1897 | DEVELOPMENT OF THE ANTHEROZOIDS OF ZAMIA 2t 
tube. The motion when swimming free in the sugar solution is 
in no way different from the action observed in the pollen tube. 
The general motion is a continuous rotation of the body, always 
in the same direction around an axis passed through the apex of 
the helicoid spiral. Viewed from the head end or apex of the 
spiral the rotation is in the direction of the hands of a clock, 
and contrary to the turns of the spiral band. They roll round, 
first here, then there, resembling in this respect the motion of 
Pandorina. After moving about rapidly for from five to ten 
minutes they usually cease all progressive motion, but continue 
to rotate for a considerably longer period. The rotary motion 
also soon ceases, but the cilia continue to vibrate for a consider- 
ably longer time. 
In fecundation the entire antherozoid unchanged swims into 
the archegonium, passing between the ruptured neck cells. 
Several antherozoids commonly enter each archegonium, from 
two to three having been found in almost every archegonium 
examined, and in one case four. Only one of these takes part 
in fecundation, and the others may be found presenting a per- 
fectly normal appearance or in some stage of disintegration. 
The study of the centrosome-like body, which formed the 
main feature of my previous paper, has continued to grow in 
interest as the investigation has progressed. No case is known, 
so far as I am informed, where true centrosomes fulfill such 
functions as are performed by the centrosome-like body in 
Zamia. The very large size of the organ; the loss of the 
radiating filaments of kinoplasm in an early stage of the division 
of the generative cell; the swelling and breaking down of the 
body in the anaphases of the same division; the disintegration 
of the central part of the body; and the final growth of the 
membrane, formed by the broken wall of the body, into the 
spiral band which bears the motile cilia of the antherozoid—are 
features and functions peculiar to the centrosome-like body of 
Zamia. It is interesting in this connection to note that the sub- 
stance of the band stains a dense blue black with Heidenhain’s 
iron hematoxylin, which is primarily a centrosome stain, 
