146 



ARCHEGONIATES. 



from the generative cell. To this phase of development Ikeno has 

 applied the term spermatogenesis. 



As soon as all the structures mentioned accumulate in the proximal 

 end of the tube, all save the generative cell begin to disorganize and 

 finally disappear. What this disorganization signifies, Ikeno remarks, 



*&? --'. ' ' ' t-r-J-I-SS 



' : 



D 



FIG. 58. Division of generative cell and further development of blepharoplasts in Cycas 



revoluta. (After Ikeno.) 



A, generative cell with nucleus in early prophase oi division ; chromatin scattered in masses of granules. 



B, same with nucleus in late anaphase ; each blepharoplast has separated into a mass of rods from 



which radiations extend ; they have nothing whatever to do with mitotic spindle. 



C, blepharoplast of B more highly magnified. 



D, cell-division is about complete ; the radiations have nearly disappeared from the mass of granules 



composing blepharoplast. 



E, two spermatozoid mother-cells, the one on the right in outline; the ciliated blepharoplast has made 



one turn about the cell ; nuclear beak is in connection with ciliated band. 



is an open question, but it seems that all of the disorganized elements 

 contribute to the nourishment of the generative cell. 



The cytoplasm of the generative cell now assumes a coarse, net-like 

 structure, and the nucleus divides (Fig. 58, A, B). The details of 

 this division will not be dwelt upon further than to state that the 

 mitotic spindle arises without the intervention of the centrosphere-like 



