Ninth Family—Scombresocidæ.
Body covered with scales; a series of keeled scales along each side of the belly. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Lower pharyngeals united into a single bone. Dorsal fin opposite the anal, belonging to the caudal portion of the vertebral column. Adipose fin none. Air-bladder generally present, simple, sometimes cellular, without pneumatic duct. Pseudobranchiæ hidden, glandular. Stomach not distinct from the intestine, which is quite straight, without appendages.
The fishes of this family are chiefly marine, some living in the open ocean, whilst others have become acclimatised in fresh water; many of the latter are viviparous, all the marine forms being oviparous. They are found in all the temperate and tropical zones. Carnivorous.
This family is represented in the strata of Monte Bolca by rare remains of a fish named Holosteus, allied to Belone or Scombresox, and by a species of Belone in the miocene of Licata.
Belone.—Both jaws are prolonged into a long slender beak. All the dorsal and anal rays connected by membrane.
The long upper jaw of the “Gar-pike” is formed by the intermaxillaries, which are united by a longitudinal suture. Both jaws are beset with asperities, and with a series of longer, conical-pointed, widely-set teeth. Skimming along the surface of the water, the Gar-pike seize with these long jaws small fish as a bird would seize them with its beak; but their gullet is narrow, so that they can swallow small fish only. They swim with an undulating motion of the body; although they are in constant activity, their progress through the water is much slower than that of the Mackerels, the shoals of which sometimes appear simultaneously with them on our coasts. Young specimens are frequently met in the open ocean; when very young their jaws are not prolonged, and during growth the lower jaw is much in advance of the upper, so that these young fishes resemble a Hemirhamphus. About fifty species are known from tropical and temperate seas, Belone belone being a common fish on the British coast. Its bones, like those of all its congeners, are green; and therefore the fish, although good eating, is disliked by many persons. Some species attain a length of five feet.
Scombresox.—Both jaws are prolonged into a long slender beak. A number of detached finlets behind the dorsal and anal fins.
The “Saury” or “Skipper” resemble the Gar-pike, but the teeth in the jaws are minute; they seem to feed chiefly on soft pelagic animals. In their habits they are still more pelagic; and the young, in which the beak is still undeveloped, are met with everywhere in the open ocean, in the Atlantic as well as in the Pacific. The European species, Sc. saurus, is not rare on the British coast; four other species have been described, closely allied to Sc. saurus.
Hemirhamphus.—The lower jaw only is prolonged into a long slender beak.
In the young both jaws are short; the upper is never prolonged, the intermaxillaries forming a triangular, more or less convex, plate. The “Half-beaks” are common between and near the tropics; some forty species are known, none of which attain to the same length as the Gar-pike, scarcely ever exceeding a length of two feet. Some of the tropical species live in fresh water only; they are of small size and viviparous.