Twelve species of Trigla are known. In the British seas the commonest species is the Grey Gurnard (Trigla gurnardus), a silvery-grey fish, more or less clouded with brown and speckled with black. A rare species with us, but very common in the Mediterranean, is the Red Gurnard, Trigla pini (Fig. 389). It is of a fine bright rose-red colour, paler beneath and more vivid about the fins, of which there are two distinct dorsal and one ventral. Beneath the pectorals are three detached rays; both jaws and front of the lower palate are armed with fine velvety teeth. The Perlon, or Sapharine Gurnard (T. hirundo), is a large and handsome fish, remarkable for the lively green and blue hues of the inner surface of its large pectoral fins.
The Flying Gurnard (Dactylopterus volitans) somewhat resembles the Triglas, but differs in having the fin-rays of the pectorals connected by membranes, by which it is enabled to support itself some time in the air, like the flying-fish; the pectorals, when extended, forming a sort of parachute (Fig. 390), which sustains it when it leaps out of the water. Several species are known.
Fig. 390. The Flying Gurnard (Dactylopterus volitans).
All nature seems to conspire against these singular creatures, while they have been gifted with the double power of swimming and flying. The flying-fish only escapes from the Bonitas, and other voracious fishes which pursue it on the bosom of the sea, to expose itself to the attacks of the inhabitants of the air. A crowd of sea-fowl, such as frigate-birds, the albatross, and the gulls, carry on a bloody war with them when they venture on flight. Enemies thus pursue the unhappy fish whatever element it betakes itself to. Nevertheless it passes from one element to the other with an energy which frequently defeats the attacks of its enemies. When it leaps from the sea to the height of five or six feet, it sustains itself for several hundred feet, changing its direction. In its flight it may be compared to that of the flying dragon; the popular name given to it is said to be derived from the grunting noise they make on being taken out of the water.
Labyrinthiform Pharyngeans.
In the fishes of this order the superior pharyngeal bones are divided into numerous and irregular little leaflets, which intersect the cellules situated under the operculum, which again serve to retain a certain quantity of water. This water preserves the gills, however, when the animal is dry, which permits them to live on shore, where they frequently contrive to creep over great distances in search of water. The genus Anabas, from ἀναβαίνω, to ascend, possess this peculiarity of organization in a remarkable degree; it enables them to leave the rivers and marshes and little watercourses of Borneo and Java, and other islands of the Indian Archipelago, and creep through the herbage or along the ground by means of the inflexions of their bodies, the dentation of their opercules, of their spines and fins. This fact, although only recently known to modern naturalists, was well known to the ancients, and has been recorded by Theophrastus.
The family of the Scomberoides is the most important group in the order, comprehending some of the fishes most useful to man, from their size, the excellence of their flesh, and their abundance. The Tunny (Thynnus, Cuv.), the Mackerel (Scomber scombrus), and the Bonita (Thynnus pelamys), have yielded, from the remotest antiquity, immense resources as human food, both in the fresh and preserved state.
The tunny, while resembling the mackerel in many respects in its general form, is rounder, and attains a much larger size, being sometimes found eight and nine feet in length, and weighing three to four hundred pounds. The upper part of the body is a bluish-black; the belly is grey, with silvery spots. These fishes sometimes present themselves in the Atlantic, but in the Mediterranean they are very abundant. At some periods of the year they approach the coast in innumerable shoals, and in numerous serried ranks, forming a vast battalion, which conceals itself under the waves, and only betrays itself on the exterior by the motion of the sea, caused by such vast numbers travelling rapidly through the water. In many localities the shoals of tunnies show themselves in the spring, pursuing their way towards the east, and in the autumn we find them pursuing an opposite direction. We see the same thing on the coast of Provence. Upon the coast of La Ciotat a first fishing takes place from the months of March to July, and a second again from July to October. But at other points of the coast they arrive at the same time from very different directions; nevertheless, in some places they are only winter visitors.