1910] HOYT—FERTILIZATION IN FERNS 363 
to emerge within two minutes after the entrance has occurred. Some- 
times they remain almost motionless in front of the archegonium and 
die after a few minutes; but often they recover and swim away. 
The movements of such sperms are strikingly different from normal 
movements. They move away quickly in almost a straight line, 
sometimes swerving slightly from their straight course, sometimes, 
upon striking an obstacle, turning slightly to one side and passing this; 
or they may move about irregularly, with irregular rotation on their 
axes. They move more in one plane than do the normal sperms, 
and do not show the marked swinging of their anterior ends that is 
characteristic of the normal movements. Often such sperms gradu- 
ally regain their spiral form and their normal spiral movements, and 
finally swim off in a fairly normal manner. A few sperms which had 
left the archegonium were observed to go to the boundary of the 
attractive region, and then turn and reenter the archegonium. 
The movements of the sperms under other conditions are exceed- 
ingly complex and varied. When sperms are placed in a very thick 
quince seed jelly, or when they enter far into a strong salt solution, 
they constantly swing their anterior ends about in large circles, at 
the same time rotating on their axes; they turn here and there, con- 
stantly changing their direction of movement, and frequently chan- 
ging their direction of rotation. Thus one sperm in thick jelly was 
observed moving slowly forward in short jerks, by half-revolutions 
first in one direction and then in the other. Such movements are 
continued as long as the sperms are alive. 
Sperms which have become attached to some solid body by their 
cilia or their vesicles perform almost every conceivable variety of 
movement which is possible for them under these conditions. They 
frequently whirl their unattached ends round and round in one direc- 
tion, and then suddenly reverse this, making several or many turns 
in the other direction. After continuing this whirling for some time, 
they often swing from side to side several times and then continue 
whirling round and round as before. They give occasional violent 
jerks and Swings, sometimes almost breaking themselves in two, 
and continue their complex movements until they die or free them- 
selves, 
Often sperms approach an open archegonium without entering, 
