IXTESTIXAL TRACT OF MAMMALS. 



191 



and the delimitation of Meckel's tract from the hind-gut is not 

 marked. The mesentery is continuous, and the mesenteric veins 

 are arranged as simple branches of the main channel. 



Text-fisrure 4. 



Intestinal tract of Notary ctes typlilojps. 

 S. Cut proximal end of duodenum. 11. Cut distal end of liind-gut. 

 The mesentery is dotted ; the veins are marked in thick black lines. 



Family Dasyuridfe. Thylacinus cynoce2)halus (text-fig. 5). 

 Sminthopsis crassicaudata. S. larapinta. 



In the Thylacine (text-fig. 5) the pattera does not differ in any 

 important respect from that of I^otoryctes, there being no caecum 

 and the three regions of the gut not being sharply marked ofl', 

 although the grouping of the tributaries of the mesenteric vein 

 suggests their presence. The calibre of the whole gut is rather 

 large and approximately the same throughout. The subsidiary 

 coils of the proximal portion of Meckel's tract are rather more 

 numerous than is represented in the figure. 



The two species of Sminthopsis showed a pattern almost 

 identical with that of Notoryctes. Dr. Beddard (P. Z. S. 1908, 

 p. 561, text-figs. Ill & 113) has described and figured the 

 intestinal tracts of AntecJdnomys laniger and Phascogale mac- 

 donellensis. It is clear that these small Dasyurids display a 

 gut-pattern in all essential respects identical with that of 

 Notoryctea. In the example of Phascogale, however, although 

 apparently full-grow^n, Meckel's tract was so simple a loop that 



