110 MR. W.S. KENT ON A NEW NUDIBRANCH. [Jan. 28, 
to the species I here introduce, it being the only one possessing a 
double row of branchial papillze down each side of the back. 
In the species recently obtained from the docks, and for which I 
here propose the name of Embletonia grayi, the branchial papille 
are developed to a still further extent, three, in the adult specimens, 
entering on each side into the formation of the second anterior fas- 
ciculus*. The oral lobes, moreover, are highly developed, while in 
Embletonia pallida they are described as being small and indistinct. 
The lingual membrane, or odontophore, again, furnishes points of 
distinction, the median denticles surpassing the lateral ones in size 
more considerably than in £. pallida; and the odontophore in this 
respect more closely approximates to that of Holis nana. The number 
of lingual plates also exceeds that possessed by Hmbletonia pallida, 
being not fewer than thirty-five, while in the latter there are said to 
be but twenty-one. 
The colour of the little Mollusk is a semitransparent white, having 
the integument of the antero-dorsal region usually more or less 
sprinkled with minute ramifying pigment-cells of a blackish hue, 
these occasionally extending over the papillee. The eyes are deeply 
sunk beneath the integument, and situated, some distance apart, 
immediately behind the tentacula; in many instances these organs 
are scarcely discernible, more especially in those specimens wherein 
the superficial pigment-cells are greatly developed. 
It is particularly remarkable that this Nudibranch is a denizen of 
water containing but about one-third of the saline constituents of 
pure sea-water. Its habits are gregarious; and its tastes appear to 
be eminently carnivorous, the luxuriant masses of Cordylophora 
lacustris clothing the submerged timber-balks in the docks proving 
a special attraction, and serving not only for the purpose of food, 
but also as a suitable nidus whereon to deposit its spawn. ‘The ova, 
or spawn, on being extruded are enveloped in a gelatinous mucus, 
adherent at first to any object wherewith it may be brought into 
contact ; this property, however, disappears after a brief exposure 
to the surrounding medium. The spawn masses are of an irregular 
oval form, each mass containing from five or six to as many as forty 
or fifty ova. 
On first leaving the egg the young are, in common with other 
Nudibranchiata, furnished with a delicate nautiloid shell, and propel 
themselves through the water with great activity by means of their 
ciliated lobes, or epipodia. Figs. 12 and 13 represent the animal 
about one month after quitting the egg; but further stages of deve- 
lopment remain to be traced. The length of the adult animal varies 
from one to as much as three tenths of an inch, though the majority 
of the specimens examined have not exceeded that of two tenths of 
an inch. 
* One or two specimens have been met with having three papille in the first 
anterior fasciculus also. 
The arrangement of the papille also holds good in distinguishing this spe- 
cies from the Calliopea bellula of D’Orbigny, figured and described in the ‘ Mag. 
de Zoologie’ for 1837. 
