498 JEAN REDMAN OLIVER 



I'Mgs. 33, 36, 37, 38 Fourth period of spermiogenesis 



I'Mg. 33 Nearly mature sponiiatozoon from the epididymis. Face view. The 

 whole structure now stains much lighter than before. The head is covered by 

 I he head cap, h.c, the posterior margin of which forms a sharp slightly curved 

 line. The posterior end of the head stains darker and immediately in front of 

 this region is a lighter zone. The neck, n, is clear and shows the two anterior 

 centrioles, Noduli anteriores, in front in contact with the head. The connecting 

 piece, pars conjunctionis, c.p., still bears a small cytoplasmic remnant, c.r. It 

 is limited anteriorly by the two Noduli pOsteriores, now equal in size, and pos- 

 teriorly by the annulus, an., still visible as a flattened disc. Neither the con- 

 necting piece nor the main piece, pars principalis, m.p., show the axial filament 

 iti this preparation. The main piece tapers posteriorly to the very slender end 

 piece, pars terminalis, e.p. 



Figs. 34 and 35 Anterior ])ortion of two nearly mature spermatozoa from a 

 tubule. The cytoplasmic remnant still adheres to the anterior end of the con- 

 necting piece. The inequality of the two Noduli posteriores is very characteristic 

 at this stage. 



Fig. 36 Profile view of nearly mature spermatozoon. The head cap is stained 

 deeply. Lettering as in figure 33. The tail is incomplete. 



Fig. 37 Head of mature spermatozoon from epididymis,, showing exceptionally 

 symmetrical insertion of the tail. 



Fig. 38 Neck, connecting piece and a portion of tlic main piece of the tail of 

 a mature spermatozoon from the epididymis. The head has been broken off, 

 leaving the two anterior centrioles, n.n., in the neck. 



