580 Buller.—Contributions to our Knowledge of the 
slime at the mouth. The vesicles are somewhat sticky, and 
sometimes become attached to various objects. A sperma- 
tozoid, in struggling to get free, may break away from its 
vesicle and lose it. Pfeffer 1 , however, has observed that, 
as a rule, the vesicle remains attached during the whole of 
the swarm-period. This is certainly the case with Gymno- 
gramine Martensii. 
Pfeffer 2 made some experiments to determine whether 
the starch disappeared during the swarm-period. He killed 
spermatozoa after they had been liberated for an hour, and 
compared the quantity of starch contained in the vesicles 
with that in the vesicles of spermatozoa when just set free. 
Although the quantity of starch appeared to have somewhat 
diminished during the swarm-period, he was obliged to admit, 
having repeated the experiment twice, that the result was 
not decisive. 
It has already been stated that the spermatozoa of Gymno- 
gramme Martensii move well for about two hours, after 
which they gradually come to rest, the time of longest 
movement being about three hours. I decided, therefore, to 
compare the amount of starch present in spermatozoa just 
liberated and such in spermatozoa after three hours’ freedom. 
Similar prothallia from the same pot were used. The experi¬ 
ments were repeated three times. It was found that the 
starch had either greatly diminished in quantity or had dis¬ 
appeared entirely. A considerable number of spermatozoa, 
after being stained with iodine, were seen to be quite free from 
starch. On the contrary, all the freshly liberated spermatozoa 
contained the usual quantity, the large and small grains 
becoming very clear with the iodine reaction. 
From the foregoing result, it would seem that Pfeffer’s 
suggestion that the starch may be used as a food material 
during the swarm-period is justified, at any rate in the case 
of Gymnogramme Martensii. If, however, the swarm-periods 
for the spermatozoa of other species of Ferns are as short as 
those given by Strasburger and Voegler it is very doubtful, 
1 Pfeffer, loc. cit., Bd. i, p. 370. 2 Ibid. 
