INTRODUCTION. g 
In the July, 1897, number of the Botanical Gazette the writer's 
second preliminary paper on **The Development of the Antherozoids 
of Zamia” appeared. The membrane formed from the outer wall of 
the centrosome-like body was found to grow into an extended band 
which assumed the form of a helicoid spiral, became appressed against 
the plasma membrane of the cell, and gave rise to the cilia of the sperma- 
tozoid. The cilia appear first as small protuberances on the band and 
gradually grow in length until mature. The structure of the mature 
spermatozoids, their motions in the pollen tube and while swimming 
free in sugar solutions, were described and figured. Their action in 
the process of fecundation was also described. 
Almost simultaneously with the publication of the writer’s second pre- 
liminary paper on ‘* The Development of the Antherozoids of Zamia,” 
Belajeff, a Russian botanist, published two preliminary papers describ- 
ing the presence of acilia-forming organ or Vebenkern in the spermatids 
of Filicinee and Equisetinez (8 and 9), which is doubtless identical 
with the similar organ in Zama and Ginkgo. They apparently origi- 
nate in the spermatids, since no trace of them could be discovered in 
the spermatid mother-cells in the resting condition or during karyo- 
kinesis. The first changes visible in the metamorphosis of the sperma- 
tid cells occur in these organs. They gradually become extended 
into a thread which assumes the form of a helicoid spiral of which the 
extended turns of the posterior end surround the nucleus. The cilia 
of the spermatozoids are developed from the anterior end of this 
spiral, appearing first as small protuberances on the thread, which 
finally become greatly extended and.form the cilia. 
In the October number of the Botanical Gazette the writer’s third 
preliminary paper, **Notes on the Fecundation of Zamia and the 
Pollen-tube Apparatus of Ginkgo,” appeared. In this paper the 
important features described were that in the fecundation of Zama 
the spermatozoid enters the protoplasm at the apex of the egg cell 
where it undergoes disintegration, the nucleus escaping from the 
cytoplasm and spiral band of the spermatozoid and passing thence 
alone to the egg nucleus with which it unites. The fecundation is 
thus a union of cells, the cytoplasmic structures of the spermatozoid 
fusing with the cytoplasm of the egg cell, while the sperm nucleus 
passes on and fuses with the egg nucleus. The spiral band which is 
developed from the centrosome-like body was shown to have no con- 
nection with the process of fecundation, remaining, after the escape 
‘of the nucleus, intact at the apex of the archegonium and gradually 
disappearing during the development of theembryo. The centrosome- 
like bodies in the generative cell of Ginkgo, first described by Hirase 
and termed *‘attractive spheres” (56), were found to originate de novo 
in the cytoplasm, and their undoubted identity with the centrosome- 
like bodies in Zamia was pointed out. These bodies in Zama and 
