MR. A. HANCOCK ON THE ANATOMY OF DORIDOPSIS. 195 
composed of numerous large, pale, oval sacculi (fig. 6 d), having their upper or external 
extremities encircled with nine or ten small rounded sacculi (e) of a yellow colour. 
These are the ovigerous sacs. The large central sacculi compose the testicular organ, 
and were found erammed full of spermatozoa in parallel order, and in various states of 
development. The connexion of the oviduct with the large sacculi was not observed; 
but a minute tube or duct was seen uniting them together, creeping over the surface 
of the organ and passing between the ovigerous sacs. The whole organ gives to the 
surface of the liver the appearance of a tessellated pavement, with large, pale, circular 
‘centres, surrounded by a dark yellow margin composed of numerous rounded pieces. 
In Polycera ocellata the so-called ovary, as in the preceding species, is formed of two 
kinds of saceuli; but in this form they are more nearly of equal size. The testieular 
sacculus (fig. 5 d) is pyriform, with the small or inner extremity attached to a twig of 
the oviduet (c) ; the broad extremity is studded with a few irregularly rounded ovarian 
saceuli (e), which open into the former. 
In Bornella digitata the appearance of the parts is very peculiar. The ovary is of a 
greenish colour, with dark dusky-green spots, which are formed by the rounded extre- 
mities of large pyriform vesicles (fig. 10 d). The tapering or inner extremities of these 
gradually subside into delicate tubes, which, uniting, go to form the oviduct (c) The 
large end of these sacculi is studded over with comparatively small rounded vesicles (e), 
which communicate with the former by very short constricted tubes, which, being of a 
black colour, are readily observed. The large pyriform vesicles were found to be filled 
with spermatozoa in bundles, and the small rounded ones, communicating with them, to 
contain eges. The former were of a pale watery-green colour, the latter of a yellowish 
hue. | 
In Seyliea pelagica the so-called ovary is made up of three globular masses, the 
surface of which has a granular appearance, as if covered with minute cells. On dividing 
one of these masses through the centre, a very beautiful structure is exposed to view. 
The greater portion of the mass is seen to be formed of two concentric layers, the outer 
(fig. 9e) of which is about half the thickness of the inner (d), and is composed of minute 
cylindrical or fusiform vesicles arranged at right angles to the surface, or in a radiating 
manner. The outer extremities of these vesicles, which frequently bifurcate, abut upon 
the surface of the mass, giving to it the granular appearance before alluded to. The 
inner layer is composed of vesicles of a similar form to those of the outer layer, but which 
are very much longer, and, radiating in like manner, have their inner extremities united 
in pairs, and joined to delicate twigs or branchlets which converge to the oviduct (c) 
that lies in the centre of the mass and issues from it to be joined by branches from the 
other ovarian masses on its way to. the mucous gland. The outer extremities of these 
Vesicles are conjoined to the inner extremities of the vesicles of the outer layer. Thus 
the vesicles of both layers are in communication with the oviduct; and here we have 
à beautiful modification of the male and female saceuli, those of the inner layer bearing 
‘permatozoa, while those of the outer produce ova. 
d I not originally mistaken the ovarian mass for a portion of the liver, I might 
Years ago have satisfied myself of the double nature of the so-called ovary; for this 
