CYCADALBS 27 



approach the free wall and trace a widening spiral of five or 

 six turns, which involves about one half of the cell wall. In 

 this process the granules are organized into a spiral band lying 

 very near or against the wall. The blepharoplast band then puts 

 out numerous short cilia which pierce the wall of the male cell, 

 on whose surface a spiral groove is developed. During this 

 process the nuclear beak disappears, and the visible connec- 

 tion between nucleus and band is cut off. The final surface 

 appearance of the male cell is that of an oval cell, broad 

 and naked behind, spirally grooved in its anterior half, and 

 with many short , m'otile cilia emerging from the groove. It 

 should be noted that Zamia, so far as Webber's preparations 

 show, gives no evidence of a nuclear beak associated with the 

 organization of the ciliated band, but it seems to move inde- 

 pendently toward the wall and assumes the spiral position. 



During the organization of the cilia the nucleus begins to 

 enlarge at the expense of the cytoplasm, until finally it attains 

 remarkable relative dimensions, bulging between the coils of 

 the band, so that it becomes spirally grooved, and is covered only 

 by a thin mantle of cytoplasm. The ciliated band is formed 

 before the two sister cells separate, and Webber has observed 

 the pair swimming while still connected. When mature, this 

 ciliated cell is visible to the naked eye in Zamia, its longer axis 

 measuring 258 to 332/^, its shorter axis being a little less. In 

 Ginkgo Hirase gives the dimensions as 82/4 by 49//.; and Ikeno 

 reports that the dimensions in Cycas are somewhat larger, but 

 evidently not to be compared with those in Zamia. 



It is these ciliated cells which have been called spermatozoids 

 or antherozoids, and such they are physiologically. Morpho- 

 logically, however, they are sperm mother cells which do not 

 organize sperms internally, but themselves pass over directly 

 into sperms, a fact which seems true of all Spermatophytes. 

 Morphologically, therefore, they are identical with the so-called 

 male cells of all ordinary Seed plants, but are peculiar in becom- 

 ing ciliated. The contrast with Pteridophytes, in which each 

 mother cell organizes an internal ciliated sperm and discharges 

 it, is sharp. The resemblance between Cycads and Pterido- 

 phytes is not in the morphological character of the cell which 

 functions as a sperm, in which the Cycads resemble the other 

 Seed plants, but in the fact that it is ciliated. 



