550 EGG AND FEMALE ORGANS OF GENERATION. 



canal, in which the mucous membrane is thick and glandular in 

 texture, and is also thrown into numerous longitudinal folds, which 

 project into the cavity of the oviduct. This portion of the oviduct 

 (d, e), extends over about nine inches of its entire length. In its 

 upper part, the mucous membrane secretes a viscid material, by 

 which the yolk is encased, and which soon consolidates into a gela- 

 tinous* membranous deposit ; thus forming a second homogeneous 

 layer, outside the vitelline membrane. 



Now the peristaltic movements of this part of the oviduct are 

 such as to give a rotary, as well as a progressive motion to the 

 egg ; and the two extremities of the membranous layer described 

 above become, accordingly, twisted in opposite directions into two 

 fine cords, which run backward and forward from the opposite poles 

 of the egg. These cords are termed the " chalazas," and the mem- 

 brane with which they are connected, the " chalaziferous membrane." 



Throughout the remainder of the second division of the oviduct, 

 the mucous membrane exudes an abundant, gelatinous, albuminoid 

 substance, which is deposited in successive layers round the yolk, 

 inclosing at the same time the chalaziferous membrane and the 

 chalazae. This substance, which forms the so-called albumen, or 

 " white of egg," is semi-solid in consistency, nearly transparent, and 

 of a faint amber color. It is deposited in greater abundance in front 

 of the advancing egg than behind it, and forms accordingly a 

 pointed or conical projection in front, while behind, its outline is 

 rounded off, 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 always directed downward, as the egg descends 

 along the oviduct. 



In the third division of the oviduct (/), which is about three and 

 a half inches in length, the mucous membrane is arranged in longi- 

 tudinal folds, which are narrower and more closely packed than in 

 the preceding portion. The material secreted in this part, and de- 

 posited upon the egg, condenses into a firm fibrous covering, com- 

 posed of three different layers which closely embrace the surface 

 of the albuminous mass, forming a tough, flexible, semi-opaque 

 envelope for the whole. These layers are known as the external, 

 middle, and internal fibrous membranes of the egg. 



Finally the egg passes into the fourth division of the oviduct (g), 

 which is wider than the rest of the canal, but only a little over two 

 inches in length. Here the mucous membrane, which is arranged 



