680 



MR. F. E. BEDDARD ON THE 



[June 16^ 



Rana demands attention before its homologies can be thus rapidly 

 disposed of. Where this tube arises from the undoubted stomach 

 there is no valve or change of a sudden character in its lining 

 membrane. Furthermore, the pancreas does not extend down 

 into the V-shaped loop which it makes with the stomach, and the 

 ducts of liver and pancreas open into the alimentary tract farther 

 up this ascending limb of the gastric U than they are represented 

 to open in Rana*. I am disposed in fact to assign the greater 

 part of this ascending limb— the first deflection from an antero- 

 posterior course which the whole alimentary tract shows — to the 

 stomach. Its lining membrane has quite the characters of that of 

 the lining membrane of the latter half of the undoubted stomach. 



Text-fig. 143. 



Alimentary tract of RJiinoderma darivini partly opened to show folds of 

 lining membrane. 



St. Posterior boundary of stomach. II. Ileum. 



It is very thick and arranged in close longitudinal folds which 

 undergo no change where the tube suddenly lessens in calibre. 

 Later on, a tendency to a reticulate arrangement also observable 

 anteriorly becomes rather more marked. This thick layer 

 suddenly ends near the top of the ascending limb of the V already 

 referred to as characteristic of this and (? all) other frogs. There- 

 after the walls of the gut are thin for a considerable distance and 

 the lumen is perhaps slightly wider. The inner surface is very 

 definitely reticulate in a honeycomb fashion. The break between 



* Haslam's Translation of Ecker's 'Frog,' p. 296, fig. 195, Dc^. 



