remarkable than those of the Archer or Shooting Fishes, which inhabit
the seas of Japan and of the Eastern Archipelago. When kept in
confinement, these fishes may be seen to shoot drops of water from
their elongated jaws at flies and other insects which attract their
attention, and to strike their prey with unerring aim at distances
of three or four feet. Another notable species of Shooting-fishes is
the Chætodon. This latter form possesses a prominent beak or muzzle,
consisting of the elongated jaws; and from this beak, as from the
barrel of a rifle, the fish shoots its watery missiles at the insects
which alight on the vegetation that fringes its native waters.
The old saying which compares great helplessness to the state of 'a
fish out of water,' does not always find a corroborative re-echo in
natural history science. As every one knows, different fishes exhibit
very varying degrees of tenacity of life when removed from their native
element. Thus a herring dies almost immediately on being taken out of
water; whilst, on the other hand, the slippery eels will bear removal
from their habitat for twenty-four hours or longer; and we have known
of Blennies--such as the Shanny (_Blennius pholis_)--surviving a long
journey of some forty-eight hours' duration, when packed amid some damp
sea-weed in a box.
But certain fishes are known, not merely to live when taken out of
water, but actually of themselves, and as part of their life and
habits, to voluntarily leave the water, and disport themselves on
land. Of such abnormal fishes, the most famous is the Climbing Perch
or _Anabas scandens_ of India, which inhabits the Ganges, and is also
found in Asiatic ponds and lakes. These fishes may be seen to leave
the water, and to make their way overland, supporting themselves in
their jerking gait by means of their strong spiny fins. They appear
to migrate from one pool to another in search of 'pastures new,'
especially in the dry season, and when the water of their habitats
becomes shallow.
The Hindu names applied to these fishes mean 'climbers of trees;' and
although statements have been made both by travellers and natives, that
the Climbing Perch has been found scaling the stems of trees, these
accounts, we fear, must be regarded as of equal value with the native
belief that the fishes fall in showers on the land 'from the skies!'
Of the power of the fishes to live for five or six days out of water,
however, no doubt can be entertained; and their ability to support life
under these unwonted conditions, is explained by the fact that certain
bones of the head are curiously contorted so as to form a labyrinth,
amid the delicate recesses of which a supply of water is retained, for
the purpose of keeping the gills moist.
The curious _Lepidosirens_ or Mudfishes, which occur in the Gambia of
Africa and the Amazon of South America, exhibit a greater peculiarity
of structure which still more completely fits them for living out
of water. In the great majority of fishes, a curious sac or bag
known as the _swimming_ or _air bladder_ is found. The use of this
structure in ordinary fishes is to alter the specific gravity of the
animals; and, by the compression or expansion of the air or gases it
contains, to enable them to sink or rise in the water at will. In the
Mudfishes, however, the air-bladder becomes divided externally into two
sacs, whilst internally each division exhibits a cellular structure
resembling that seen in the lungs of higher animals. Then also, this
elaborate air-bladder communicates with the mouth and throat by a tube,
which corresponds to a windpipe. The nostrils of the Mudfishes further
open backwards into the mouth; whilst in all other fishes, except in
one genus, the nostrils are simple, closed, pocket-like cavities. And
it may lastly be noted that the _Lepidosirens_ are provided with true
gills, like their ordinary and more commonplace neighbours.
These remarks serve to explain the 'reason why' these fishes can exist
for months out of water. Thus, on the approach of the hot season,
the Mudfishes leave their watery homes, and wriggle into the soft
mud of their rivers. Here they burrow out a kind of nest, coiling
head and tail together; and as the mud dries and hardens, the fishes
remain in this temporary tomb, breathing throughout the warm season
like true land-dwellers, by means of the lung-like air-bladder. When
the wet season once more returns, the fishes are aroused from their
semi-torpid state by the early rains moistening the surrounding clay;
and when the pools and rivers once more attain their wonted depth, the
_Lepidosirens_ emerge from their nests, seek the water, breathe by
means of their gills, and otherwise lead a true aquatic existence.
With such a combination of the characters of land and water animals, it
is little to be wondered at that the true position of the Mudfishes in
the zoological scale should have formed a subject for much discussion.
They appear, however, to be true fishes, and not amphibians, and they
therefore may legally occupy a prominent position among the oddities of
their class.
Other curious beings included among the fishes are the so-called
Globe-fishes (_Diodon_, &c.), which derive their name from their
power of distending their bodies with air at will; and their bodies
being usually provided with spines, they may be judged to present a
rather formidable front to any ordinary adversary, in their expanded
condition. Then also we have the curious Trigger-fishes (_Balistes_),
so named from the prominent pointed spine in front of the first of
the back-fins; this spine firmly holding its erect position until the
second spine or fin-ray be depressed, when the first spine is released
by mechanism resembling that of the trigger of a gun. The obvious
use of such an apparatus is clearly of a defensive kind; and it is
remarkable to find a familiar mechanical appliance of man so accurately
reproduced in the fish--or rather, _vice versâ_.
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Printed and Published by W. & R. CHAMBERS, 47 Paternoster Row,
LONDON, and 339 High Street, EDINBURGH.
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_All Rights Reserved._
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Transcriber's Note--The following correction has been made to this
text: on page 73, "torwards" changed to "towards".