34i 
during incubation in the common fowl. 
tracts considerably : some time after it is nearly obliterated ; 
and on the pedicle, the rudiments of a new yelk are formed. 
The yelk-bags are exceedingly vascular ; the outer mem- 
brane of the yelks is connected to them by vessels and fasci- 
culi of fibres, but easily separated. 
The yelk, while in the ovarium, has an oval form, and lies 
with its long axis towards the pedicle of the bag. See Plate 
XXXII. figures 1, 2, 3, 4, 5. 
In its passage along the oviduct the yelk acquires the 
albumen, and before it comes to the lower end, the albumen 
is covered by a very fine membrane. 
In this passage the thread-like substances, called by Mr. 
Hunter the poles, by others the chalazes, are formed ; and 
terminate in the double membrane, which is added at the 
time the egg has reached the enlargement at the lower end of 
the oviduct. In the cloacus the shell is formed. If the egg is 
taken out before it has acquired a shell, it remains soft for 
several days ; in one instance, after four days, it was so semi- 
transparent as to receive a yellow tint from the yelk. On 
puncturing the covering, the contents rushed out, but im- 
mediately resumed their form, being inclosed in the thin 
membrane of the albumen. The molecule with its areola, 
and the chalazes, were distinctly seen. The whole contents 
had less volume than the shell, particularly in the long axis, 
being truncate at both extremities. When immersed for an 
hour and half in distilled vinegar, the albumen and other 
parts had become somewhat coagulated. Plate XXXII. fig. 
6, 7, 8,9. 
In the new laid egg the appearances are exactly the same. 
