Fig. 63. — Diagram of spermatogenesis in Helix (after Gatenby (30b, 35) ). 

 A, Spermatocyte, B and C, Spermatocyte divisions. D, Early Sper- 

 matid. E, F, G, Spermateleosis. Ab., acroblast ; As., acrosome ; 

 Ce., centrioles ; Ch., chromosomes ; G., Golgi apparatus ; /., idiosome ; 

 J/., mitochondria ; X., nucleus ; P.N.G., post-nuclear granule ; T.f., 

 tail filament ; T.s., tail sheath ; Vac, vacuome. 



To face p. 140. 



