138 MESSRS. ALDER AND HANCOCK ON 
large, rounded organ, with the interior laminated. This is apparently the same as the 
pancreatic origin in the Dorides. 
The central portion or tube of the gastro-hepatic apparatus is large and folliculated : 
it opens into the left side of the stomach, a little in advance of the belt of horny pro- 
cesses. From this point, and from the corresponding point on the opposite side, folli- 
culated branches are sent to the anterior branchial processes; and similar branches 
from the central tube penetrate the posterior processes. The hepatic glands within the 
processes are very slender, and are delicately branched. All these characters of the 
digestive system are alike common to Tethys, with the exception of the belt of horny 
processes encircling the stomach, and the branching of the hepatic gland within the 
branchial processes, which two features seem to distinguish Melibe. 
The reproductive organs also closely resemble those of Tethys: there is the same 
peculiar form of the mucous gland in connexion with the female channel, the same 
single, almost sessile, spermatheca, and the same rounded compact gland interposed 
between the glandular tube of the penis and the oviduct. 
In the nervous system this relationship is likewise seen. The principal ganglions are, 
as in Tethys, fused into a single mass ; and, as in that genus, they exhibit in the same 
conspicuous manner the globular structure well known in the Mollusca, the whole 
mass being composed of distinct globules of various sizes. The eyes are sessile on the 
anterior portion of the cerebral mass. 
MELIBE FIMBRIATA, 0. Sp. (Pl. XXXIII. figs. 6, 7.) 
Body elongated and elevated, nearly linear, much compressed at the sides, and taper- 
ing to a narrow tail; skin rather thick, soft, and covered throughout with slender fim- 
briated filaments ; colour ochre-yellow, deepening to fulvous on the back, spotted and 
blotched with darker shades of the same colour. Veil large, convex, covering the head 
like a hood; the margins fringed with numerous linear filaments. ‘Tentacles with nine 
or ten laminz, sharply angulated at the sides, and divided in front by a strong midrib ; 
they are placed within cup-like sheaths, supported on long, narrow, linear footstalks, 
situated on the posterior part of the veil. Branchial processes very large, wedge-shaped, 
thin, and coming to an edge at the upper margin, which is widened a little and trun- 
cated ; much thickened below, where they are attached by a slight peduncle: the sur- 
face is fimbriated like the body. They are set in a row of six or seven on each side of 
the back, extending nearly to the tail, the posterior ones smallest ; they are flexible, and 
often bent over at the ends. Foot very narrow and grooved. Length 7 or 8 inches. 
The Melibwa viridis of Kelaart is probably a variety of this extraordinary-looking 
animal in a young state ; but as the name of viridis is quite inappropriate to our species, 
and would lead to an erroneous impression of its colour, we have not thought it desirable 
to adopt it, especially as this name has not got a footing in science. A small, white, 
