IXTESTIXAL TBACT OF BIRDS. 



251 



Meckel's tract is short, and forms a circular expanse wit:. :^. diverticulum nearly at 

 the central point. The posterior region of the tract, however, shows traces of former 



Fig. 6y. 



^_l-_ X 



m 



l^-~^; 



Intestinal Tract of Cypftlus apvi. 



complexity, in that it is drained partly by a bridsing vein, a circumstance to which 1 

 attach importance as evidence that the apparent simplicity of the gut is pseudocentric. 

 The cceca are absent, and the rectum is straight and wide. 



Trochilid.£. — I have examined a number of Humming-birds, and found that the 

 conformation of the gut was in every case practically identical ^v ' Cupselu^. 



It is worth while pointing out that the Humming-birds ditfer clearij .-. . _ .^formation 

 of the gut from the Passerine Xectariniidge, although in both the small size hn? brought 

 about a remarkable simplicity. The Xectariniida? possess the Passerine nij - cteca, 

 and show clear indications of the spiral t\vist in Meckel's tract which is a striking 

 Passer ne character, and there is no trace of either of these peculiarities in the 

 Humming-birds. 



COLII. 



I have already described and figured tlie intestinal tract of Colius capemi^ [z6. tig. 21). 

 It is relatively shorter and wider than in any other bird that I have examined, and this 

 modification, no doubt due to small size and frugivorous habit, has obliterated practically 

 completely tlie underlying morphological form. The gut consists of a very wide 

 duodenum, a Meckel's tract bearing a small diverticulum, and consisting of a simple 

 loop similar to the duodenum in size and appearance, and a short, wide rectum. There 

 are no traces of cieca. 



