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 



Ovary 



YbHr ert,terir<.a the 



Calyx 



La*st portion of duct I 

 opened, &howirty r 

 completed egg 



Pa^&a,o;e through 

 which the 

 i& expelled 



Second 



-the oviduct 

 where the 

 is formed 



Third, portion, 



\ the 



After Dalton. 



FIG. 145. 



emae re 



Vent or oloo.cs. 



productive 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 



