Osseous labyrinth of the Human Ear.
a, Oval or vestibular fenestra; b, round or cochlear fenestra; c, external or horizontal semicircular canal; d, superior or anterior vertical semicircular canal; e, posterior or inferior vertical semicircular canal; f, the turns of cochlea.
The senses of the fishes are also in perfect harmony with the peculiarities of their mode of life. Their eyes are indeed wanting in the fire and animation which gives so much expression to the physiognomy of the higher animals, but the structure of these organs is admirably calculated for the element in which they are plunged, as the spherical form and great size of the crystalline lens, by concentrating the rays of light, enables them to see with distinctness even through so dense a medium as that which surrounds them. When water is clear, smooth, and undisturbed the sight of fishes is very acute, a circumstance well known to anglers, who prefer a breeze undulating over the surface, as they can then approach much nearer the objects of their pursuit and practise their artful dodges with a much better chance of success. The eyes in fishes are observed to occupy very different positions in different species, but their situation is always such as best to suit the exigencies of the particular fish. Thus in the star-gazer and sea-devil, that watch their prey from a muddy concealment, they are very appropriately placed at the top of the head, while in the flat-fishes, where an eye on the side habitually turned towards the ground would have been useless, the distorted head, by placing both eyes on the same level, affords them an extensive range of view in those various directions in which they may either endeavour to find suitable food or avoid dangerous enemies. That fishes are not deficient in the sense of hearing may be seen at once by the annexed illustrations, which show a marked similarity of organisation between the human ear and that of the perch. It is well known that they start at the report of a gun, though it is impossible for them to see the flash. Sir Joseph Banks used to collect his fishes by sounding a bell, and the Chinese call the gold-fish with a whistle to receive their food. In spite of their scaly covering, the fishes are not unprovided with organs of touch. The lips in many species are soft, and the mouths of others, such as the red mullet—for which such enormous sums were paid by the Roman epicures—are provided with barbules largely supplied with nerves, which no doubt enable them to distinguish the objects with which they come in contact. In the three elongated rays of their pectoral fins the gurnards may be said to possess fingers to compensate for their bony lips; and in many other fishes these modified arms or forefeet are applied as organs of feeling to ascertain the character of the bottom of the water. "You may witness the tactile action of the pectoral fins," says Professor Owen,[N] "when gold-fish are transferred to a strange vessel; their eyes are so placed as to prevent them seeing what is below them; so they compress their air-bladder, and allow themselves to sink near the bottom, which they sweep, as it were, by rapid and delicate vibrations of the pectoral fins, apparently ascertaining that no sharp stone or stick projects upwards, which might injure them in their rapid movements round their prison." Whether fishes possess any high degree of taste is a subject not easily proved; but, to judge by the large size of their olfactory nerves, their sense of smell is probably acute.
[N] "Lectures on Comparative Anatomy."
Red Mullet.
Gurnard.
Wolf-Fish.—(Anarrhicas lupus.)
The life of fishes is a state of perpetual warfare, a constant alternation of flight and pursuit. Prowling through the waters, they attack and devour every weaker being they meet, or dart away to escape a similar lot. Many of them are provided, besides their swiftness and muscular power, with the most formidable weapons. Thus the Sea-wolf has six rows of grinders in each jaw, excellently adapted for bruising the crabs and whelks, which this voracious animal grinds to pieces, and swallows along with the shells. When caught, it fastens with indiscriminate rage upon anything within its reach, fighting desperately, even when out of its own element, and inflicting severe wounds if not cautiously avoided. Schönfeld relates that it will seize on an anchor, and leave the marks of its teeth behind, and Steller informs us that one which he saw taken on the coast of Kamschatka frantically seized a cutlass with which it was attempted to be killed, and broke it in pieces as if it had been made of glass. No wonder that the fishermen, dreading its bite, endeavour as soon as possible to render it harmless by heavy blows upon the head. The great size of the monster, which in the British waters attains the length of six or seven feet, and in the colder and more extreme northern seas is said to become still larger, renders it one of the most formidable denizens of the ocean. It commonly frequents the deep parts of the sea, but approaches the coasts in spring to deposit its spawn among the marine plants. Fortunately for its more active neighbours, it swims but slowly, and glides along with the serpentine motion of the eel.