250 



ME. W. P. PYCEAPT ON THE MOEPHOLOGT AND 



Pig. 7. 



Cseca of Rhea americana. 



s.i.= small intestine. 

 c. = C£eca. 

 Z.i'.=large intestine, forming 7\?.=rectal loop. 



mesenteric vein. The distal limb of the duodenum presented a short lateral diver- 

 ticulum, and the caeca are relatively longer than in Casuarius, and, as has been 

 described frequently, were marked by the attachment of a spiral valve. But the rectal 

 part of the intestine, that supplied by the posterior mesenteric vein, is expanded into 

 an enormous coil swung at the circumference of a semicircular expansion of its 

 mesentery. Only in Chauna, and in the Eagles and Petrels, have I found the slightest 

 trace of a convergent resemblance to this feature, but in the latter the subsidiary rectal 

 loops, although supplied by the rectal vessel, lie above the cseca." 



According to Beddard the spiral valve of the caeca contains about twenty turns. 

 These cseca, he points out, are furthermore remarkable in that they open into the 

 rectum by a common orifice, thus differing from those of all other birds. 



The cseca of the Tinamous resemble those of Casuarius ; Calodromas elegans, 

 however, affords a remarkable exception, differing as it does in this matter from all 

 other known birds. These cseca have been described and figured by Beddard [6]. 

 They are much wider than usual, and have the outer walls produced into numerous 

 prominent diverticula decreasing in size from behind forwards. 



