Messrs. Hancock and Embleton on the Anatomy o/Eolis. 89 
being placed ebiefly on tbe right side^ partially covered by the 
stomach which dips down on the median line between them and 
the posterior border of the buceal mass ; all their outlets leading 
to a common orifice, which is situated on the right side between 
the terminations of the rows of papillae and the margin of the 
foot, and a short way behind the dorsal tentacles. 
This orifiee exists at the depressed apex of a small conical nip- 
ple or papilla, formed by a projecting and slightly puckered fold 
of skin, and is readily seen. When this orifice is laid open, a 
vestibule, or small cavity, is discovered, on the inner wall of which 
are three perforations, two being easily discovered, surrounded 
by a wrinkled and projecting border of skin, one directly in front 
of the other ; a third may be detected with some pains among the 
folds around the posterior opening, and at its anterior part. Of 
the two openings first mentioned the anterior leads to the male 
apparatus ; the posterior, which is the largest of the three, leads to 
the female organs ; and the third, by far the smallest, leads to the 
spermatheca. Such is the state of the external parts in their 
most perfect state of eontraction, after death, or in the absence 
of sexual exeitement during life. But during the breeding sea- 
son it is often found that the vestibule is obliterated by the pro- 
trusion outwardly of its inner wall, and then the anterior aperture 
is replaeed, as it were, by a curved conieal projection with its con- 
cavity posteriorly. This projection is the penis in a partial state 
of protrusion, and directly behind the base of it is seen the large 
female orifice, and immediately within this exists the third and 
smallest opening. 
To obtain a complete view of the internal generative organs, it 
is neeessary to remove all the other viseera. The ovary, PI. III. 
fig. 1 d, is then seen as before mentioned, filling nearly the whole 
of the posterior part of the eavity of the body. It is of a pale yel- 
low colour, lobulated and granular, broad and thick in front, ta- 
pering behind. Its anterior surface is concave, and moulded upon 
the parts directly in front. These are two large, delicate, semi- 
pellucid, convex and somewhat rounded lobes of a gland accessory 
to the female parts, PI. III. fig. g g, which we will call the 
mucus-gland, since it appears to secrete the mucus-like envelope 
of the ova, as will afterwards be seen. 
These lobes are continuous with each other below, but above 
there is a deep fissure between them running from behind forwards. 
At the posterior end of the fissure lies the convoluted part of the 
oviduet, fig. I /, which runs forwards into the fissure. Under 
the eonvolutions of the oviduct lies the spermatheca with its duct, 
fig. I A, i. At the anterior end of the fissure, and resting on 
the front of the right lateral lobe of the mucus- gland, lies a long 
pale-flesh-coloured much-convoluted tube, fig. I c, the testis, one 
