438 W. A. HASWELL. 
and wide ejaculatory duct leads to the male aperture at the 
extremity of the penis. The penis is devoid of any chitinous 
parts. It is in the form of a truncated cone with muscular 
walls and an epithelium of cylindrical cells. 
There are two very distinct kinds of spermatozoa—a larger 
and asmaller. The larger, or “giant” form (fig. 15) is °35 
mm. in length—about eight or ten times the length of the 
smaller. It is a long, cylindrical filament. Of this the pos- 
terior portion, which tapers very finely, represents the tail, . 
the greater part of the filament representing the middle-piece. 
Along the length of the middle-piece and tail runs a very in- 
conspicuous, contractile, spiral flange. The head is repre- 
sented by the anterior portion of the filament, which is not 
modified in any marked way, but is distinguishable from the 
middle-piece merely by being usually bent at an acute angle 
on the latter, and by being devoid of the spiral flange. No 
chromatin elements were brouglit into view in any part by the 
action of methylene-blue or gentian, unless two rows of minute 
granules which run throughout the length of the middle-piece 
are of this nature. 
The smaller sperm (fig. 14) has likewise no definite head, 
but the anterior end is slightly enlarged, and terminates in 
an abrupt, nearly transverse, face. Some distance behind 
this the sperm becomes distinctly compressed, and this com- 
pression 1s continued to near the posterior extremity, where a 
short, uncompressed, filamentous portion represents the tail. 
Staining with gentian-violet brings out a series of granules 
in the axis of the middle-piece increasing in bulk towards its 
posterior end. The smaller sperm moves actively with a 
wriggling motion, during which it is thrown into a spiral. 
The movement is intermittent, and, when it ceases, the sperm 
usually becomes straightened out, but sometimes assumes 
various definite curves. The giant sperm moves with a gliding 
motion when a number are in contact, unless they are wedged 
very close. But it also sometimes executes wriggling move- 
ments of the tail part, which are much less active than those 
of the smaller sperm. 
