Arrhamphus.—Mouth formed as in Hemirhamphus, except that the lower jaw is not produced into a beak. Pectoral fins of moderate length.
One species (A. sclerolepis) from the coast of Queensland (not New Zealand); it may be regarded as a Hemirhamphus, with retarded development of the lower jaw.
Exocoetus.—Jaws short, intermaxillaries and maxillaries separate. Teeth minute, rudimental, and sometimes absent. Body moderately oblong, covered with rather large scales. Pectorals very long, an organ of flying.
Fig. 281.—Flying Fish; Exocoetus callopterus.
Forty-four different kinds of “Flying-fishes” are known from tropical and sub-tropical seas; some have a very wide range, whilst others seem to remain within one particular part of the ocean; thus, the species figured, E. callopterus, has been hitherto found on the Pacific side of the isthmus of Panama only. Their usual length is about 10 or 12 inches, but specimens of 18 inches have been caught. They always live in shoals, and their numbers at certain times and localities are immense; thus, at Barbadoes many boats engage in their capture, as they are excellent eating. The pectorals are in the various species of unequal length; in some they extend to the anal fin only; in others (and these are the best fliers) to the caudal. A few have curious, barbel-like appendages at the lower jaw, which may disappear with age or be persistent throughout life. The literature on the subject of Flying-fishes is very extensive, and great diversity of opinion exists among observers as regards the mode and power of their flight; but the most reliable agree that the fishes do not leave the water for the purpose of catching insects (!), and that they are unable to move their fins in the manner of a bat or bird, or to change voluntarily the direction of their flight, or to fly beyond a very limited distance. The most recent enquiries are those of K. Möbius (“Die Bewegungen der Fliegenden Fische durch die Luft,” Leip. 1878, 8vo), the chief results of which may be summed up thus: Flying-fish are more frequently observed in rough weather and in a disturbed sea than during calm; they dart out of the water when pursued by their enemies, or frightened by an approaching vessel, but frequently also without any apparent cause, as is also observed in many other fishes; and they rise without regard to the direction of the wind or waves. The fins are kept quietly distended, without any motion, except an occasional vibration caused by the air whenever the surface of the wing is parallel with the current of the wind. Their flight is rapid, but gradually decreasing in velocity, greatly exceeding that of a ship going 10 miles an hour, and a distance of 500 feet. Generally, it is longer when the fishes fly against than with or at an angle to the wind. Any vertical or horizontal deviation from a straight line is not caused at the will of the fish, but by currents of the air; thus they retain a horizontally straight course when flying with or against the wind, but are carried towards the right or left whenever the direction of the wind is at an angle with that of their flight. However, it sometimes happens that the fish during its flight immerses its caudal fin in the water, and by a stroke of its tail turns towards the right or left. In a calm the line of their flight is always also vertically straight, or rather parabolic, like the course of a projectile, but it may become undulated in a rough sea, when they are flying against the course of the waves; they then frequently overtop each wave, being carried over it by the pressure of the disturbed air. Flying-fishes often fall on board of vessels, but this never happens during a calm, or from the lee side, but during a breeze only, and from the weather side. In daytime they avoid a ship, flying away from it; but during the night, when they are unable to see, they frequently fly against the weather-board, where they are caught by the current of air, and carried upwards to a height of 20 feet above the surface of the water, while, under ordinary circumstances, they keep close to it. All these observations point clearly to the fact that any deflection from a straight course is due to external circumstances, and not to voluntary action on the part of the fish.
Tenth Family—Esocidæ.
Body covered with scales; barbels none. Margin of the upper jaw formed by the intermaxillaries mesially, and by the maxillaries laterally. Adipose fin none; the dorsal fin belongs to the caudal portion of the vertebral column. Stomach without blind sac; pyloric appendages none. Pseudobranchiæ glandular, hidden; air-bladder simple; gill-opening very wide.
This family includes one genus only, Esox, the “Pikes,” inhabitants of the fresh waters of the temperate parts of Europe, Asia, and America. The European species, E. lucius, inhabits all three continents, but the North American waters harbour five, or perhaps more, other species, of which the “Muskellunge,” or “Maskinonge” (E. estor) of the Great Lakes attains to the same large size as the common Pike. The other species are generally called “Pickerell” in the United States.
