in Doris, with the pericardium by means of a piriform organ with a strongly lamellated
interior.
R eproductive S ystem.
(See fig. 7, p. 43).
The genitalia fall into two portions, the hermaphrodite gland and the anterior genital
mass, the hermaphrodite duct forming a bridge between them. The hermaphrodite gland
in JE.papillosa1 is an elongate, conical, and practically solid mass, although it is composed of
numerous lobes in contact but still separate from one another. I t lies below the main
posterior duct of the stomach and fills the remainder of the posterior body-cavity. The
lower surface shows a division into right and left halves, which, however, is not very
distinct and usually not visible at all from above. The general structure of the gland is
as in Doris. The smaller follicles contain ova and open into a central space in which the
spermatozoa are developed. The animals are protandrous. According to Pelseneer
young individuals show merely circular sacs containing spermatozoa with no trace of
accessory ovarial follicles. These are developed later as outgrowths of the wall of the
circular sac. As in Doris, the ducts of the various lobes meet and unite to form a single
duct which passes to the anterior genital mass. This varies in size and appearance at
different seasons, but consists mainly of an exceedingly intricate mucus-albumen gland
complex. The mass is bifid,2 and the cleft between the two divisions is filled by the
spermatotheca, which is often very large and purple.
On reaching the anterior genital mass the hermaphrodite duct swells into the thicker
tube known as the ampulla (6), which forms two or three short coils and^rafen
bifurcates into the male and female branches. The former consists of the long and much
convoluted vas deferens (c). This organ does not bear a prostate in any known
vEolid except Ghlamylla, but the upper part is often thick and spongy compared with the
thinner and more muscular part near the exit. In yD. papillosa the diameter is uniform
and the walls consist of three layers; the two outer are muscular and the innermost
secretes a fluid.3 The coils of this tube are extremely complicated and at many points it
seems about to enter the mucus-gland, but’ it terminates in the bag containing the
intromittent organ, which is muscular, conical, and of considerable size. Thus the bag
need not be entirely everted as in Doris tuberculata, but forms a prseputium around the
glans. In JE. pa/pillosa the male genitalia are quite simple, but in other Solids spines and
accessory glands of many kinds are found.
Though the topography of the female organs is not quite the same as in the Dorids,
they consist, as there, of two portions or sections, namely the oviducal section in which
the ova are fertilized and provided with various envelopes previous to expulsion; and the
vaginal section in which the spermatozoa of another individual are. received and stored in
a spermatotheca. The two sections join before they reach the exterior, and both open
1 Other Solids show some variations from this arrangement, though it is the most common, e.g.
the gland may lie beside or above the branches of the alimentary system, and some lobes may be
exclusively male while others are exclusively female.
2 This conformation is obvious in the breeding season, but less striking at other times.
8 Probably a prostatic fluid in which the spermatozoa can move.
into one cavity so that externally only two orifices are visible (male and female), not three
as in Doi'is.
Immediately after the bifurcation of the hermaphrodite tube into vas deferens and
oviduct, the latter makes a short, sharp turn backwards and then a similar turn forwards,
thus describing a course like the letter V. From the base of the V issues a fairly long duct
which communicates with the spermatotheca, and the right limb of the V bifurcates again.
One branch, which is short, enters at once into the mucus-albumen gland complex; the
other, which is longer, runs to the external duct of the same complex and debouches with
it in a common atrium. The disposition is somewhat difficult to describe, but will perhaps
be understood by a reference to Figure 7. I t will be observed that in this figure, as in a
dorsal view of a dissected specimen, the vaginal duct seems to cross the oviduct because
the spermatotheca lies on one side of the oviduct and the continuation of its duct lies on
the other. But though the spermatotheca occupies this position in all the specimens
which I have examined, it should perhaps be regarded morphologically as merely
communicating with the oviduct, not as forming a prolongation on the other side of it. In
any case, however, a small portion of tube must function both as the oviduct and as the
vaginal duct at different times. The arrangement figured by Alder and Hancock for
Facelina coronata does not present this peculiarity, but I have not been able to verify
their account of the genitalia in that species.
Thus starting from the exterior, the vaginal duct of 2E. papillosa begins as an opening
in the wall of the female atrium, situated some little distance within and invisible from
outside. It then runs straight to the oviduct, unites with it for a short distance and then
emerges as a moderately long duct leading to the spermatotheca. There is only one
spermatotheca, not two as in Doris, and I have not seen in any specimen the organs
described by Alder and Hancock as accessory glands, or at any rate have not found
them so fully developed. But as it approaches the spermatotheca the duct dilates,
becoming somewhat uncertain in outline, and its bulges may sometimes assume the
proportions indicated in the Monograph1 (Fam. 3, PI. 8, fig. 2). The spermatotheca
usually (if not always) exhibits a longitudinal fold (due to the pressure of the mucus-
albumen gland complex on either side) which divides it into two portions. They do not,
however, appear to have different functions or to be of any morphological importance.
The walls of the spermatotheca contain a muscular layer; those of the ducts are thin,
fragile, and not muscular.
The portion of the oviduct which lies between the termination of the hermaphrodite
ampulla and the albumen gland is short although it comprises two sharp turns. The
structure of the mucus-albumen gland complex is a little clearer than in Doris, because
the component parts are less compressed. I t is a coiled and flattened tube (which is
simply the dilated oviduct) provided with glandular walls and also receiving the secretion
of the albumen gland. Three separate portions can be distinguished: (a) The albumen
gland. This appears in preserved specimens as a flat, yellowish mass (g), not tubular, and
harder than the parts which adjoin it. I t lies at the back of the anterior genital mass
near the point where the oviduct passes into this latter. In external appearance the
1 The proportions shown in the Ann. and Mag. Nat. Hist, for 1848 (vol. i. pi. 3, fig. 2) are even
more considerable.