158 



THE DEVELOPMENT OF THE GAMETES OR SEX CELLS 



of Golgi substance and mitochondria moves away from the central portion 

 (i.e., away from the centrosphere) of the yolk nucleus and becomes scattered 

 and dispersed as small fragments within the cytosome (fig. 68F, G). The 

 yolk nucleus as an entity thus disappears, and its fragments become immersed 

 within the substance of the cytoplasm. Coincident with this dispersion of 

 yolk nuclear material, rapid formation of small yolk spherules and fat droplets 

 occur (fig. 68H). It appears thus that the formation of the deutoplasm com- 

 posed of fat droplets and yolk spherules is directly related to the activities 

 of the Golgi substance and chondriosomes. 



MITOCHONDRIAL 

 YOLK SPHERES 



SECOND TYPE OF 

 YOLK FORMED 

 AROUND 

 MITOCHONDRIAL 

 YOLK SPHERES 



GOLGI APPARATUS 

 OF FOLLICLE 



^% 



«-i GOLGI APPARATUS 



TYPE 2 



B. 



Fig. 89. (A) Cytoplasm of oocyte, showing formation of a second kind of yolk (the 

 M-C-yolk) in a vacuole surrounding the M-yolk sphere. (After Brambell, '25.) (B) 

 Passing of Golgi substance from the follicle cells mto the ooplasm of developing oocyte 

 of the fowl. (After Brambell, '25.) 



QUANTITATIVE DIFFERENCES 



QUALITATIVE DIFFERENCES 



Fig. 90. Diagrams showing contrasting theories explaining the organization of polarity 

 of the cytoplasm of the fully developing egg or oocyte. Diagram at left shows polarity 

 explained according to quantitative differences, while the diagram to the right shows 

 qualitative differences. A = animal pole; V = vegetal pole. E represents a substance or 

 a factor, while EN-1, EN-2, etc., represent different quantities of substance E distributed 

 from pole to pole. SEC. SEN and SM are different chemical substances assumed to be 

 responsible for the determination of the ectoderm, entoderm, and mesoderm of the de- 

 veloping embryo. (After Barth: Embryology, New York, Dryden Press.) 



