GERM CELLS OF HERMAPHRODITES 203 



in the autosomes. In Helix the oogonia and sperma- 

 togonia arise from cells that are similar in size and 

 constitution (Fig. 60, A). When the germ-cell 

 nuclei reach the bouquet stage, a Nebenkern appears 

 near the side against which the chromatin threads 



FIG. 60. Helix pomatia. Stages in the differentiation of male and 

 female sex cells. A. Young oocyte. B. Later stage of oocyte 

 showing faint Nebenkern. C. Young spermatocyte. D. Later 

 stage of spermatocyte showing well-marked Nebenkern. E. Still 

 later stage of spermatocyte containing Nebenkern consisting of 

 banana-shaped rods. (From Demoll, 1912.) 



become packed. This Nebenkern is probably a 

 product of the nucleus; it appears in the female 

 cell only as a slightly darker area of cytoplasm (Fig. 

 60, B) but in the male cell is more dense (D), later 

 consisting of a number of darkly staining banana- 

 shaped pieces (E). With the appearance of the 

 Nebenkern the specific growth of the female cells 



