112 THE STRUCTURE OF THE FOWL 



with the nucleus of the ovum in the process of 

 fertihsation. 



The later phases of the stage of gro^vth 

 produce an increasing projection of the follicle 

 within which the ovum is contained, with the 

 result that its connection with the main ovarian 

 mass is ultimately reduced to a narrow pedicle. 

 The follicle finally ruptures along a predestined 

 linear stigma, and the ovum, surrounding 

 itself with a vitelline membrane, falls into the 

 wide infundibulum of the oviduct. The 

 follicle now shrivels up without the formation 

 of anything comparable to the corpus luteum 

 of mammals. 



The ovum is propelled along the oviduct 

 in a spiral manner by the contractions of the 

 walls of the tube, and during its passage 

 receives the albumen, shell -membranes, and 

 shell. In the oviduct, also, fertilisation occurs 

 and a certain amount of division, or segmenta- 

 tion, takes place. 



Fertilisation. — The process of fertilisation 

 consists of the union of the ovum and sperma- 

 tozoa. Spermatozoa are capable of travelling 

 the entire length of the oviduct and lie in wait 

 for the newly- extruded ova in the region of 

 the infundibulum. It is evident that they 



