582 Bnller,—Physiology of the Spermatozoa of Ferns, 
spermatozoa brings them to rest. Recovery takes place on 
reabsorption of the water. The protoplasm of the spermatozoa 
is penetrated very slowly or not at all by sugar and neutral 
salts, rapidly by glycerine, and very rapidly by alcohol. 
The swarm-period of the spermatozoa of Gymnogramme 
Martensii is about 120 minutes. Previously determined 
swarm-periods are much shorter. 
The starch in the vesicles of the spermatozoa of Gymno¬ 
gramme Martensii disappears during the swarm-period. 
The work for the above paper was done between November, 
1898, and August, 1899, during the term of an 1851 Exhibition 
Scholarship, in the laboratory of Professor Pfefifer at Leipzig. 
I have much pleasure in acknowledging with my best thanks 
his kind advice and stimulating criticism. 
