4 o2 SPINY-FINNED GROUP. 



the pectoral fins. They are further characterised by the blunt and short-jawed 

 head, and the moderately long oblong body invested in a coat of rather large-sized 

 scales ; the teeth, when present at all, being minute or rudimental. The ordinary 

 length of a flying-fish is from 10 inches to a foot, although specimens are 

 occasionally met with half as long again ; and whereas the common form ranges 

 round the world, the distribution of some other species is extremely restricted, one 

 being recorded only from the seas on the Pacific side of the Isthmus of Panama. 

 The species differ considerably in the length of the pectoral fins ; those in which 

 they reach to the tail-fin being capable of taking the longest flights, whereas in 

 some others they do not extend beyond the anal. Associating in shoals, which are 

 sometimes of immense size, all these fish are pelagic in their habits, and all are 

 capable of taking the skimming flight from which they derive their name. That 

 these fish take their flights primarily to escape from their enemies may be regarded 

 as certain ; and it is equally well ascertained that the continuance of the flight is 

 due to the original impetus of the leap from the water, and is not prolonged by 

 any flapping of the fins. From my own observations I am, however, of opinion 

 that the pectoral fins are vibrated rapidly on first leaving the water for a few 

 seconds, doubtless from a continuation of the swimming motion while in the 

 water, after which they become entirely motionless. During flight, the colour of 

 these fins may appear either white or brown, when seen from above, according to 

 the incidence of the light. So far as I have seen, flying-fish are unable to change 

 the direction of their course to any marked extent ; but on this point, as will be 

 seen from the two following accounts, there is some difference of opinion among 

 observers. The first of these two accounts is abridged by Dr. Giinther from one 

 published by Dr. Mobias, and runs as follows : " Flying-fish are more frequently 

 observed in rough weather and in a disturbed sea than during calms ; 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 any 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 course of the wind. Their flight is rapid, but gradually decreasing in 

 velocity, greatly exceeding that of a ship going ten miles an hour, and extending 

 to a distance of five hundred feet. Generally, it is longer when the fish fly against 

 than with, or at 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 ; the 

 fish retaining a horizontally straight course when flying with or against the wind, 

 but being carried to one side whenever the direction of the latter is at an angle to 

 that of their flight. It may, however, happen that in the course of its flight a fish 

 may dip its tail in the crest of a wave, thus changing its direction to the left or 

 right. In calm weather the line of flight is always also vertically straight, or 

 rather parabolic, like the course of a projectile, but in a rough sea, when the fish 

 are flying against the course of the waves, it may become undulating. In such 

 instances the flying-fish frequently overtop each wave, being carried over by the 

 pressure of the disturbed air. Flying-fish often fall on board vessels, but this 

 never happens during a calm, or from the lee-side, always taking place in a breeze 



