222 MR. F. E. BEDDARD ON THE [Feb. 1, 



descending direction. Its origin from the small intestine — 

 though, as is well known, there is no caecum — is quite marked, 

 and cannot be missed. This descending origin is decidedly on 

 the left side of the body, the origin of the duodenum on the 

 right side really occupying the position so often seen in mammals 

 to be occupied by the caecum. The first part of the colon is quite 

 loosely arranged, and although six tolerably regular folds are 

 figured by Gratiolet, it must not be inferred from the stress 

 laid upon these folds by him and by Flower, that they are 

 definite entities. On the contrary, the colon is in this region 

 entirely lax and can be passed through the fingers in a perfectly 

 straight line without in the least damaging the mesocolon by 

 which it is suspended. There is, in fact, no really definite 

 series of colic loops. The colon happens to lie in this way or 

 that to meet the conditions of space ; but it is as free from any 

 ansae coli as is that of the Primates or the Marsupialia, &c. 



We have to note therefore, in the first place, that Hippo- 

 potamus in the arrangement of the gut is more primitive than 

 is any other Artioclactyle, or indeed than any other Ungulate, 

 excepting perhaps the Elephant. In surveying the various Orders 

 of Mammals with reference to the coiling of the gut *, I was 

 unable to find any Artiodactyle which had not a very specialised 

 gut. Even Tragulus, which lies near to the base of the series, 

 so far as living Artiodactyles are concerned, showed all the typical 

 artioclactyle features in the arrangement of its colon and in 

 the permanent loops thereof. The animal therefore furnishes 

 additional, evidence in favour of the contention that the gut 

 undergoes an evolution in separate groups, the stages being in all 

 cases the same in general outline. A knowledge of the intestinal 

 tract of the Hippopotamus thus fills a very considerable hiatus 

 in what is known concerning the group of Artiodactyles. 



It is, however, important to notice that while the gut of the 

 Hippopotamus represents Stage II. among the Artiodactyles f, 

 a stage which has been hitherto missing in that group, there is 

 not a precise correspondence between the gut and that of, for 

 example, a Kangaroo which represents the same stage. The 

 intestinal tract of Hippopotamus is distinctively Artiodactyle, or 

 at least Ungulate, in various features to which I now shall 

 direct attention. In the first place, the position of the vanished 

 caecum is on the left side of the body, and the colon therefore 

 commences by passing in a downward direction. This is precisely 

 what we find in other Ungulates, for example in Hyrax%. The 

 second feature of importance in which the gut shows an Ungulate, 

 and this time a distinctively Artiodactyle, character, is in the 



* " On the Anatomy of Antecltinomys, &c," P. Z. S. 1908, p. 561. 



f I am not absolutely certain whether the gut of Hippopotamus may not really 

 belong to Stage I. Gratiolet speaks of a continuous mesentery for both small and 

 large intestine. Unfortunately my own notes are defective as to this point. 



J See Beddard, " On the Anatomy of Antechinomys, &c," P. Z. S. 1908, p. 582, 

 fig. 115. 



