B.P.L—3. Vv. P,P. —88. 
SPERMATOGENESIS AND FECUNDATION OF ZAMIA. 
By Hersert J. WEBBER, 
Physiologist. 
INTRODUCTION. 
Within recent years renewed interest has been awakened in the 
phenomena accompanying spermatogenesis in plants, due largely to 
researches on certain cycadaceous plants and Pteridophytes in which 
the cilia of the spermatozoid have been found to develop from a body 
resembling a centrosome. This interest was greatly enhanced by the 
fact that the enormous spermatozoids of the Cycadacee and Ginkgo 
were but newly discovered, and in groups of plants where motile 
sexual cells had not been known to occur. Zoological activity in this 
direction has also been very great in recent years, a number of cases 
having been described in which it is claimed that the axial filament is 
developed directly from the centrosome which here forms the so-called 
middle piece (Mittelstiich) of the spermatozoon. 
The writer’s investigations on the spermatogenesis and fecundation 
of Zamia and Ginkgo began in 1897, and since that time several pre- 
liminary papers and short notes have been issued in various places. 
In 1897 three preliminary papers were published in the Botanical 
Gazette and a short note in the Report of the British Association for 
the Advancement of Science. In 1898 additional observations were 
described in a report read at the American Association for the Advance- 
ment of Science, and in 1900 still further observations, particularly 
on the morphology and development of the pollen tube apparatus, were 
described. The present paper covers the ground connectedly, more 
in detail, and with illustrations. The investigation is of considerable 
interest as throwing light on the phenomena accompanying fecunda- 
tion and on the relation of the cilia-forming organs of spermatogenous 
cells to centrosomes or centrospheres. 
SUMMARY OF RECENT LITERATURE. 
‘The following summary of the recent literature on the spermato- 
genesis of Pteridophytes, cycadaceous plants, and Ginhgo, arranged 
in order of publication, will give an idea of the advancement of our 
knowledge in this direction. 
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