355 
during incubation in the common fowl. 
domen opened ; the heart and the lobes of the liver turned 
aside to show the course of the principal trunks of the blood- 
vessels which go to the vesicle and to the areolar membrane ; 
the yelk, at this period, is still entirely without the body of 
the embryo. Magnified 2 diameters. 
A. A. a portion of the amnion. B.B.B. the vesicle. C.C. 
a portion of the areolar membrane. 
Plate XXXIX. 
Fig. 1. An egg , opened eighteen days after incubation. Na- 
tural size. 
Fig. 2. The same egg, with the external half of the vesicle 
removed. Natural size. 
Fig. 3. The chick taken from the same egg ; the thorax 
and abdomen laid open to show that the greater part of the 
yelk is now drawn into the body. Natural size. 
Plate XL. 
Fig. 1. An egg, opened twenty days after incubation, the 
vesicle and amnion entirely removed, to show the natural 
position of the perfectly formed chick. Natural size. 
Fig. 2. The chick taken out of the same egg, to show that 
the yelk is now entirely drawn into its body, only some small 
portion of the vesicular membrane protruding from the orifice 
of the abdomen, which is not yet quite closed. Natural size. 
Fig. 3. The same chick opened, to show the natural posi- 
tion of the viscera and the yelk at this period of the incuba- 
tion. Natural size. 
