362 BOTANICAL GAZETTE [MAY 
with respect to the archegonium, not by one large swing, but by a 
series of small swingings of their anterior ends and rotation on their 
axes as they go forward, thus reaching the archegonium by a number 
of successive changes in their spiral course. This reaction is char- 
acteristic for those sperms whose movements were sufficiently slow 
to be followed exactly. A few sperms were observed pursuing a 
markedly spiral course to the archegonium, and turning back when- 
ever their movements tended to carry them away from it; and in all 
these cases where the movement was sufficiently slow to be followed, 
the sperms attained their orientation by a series of gradual swingings 
of their axes toward or away from the archegonium. 
Occasionally, the sperms are observed to collect in a certain 
region, either in front of an archegonium or at some spot on a pro- 
thallus, and to swim about in this field. These react by turning 
back when they reach the boundaries of a fairly definite region, and 
only occasionally does one leave the group. Sperms entering this 
region do not react, but upon passing through and tending to leave 
it on the other side they react by turning back (fig. 10). These 
reactions are strictly comparable with those described by JENNINGS 
for Paramecium, and with the “apobatic”” movements described by 
ROTHERT for certain bacteria. 
It has been mentioned that some sperms will approach an arche- 
gonium without entering. Many of those which have been attracted 
and have gathered at the mouth of a full neck will suddenly leave 
the field of attraction; others which have entered and have passed 
down the neck will suddenly emerge at great speed, although others 
at the same time are being attracted and are entering. Since others 
are attracted it does not seem probable that the attractive substance 
has become repellent. We must believe, rather, that these sperms 
have become physiologically changed, so that they now react nega 
tively to a substance to which they previously reacted positively. 
Such emerging sperms are long and drawn out to almost a straight 
line; they shoot out violently from the archegonium, often forcing 
their way through the crowd of sperms collected at the mouth. They 
sometimes emerge backward, but usually come out with their anterior 
end foremost. They are sometimes seen to come from a great dis- 
tance down the neck, apparently from the venter, and may beg! 
