588 



REPRODUCTION. 



FIG. 162. 



food in a similar direction. While passing through the first five or 

 six centimetres of the oviduct (c, d), where the mucous membrane is 

 smooth and transparent, the yolk absorbs a certain quantity of fluid, 

 becoming consequently softer and more flexible. It then passes into a 

 second division of the canal, in which the mucous membrane is thicker 

 and more glandular in texture, and arranged in longitudinal folds. 



This portion (d, e) extends over about 22 

 centimetres, or more than one-half the 

 length of the oviduct. In its upper part, 

 it secretes a viscid material, which con- 

 solidates into a gelatinous deposit around 

 the yolk, thus forming a second envelope, 

 outside the vitelline membrane. 



The peristaltic movements of the ovi- 

 duct are such as to give a rotary, as well 

 as a progressive motion to the egg ; and 

 by this means the two extremities of the 

 gelatinous envelope become twisted in 

 opposite directions, forming rope-like ex- 

 tensions at the two poles of the egg. They 

 are termed the "chalazae," or suspensory 

 cords, and the membrane with which 

 they are connected is the " chalaziferous 

 membrane." 



Throughout the remainder of this part 

 of the oviduct, an albuminous substance 

 is deposited in successive layers round 

 the yolk, inclosing the chalaziferous mem- 

 brane and chalazse. This substance, the 

 so-called albumen, or " white of egg," is 

 gelatinous in consistency, nearly trans- 

 parent, and of a faint amber color. It is 

 deposited in greater abundance in front 

 of the egg than behind it, and thus forms 

 a conical projection anteriorly, while be- 

 hind, its outline is parallel with the 

 spherical surface of the yolk. In this way, 

 the egg acquires, when covered with its 

 albumen, an ovoid form, of which one end 

 is round, the other pointed ; the pointed 

 extremity being directed downward, as 

 the egg descends through the oviduct. 



FEMALE GENERATIVE ORGANS OF THE FOWL. a. Ovary. 6. Graafian follicle, from which the 

 egg has just been discharged, c. Yolk, entering upper extremity of oviduct, d, e. Second por- 

 tion of oviduct, in which the chalaziferous membrane, chalazse, and albumen are formed. /. Third 

 portion, in which the fibrous shell membranes are produced, g. Fourth portion laid open, show- 

 ing the egg completely formed, with its calcareous shell, h. Canal through which the egg is 

 discharged. 



