506 



STEUCTURE AND CLASSIFICATION OF BIRDS 



cassowary, but the duodenal loop was strong, longer, and 

 narrower. It is interesting to find from Mitchell's paper 

 that the intestine of Bhea is somewhat intermediate between 

 that of Struthio and that of Casuarius. ' The anterior portion 

 resembled Casuarius ; the rectum had an expansion recalling 

 that in the ostrich, but much less strongly marked.' 



The following table contains measurements of the ali- 

 mentary tract ^ in the Struthiones : — 



All the Struthiones have cseca, which are especially deve- 

 loped in the ostrich, where they have been described by Sir 

 EvERARD Home as well as by Gadow. Apart from their 

 length and structure the most remarkable fact about them 

 is that, in contradistinction to what we find in other birds, 

 they are inserted by a common orifice. 



These cseca dwindle gradually in diameter towards the 

 tip, and are provided internally with a spiral valve of about 

 twenty turns. I have attempted to compare these cseca with 

 those of the Martineta tinamou (see p. 488) . In the latter 

 bird the cseca are furnished with numerous short diverticula, 



' E. Bemocohamps, ' Sur la Glande Gastrique du Nandou,'' Btdl. Ac. Belg. L 

 <1880), p. 114. 



