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the sipnaaits a ‘membranous fet m; the thickness of 
whose parietes are a multitude of glands whose juices babert 
the aliment ; and finally, the gizzard, armed with t power- 
ful muscles, united by two radiated tendons, | and Pci? inter- 
nally with a cartilaginous kind of velvet. The food _ is ‘the: 
more easily ground there, as birds constantly. swallow small 
stones, in order to increase its triturative power: * 
In the greater part of the species which feed exclusively. 
on flesh or fish, the muscles and villous coat of the ony 
are greatly attenuated; and it seems to make but a single sac 
with the membranous stomach. ae sat 
The dilatation of the crop is also sometimes: ‘wanting. ae 
The liver pours its. bile into the intestine by two ducts, 
which alternate with the two or three through which the 
pancreatic fluid passes. The pancreas of Birds is large, but 
their spleen is small; the epiploon is wanting; its functions, 
‘ 
however, are partly fulfilled by the partitions of the air cavi- — 
ties; two blind appendages are situated near the origin of the 
rectum, and at a short distance from the anus ;_ they are longer 
or shorter, according to the regimen of the genus. In the’ 
Herons it is short; in other genera, that of the Woodpeckers _ 
for instance, it is totally deficient. 
The cloaca is a pouch, in which the rectum, ureters, sper- 
matic ducts, and in the female, the oviduct, terminate 3 it 
opens externally, by the anus. Strictly speaking, Birds do 
not urinate, as that excretion mingles with their solid exere- — 
ment. In the Ostriches alone, is the cloaca sufliciently adatea 
to allow of an accumulation of the urine. 
In most genera§ coition is effected by the simple juxta- 
position of the anus; the Ostriches, and several of the Palmi- 
pedes, however, have a penis furrowed with a groove, through 
which the semen passes. The testes are situated internally, 
and near the lungs; only one oviduct 1 is developed ; ‘the other 
is reduced to a small sac. 
The egg, detached from the ovary, where it consists merely 
of yolk, imbibes that external fluid, called the white, in the 
upper part of the oviduct, and becomes invested with its shell 
at the bottom of the same canal. The chick contained within 
. 
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