PLATE XXVIII. 



K*t. 



Via. 178. Semi-diagrammatic representation of devel- 

 opment of human spermato/oon. 



a-;/, s-v<-n stages in the transformation of a sper- 

 matid into aspermato/uon (f/j ; A. diagram of structure 

 of si ripe spermato/oon. 



a-f: Zx, cell substance : A', nucleus : ]'(', proximal 

 ct-ntrosome : DC, distal centrosome ; S'A', (ail. 



g-h: ,Sfc., head : /;/.*/.. terminal globule ; T.s/.. body 

 or middle piece; Hut., main segment ; Ext., end piece ; 

 .if., axial thread ; 7/i, inner capsule : Kjth., spiral cap- 

 .-ule : //n, outer capsule ; ,Ss.. annular thickening. 



(We are indebted to Dr. Mevcs for this plate.) 



