24 MORPHOLOGY OF SPERM ATOPHYTES 



daughter cells divide in the usual way, and heavy walls are 

 again formed. Within this heavy four-celled and often lobed 

 case the microspores are organized. 



The first comparatively full account of the germination of 

 the microspore seems to have been that of Juranyi 5 for Cera- 

 tozamia longifolia. In 1896, in a preliminary paper, 20 fol- 



FIG. 22. Cycas revoluta, development of the ciliated male cell : A, male gametophyte 

 of three cells, vegetative or '' prothallial " cell (/}, generative cell, and tube cell (t\ 

 x 500 ; B, the generative cell (a) rounded off, x 200 ; f, the generative cell (a) show- 

 ing division of nucleus into stalk and body nuclei, x 500 ; 7>, first appearance of 

 blepharoplasts in enlarging body cell (i), and diminishing stalk nucleus (s), x 500 ; 

 E, body cell (b) shortly before division, showing well-developed blepharoplasts (c 1 ), 

 x 750 ; F, the two male cells resulting from the division of the body cell, showing 

 the beaked nuclei, x 200; G, II, /, later stages in the development of the ciliated 

 male cell, x 200. After IKEXO. 



lowed by the full paper 28 in 1898, Ikeno presented a detailed 

 account for Cycas revoluta; while in 1897 Webber 25 > 2Q ' 27 pub- 

 lished his results for Zamia integrifolia. One of the authors 

 has also examined Mr. Webber's preparations. The sequence 

 of events is as folloAvs (Figs. 22, 23) : 



A small lenticular cell is cut off and persists, and as it seems 



