1896. ] INTESTINAL TRACT OF BIRDS. 147 
resemblance to the Ostrich is heightened by the fact that in 
Chauna and the Ostrich the rectum, by being thrown into a sub- 
sidiary set of folds, departs in a similar way from the common type. 
The resemblance between Chauna and Fhea is very striking. 
The Ducks and Geese (fig. 11) display a very definite and simple 
modification of the ground-type. It consists simply in the elon- 
gation of a limited number, generally five, of the primitive irregular 
loops of the circular loop. Ina young Bernicla magellanica, still 
in its down plumage, the duodenum and the third part of the gut 
were in the typical condition, but the circular loop was already 
pulled out into three or four subsidiary loops, of which the longest 
bore the yolk-duct vestige. In adult Ducks, Geese, and Swans 
the arrangement differed in uo essential respect from the drawing 
Fig. 11. 
Cygnus atratus ; intestinal tract. a’, short-cireuiting vessel divided. 
(fig. 11). The duodenum was simple. The duodenal vessel received 
short-circuiting veins from the hinder portion of the circular loop. 
A striking feature of the minor loops on the front part of the 
mid-gut is the presence upon them of minor loops. ‘The circular 
luop had a huge median mesenteric vein, which ran out to the 
much elongated subsidiary loop bearing the yolk-duct. It gave 
off three vessels to three expansions of the proximal part of the 
circular loop, vessels to a long and short distal expansion, and a 
vessel to the straight part of the loop along which the ceca were 
attached. The rectum was straight and in the typical fashion 
was supplied by a posterior mesenteric vein. 
FALCONIFORMES. 
I have not had the opportunity of examining any of the Catharte. 
The Accipitres show a marked divergence from the common type. 
The gut generally is enormously long, especially in the fish-eaters. 
From the point of view of relation to type, I cannot see that there 
is any special relation between the Accipitrine deviation and the 
JGe 
