, whilst in some of the Herpestoids it is 

 always absent (Nandinia) or occasionally absent and always small in Arctitis. In the 

 Arctoids, as a whole, it may be said that Meckel's tract is relatively longer and more 

 complicated, but, on the other hand, in Hyama it is conspicuously long. The hind-gut, 

 which appears to be in process of reduction in the group, is without doubt shorter and 

 less differentiated in the Herpestoids than in the Arctoids. 



vol. xvn. — pakt v. No. 9. — December, 1905. 3x 



