528 ZOOLOGY. 
liver are still im situ. The muscular stomach or gizzard 
(St) of the main figure is represented very large, being 
distended with food; it is sometimes found much con- 
tracted; it is not sharply separated from the glandular 
stomach, the two being in reality only the greatly modified. 
anterior and posterior divisions of the same dilatation. The 
opening of the glandular stomach and the origin of the 
small intestine are near together upon the anterior border 
of the gizzard. The walls of this last organ are remarkable 
for the enormous development of the muscular layers, 
especially in the graminivorous birds, under which pigeons. 
are to be included ; the muscles radiate on each side from 
a central tendinous space. The small intestine has nu- 
merous coils, in the first of which lies the pancreas (Pan), 
very much asin mammals. The large intestine (2) is rel: 
atively short ; its commencement is markcd by two small 
diverticula, distinctive of birds.* These appendages are 
well developed in some species, as, for instance, the Galli- 
nacee, while in the bustard they have been described as. 
three feet long. Gegenbaur considers the cesophagus, crop, 
and stomach to be derived from the forc-gut, the small in- 
testine from the mid-gut, and the large intestine from the 
hind-gut of the embryo. The cloaca (C7) is tho short and 
widened termination of the alimentary canal, and further 
receives four ducts, the two ureters (Ur), and in the male 
the two vasa deferentia (Vd), in the fevale the two ovi- 
ducts. 
The digestive canal has two glandular appendages, the 
pancreas (Pan) and the liver (Zz); the former, as in 
birds generally, is quite large, whitish, and sends out a pro- 
longation, which extends to the spleen ; it has two ducts. 
The liver (Zz) is very voluminous, dark reddish brown in 
color, and forms two lobes, which rest upon the apex of the 
heart and the gizzard, and conceal the glandular stomach. 
There is no gall-bladder, a somewhat unusual feature among 
birds, but there are two bile-ducts, the larger and shorter 
* Some snakes have a single diverticulum, as is said to be the case- 
witb herons. 
