STRUCTURE OF THE SPERMATOZOON. 
321 
cient data to go upon. In all I found the filament very fine, 
and requiring great care in the illumination to show it pro- 
perly, as when, after a good deal of trouble it was shown 
well with the ^ immersion, I found I could readily see it 
with the y’g oil, and even the -^V oil immersion. 
The drawing was made from a specimen prepared in a 
mixture of glycerine and absolute alcohol, and drawn with 
Messrs. Powell and Lealand’s — oil immersion and A eye- 
piece. The filament is very fine, and is connected to the 
tail by a membrane, which is much wider than in the 
Amphibia, and allows it to move further from the tail ; it 
is also longer than in the Amphibia, and is more folded in 
consequence. I found in one specimen a number of heads 
with no corresponding tails. I have not, however, been 
able to get at the history of the individual who supplied it. 
