ON THE FLIGHT OF THE FLYING-FISH. 473 
so far as I am aware, been determined by actual observation. 
Most observers are of opinion that these singular creatures glide 
up the wind, and do not beat it after the manner of birds; so 
that their flight (or rather leap) is indicated by the are of a circle, 
the sea supplying the chord.” 
From a careful examination of the structure and action of 
these, fins Pettigrew was able to satisfy himself that “they 
act as true pinions within certain limits.” That this restrictive 
phrase, ‘“ within certain limits,” is intended to exclude a flapping 
motion is evident from the following :—‘‘ The flapping and gliding 
action of the wings constitute the difference between ordinary 
flight and that known as skimming or sailing flight. The flight 
of the Flying-fish is to be regarded rather as an example of the 
latter than the former, the fish transferring the velocity acquired 
by the vigorous lashing of its tail in the water to the air.” 
Pettigrew shows that all kinds of wings, when extended in 
flight, have a kite-like action, or a ‘‘combined parachute and 
wedge action,” independent of any beating movement ; and it is 
” this action alone that he refers when he says the pectorals 
“act as true pinions within certain limits.” 
So much for the negative testimony. 
In favour of the flapping motion of these fins we have 
the testimony of Capt. de Freminville,* who says :—‘‘I have 
been able to convince myself that they (Flying-fish) do actually 
fly, impressing upon their fins, which serve them as wings, a 
rapid movement—a species of vibration (frémissement)—which 
sustains them and causes them to advance through the air.” 
Speaking of these fish, which he saw on the way from Callao to 
Lima, De Tessan+ says :—‘‘ J’ai trés-bien vu un poisson-volant 
battre d’abord des ailes en l’air, et puis les faire vibrer en planant.” 
In the ‘Reise der Novara’ (1857-59), p. 109, occurs (according 
to Professor Mobius) the statement that ‘‘ Careful observation 
enables one to see that the wing-like pectoral fins of the Flying- 
fish are peeps of a vibrating movement, like the munis of a 
Grasshopper.” * * ie * * 
A. v. Humboldt t says:—“‘ Notwithstanding the astonishing 
swiftness of their movement, one can convince oneself that the 
* Ann. des Sci. Nat., vol. xxi., p. 102, 1830. 
+ ‘Voyage autour du Monde sur la Vénus,’ Paris, 1844. 
{ ‘ Reise in die Aequinoctial-Gegenden des neuen Continents’ (1819). 
3 P 
