SECT. II 



PHANEROGAMIA 



487 



FIG. 450. Formation of Spermatozoids in //(' fluri/lnnn. (i, Mature polleH7gratn (X 800); 

 v, vegetative prothallial cell the dark streak at its base indicates the position of another 

 crushed cell ; k, nucleus of the pollen-tube ; sp, spermatogenous cell. 6, c, rf, stages in the 

 development of the antheridium (h, c x 400 ; d x 200) ; v, persisting vegetative cell growing 

 into the sterile sister-cell of the antheridium (s) ; m, mother-cell of the antheridium, i.e. mother- 

 cell of the spermatozoids; e, exine. In the mother-cell the large blepharoplasts (bl) which form.the 

 cilia are visible ; in 6 and c they are star-shaped , while in il they are composed of small granules, 

 which will form the cilinm-forming spiral band. Starch-grains are present in the pollen-tube, 

 and in c they are appearing in the vegetative cell and the sister-cell, both of which in d^are 

 packed with starch. In d the two spermatozoids (sj>) derived from the mother-cell are/seen 

 divided from one another by a wall. (After H. .1. WEBBER.) 



Fn.. 4;">1. Upper end of the pollen-tube of /.// /u 

 floridana, showing the vegetative prothallial 

 cell (v), the sterile sister-cell (s), and the two 

 spermatozoids. o, Before movement of the 

 >l>errnatozoids has commenced ; 6, after the 

 beginning of ciliary motion ; the prothallial cell 

 is broken down and the separation of the two 

 spermatozoids is taking place, (x circa 75. After 

 H. J. WEBBER.) 



Fn.. 4.VJ. -xfum/'" jiiii'iiimin. Mature, free- 

 swimming sperrnato/oid. (xlf>0. After 

 H. .1. WEBBER.) 



2 I 2 



