THE FEMALE 



59 



The process of maturation involves contributions from the nucleus 

 and the cytoplasm. First, chromatin nucleoli aid in the synthesis of 

 yolk, and second, the breakdown of the germinal vesicle allows an 

 intermingling of the nuclear and the cytoplasmic components. Only 

 a small portion of the germinal vesicle is involved in the maturation 



Ovarial wall of Rami temporaria. Note young trans- 

 parent eggs (stages 1 and 2) and larger opaque eggs 

 {stage 3). The arrow points to an isolated nucleus 

 from another egg (stage 3) , which has floated into the 

 field. (Courtesy, W. R. Duryee, 1950, Ann. N. Y. 

 Acad. ScL, 50, Art. 8.) 



spindle so that it may be at this time that the nucleus exerts its initial 

 influence on the cytoplasm. All cytoplasmic differentiations must be 

 initiated at a time when the hereditary influences of the nucleus are 

 so intermingled with it. 



Growth Period to Primary Oocyte Stage. Growth is achieved 

 largely by the accumulation of yolk. As soon as growth begins the 

 cell no longer divides by mitosis and is known as an oocyte rather 

 than an oogonium. The growth process is aided by the centrosome, 



