320 THE FLYING FISH. 



" The principal external agents employed in tins mode of locomotion are the large 

 lobe of the tail fin and the broad transparent pectoral fins, which, on this occasion, serve 

 at least as a parachute, and which, being situated close to the back, place the centre 

 of suspension higher than the centre of gravity. It is also curious to notice how well 

 the specific gravity of the fish can be regulated, in correspondence with the element 

 through which it may move. The swim-bladder, when perfectly distended, occupies 

 nearly the entire cavity of the abdomen and contains a large quantity of air ; and in 

 addition to this, there is a membrane in the mouth which can be inflated through the 

 gills ; these two reservoirs of air affording good substitutes for the air-cells so freely 

 distributed within the bones of birds, and having the additional advantage of being 

 voluntary in their function. 



The pectoral fins, though so large when expanded, can be folded into an exceedingly 

 slender, neat, and compact form ; but whether they are employed in swimming in the 

 closed or expanded state, I have been unable to determine. 



Under some circumstances of excitement, these fish will leap over the bulwarks 

 of a ship and be killed by the violence with which they strike against the deck or 

 spars. This usually occurs at night, or early in the morning, and a light displayed from 

 the chains of a vessel on a dark night will bring many of them on board in the same 

 manner. Their flesh is the bonne louche of voyagers ; it bears some resemblance to that 

 of the herring. Although the Flying-fish excites so much commiseration for its per- 

 secuted state, it is itself predaceous, feeding chiefly on smaller fishes." 



The ancients were well acquainted with the Flying-fish, and in their narrative seven 

 improved upon its powers, as was customary with the voyagers of those days, and 

 asserted that, as soon as night came on, this fish left the ocean, flew ashore, and slept 

 until morning safe from the attacks of its marine enemies. The generic name of 

 exoczetus, literally a " sleeper-out," refers to this supposed habit. 



THE reader will doubtlessly remember that the power of sustentation in the atmosphere 

 for a more or less prolonged period is exhibited in the three preceding orders of vertebrated 

 animals, and that, in every case, this object is attained by the modification of parts already 

 existing, and not by the addition of special members. 



In the bats, for example, the lengthened bones of the fore-limbs, together with the 

 extension of the skin, form a flying apparatus of wonderful perfection, and in the creatures 

 that are popularly, though erroneously, called " flying " squirrels and " flying " rats, the 

 capability of passing through considerable distances, upborne by the air, is achieved by 

 a development of a similar nature but of less extent, the skin of the sides being much 

 widened, though the limbs retain their usual comparative dimensions. These, as well as 

 other creatures who move through the air on the same principle, ought rather to be termed 

 " skimmers." 



In the birds the power of flight is physically owing to the development of the fore- 

 limbs and the modification of the structures which clothe the skin. In the two succeeding 

 orders of vertebrates, no truly flying species are at present known to exist. The only 

 reptile that in this period of the world's history is enabled to sustain itself in the air, even 

 for a limited space, is the little flying dragon, a creature which has its ribs nearly straight 

 instead of curved, and by means of this formation is enabled to sweep from one tree to 

 another just like the flying squirrel. But in the older ages of the world, flying reptiles 

 were abundant, with " wings " that measured some thirty feet from tip to tip, and evidently 

 both agile and strong of flight like those of the bat, to which they bear a great resemblance. 

 Lastly, we have several examples among the fishes, where the pectoral fins, answering to 

 the fore-limbs of the higher vertebrates, are so greatly expanded and enlarged, that they 

 can oe spread horizontally, and bear their owner on a short course through the air. 



In any case, the power of flight is wonderful, but in the fish it seems almost to partake 

 of the miraculous, inasmuch as these creatures inhabit a different element, and do not even 

 breathe the atmosphere into which they are capable of launching themselves. Yet, when 

 more closely examined, the flying power of the fish is not one whit more remarkable than 

 the diving powers of the otter and penguin, both of which creatures are able to leave their 



