[GENUS DELPHINUS—THE MARINE DOLPHINS.]
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1. Gangetic Dolphin—Platanista Gangetica. 2. Round-headed River Dolphin—Orcella brevirostris. 3. Gadamu Dolphin—Delphinus Gadamu. 4. Freckled Dolphin—Delphinus lentiginosus. 5. Black Dolphin—Delphinus pomeegra. |
These are characterised by a convex forehead, with a protruding muzzle which forms a sort of beak; they have teeth in both jaws, numerous and conical, broad and high cranium, nasal passages vertical, no cæcum. They are gregarious in habit, carnivorous and extremely swift, but they must not be confounded with the dolphin of sailors, which is a true fish (Coryphæna hipparis) of great velocity and brilliant colours, which change like rainbow tints when the fish is dying. I have several times in vain tried to catch the fleeting shades with both oil and water-colours, but without success; for within a few minutes they change from the most vivid of greens and blues to a pale silvery grey. The true dolphin, of which we are treating, is the dolphin of the ancients, represented in all the old pictures and sculptures. They have a medium dorsal fin, and the pectoral flippers are about two-thirds longer than the breadth.
[NO. 260. DELPHINUS PERNIGER.]
The Black Dolphin (Jerdon's No. 142).
HABITAT.—Bay of Bengal.
DESCRIPTION.—"Twenty-six teeth on each side above and below, obtuse, slightly curved inwards; of a uniform shining black above, beneath blackish."—Jerdon.
SIZE.—Total length, 5 feet 4 inches.
This species was taken in the Bay of Bengal and sent to the Asiatic Society's Museum by Sir Walter Elliot, but it does not appear to be mentioned by Professor Owen in his notice of the Indian Cetacea collected by Sir Walter Elliot.
[NO. 261. DELPHINUS PLUMBEUS.]
The Lead-coloured Dolphin (Jerdon's No. 143).