40 GERM-CELL CYCLE IN ANIMALS 



which stain with crystal violet after Benda's method, 

 and appear to be mitochondrial in nature. At a 

 slightly later stage (Fig. 8, C ; position C in Fig. 7) 

 the nucleus is larger and contains several small 

 spherical chromatic bodies besides the nucleolus. 

 The cytoplasm has increased more rapidly in volume 

 and a corresponding increase in the number of mito- 

 chondrial granules has also taken place. Further 

 growth results in an increase in the volume of both 

 nucleus and cytoplasm (Fig. 8, D; position D in 

 Fig. 7), and a slight increase in the number of mito- 

 chondria. Whether these bodies developed de novo 

 or by division of the preexisting granules could not 

 be determined. 



In succeeding stages growth is very rapid. The 

 cytoplasm (Fig. 8, E; position E in Fig. 7) still 

 remains homogeneous except for the mitochondria, 

 which increase slightly in size and become situated 

 as a rule near the periphery. The nucleus at this 

 time contains a large number of chromatin granules 

 and a diffuse reticulum. Part of an older oocyte 

 is shown in Fig. 8, F (position F in Fig. 7) ; the cyto- 

 plasm has assumed a reticular appearance; the 

 mitochondrial granules are present in greater num- 

 bers, and the nucleus is larger, oval in shape, and 

 contains a distinct reticulum with many chromatin 

 bodies of various sizes. A still older oocyte (Fig. 

 8, G ; position G in Fig. 7) is interesting particularly 

 because of the rapid increase in the mitochondria and 

 the localization of these near the periphery. From 

 this stage on the character of the contents changes 



