DOLPHIN  , a name properly belonging to the

common cetacean mammal known as Delphinus delphis, but also applied to a number of more or less nearly allied species . The dolphins, bottle-noses, or, as they are more commonly called, " porpoises," are found in abundance in all seas, while some species are inhabitants of large rivers, as the Amazon . They are among the The Common Dolphin (Delphinia delphis) . smaller members of the cetacean order, none exceeding 10 ft. in length . .Their food is chiefly fish, for the capture of which their long narrow beaks, armed with numerous sharp-pointed teeth, are well adapted, but some also devour crustaceans and molluscs . They are mostly gregarious, and the agility and grace of their movements in the water are themes of admiration to the spectators when a " school of porpoises " is playing round the bows of a vessel at sea . The type of the group is the common dolphin (D. delphis) of the Mediterranean and Atlantic, which usually measures 6 to 8 ft. in length, and is thickest near the centre, where the back fin rises to a height of 9 or ro in., and whence the body tapers towards both extremities . The forehead descends abruptly to the base of the slightly flattened beak, which is about fi in. long, and is separated from the forehead by a transverse depression . . The mouth is armed with sharp, slightly curved teeth, of uniform size, varying in number from forty to fifty on each side of both jaws . The aperture of the ear is exceedingly minute; the eyes are of moderate size and the blow-hole is crescent-shaped . The colour of the upper surface is black, becoming lighter on the flanks, and perfectly white below . Dolphins are gregarious, and large herds often follow ships .

They exhibit remarkable agility, individuals having been known to leap to such a height out of the water as to fall upon the

deck . Their gambols and apparent.relish for human society have attracted the attention of mariners in all ages, and have probably given rise to the many fabulous stories told of dolphins . Their appearance at sea was regarded as a good omen, for although it presaged a tempest, yet it enabled the sailors to steer for a place of safety . The dolphin is exceedingly voracious, feeding on fish, cuttlefishes and crustaceans . On the south coast of England it lives chiefly on pilchard and mackerel, and when in pursuit of these is often taken in the nets . The female brings forth a single young one, which she nurses most carefully . Her milk is abundant and rich, and during the operation of suckling, the mother floats in a slightly sidelong position, so as to allow of the necessary respiration in herself and her young . The dolphin was formerly supposed to be a fish, and allowed to be eaten by Roman Catholics when the use of flesh was prohibited, and it seems to have been esteemed as a delicacy by the French . Among the seafaring population of Britain the name " dolphin " is most usually given to the beautifully coloured fish Coryphaena hippuris —the dorado of the Portuguese, and it is to the latter the poet is alluding when he speaks of " the dying dolphin's changing hues." Many other allied genera, such as Prodelphinus, Steno, Lagenorhynchus, &c., are also included in the family Delphinidae, some of which live wholly in rivers . Beside these there is another group of largely freshwater species, constituting the family Platanistidae, and typified by the susu (Platanista gangetica), extensively distributed throughout nearly the whole of the river-systems of the Ganges, Brahmaputra and Indus, ascending as high as there is water enough to swim in, but never passing out to sea . It is about 8 ft. long, blind and feeds on small fish and crustaceans for which it gropes with its long snout in the muddy waters at the bottom . Inia geoffroyensis, the single species of its genus, frequents the Amazon, and reaches an extreme length of 8 ft .

It is wholly

pink or flesh-coloured, or entirely black, or black above and pink beneath . A third is the La Plata dolphin, Stenodelplzis blainvillei, a species about 5 ft. in length . Its colour is palish brown, which harmonizes with the brown-coloured water of the estuary of the Rio de la Plata .