282 
Shazv. — The Fertilization of Onoclea. 
5. The first division of the egg was in no case found until 
more than a week after fertilization. 
6. It is suggested that the egg becomes plasmolysed as 
soon as the first spermatozoid enters it, and that this serves 
as a provision against injury by following spermatozoids. 
The work which forms the basis of this paper was done 
in the Botanical Laboratory of Leland Stanford Junior Uni- 
versity, with the kind advice and encouragement of Professor 
Douglas H. Campbell, for which the writer takes pleasure 
in here expressing his thanks. The paper was written and 
most of the figures were drawn during the summer of 1897, 
in the Hopkins Seaside Laboratory, a branch of the University 
located at ‘Pacific Grove, California. 
A detailed account of the development and structure of 
the spermatozoid of the Ferns was given by Belajeff 1 before 
the above paper was written, but it had not then been seen 
by the writer. In that account Belajeff brought out the fact 
that there is a specially differentiated body in the cyto- 
plasmic band of the spermatozoid which gives rise to the cilia. 
He described the development of this body (the ‘ Nebenkern ’), 
from a small body near the nucleus of the ‘ spermatozoid 
mother-cell,’ into a thread-shaped body in the mature sper- 
matozoid. The writer 2 of the present paper subsequently 
found these ‘ Nebenkerne ’ in the antheridia of Onoclea before 
and during the last cell-division by which the so-called c sper- 
matozoid mother-cells ’ are formed. But the cilia-bearing 
portion of the spermatozoid of the Fern, like that of the 
Cycad as described by Webber 3 , takes no active part in what 
may be regarded as the essential process of fertilization, and 
therefore no extended reference to these works need be 
appended to the foregoing account of fertilization. 
1 Wl. Belajeff, Three preliminary papers in the Berichte d. deut. Bot. Gesell., 
*$ 97 , P -337 ff- 
2 W. R. Shaw, liber die Blepharoplasten bei Onoclea und Marsilia, 1898. 
Soon to appear. 
3 Webber, ’ 97 , 2, 227. 
