8 SPERMATOGENESIS AND FECUNDATION OF ZAMIA. 
The occurrence of spermatozoids in Ginkgo was first announced by 
Hirase, a Japanese botanist, in a short note in Japanese in the Botan- 
ical Magazine of October, 1896, and a few months later in a prelimi- 
nary contribution, ** Untersuchungen tiber das Verhalten des Pollens 
von Ginkgo biloba,” published in Botanisches Centralblatt, Nos. 2 and 8, 
Band 69, appearing January, 1897. The important features here 
described, other than the fact of the occurrence of motile spermato- 
zoids in one of the phanerogams where they had never before been 
known to occur, was the structure of the mature spermatozoid, which 
was described as consisting of a nucleus completely surrounded by 
cytoplasm. While Belajeff had strongly maintained that the cytoplasm 
entered into the structure of the spermatozoids of certain ferns and of 
Chara, this was yet considered doubtful. Hirase says: 
Die Spermatozoiden von Ginkgo haben eine andere Gestalt als die der héheren 
Kryptogamen. Sie sind eiférmig, 824 lang bei 49% Breite; in der Mitte sitzt der 
Zellkern, welcher durch Cytoplasma vollig umschlossen ist. Der Kopf besteht aus 
drei nie erstreckbar gebauten Spiralwindungen, worauf viele Cilien wurzeln, auch ist 
ein spitzer Schwanz vorhanden. 
About the same time (November 20, 1896) Professor Ikeno, another 
Japanese botanist associated with Hirase in the University of Tokyo, 
announced the discovery of spermatozoids in Cycas. The first an- 
nouncement appeared in the Botanical Magazine, November 20, 1896, 
and was almost immediately followed by a short statement in Botani- 
sches Centralblatt (61). Here, as in the case of Hirase’s preliminary 
announcements above referred to, the articles are limited to a simple 
statement of the occurrence of the spermatozoids and their structure, 
nothing being given as to their development. Ikeno wrote: 
Sie sind etwas grésser als die letzteren [those of Ginkgo] und enthalten Zellkern 
und Cytoplasma. Der Zellkern nimmt den mittleren Theil derselben ein und wird 
von dem Cytoplasma véllig umhullt. Der Kopf besteht aus vier Spiralwindungen 
und trigt sehr reichlich Cilien. Im pollinschlauch findet man zur richtigen Zeit je 
zwei durch die Theilung der generativen Zelle entstandene Spermatozoiden. 
In the June, 1897, number of the Annals of Botany, Ikeno and 
Hirase (68) together published a short note in English announcing 
the discovery of spermatozoids in Cycas and Ginkgo. However, no 
important additional facts were given. 
In the June, 1897, number of the Botanical Gazette the writer's 
first preliminary paper, entitled ‘‘ Peculiar Structures Occurring in 
the Pollen Tube of Zamia,” appeared. The pollen tube apparatus was 
described and the central cell (generative cell) was traced through its 
erowth up to the close of its division just preceding the formation of 
the spermatozoids. Very large centrosome-like bodies were found 
‘in the central cell and their growth, structure, separation of outer 
membrane into segments during division, 4nd disconnection with spin- 
dle formation was described and figured. The discovery of motile 
spermatozoids was also announced, but their development was not 
explained. 
