44 Papers from the Marine Biological Laboratory. 
the thread moves continuously on until it is entirely free from the outer 
case. The thread as it uncoils must have a somewhat similar twisting 
and this probably accounts for the alternate swellings and constrictions 
along the thread. This appearance is very much more marked near 
the coils than toward the free extremity where the twist would have 
time to adjust itself somewhat. Focussing on the narrow parts shows 
the places of twisting marked by wrinkles and striations in the mass. 
The outer tunic does not shrink nearly as much as it does in the 
squid spermatophore and the middle tunic does not swell nearly as 
much. Indeed they hardly seem to give evidence of all of the power 
that is needed for ejaculation. The whole process is very deliberate. 
It is very possible that the liquid that occupies the space between the 
tunics and the ejaculatory apparatus and sperm mass has osmotic 
properties that are important in the process of ejaculation. 
In the spermatophore before ejaculation much lumpy, granular 
material is present in this liquid. This seems to become much more 
liquid as ejaculation continues. It would seem that most of this 
would be thrown out ahead of the sperm thread, but this is not the 
case. The end of the sperm thread is crowded in against the ejacula- 
tory apparatus in such a way that, when this finally evaginates and 
leaves a free opening to the outside, the sperm thread fills this opening 
at once and the liquid remains inclosed between it and the evaginated 
tube. It is not free to escape in quantities until the sperm mass has 
unwound and the thread of which it was composed has been entirely 
discharged. 
Evidently the spermatophores of Octopus and the squid, while built 
on similar plans, are adapted for quite different actions. It may be of 
service to call attention to some of the important differences. 
The squid spermatophore is adapted for very quick service and for 
filling a reservoir with the entire mass of sperm and sticking it to the 
body of the female. The contents slowly escape from the reservoir 
and are stored in a special receptacle, or fertilize the eggs as they 
leave the oviduct. 
The octopus spermatophore is adapted for very deliberate service. 
The sperm mass is not stored in a special reservoir and there is no 
provision for sticking it to the body of the female. The sperm are 
introduced directly into the oviducts of the female, where they are 
stored until the eggs are ready to be laid. 
The squid spermatophore is accordingly more complicated in 
structure and is under greater tension than that of Octopus. It has a 
cement body, which is entirely absent in Octopus. It has an outer 
membrane and inner tunic that are used in making a sperm reservoir, 
and has these structures attached to the cement body,so it may be 
ruptured at the right time. These are absent in Octopus. The sperm 
thread is also closely packed and bound into a mass that is inclosed in 
