INDIAN NUDIBRANCHIATE MOLLUSCA. 137 
the margins and crest much expanded. The head a little produced and truncated. 
Branchial lobes, two pairs, placed rather further back than in the preceding species, 
ovate, rather thin and flexible. Branchial tufts finely fimbriated, scattered over the 
inner sides of the lobes and on the back ; caudal crest nearly obsolete, the posterior 
extremity much compressed and extending into a fine point. Length about an inch. 
Rare: only a single individual was taken. 
Family TETHIDA, Alder & Hancock. 
Body elongate or ovate. Cloak indistinct or wanting. Veil large, funnel-shaped. 
Tentacles two, dorsal, retractile within sheaths. Branchiz plumose, clavate, or muri- 
cated, set in single series on the sides of the back. Anus latero-dorsal. Mouth with- 
out tongue or jaws. 
Genus Metisez, Rang. 
Body elongate, compressed, without cloak. Head with a large hood-like veil fringed 
at the internal margin. Tentacles two, small, with long pedunculated sheaths. Branchiz 
large, clavate or wedge-shaped, set in single series on each side of the back. Foot 
linear, grooved. 
Our specimens were too much injured to enable us to determine the anatomy with 
anything like minute accuracy. We succeeded, however, in ascertaining sufficient to 
prove that Melibe is very closely related to Tethys. ‘This is obvious enough from an 
examination of the digestive and reproductive organs. 
In Melibe the buccal organ is provided with neither tongue, jaws, nor collar ; it is 
not by any means very distinctly marked, formed as it were by a mere enlargement of 
the cesophagus, and having little or no increase of muscular power. It opens in front 
through fleshy lips, situated towards the lower margin of the veil; and the cesophagus 
passes from behind as a very short, somewhat constricted tube. The stomach is a 
rather large pyriform pouch, with its small extremity placed backwards. It lies diago- 
nally across the anterior portion of the visceral cavity, and is divided into an anterior 
and posterior chamber by a slight constriction near the centre. The interior of the 
lower portion of the posterior chamber is encircled transversely by an almost complete 
belt of horny, compressed, lancet-shaped processes, similar to those in the gizzard of 
Scyllea ; so that this division of the stomach should perhaps be looked upon as a giz- 
zard. A little behind this belt is situated the pyloric orifice. The intestine is short 
and wide ; it passes from the posterior extremity of the stomach, and turns immediately 
backwards ; it then bends to the right, and terminates in a nipple-formed anus on the 
side of the back. At the point where the intestine joins the stomach, there is a rather 
: T2 
