SEXUAL ACTIVITIES OF THE SQUID 393 
changes in elasticity and the freedom with which membranes 
will move on each other may be disturbed. After the sper- 
matophores have been in the solution some minutes, if they are 
to be used for work for a long period, more sea-water may be 
used to dilute the solution. Generally it is best to use material 
that has recently been put into the solution. 
The method used in studying ejaculation was to remove the 
spermatophore from the magnesium chloride solution to a watch- 
glass with a little sea-water, placed on a black background. 
The cap thread was then grasped with forceps and the whole 
spermatophore shaken. With a reasonably powerful engraver’s 
glass held on the head with a spring the process of ejaculation 
may be watched, and with a large-mouthed pipette filled with 
formaldehyde the process can be stopped when desired. The 
time for ejaculation may be slowed down to take from a minute 
to two minutes, so it is possible to supplement observations 
made on the fixed material by observations on the ejaculating 
spermatophores. 
It is necessary to concentrate attention on one portion at a 
time, but there is no difficulty in following movements of parts 
under the lens of a compound microscope. The chief trouble 
is in focusing attention on particular parts, for everything is 
moving at the same time and the mechanism is too complicated 
to be taken in at a glance and too large for all to be under a lens 
of sufficient power at one time. 
As the process of ejaculation is somewhat complicated, a 
series of diagrams are given on plate 6, from which all portions 
not essential to understanding the process have been eliminated. 
By referring to these diagrams at this time it will be easier to 
follow the processes of ejaculation as they are given in other 
figures and descriptions. 
The cap end of the cap thread is flattened and is apparently 
applied and cemented to the outer tunic in a somewhat spiral 
manner so the otherwise open end of the tunic is held shut. 
When the thread is pulled it loosens where cemented (fig. 4), 
and the end of the outer tunic is allowed to open. There is 
evidently some tearing, but not much. 
