THE OVIDUCT 301 
network of fine blood vessels. The upper opening of the oviduct 
is expanded in the shape of a funnel to facilitate the entrance 
of the ovum when it emerges from the yolk sac. The duct on its 
re 
x (Yolk entering the 
| funnel-shaped 
$, 
‘ oviduct 
Sul 
Calyx or. yolk sack 
: iN Second portion 
3 of the oviduct 
where the albumin 
tis formed 
[ZAird portion where 
the shell is added 
opened showing 
Last portion of: ae | 
completed egg 
Passage through| { 
which the e997 
zs expelled. R 
Vent or cloaca 
After Dalton. 
Fig. 145.—Female reproductive organs. 
way to the cloaca lies in folds, being lapped upon itself three times 
before it finally passes into the cloaca. 
When the yolk enters the oviduct it consists of a yellow mass, 
called the “‘ vitellus,’’ enclosed in a thin membrane, the “ vitelline ”” 
membrane. Fertilization takes place in the upper part of the ovi- 
duct before any albumin has been added, and if at this time the 
