i68 Memoirs of the Indian Museum. [Vol. II, 
distal half is of a light colour. The gill-openings are of a moderate size and are situ- 
ated just below the pectoral fins. 
The branchiostegal rays are six in number arranged in an upper and lower set of 
three each, with a wide space between. There are three free gill-arches but the first 
bears no filaments. There is a fourth gill-arch incorporated in the pharynx wall 
which bears filaments on its oiiter side. There are no gill-rakers and no pseudo- 
branch. 
The upper jaw bears an irregular series of small teeth, the lower jaw a similar 
series of larger teeth. The teeth are depressible inwards. There are seven large 
pterygoid teeth on either side close to the opening of the gullet. Colour black 
throughout. 
One specimen, 65 mm. long, from 888 fathoms, off the Travancore coast. Station 
307. Registered No. 
Melanocœtus, sp. 
Iliustr. Zool. '‘Investigator,” Fishes, plate xlv, fig. 4 (1909). 
There is a small specimen of this genus which differs from other known species 
in several important respects. Although the specimen is complete, it is somewhat 
distorted and it is difficult to be sure of the appearance it would present during life. 
Its most striking peculiarity is the apparent absence of the anal fin ; dissection shows 
that there were four rays in the position of this fin which were apparently subcutane- 
ous, lying parallel with the lowest ray of the caudal fin. Of the presence of these rays 
there is no doubt, but one cannot be sure how far they would be erected during life. 
Another peculiarity is the form of the abdomen, which is much compressed and 
extends backwards beneath the caudal fin, encroaching on the space which is occupied 
by the anal fin in other species of the genus. The teeth are of unusual length ; there 
are about fifteen on either side in the upper jaw and twelve in the lower jaw. The 
longest tooth is more than half the length of the lower jaw. The vomer forms a 
prominent transverse ridge bearing a long median tooth accompanied by four others, 
two on either side. The proportions cannot be given with certainty as the eye and 
pectoral fin on one side are considerably higher than on the other ; this is evidently 
the result of artificial distortion. 
One specimen measuring 20 mm. from the Arabian Sea, 947 fathoms. Station 184. 
Registered No. 
Family MALTHIDÆ. 
Dibranchus nudiventer , sp. nov. 
Iliustr. Zool. “ Investigator Fishes, plate xlv, fig. 2. (1909). 
Resembling D. nasutus, Alcock, but differing in that the lower surface of the 
disk and tail is devoid of spines. 
The distance between the snout and the gill-opening is hardly greater than the 
distance between the gill-opening and the root of the tail, and is equal to the greatest 
