42 
Memoirs of the Indian Museum. 
[VOL. II 
T. hardwickii ?) in the collection of the Indian Museum, but unfortunately I have not 
been able to trace its history or provenance. The specific characters of the only known 
species of the genus are so imperfectly recorded that I hesitate to identify the specimen , 
which is both immature and faded. 
Benthobatis is a deep-sea genus, but the relations between it and Narcinc correspond 
so closely with those between my new genus Bengalichthys (which is a shallow- water 
genus) and Astrape, that I am obliged to discuss it at some length. 
Both the species and the genera of the family are in some cases closely related, 
and it is often difficult to distinguish between them unless fresh or well-preserved 
material is used. This is particularly the case as regards the genera Narcine and 
Torpedo. Stuffed skins of these forms are practically useless for purposes of identi- 
fication, unless the greatest care has been taken to preserve the natural features. The 
naked, glandular skin is particularly liable to become distorted, while the colour, al- 
though sufficiently permanent in spirit unless the specimens are exposed to a strong 
light, invariably darkens in skins, so that all the markings disappear. 
The ridges or processes on the roof and floor of the mouth form in some genera as 
useful a diagnostic character as is the case in certain genera of Trygonidæ, but one 
that can only be investigated properly by dissecting out the mouth. 
The Torpedoes do not appear to be used as food in India, at any rate habitually. 
Those caught in the seine-nets at Puri are invariably thrown away. 
Genus Torpedo, Duméril. 
Disk distinct from tail, which is stout, bears a well-developed caudal and two dorsal fins 
and has a fold on either side. Pectoral fins well developed ; pelvic fins not joined 
behind the anus. Eyes distinctly separated from spiracles. Nasal valves con- 
fluent into a quadrangular flap. Teeth pointed, with a single cusp and a flat 
base ; cleft of mouth wide and U-shaped. 
Only one species has as yet been found in Indian seas, or at any rate definitely 
identified. I am much indebted to Mr. Boulenger for examining photographs of an 
Indian specimen of this species and confirming my identification. 
Torpedo marmorata , Risso. (Pis. iiia, fig. 4, and v, fig. 3.) 
T. galvanii, Bonaparte, Faun. Ital., vol. iii, Pesci, plate (1832-41). 
T. marmorata, Günther, op. cit., p. 450. 
Disk broadly truncated in front, broader than long, rather longer than the tail. The 
latter very broad at the base. The dorsal surface covered with minute wrinkles, 
which run longitudinally on the anterior part of the disk and transversely on the 
posterior. The eyes nearly as large as the spiracles, from which they are sepa- 
rated by a distance less than their own diameter. The posterior and lateral 
margins of the spiracles provided with a row of somewhat stout, irregular, conical 
processes. 
The mouth is situated between two deep, rather lengthy longitudinal folds, which 
approach one another posteriorly and diverge anteriorly. The teeth occupy nearly 
