174 BULLETIN OF THE 
anywhere the trace of a connection with the intestine. On general 
grounds one would be inclined to believe that the single terminal open- 
ing was that of a cloaca; but no evidence of any connection between 
the end of the intestine and this thin-walled portion communicating 
with the dorsal sac was obtained. It must then remain for future 
investigations to decide whether this is morphologically a cloaca or 
merely a vas deferens. 
The hypodermis in the terminal papilla is composed of a single layer 
of approximately cubical cells (Plate VII. Fig. 90). This is the only 
portion of the body wall in which the boundaries of the hypodermal 
cells can be seen. 
The spermatozoa are usually found in such enormous numbers that 
it is difficult to make out their true shape. They appear much like 
micrococci, and when seen alone (Plate IV. Fig. 55) are slightly oval, 
highly refractive bodies 1 a in diameter. The merest indication of a pro- 
toplasmic envelope surrounding them is found in the shape of a very 
narrow light peripheral zone. They stain very deeply, and their minute 
size renders it impossible to recognize any structure in them. It is 
probable that, as in other Nematodes, the spermatozoa undergo some 
metamorphosis after being introduced into the body of the female. 
From one individual spermatic masses were voided into the sea-water 
in which it was kept. There was no sign of motion in the mass when 
flattened under a cover glass, and when dried on a cover glass and 
stained nothing besides the oval spermatozoa could be seen, except a 
certain amount of coagulated fluid. 
There may be found in the dorsal sac as well as in the body cavity 
of certain male specimens peculiar pale bodies, not easily stainable and 
varying greatly in form. They are probably the same as those which 
Biirger (p. 647) speaks of as “ovale Gebilde von mattem Glanze, an 
denen nicht zu errathen war, ob sie gleichfalls Kerne oder Kinlagerungen 
bedeuten." Macerations show that they are probably parasitic Grega- 
rinida, the various appearances obtained from sections being due to 
their having been cut in different planes (Plate VII. Fig. 91). 
b. Female. 
I do not believe that any of the previous observers have had a fe- 
male. Verrill (79) described the posterior end in the “female” as 
“gubtruncate with a small terminal papilla." This applies exactly 
to some males, and, as Figure 56 (Plate IV.) shows, is very unlike the 
