86 SPERMATOGENESIS AND FECUNDATION OF ZAMIA. 
It disappears later, during the formation of the embryo, being appar- 
ently absorbed during the process. 
(24) The function of the blepharoplast from the results obtained in 
this study appears to be simply the formation of the motile cilia and 
the transportation of the male cell. It forms the machinery of loco- 
motion. 
(25) The greatest interest in the present paper is in the relation of © 
the blepharoplast to centrosomes or centrospheres. They are found 
to differ from centrosomes as generally understood (1) in not forming 
the center of an aster at the pole of the spindle, being located entirely 
outside of the spindle in Zamia, Ginkgo, and Cycas; (2) in having no 
connection with spindle formation; (3) in being limited to the division 
of a single cell, thus to one cell generation, no similar organ appear- 
ing in any other stage of the plant’s development, so far as known, 
and (4) in having a function differing from that of any typical cen- 
trosome, so far as known in plants. 
(26) Considering the organs distinct from centrosomes, the writer 
in an earlier preliminary paper called them blepharoplasts. This the 
writer contends was justifiable and proper, even if the organs are finally 
proven to be the homologues of centrosomes. They are now very 
certainly specialized organs functioning only as cilia formers. 
Wasuineton, D. C., May 1, 1907. 
Notre.—Since this monograph went to press severa: important papers 
bearing directly on the subject have appeared, but as these do not 
serve to change the writer’s conclusions or materially affect the dis- 
cussion, no special consideration of them is here necessary. The most 
important of these is Dr. S. Ikeno’s paper entitled ‘*‘ Contribution a 
Pétude de la fécondation chez le Ginkgo biloba,” published in 1891 
(Ann. d. Sci. Nat. Bot. VII, sr. 18: 305-318). 
