44: MORPHOLOGY OF SPERMATOPHYTES 



multiciliate sperm, the blepharoplast forming the cilia-bearing 

 band, which a beaklike process put out by the nucleus seems to 

 guide in organizing the spiral of about three coils. 



Although this general account is the same as that given for 

 Cycads, there are at least two differences in detail which deserve 

 mention. Hirase states that the division of the generative cell 

 of Ginkgo is only a nuclear division, or at least that there is no 

 dividing wall, and that the nonfunctional nucleus is gradually 

 thrust out of the cell by the large development of the function- 

 al nucleus. He further states that when the cilia-bearing band 

 is about to be organized by the blepharoplast, the latter puts out 

 a hooklike process which attaches itself to the nucleus, and fol- 

 lowing this the nuclear beak develops with the hooklike process 

 attached to its tip. Hirase's observations indicate that the 

 initiative which results in the nuclear beak proceeds from 

 the blepharoplast, while Ikeno's observation indicates that the 

 initiative proceeds from the nucleus itself. It will be remem- 

 bered that Webber observed no nuclear beak in Zamia. 



The homology of these ciliated cells functioning as sperms, 

 and the reason for not regarding them as the morphological 

 equivalents of the multiciliate sperms of Pteridophytes, but 

 rather the equivalents of the so-called male cells common to all 

 Spermatophytes, are fully stated in connection with the Cy- 

 cads. Hirase's figures show a wall inclosing the ciliated cell, 

 presumably the wall of the mother cell (male cell), but no 

 reference is made to it in the text. If this represents the real 

 situation, it would follow that the ciliated cell in Ginkgo is mor- 

 phologically a sperm, being organized within a mother cell and 

 discharged from it. This view is clearly supported by the re- 

 cent figures and statement of Fujii, 14 \vhich represent the multi- 

 ciliate sperm as distinctly organized within the mother cell and 

 discharged from it. The details of development are so nearly 

 identical with those in Cycas and Zamia, that it seems improb- 

 able that such an important difference could occur. If it be true 

 that the ciliated sperm in Ginkgo is morphologically a sperm, and 

 not merely a ciliated mother cell, it would follow that Ginkgo is 

 still more fernlike than was supposed, and unlike other Gymno- 

 sperms and all Angiosperms in the feature that its sperm mother 

 cells do not function as male cells. It must be remembered that 

 Ginkgo is a much older type than are the Cycads investigated, 



