218 



DE. P. CHALMEES MITCHELL ON THE 

 G A L L I. 



MEGAPODID-S:. In Talegallus Lathami (fig. 38) the duodenum is a straight, narrow 

 loop of moderate length. Meckel's tract is swung at the periphery of an expanse of the 

 mesentery, and forms almost a complete circle of which the middle mesenteric vein, 

 running from the Meckel's diverticulutn, forms a diameter ; for the greater part of its 



Fig. 38. 



Intestinal Tract of Talegallus Lathami. Lettering as before. 



course this tract is thrown into very regular corrugations, but its distal portion is nearly 

 straight. The recurrent factor of the middle mesenteric vein supplies a considerable part 

 of Meckel's tract. The caeca are of moderate length and are drained partly by a 

 " bridging " vein, and the rectum is fairly long and very slightly thrown into folds. A 

 striking feature in Talegallus, as in other Galli, is the conspicuous visceral nerve (v.n.), 

 which in this bird is a ganglionated chain following the sweep of Meckel's tract. 



CEACID^E. In Crax Daubentoni (fig. 39) the only notable difference from Talegallus 

 in the formation of the gut relates to Meckel's tract. This area is much elongated 

 distally, with the result that the recurrent factor of the middle mesenteric vein (r.) which 

 supplies the distal portion of the tract is much enlarged, and appears to be the direct 

 continuation of the middle mesenteric. That vein, however, in the embryo runs out as 

 usual to the diverticulum as I figured in the case of Argus giganteus (26. fig. 2), and its 

 real termination in the adult is one of the minor branches of the main blood-channel. 



