286 E. A. ANDREWS 
thick walls, but only rods of sperm enveloped in some slight se- 
cretion from the deferent duct, or possibly that of the papilla 
or of the glands of the spiral. The thin walls of these tubes break 
open, hernia like, and sperms ooze out. 
The separation of the sperm from the secretion of the deferent 
duct may be due merely to the diminution in diameter of the tub- 
ule; the pressure of the duct would drive the central part of the 
current faster than the envelope and thus the central sperm might 
flow out of the very narrow tip of the canula and leave the envel- 
ope of secretion behind in the wider parts of the tubule. Finally, 
when enough sperm had passed along to fill the annulus, the envel- 
oping secretion might be forced out and this would make that 
wax-like mass that fills the external parts of the annulus and pro- 
jects in excess from its mouth as the so-called sperm plug. Pos- 
sibly again the piston movements of the radius might come into 
play to clean out the secretion from the stylet tubule and ram it 
into the annulus. In fact in the last stages of conjugation of one 
pair slow and repeated movements of advance and recession of the 
triangle were seen which may be interpreted as concerned with 
plug making. 
The use of the glands of the spiral is not known. Possibly their 
secretion cleanses the surfaces to be used in sperm transfer and 
aids in keeping water from the sperm. Possibly the secretion 
may help the enveloping secretion of the deferent duct to adhere 
to the walls of the tubule of the spiral and thus hold it back till 
the sperm has passed on into the annulus. 
THE RIGHT AND LEFT DUPLICATION OF STYLETS 
The striking fact of the exact duplication of both first and sec- 
ond stylets right and left suggests questions as to the use of right 
and left in conjugation. Are both sidesused at each conjugation? 
Again the remarkable dimorphism of the females of C. affinis 
and of probably all other species of that genus, which expresses 
itself in the occurrence of females with the vestibule of the sperm 
pocket opening a little to the right of the middle line and of 
females with the pocket opening to the left, so that the symmetry 
