1896.] INTESTINAL TRACT OF BIRDS. 155 
loop of the mid-gut with its special vein apparently being a remi- 
niscence of the stage with functional ceca. 
In the Parrots, Macaws, and Parrakeets that I have examined 
the gut presents no great divergences. It is invariably very long 
and slender, and the subsidiary loops are folded upon each other, 
and twisted and doubled in a very perplexing manner. Moreover, 
the masses of twisted gut are overgrown by connective tissue loaded 
with fat, and short-circuiting connections between the veins are 
common. ‘The relation to the common type, however, is easily 
made out. Ara ararauna (fig. 21) may serve as an instance; the 
Fig. 21. 
Ara ararauna ; intestinal tract. sx, short-circuiting vessel divided. 
duodenum is considerably wider than the rest of the gut, and is a 
simple loop, partly curved at the end. The circular loop is enor- 
mously expanded and is pulled out into a number of subsidiary 
loops, four in number, as in Ara, but numerous minor subsidiary 
loops usually occur between them. ‘The first of the four is short 
in Ara; the second, as in the others that I have examined, bears 
the vestige of the yolk-duct at its extremity; the third and fourth 
are very long, and the fourth has a short-circuiting vein to the duo- 
denum, and corresponds to the part of the circular loop along which 
the ceca run in the primitive type. The rectum is straight and 
bears no trace of ceca. The three main veins—the duodenal, the 
median, and the posterior mesenteric—occur in the typical fashion. 
When the minor loops between the four subsidiary loops are 
abundant, as, for instance, in Chryosotis, the gut bears a resemblance 
