360 BOTANICAL GAZETTE [MAY 
new direction. The result of this is that they experience the con- 
ditions on all sides before they continue their course in a new direction. 
In going in a new direction they may turn up, down, or to one side. 
Apparently the direction toward which they turn is that toward which 
the anterior end of their spiral points, but their small size made it 
impossible to determine this with certainty. 
The movements shown in the negative and positive reactions are 
of the same kind as those described above. If a crystal of some salt, 
such as potassium nitrate, sodium chloride, etc., be placed at the 
edge of a drop containing sperms, a solution repellent to the sperms 
diffuses into the water. Sperms approaching this solution show 
various movements. Some of them swing their anterior ends through 
large circles, at the same time revolving on their axes, and then go 
forward as described above; such sperms often turn almost immedi- 
ately from the stimulant and leave the injurious region. Most sperms, 
however, swing their anterior ends through smaller circles and make 
small turns. Such a turn may carry them into the solution, along- 
side of it, or away from it. If it carries them away, they usually 
continue this course; but if it carries them in or alongside, they 
turn again and again until they are headed away from the source 
of stimulation, and then continue forward. ‘These sperms, therefore, 
usually wander here and there about the field before being headed 
away from the stimulant. Fig. 2 illustrates the course pursued by 
such sperms. 
In a study of the positive responses of the sperms to the arche- 
gonium, it is immediately seen that the reactions are varied. While 
some sperms seem at first sight to turn directly and enter the arche- 
gonium immediately (figs. 3 and 4), others enter only after wandering 
about the field, occasionally going past the archegonial mouth and 
then turning back (jigs. 5 and 6), while others pass indifferently 
(fig. 7), or change their courses without entering (jigs. 8-10), or turn 
and leave the region (figs. rr and 12). The sperms swimming in 
water move with great speed, but upon reaching the region in front 
of an open archegonium, they are slowed up by the extruded slime. 
A close examination of those sperms which seem to enter by turning 
directly to the archegonium shows that some of these slow up suddenly 
and swing their anterior ends through large circles, at the same time 
