360 
SCANDINAVIAN FISHES. 
whereas in other fishes, we need hardly say, this gas 
almost entirely fills the air-bladder. 
Mobius also observes that these fishes are assisted 
in their flight by the flat shape of the belly, where the 
lateral lines, which are raised as in the preceding genus, 
follow the ventral margins. The lateral lines thus, to 
a certain extent, increase the width of the bearing sur- 
face. The well-developed palatal curtains or transverse 
dermal folds in the mouth behind the margins of the 
upper and lower jaws, are also of service, for they re- 
tain the water that is enclosed in the cavity of the 
mouth, thus keeping the branchial lamclhe moist during 
the passage of the fish through the air. 
In many cases fear is probably the first cause of 
the aerial flight of the Flying-fish: as we have just, 
observed with respect to the Saury, the Flying-fish also 
seeks refuge in the air from its pursuers, especially the 
Dolphin-fishes (Corypluena) and Bonitos, or sometimes 
springs up in terror before the bow of a vessel under way. 
Fig'. 96. Transverse section of a Flying-fish: v, vertebr®; r, kidneys; 
ves, air-bladder; g , organs of generation; l, lateral lines; i, intestine. 
After Mobius. 
Often, however, this habit is due to the same instinct 
that impels the Garpike to leap out of the wafer as if 
in sport; and like other fishes that are closely packed 
in shoals, they often leap in order to escape the crush 
or to pass one another. They appear on the wing of- 
tener in stormy weather or a steady breeze than in a 
dead calm. They generally keep only a few feet above 
the surface; and when they rise higher, as in the cases 
where they have fallen on the deck of a vessel as much 
as 5 metres above the water, this is also due, says 
Mobius, to the influence of the air-currents (fig. 97). 
The Flying-fish always come on board on the windward 
side in a fresh breeze and, in most cases, at night, 
when in spite of their large eyes they cannot see the 
ship and avoid it. On the windward side of vessels 
that have sailed during the night through some part of 
the ocean where Flying-fish abound, spots of blood and 
° Zoologist, 2 ser., vol. VIII (1873) p. 3739. 
6 Ibid. 1874, p. 3838. 
the scales of Flying-fish are often found in the morning; 
and when the sailors swab the decks, they sometimes 
come across no small numbers of Flying-fish, a welcome 
and agreeable change in the seamen’s fare. Some of 
the Flying-fish have thus been dashed against the ves- 
sel's,. side in their rapid flight and killed: but others 
have been borne over the bulwarks by the current of 
air that rushes up the windward side of the vessel, 
and have fallen on deck. 
r fhe small jaw-teeth of the Flying-fish show that 
its food must consist of small, weak marine animals of 
the lower classes. Their pharyngeal apparatus resembles 
that of the Garpike, there being two upper pharyngeals 
on each side, the posterior (larger) pair closely united 
at the mesial line of the palate, and one triangular lower 
pharyngeal pointed in front, all closely set with cylin- 
drical, obtusely pointed teeth. The gill-rakers are 
also like those of the Garpike, the outer row on the 
first branchial arch being thickly set and setiform, and 
Fig. 97. Flying-fish lifted by the wind and cast on the deck of a 
vessel, which is shown in transverse section. After Mobius. 
the inner row verrucose and more scattered, like both 
rows on the other branchial arches. The gill-openings 
are large, but close firmly and tightly: the branchio- 
stegal membranes are entirely separate, but the left 
closely covers the right in front. 
Little is yet known of the propagation of the 
Flying-fishes. Their eggs, like those of the Garpikes, 
are superficially furnished with filiform appendages. 
Mathew" supposed that the spawning took place and 
the eggs were developed in the open sea, since he had 
found young Flying-fish, less than 3 cm. long, leaping 
on the water, like grasshoppers on land, thousands of 
miles from the nearest coast. Saunders 5 , on the other 
hand, found Flying-fish (he is also silent as to the 
species) crowding in to deposit their eggs in rocky 
crevices and holes under the water, on the Chincha 
Islands off the coast of Peru. This was at the end of 
* 
