1908.] ANTECHINOMYS AND OTHER MARSUPIALS. 575 



of the liver-lobe with the ligamentum cavoduodenale. The two 

 mesenteries were quite continuous. In Echidna also and other 

 types in which this membrane exists, the liver descended to the 

 level of the recurrent duodenal loop, where it was attached by 

 the ligamentum cavoduodenale. In Hyrax, howevei-, the extreme 

 end of the liver is distant from the end of the duodenal loop by 

 a space of fully three inches. There is thixs an impossibility of 

 finding a state of affairs like that described above in Ursus. In 

 Hyrax the duodenum in the ascending limb courses over the 

 right kidney, to which it is firmly attached by membrane ; the 

 same kidney is equally attached to the liver by an hepato-renal 

 ligament. Thus we have a series of membranes connecting 

 the liver with the ligamentum cavoduodenale. Klaatsch has 

 regarded this as the equivalent of the entire ligamentum hepato- 

 cavoduodenale, the arrangement of which with respect to its 

 several elements will evidently depend upon the relative positions 

 of the several viscera concerned. 



(2) The Perinanent Loops of the Colon. — As a rule, with but 

 few exceptions, the Mai-supials possess none of those permanent 

 loops of the colon which have been termed by Tullberg " ansse 

 coli," and by Klaatsch " flexurse coli." This is evident from the 

 figures given by Klaatsch and Mitchell and from the descriptions 

 of others, to some of which I have referred above. Nevertheless, 

 the group is not absolutely to be characterised thus. I have 

 found in one example of Didelphys virginiana a distinct perma- 

 nent loop which was rather wide and lay at a considerable distance 

 behind the cfecum. The specimen in which this occurred was a 

 male, and in a female of the same species there was no such loop. 

 I do not connect the variation with sex, but note its presence 

 as indicative of the commencing formation of these special loops 

 in the Marsupialia. I also observed something of the same kind 

 in an individvial of Trichosurus vuljiecula. Furthermore, in 

 several species of Macropus * (i. e. M. woodumrdi, M. melanops, 

 and M. hageyibecki) the colon shortly after it issues from the 

 caecum and just below the stomach is slightly flexed, and perma- 

 nently so, into a wavy outline of one or two undulations. This 

 again is perhaps to be looked upon as a commencement of the 

 ansfe coli of more highly difierentiated forms. 



The permanent loops of the colon have been described in a 

 gi'eat many mammals and by many zoologists. I have, however, 

 in the course of the past year accumulated a considerable number 

 of facts in this department of anatomy which pai"tly confirm the 

 results obtained by others, are partly new (so far as I am aware), 

 and in some cases enable me to distinguish between already 

 published descrij^tions that do not happen to be in entire 

 harmony. As to the latter section it must be borne in mind 



* Quite possibly in others ; but I have no notes on the point except of the species 

 mentioned above. 



Proc. Zool. See— 1908, No. XXXYII. 37 



