146 



THE DEVELOPMENT OF THE GAMETES OR SEX CELLS 



PROACROSOMIC SUBSTANCE 



PROACROSOMIC 



GRANULES 



AXIAL FILAMENT 



Fig. 80. Morphogenesis of guinea-pig and human sperm. (A) Spermatocyte of guinea 

 pig before first maturation division. The Golgi complex with included proacrosomic 

 granules and centrioles is shown. (After Gatenby and Woodger, '21.) (B) Young sister 

 spermatids of guinea pig. (C) Later spermatid of guinea pig showing acroblast with 

 proacrosomic granules. (D) Young human spermatocyte, showing Golgi apparatus with 

 proacrosomic granules similar to that shown in (A). (After Gatenby and Beams, '35.) 

 (E) Spermatid of guinea pig later than that shown in (C), showing acroblast with Golgi 

 substance being discarded from around the acroblast. (F) Later human spermatid, 

 showing Golgi substance surrounding acroblast with acrosome bead. (After Gatenby and 

 Beams, '35.) (G) Later human spermatid, showing acroblast, with acrosome bead 

 within, surrounded by a vacuole. (After Gatenby and Beams, '35.) (H) Later spermatid 

 of guinea pig, showing outer and inner zones of the acrosome. The inner zone corresponds 

 somewhat to the acrosome bead shown in (G) of the human spermatid. (After Gatenby 

 and Wigoder, Proc. Roy. Soc, London. s.B.. 104.) 



female gamete. In the male gamete, on the other hand, the meiotic processes 

 are completed before morphological differentiation of the cytoplasm is initiated. 

 Another distinguishing feature in the morphogenesis of the sperm relative 

 to that of the egg is that the cytoplasmic differentiation of the sperm entails 

 a discarding of cytoplasm and contained cytoplasmic structures, whereas the 

 oocyte conserves and increases its cytoplasmic substance (fig. 68). In regard 



