ALIMENTARY TRACT OF CERTAIN BIRDS. 



69 



I have dissected one example of the New World Vultin-e, 

 Gypagvbs papa, whose intestinal tract I am able to compare with 

 that of Cathartes aura described by Mitchell. In view of the 

 fact that the American Vultures have been regarded by many 

 systematists as being quite remote in their affinities from the Old 

 World Vultures, indeed from the Accipitres generally, it is 

 very important to bring together all contributions that are possible 

 towards settling this vexed question. The duodenal loop differs 

 from that of Cathartes anrl is, indeed, quite like that of Falco 

 feldeggi figured by Mitchell*. The distal extremity is folded over 



Text-fig. 20. 



Inteslinal tract of Spizaetus bellicosus. 

 Lettering as before. 



upon itself in a fashion that does not appear to occur among 

 Picarian birds. The jejunal loop is arranged in a spiral fashion like 

 many birds, including, however, Tinnunculus, in which Gypagus 

 appears to difier from Cathartes. The ileic loop is simple. The 

 kink so characteristic of Accipitres (but also found in other birds, 

 including Bucorvus) above the position of the caeca in other birds 

 is present as in Cathartes. It is not, in fact, possible to locate 

 Gypagus definitely in the sj^stem. 



I have also examined Cathartes aura (see text-fig. 21), and in 

 most matters I am able to confirm Mitchell, as will have been 



* Trans. Linn. Sec. t. c. fig. 33, p. 211. 



