OVUM. 



53 



The name of ovary is in all animals applied 

 to the organ, however varied in its structure 

 and relations, in which the ova are formed. 

 As already indicated, however, it is to be 

 observed, that in the higher animals, it is 

 only the ovule, or yolk, with its germinal vesi- 



cle and enclosing membrane that is formed 

 in the ovary, while the external or cortical 

 parts of the ovum are added to these in their 

 descent through the female passages after 

 leaving the ovary. There are some examples 

 in which it would appear that the whole 



Fig. 35. 



Relation of the ovaries, ovum, oviduct and uterus in Mammalia. 



A. Gravid uterus, &c. of the rabbit, ten days advanced in pregnancy; a' a, right and left ovaries, 

 four corpora lutea in the right, two in the left; b'b, fimbriated openings of e' c, the Fallopian 

 tubes; did, the right and left cornua of the uterus; d>, with four dilatations from contained ova, d, 

 with two dilatations, one of which is opened to show the ovum ; e, the body of the uterus ; /, the 

 vagina. 



B. A diagrammatic transverse section of the human uterus, at twelve or fourteen days after conception, 

 somewhat less than the natural size; e, the uterine cavity, near which the ovum with its villous 

 chorion is involved in the substance of the decidua indicated by the dotted shading ; c' c, the Fallo- 

 pian tubes cut short, by one of which the ovum had previously descended while still of small size. 



c. Enlarged view of the exterior of the human ovum, of twelve or fourteen days after conception, 

 showing the villi of the chorion projecting from its surface. 



E 3 



