260 BOTANICAL GAZETTE [march 



they stand out clearly a little apart from the chromosome groups. 

 From this time onward thev become increasingly distinct. As 



memb 



centrosomes 



comDleted thev mov 



from the nucleus and take up positions nearer the cell membrane 

 (fig. 6). 



(spermatids) 

 ind off from 



In prob- 



ma 



owin 



them. In each androcyte the blepharoplast, as we may 



call the centrosome in view of the function it performs in t 

 which it now occupies, enlarges considerably and becomes 



what elongated. 



il search has been made in the cytoplasm of the an- 

 drocytes for accessory structures corresponding to the "chroma- 



toider Nebenkorper" (Ikeno 6) or " limosphere ' ' (Wilson io), 

 the "percnosome" and the "apical body" (Allen 2) described 

 by other investigators of bryophyte spermatogenesis; but, as 

 Woodburn (12) also reports, nothing which can confidently be 

 regarded as such a body has been found. Occasionally there is 

 observed in the cytoplasm a darker area, which, although it is 

 as a rule rather vague in outline (fig. 7, below and at left of nucleus 

 in each cell), may in certain cases be more definitely delimited 

 (fig. 9). A similar appearance is also often seen in the later stages 

 of spermatogenesis (figs. 15, 16, 18, 19). It may well be that we 

 are dealing here with a limosphere or other accessory body, but 

 without more trustworthy evidence for its constant presence and 

 regularity in behavior, at present it does not seem advisable to 

 attribute to this body any special significance in the case of Blasia. 

 The cytoplasm of the androcyte frequently contains a large vacuole, 

 which may or may not lie near the blepharoplast (fig. 8) . 



The blepharoplast now begins to undergo a series of trans- 

 formations which ultimately result in the formation of the cilia- 

 bearing thread of the spermatozoid. After elongating very 

 slightly, as previously noted, the bleDharoplast becomes constricted 



