STUDIES OF FERTILIZATION IN NEREIS 
III. THE MORPHOLOGY OF THE NORMAL FERTILIZATION OF NEREIS 
IV. THE FERTILIZING POWER OF PORTIONS OF THE SPERMATOZOON 
FRANK R. LILLIE 
From the Marine Biological Laboratory, Wood’s Hole, Mass., and the Hull 
Zoological Laboratory, University of Chicago 
ERRATA 
Line 6, page 201, volume 12, number 2, February, 1912, “‘the duration of life 
of others to insufficient complete egg-laying,’”’ should read ‘‘the insufficient 
duration of life of others to complete egg-laying.’’ 
THE JOURNAL OF EXPERIMENTAL ZOOLOGY. 
Ill. THE MORPHOLOGY OF THE NORMAL FERTILIZATION OF NEREIS 
1. The spermatozoén: (Fig. 1, a, b, c, d) 
The spermatozoa are unusually large. The head terminates 
in a very delicate perforatorium which possesses a slight distal 
enlargement.! Between the base of the perforatorium and the 
chromatin of the head is some differentiated material forming a 
head-cap (h. c.). This is very distinctly differentiated in position 
and staining reaction from the chromatin of the head. The chro- 
matin of the head is not so condensed as in most spermatozoa; 
1 In the living spermato6én the perforatorium is shorter and shaped more like 
the spike of a helmet. 
413 
THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 12, No. 4 
MAY 1912 
