This small family consists of strictly marine and partly pelagic species referred to two genera, Stromateus and Centrolophus. The former lacks ventral fins, at least in the adult stage, and is represented by about ten species in almost all the tropical and warmer seas. Centrolophus, hitherto known from two or three European species only (of which one occasionally reaches the south coast of England, where it is named “Black-fish”), has recently been discovered on the coast of Peru, and has probably a much wider range.
Fifth Family—Coryphænidæ.
Body compressed; eye lateral. Teeth small, conical, if present; œsophagus smooth. No bony stay for the præoperculum. Dorsal fin single, long, without distinct spinous division. More than ten abdominal and more than fourteen caudal vertebræ.
All the members of this family have pelagic habits. Representatives of it have been recognized in some fossil remains: thus Goniognathus from the Isle of Sheppey, and the living genus Mene (Gastrocnemus) at Monte Bolca.
Coryphæna.—Body compressed, rather elongate; adult specimens with a high crest on the top of the head; cleft of the mouth wide. A single dorsal extending from the occiput almost to the caudal, which is deeply forked; no distinct dorsal and anal spines. The ventrals are well developed, and can be received in a groove on the abdomen. Scales very small. Rasp-like teeth in the jaws, on the vomer and the palatine bones. Air-bladder absent.
Fig. 202.—Dolphin from the Atlantic.
Generally, though by misapplication of the name, called “Dolphins.” About six species are known, each of which is probably distributed over all the tropical and sub-tropical seas. Strictly pelagic in their habits, they are most powerful swimmers; they congregate in shoals, and pursue unceasingly the Flying-Fish, which try to escape their enemies by long flying leaps. They attain to a length of six feet, and are eagerly caught by sailors on account of their well-flavoured flesh. The beauty of their, unfortunately fugitive, colours has ever been a subject of admiration. As far as the colours are capable of description, those of the common species (C. hippurus), which is often seen in the Mediterranean, are silvery blue above, with markings of a deeper azure, and reflections of pure gold, the lower parts being lemon-yellow, marked with pale blue. The pectoral fins are partly lead colour, partly yellow; the anal is yellow, the iris of the eye golden. These iridescent colours change rapidly whilst the fish is dying, as in the Mackerel. The form of the body, and especially of the head, changes considerably with age. Very young specimens, from one to six inches in length, are abundant in the open sea, and frequently obtained in the tow-net. Their body is cylindrical, their head as broad as high, and the eye relatively very large, much longer than the snout. As the fish grows the body is more compressed, and finally a high crest is developed on the head, and the anterior part of the dorsal fin attains a height equal to that of the body.
Brama.—Body compressed, and more or less elevated, covered with rather small scales; cleft of the mouth very oblique, with the lower jaw longest. Dorsal and anal fins many-rayed, the former with three or four, the latter with two or three, spines; caudal deeply forked. Ventrals thoracic, with one spine and five rays. The jaws with an outer series of stronger teeth.
Pelagic fishes which, like the allied genus Taractes, range over almost all the tropical and temperate seas.