REPORT ON THE NUDIBRANCHIATA. 
139 
end high, rounded; the upper side rather flat, with an impression of the upper side of the 
lung ; the small right side is rounded with a longitudinal furrow beneath for the intes- 
tine (which in its last part runs over the vesicula seminalis) ; the larger left side is 
arched. The body consists of a smaller yellowish-brown hinder portion, the hermaphrodite 
gland, whose under margins embrace the greyish coloured seminal bladder ; and a larger 
yellowish- white anterior portion, the mucous and albuminiparous glands (PI. V. fig. 26, b ; 
PI. VI. fig. 1 2, b); both can be easily freed from each other. The hermaphrodite gland shows 
an arched upper surface traversed by fine furrows, but on the under surface there is a 
deep egg-shaped depression (for the seminal bladder) ; it is made up of two halves, nearly 
equal and not quite separated ; in front and in the middle line, a portion of the yellowish- 
white hermaphrodite duct is visible upon its upper surface. The gland is as usual made 
up of a number of variously-sized lobes ; the smallest lobes are pear-shaped (PI. VI. fig. 
13), with numerous ovarian follicles on the upper surface; there were no developed 
genital ^products. The short efferent ducts (fig. 13, a), which take their rise from these 
lobes, unite with each other to form thicker ducts ; finally, there are two main ducts, 
forming a single duct, at the hilus of the gland, which runs over its upper surface with 
corkscrew-like windings, which when uncoiled have a length of 5 '5 cm. with a diameter 
of '6 mm. The duct opens behind on the under side of the anterior genital mass, near 
the albuminiparous gland. 
The anterior genital mass (PI. V. fig. 26, b ; PI. VI. fig. 12, b) is hardly half as large 
as the hermaphrodite gland; it is flattened on the upper side and arched on the lower 
side ; the left half is larger than the right, and separated by a furrow, which is more 
conspicuous on the lower side. The left hand portion is more yellowish in colour ; the 
right hand portion whitish, with finer windings ( albuminiparous gland). The cavity of 
the mucous gland is narrow below, and passes into its narrow duct (fig. 12, c), which 
has fine longitudinal folds ; the duct of the seminal bladder joins it at its base ; it then 
becomes wider, its length being 15 mm., diameter '9-1 mm. ; it runs along the outside 
of the rectum as far as the body-wall, in which it then lies, and was followed with 
difficulty beneath the lung as far as the hinder portion of the (female) genital furrow to 
the vulva (PL V. fig. 2), this portion measuring 4 mm. in length. The outermost portion, 
the vagina, has fine longitudinal folds. The seminal bladder is spherical, about 10 
mm. in diameter, of a dirty yellowish-grey colour, 1 and was filled with ochre-yellow debris ; 
its duct is delicate and coiled, measuring when unrolled 15 mm. long. 2 — The end of the 
hermaphrodite duct behind, on the under surface of the anterior genital mass, bifurcates in 
the usual way at the albuminiparous gland ; the female branch is short and opens near 
1 The anterior genital mass was so hardened that it was impossible to make out with certainty the relations of 
its constituent parts. 
2 Stoliczka (Malacology of Lower Bengal, I., On the genus Onchidium, Journ. of Asiatic Soc., vol. xxxviii., 
part 2, 1869, p. 92) found the seminal bladder filled with a brownish-yellow mass, which contained bodies like sponge 
spicules, and others like the “ peculiar arrows connected with the copulation of Helices.” (It) 
