MATURATION OF GAMETES 145 



of equality in the daughter cells of the developing male gamete during and 

 following the maturation divisions, an entirely different condition is found 

 in the developing female gamete. In the latter, one of the secondary oocytes 

 is practically as large as the primary oocyte, while the other or first polar 

 body (polocyte) is extremely small in cytoplasmic content although the nuclear 

 material is the same (fig. 117D). During the next division the secondary 

 oocyte behaves in a manner similar to that of the primary oocyte, and a 

 small second polocyte is given off, while the egg remains large (fig. 1 17E, F). 

 Unlike the secondary spermatocyte, the secondary oocyte does not form a 

 nuclear membrane. The polar body first formed may undergo a division, re- 

 sulting in a total of three polar bodies (polocytes) and one egg (ootid). 



/. Resume of the Significance of the Meiotic Phenomena 



In view of the foregoing data with regard to the behavior of the male and 

 female gametes during meiosis, the significant results of this process may be 

 summarized as follows: 



( 1 ) There is a mixing or scrambling of the chromatin material brought 

 about by the crossing over of genie materials from one chromatid to 

 another. 



(2) Much chromatin material with various genie combinations is discarded 

 during the maturation divisions in the oocyte. In the latter, two polar 

 bodies are ejected with their chromatin material as described above. 

 The egg thus retains one set of the four genie combinations which 

 were present at the end of the primary oocyte stage; the others are 

 lost. (A process of discarding of chromatin material occurs in the 

 male line also. For although four spermatids and sperm normally de- 

 velop from one primary spermatocyte, great quantities of sperm never 

 reach an egg to fertilize it, and much of the chromatin material is 

 lost by the wayside.) 



(3) A reduction of the number of chromosomes from the diploid to the 

 haploid number is. a significant procedure of all true meiotic behavior. 



(For more detailed discussions and descriptions of meiosis, see De Robertis, 

 et al., '48; Sharp, '34, '43; Snyder, '45; White, '45.) 



4. Cytosomal (Cytoplasmic) Maturation of the Gametes 

 a. General Aspects of Cytoplasmic Maturation of the Gametes 



During the period when the meiotic prophase changes occur in the nucleus 

 of the oocyte, the cytoplasm increases greatly and various aspects of cyto- 

 plasmic differentiation are effected. That is, differentiation of both nuclear 

 and cytoplasmic materials tend to occur synchronously in the developing 



