Seminal Products in Limpets. By W. H. Dall. LOT 
investing membrane, for the space of an inch from the posterior 
end of the median line, forward, the ducts were swollen and 
enlarged. They projected in a marked manner from the smooth 
and evenly rounded normal surface, like “‘ varicose veins,” except 
that the ducts are nearly parallel. In the ripest portions the 
delicate investing membrane of the testis had become ruptured or 
perforated, and the seminal matter exuding from these punctures 
had been solidified by the alcohol in little rounded grains or 
particles, which had not been disturbed by the careful manipulation 
of dissection. 
At those points where the congested or enlarged ducts were in 
mechanical contact with the roof of the perivisceral cavity, that 
is to say, the floor of the renal sac, numerous minute, but plainly 
visible, oval perforations appeared. These were oblique to the 
general plane of the membrane, the opening on the side adjacent 
to the testis being usually directed somewhat backward instead of 
vertically downward. They had also something of a funnel shape, 
being larger on the side toward the testis, and some of them 
were twice as large as others. The largest had a diameter of ‘015 
inches, and would admit the passage of a fine bristle into the renal 
sac. On applying slight pressure from above, the fluids contained 
in the renal sac passed through in a minute jet. They were 
irregularly distributed, corresponding in locality to the ripeness of 
the ducts of the testis. Except where the testis in its ripe con- 
dition was in immediate proximity or actual contact with the 
membranes of the renal sac, no such orifices or pores were to be 
found. In the other specimens in which the testis or ovary showed 
none of these signs of maturity, no such orifices could be detected. 
The membranes in such cases presented a smooth and practically 
impervious surface in every part. 
It would seem as if these facts gave a final solution to the diffi- 
culty as follows: 
When the ovary or testis is ready to discharge its products, 
that portion of it which is ripe evinces its condition by an en- 
largement of the ducts, continuing until dehiscence takes place. 
Coincidently, the superincumbent membranes of the renal sac 
(whether by sympathy with the congestion of the seminal organ 
or otherwise) become lax and perforations make their appearance 
immediately adjacent to the dehiscent ducts. Through these 
orifices the seminal products make their way. A contraction of 
the pedal muscles would be sufficient to cause the ejection. After 
reaching the renal sac, the question of the extrusion of the ova or 
semen presents no difficulties. ‘The same agency which empties 
the sac of its secretions through the renal papilla would suffice to 
eject the seminal products, which floating in the water would cause 
the fertilization of the ova as in the case of Chiton. 
