444 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
as much as five months after sperm had been put into the annulus 
laid eggs that developed. 
That the sperm placed in the annulus actually fertilizes the eggs, 
rests upon indirect evidence. In the above isolation cases, it must 
be that the sperm in the annulus was used to fertilize the eggs, or 
else that they developed parthenogenetically. But it was found 
that careful removal of the annulus full of sperm from females 
about to lay, did not prevent the normal laying of eggs, but that 
these eggs did not develop; while in other cases where the annulus 
was removed after laying the eggs, the eggs did develop, so that it 
seems demonstrated that the sperms preserved in the annulus are 
used to fertilize the eggs. 
When the sperm is removed from the annulus, it soon swells and 
becomes disorganized in fresh water. Its preservation for so long a 
period is of unusual interest in these animals living in fresh water in 
which the sperm is transferred from male to female, not directly into 
the egg passages, but indirectly into an external pocket, a mere fold 
in the shell, kept there for weeks or months and finally brought into 
connection with the eggs without being destroyed by the water. This 
exclusion of water from the sperms embraces three periods and sets of 
organs from the time they leave the vas deferens till they meet the egg. 
In the first, sperm are transferred by the male into the annulus, in the 
second they are kept sealed up in the annulus, and in the third they 
are got out of the annulus and reach the eggs. We may refer to these 
as transfer, preservation, and discharge. 
The details of transfer may be elsewhere described, but the chief 
facts are as follows. The male everts the bent nozzle-like papillae 
at the mouths of the vasa deferentia and through them discharges 
sperm into an actual tube that passes down each of the two first 
abdominal appendages, or stylets, and manages to keep the contact 
of the papilla and tube a close one by means of the special soft mem¬ 
brane on the second stylet of each side. Both first and second stylets 
right and left are locked together by a peg-and-groove contrivance. 
The sperm thus passes through a closed tube, as it were a temporary 
extension of the vas deferens formed by adding onto it the stylet tube, 
as far as the tip of the pointed and specialized stylet. As this tip is 
actually thrust into the interior of the cavity of the annulus, the sperm 
is put from the testes into the annulus without coming into the water. 
The manipulation and introduction of sperm continues a long time 
