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II. The Cytology of the Gametophyte Generation. 
The first is the relation of the antherozoids to light. It was stated 
in a former paper that light is essential to their mobility. It is true that 
light has a very great influence upon the antherozoids, as will be shown 
again, but if they are really ready for liberation they will on immersion 
display their activity at any hour, night or day. 
The second point relates to chemotaxis in fertilization. Buller has 
recently performed some experiments on the eggs of certain animals, which 
lead him to infer that in external fertilization there is no such thing as 
chemotactic attraction of the spermatozoids. He seems inclined to follow 
Bordet, and to extend this generalization so as to include the Fucaceae. 
Thus he says in explaining Bordet’s conclusions : ‘ According to this 
observer it is simply the ability of the spermatozoa to adhere to surfaces 
by the tip of one of the cilia which leads to their collection upon an egg, 
while their meeting with it is a matter of chance. A few observations of 
my own at Naples upon the fertilization of Cystoseira barbcUct did not 
reveal to me any certain attraction of the spermatozoids from a distance, 
but the collection of the spermatozoids upon the eggs in consequence of 
their ability to cling to surfaces was clearly seen. Nevertheless in view 
of the positive statement of Strasburger a careful re-investigation of the 
question seems to be desirable. 5 It is not my intention at present to 
discuss the question of chemotaxis in the Fucaceae. As regards Dictyota , 
however, it would be difficult to find anywhere a stronger suggestion of 
attraction at a distance than is offered by the phenomenon described above, 
where, out of several hundred eggs crowded together in a small dish, a few 
here and there are surrounded by several layers of spermatozoids, while 
the great majority of the eggs have none attached to them. Nor can it 
be said that in the former case the crowd of antherozoids are entangled 
in a mucilaginous envelope, for in the first place their movements are 
absolutely unrestrained, and furthermore, staining with gentian violet fails 
to demonstrate the presence of any such substance. 
During the process of fertilization the eggs of Dictyota do not revolve 
as do those of Fucus , but the antherozoids, unless too crowded, slowly gyrate 
with the end of the cilium resting upon the surface of the egg. At the 
same time the body of the antherozoid displays a rapid vibratory motion. 
Frequently the cilium, instead of being straight, presents a wavy appearance 
(figured in the ’97 paper). When the sperm is becoming less active waves 
can be seen travelling along the length of the cilium. 
It has been far more difficult to trace by means of sections the path 
of the spermatozoid through the cytoplasm to the nucleus than it was 
in Fucus , and the reasons for this are obvious from the description 
given above. The examples observed are too few in number to enable 
one to base any conclusions upon them. The case shown in Fig. 20 
is interesting for various reasons. The dark object seen to the right 
