248 ME. ~W. P. PYCEAFT ON THE MOEPHOLOGY AND 



of the vomer. It can be readily prepared in a well-macerated skull by carefully 

 removing the vomer. It was first described by W. K. Parker [77] in Rhea. 



THE ALIMENTARY CANAL. 



Buccal Cavity. 



The buccal cavity of the Palceognathce presents one noticeable feature wherein it 

 differs from that of the Neognathce (PI. XLV. fig. 1) : since, in the former, the 

 posterior nares, or choanse, form a wide, open, more or less cordiform aperture, divided 

 by a median septum into right and left lateral moities ; in the Neoc/nathw the 

 choanse are slit-like. The Eustachian aperture lies immediately caudad of the choanse. 



In all the Palceognathce the tongue is more or less vestigial. The glottis is also 

 a relatively wider aperture than in the Neognathce. In Casuarius the tongue has a 

 denticulate free edge. 



The Convolutions of the Intestine. 



Dr. Gadow, in his paper "On the Intestinal Convolutions in Birds" [26], considered 

 the flightless members of the Palceognathce a very heterogeneous group, because of 

 the great diversity in the length and arrangement of the main gut and in the develop- 

 ment of the cseca. " In none of these birds has it come to the development of closed 

 and well-developed loops of the mid-gut (with the exception of the duodenum). In 



this respect they represent the lowest type amongst the recent birds Their 



connections with recent Carinatee are distant. Nearest of them to the latter comes 

 Apteryx through more defined loops, and the Crypturi seem to represent the link. . . . 

 All the Archceopalatince agree with each other in having the second loop right-handed 

 and the third left-handed ; this is a feature which occurs again only in the Crypturi, 

 Gallince, Opisthocomus, and in the Cuculidce!' 



Amongst the Neognathce, it will be remembered, Gadow was enabled to demonstrate 

 a greater harmony, the convolutions of the intestines being always referable to one of 

 seven types. 



Dr. Gadow's conclusions, it should be remarked, are based upon a study of the 

 coiling of the intestines within the body-cavity. 



Mr. Mitchell [60], who approached the study of the intestinal tract from a different 

 point of view, viz., after its removal from the body, and the severance of certain 

 vessels and secondary connections, which reveal the nature of the convolutions of the 

 gut along its attachment to the ventral border of the dorsal mesentery, and the 

 position of the diverticulum caecum vitelli and its relation to the middle mesenteric 

 vein, entirely confirms Dr. Gadow's conclusions as to the primitive nature of the 

 Palceognathce. judged by this standard. He remarks : — " It is plain that, so far as 



