"Carvilius Pollio," says Pliny, "a man of great invention in matters pertaining to luxury, was the first who cut the plates of the tortoise for veneering or inlaying." The Romans imported large quantities of this precious article from Egypt, and under the reign of Augustus, the wealthy patricians used even to inlay the doors and columns of their palaces with it. When Alexandria was taken by Julius Cæsar, the warehouses were so full of tortoise-shell that the conqueror proposed to make it the principal ornament of his triumph.

The use of tortoise-shell for the decoration of houses and furniture is long since out of fashion, but it is still in great request for the making of combs and boxes. By steeping it in boiling water it softens, and may then, by a strong pressure, be moulded into any form. When a considerable extent of surface is required, different pieces must be joined together. This is done by scraping thin the edges of the pieces to be united, and laying them over each other while they are in the heated and softened state; strong pressure being then applied, they become completely agglutinated. It is in this way that gold, silver, and other metals for different ornaments are made to adhere to tortoise-shell.

When, at the beginning of the chapter, I mentioned that the lizards had entirely forsaken the ocean, I forgot that the Galapagos Islands in the South Sea, right under the Equator, exclusively possess a maritime animal of this kind, which, from its being the sole existing representative, or dwindled descendant of the giant oceanic saurians of yore, is far too interesting to be passed unnoticed. This lizard is extremely common on all the islands throughout the Archipelago. It lives exclusively on the rocky sea-beaches, and is never found,—at least Mr. Darwin never saw one,—even ten yards inshore. It is a hideous-looking creature, of a dirty black colour, stupid and sluggish in its movements. The usual length of a full-grown one is about a yard, but there are some even four feet long. These lizards were occasionally seen some hundred yards from the shore, swimming about; and Captain Collnett, in his "Voyage," says they go out to sea in shoals to fish. With respect to the object, Mr. Darwin believes he is mistaken; but the fact, stated on such good authority, cannot be doubted. When in the water the animal swims with perfect ease and quickness by a serpentine movement of its body and flattened tail; the legs, during this time, being motionless and closely collapsed on its sides. A seaman of the "Beagle" sank one with a heavy weight attached to it, thinking thus to kill it directly; but when an hour afterwards he drew up the line the lizard was quite active. Their limbs and strong claws are admirably adapted for crawling over the rugged and fissured masses of lava, which every where form the coast. In such situations a group of six or seven of these hideous reptiles may oftentimes be seen on the black rocks, a few feet above the surf, basking in the sun with outstretched legs.

Mr. Darwin opened the stomach of several, and in each case found it largely distended with minced sea-weed, of a kind growing at the bottom of the sea, at some little distance from the coast. The nature of this lizard's food, as well as the structure of its tail, and the certain fact of its having been seen voluntarily swimming out at sea, absolutely prove its aquatic habits; yet there is in this respect one strange anomaly, namely, that when frightened it will not enter the water. From this cause it is easy to drive these lizards down to any little point overhanging the sea, where they will sooner allow a person to catch hold of their tail than jump into the water. They do not seem to have any notion of biting; but when much frightened they squirt a drop of fluid from each nostril. One day Mr. Darwin carried one to a deep pool left by the retiring tide, and threw it in several times as far as he was able. It invariably returned in a direct line to the spot where he stood. It swam near the bottom with a very graceful and rapid movement, and occasionally aided itself over the uneven ground with its feet. As soon as it arrived near the margin, but still being under water, it either tried to conceal itself in the tufts of sea-weed, or it entered some crevice. As soon as it thought the danger was past, it crawled out on the dry rocks and shuffled away as quickly as it could. Mr. Darwin several times caught this same lizard by driving it down to a point, and, though possessed of such perfect powers of diving and swimming, nothing could induce it to enter the water; and as often as he threw it in, it returned in the manner above described.

Perhaps this singular piece of apparent stupidity may be accounted for by the circumstance that this reptile has no enemy whatever on shore, whereas at sea it must often fall a prey to the numerous sharks. Hence, probably urged by a fixed and hereditary instinct that the shore is its place of safety, whatever the emergency may be, it there takes refuge. On a comparison of this singular animal with the true iguanas, the most striking and important discrepancy is in the form of the head. Instead of the long pointed narrow muzzle of those species, we have here a short obtusely truncated head, not so long as it is broad; the mouth consequently is capable of being opened to only a very small extent. From this circumstance, and from the crest on its head, it has received the Latin name of Amblyrhynchus cristatus.

The serpent race, which thrives so abundantly in the tropical forests and morasses, has also its marine representatives in the Indian and Pacific Oceans, where more than fifty species of Hydrophis, Pelamys, and Chersydra have been found. They are distinguished from their terrestrial relations by the flattened form of their tail, the planes of which being directed vertically give it the properties of a powerful oar, in striking the water by lateral oscillations. These sea-snakes always appear to prefer calms, swimming on the still surface in an undulating manner, never raising the head much from the surface, or vaulting out of the water. They dive with facility on the approach of danger, but do not appear to be particularly timid.

The Pelamys bicolor is very common from India to Otaheite. In the seas of Mindoro and Sooloo, Mr. Adams saw thousands swimming on the top of the water, especially in eddies and tide-ways where the ripple collects numerous fish and medusæ, which principally constitute their prey. Their tongue is white and forked, differing in respect of its colour from the tongue of other snakes, which is generally black. The water-snakes, which are frequently beautifully banded, and as thick as a man's leg, are said to be highly venomous. Captain Cook, in one of his voyages, "saw abundance of water-snakes, one of which was coming up the side of our ship, and our men beat it off. The Spaniards affirm there is no cure for such as are bit by them; and one of our blacks happened to fall under that misfortune, and died notwithstanding the utmost care was taken by our surgeons to recover him."

Such are the real sea-snakes as they are met with by ordinary travellers, while the great sea-serpent, which from time to time dives up in the columns of the newspapers, must, until better evidence be brought forward for its existence, be banished to those dim regions peopled by unicorns, griffins, krakens, and tailed men.

Olaus Magnus, it is true, speaks of the great sea-snake as if it made its daily appearance on the Norwegian coast. According to him, it inhabits the rocky caves near Bergen, and wanders forth at night, particularly by moonshine, to commit its depredations by sea and land; as calves and pigs seem to suit its appetite as well as fishes and lobsters. The body is covered with scales, a long mane flows along the neck, and the head, furnished with two glistening eyes, rises like a mast out of the water. It often attacks ships, and picks up seamen from the deck. This description may serve as an example of the boldness with which authors have sometimes asserted the most extravagant things.

The Greenland missionary Egede tells us in his Journal, that "on the 6th of July, 1734, there appeared a very large and frightful sea-monster, which raised itself so high out of the water that its head reached above our main-top. It had a long sharp snout, very broad flappers, and spouted water like a whale. The body seemed to be covered with scales, the skin was uneven and wrinkled, and the lower part was formed like a snake. After some time the creature plunged backwards into the water, and then turned its tail up above the surface, a whole ship-length from the head."

It is hard to disbelieve so pious and excellent a man, whose excited fancy no doubt gave extraordinary forms and dimensions to some commoner sea-animal of large size; but the testimony of a Scoresby, who during his frequent Arctic voyages never saw anything of the kind, would have been more convincing.

If to this account of Egede be added the reports of some other northern divines, such as Pontoppidan, the missionary Nicholas Græmius, and Maclean, who either pretend to have actually seen the monster or write about it from hearsay—and the testimony of a few seamen, among others of Captain M'Quhae of the Dædalus, who, on the 6th of August, 1848, saw a sea-snake on his homeward voyage from the East Indies; we have all the evidence extant in favour of the existence of the monstrous animal.

In opposition to these testimonies, incredulous naturalists beg to remark, that no museum possesses a single bone of the huge snake, and that its body has nowhere been found swimming on the ocean or cast ashore. They therefore agree with Professor Owen in regarding the negative evidence, from the utter absence of any recent remains, as stronger against their actual existence than the positive statements which have hitherto weighed with the public mind in favour of their reality; and believe that a larger body of evidence from eye-witnesses might be got together in proof of the reality of ghosts than in proof of the existence of the great sea-serpent.

The plain truth seems to be that lines of rolling porpoises, resembling a long string of buoys, first gave origin to the marvellous stories of the fabulous monster. For, keeping in close single file, and progressing rapidly along the calm surface of the water by a succession of leaps or demivaults forward, part only of their uncouth forms appears to the eye, so as to resemble the undulatory motions of one large serpentiform animal.

CHAP. XII.

THE MARINE FISHES.

The bosom of the ocean is full of mysteries; it conceals a whole world of curiously-shaped animals, which the naturalist only superficially knows, and may, perhaps, never be able to fathom. To observe the habits of terrestrial animals, and accurately to determine their various species, is a comparatively easy task; but the denser element in which fishes live prevents us from following their motions with exactness, from studying their instincts, and from noting with fidelity their specific differences.

Since Pliny, who mentions but seventy-four different kinds of fishes, the number of known species has indeed enormously increased. The ancients, who knew only the waters of the Mediterranean and a very small part of the ocean, had no conception of the finny multitudes inhabiting the tropical and icy seas; but although modern science has succeeded in describing and picturing above eight thousand different kinds of fishes, yet there can be no doubt that many still unknown species dwell in the depths of ocean, or in the distant seas which are but seldom visited by the European mariner.

If the whole economy of the world of fishes were opened to our view, the magnificent picture would, no doubt, give us additional reasons for admiring the infinite wisdom of the Creator; but the little we do know suffices to convince us that the same wonderful harmony existing between the anatomical structure and the outward relations or mode of life in birds and mammiferous quadrupeds is also to be found in fishes, and that these creatures, though occupying a lower grade in Creation, are no less beautifully adapted to the peculiar element in which they are destined to live and move.

This strikes us at once in their external form, which, though subject to great variety, being sometimes spherical as in the globe-fish, or cubical as in the ostracion, or expanded as in the skate, or snake-like as in the eel, is generally that of an elongated oval, slightly compressed laterally, a shape which enables the fishes to traverse their native fluid with the greatest celerity and ease. We wisely endeavour to imitate this peculiar form in the construction of our ships, yet the rapidity with which the fastest clipper cleaves the waters is nothing to the velocity of an animal formed to reside in that element. The flight of an arrow is not more rapid than the darting of a tunny, a salmon, or a gilt-head through the water. It has been calculated that a salmon will glide over 86,400 feet in an hour, that it will advance more than a degree of the meridian of the earth in a day, and that it could easily make the tour of the world in some weeks, were it desirous of emulating the fame of a Cook or of a Magellan. Every part of the body seems exerted in this despatch; the fins, the tail, and the motion of the whole backbone assist progression; and it is to this admirable flexibility of body, which mocks the efforts of art, that fishes owe the astonishing rapidity of their movements.

Whales and dolphins move onwards by striking the water in a vertical direction, while fishes glide along by laterally curving and extending the spine. In some species, such as the eel, the whole body is flexible; but most of them paddle away with their tail to the right and left, and are thus driven forwards by the resistance of the water. Consequently the power of fishes is chiefly concentrated in the muscles bending the spine sideways, and generally we find these parts so much developed as to form the greatest part of the body.

The fins are the most important auxiliary organs of locomotion in fishes. The dorsal, caudal, and anal fins serve by their vertical position to increase the extent of the rowing surface, and to maintain the animal's balance, while the pectoral and ventral fins, which must be considered as the representatives of the fore and hind limbs of other vertebrata, are, moreover, of great assistance in directing its movements. With the help of these organs, fishes can advance or retrograde, ascend or descend in the water as they please, and it is curious to observe how, alternately extending or contracting one fin or the other, they gracefully plough the liquid element in every direction.

It is no less wonderful how perfectly the size and texture of the fins corresponds with the habits and necessities of the different species of fishes. Those which traverse vast portions of the ocean, or have frequently to struggle against swelling waves, are furnished with large and strong fins, while these organs are soft in the species which confine themselves to greater depths, where the winds cease to disturb the waters.

From the great variety which is met with both in the number and position of the fins, they are also of the greatest use in the classification of fishes, and afford the naturalist many of the chief characters which serve to distinguish the several orders, families, genera, and species of these aquatic vertebrates.[M]

The Chondropterygii are subdivided into three orders:

The osseous fishes, which are far more numerous, are subdivided into six orders:

The three following orders of the osseous fishes have the rays that support the fins soft and composed of numerous pieces articulated with each other, with the exception in some cases of the first ray of the dorsal, or of the pectoral. Their leading character is afforded by the situation or absence of the ventral fin, which in the

To the abdominal soft-rayed fishes belong the herring, salmon, pike, sly, and carp families; to the subbrachial, the cod family, the side-swimmers, and the lump fishes; and, finally, to the apodal malacopterygians, the single family of the anguilliform fishes. The small order of the

Most fishes possess a remarkable accessory organ of locomotion in the air-bladder or swim-bladder which extends to a greater or smaller distance along the ventral surface of the spine, and enables them voluntarily to increase or diminish the specific gravity of their body. When they contract this remarkable gas-reservoir, or press out the included air by means of the abdominal muscles, the bulk of the body is diminished, its weight in proportion to the water is increased, and the fish swims easily at a greater depth. The contrary takes place on relaxing the tension of the abdominal muscles; and thus we see fishes rise and fall in their denser element by the application of the same physical law which is made use of by our aëronauts, to scale the heavens or to descend again upon the earth. Those fishes which are destined to live at the bottom of the sea or to conceal themselves in the mud, such as eels and skates, have either no air-bladder or a very small one—for economical Nature gives none of her creatures any organ that would be useless to them. Even the slimy glutinous matter which is secreted from the pores of most fishes, and lubricates their bodies, assists them in gliding through the waters, so that no means have been neglected to promote the rapidity of their movements.

The skin of fishes is but seldom naked; in most species it is covered with scales, that sometimes appear in the form of osseous plates, as in the ostracions, or project into formidable prickles, as in the porcupine-fish, but generally offer the aspect of thin laminæ, overlapping each other like the tiles of a roof, and embedded, like our nails, in furrows of the skin. In nearly all the existing fishes, the scales are flexible and generally either of a more or less circular form (cycloid), as in the salmon, herring, roach, &c., or provided with comb-like teeth projecting from the posterior margin (ctenoid), as in the sole, perch, pike, &c.; while the majority of fossil fishes were decked with hard bony scales, either rhomboidal in their form, of a highly polished surface, as in our sturgeons (ganoid), and arranged in regular rows, the posterior edges of each slightly overlapping the anterior ones of the next, so as to form a very complete defensive armour to the body; or irregular in their shape and separately imbedded in the skin (placoid), as in the sharks and rays of the present day.

The scales of almost any fish afford admirable subjects for microscopic observation, but more particularly those of the ctenoid kind, which exhibit a brilliancy of reflected light, and a regularity of structure, such as no human mosaic could ever equal.

Many of our European fishes are richly decorated with vivid colours, but their scaly raiment is generally far from equalling the gorgeous magnificence of the fishes of the tropical seas.

If in the birds of the equatorial zone a part of the plumage sparkles with a gem-like brilliancy, all the colours of the rainbow combine to decorate the raiment of the tropical fishes, and no human art can reproduce the beauty of their metallic lustre, which at every movement in the crystalline waters exhibits to the enchanted eye new combinations and reflections of the most splendid tints.

The gaudiest fishes live among the coral reefs. In the tepid waters, where the zoophytes, those sensitive flowers of the ocean, build their submarine palaces, we find the brilliant Chetodons, the gorgeous Balistinæ, and the azure Glyphysodons gliding from coral branch to coral branch like the playful Colibris, that over the Brazilian fields dart from one lustrous petal to another.

Oxygen is as necessary to fishes and other marine creatures as it is to the terrestrial animals, but as they are obliged to draw it from a denser element, which absorbs but a small volume of air, their gills are necessarily differently constructed from the lungs of the creatures breathing in the atmosphere. In most species, comprising all the bony fishes, and the sturgeons, among those which have a cartilaginous skeleton, we find on either side of the throat five apertures, separated from each other by four crooked, parallel and unequal bones, and leading to a cavity, which is closed on the outside by an operculum or cover. In this cavity, and attached to the bones, are situated the delicate membranes, bearded like feathers, which serve to aërate the blood. The water constantly flows through the gills in one direction, entering by the branchial apertures of the throat, and emerging through the operculum. This is, in more than one respect, a most wise provision of Nature; for if the fishes were obliged to receive and reject the water by the same aperture, as we do the air, each expiration would evidently drive them backwards, and consequently retard their movements. It is also evident that the delicate fringes or folds of the gills would soon get into disorder if the water were carried through them in two opposite directions.

In most of the cartilaginous fishes, such as the sharks, rays, and lampreys, the gills are differently formed, the water not passing into a cavity closed by a cover, but flowing directly outwards through five (in the shark) or seven (in the lamprey) vents or spiracles. In these species also the gills are fixed, their margins being attached. Though the whole breathing apparatus of a fish is comprised in a small compass, its surface, if fully extended, would occupy a very considerable space; that of the common skate, for instance, being equal to the surface of the human body. This single fact may convince us of the numberless ramifications and convolutions of the gills, in which the water is elaborated and attenuated in the course of giving out its air; and how wonderfully Nature has contrived to effect her purpose with the greatest economy of space.

Respiration is a species of combustion, and this must necessarily be very slow in an element which contains so small a portion of oxygen. No wonder that the circulation of the blood in fishes is equally tardy. Their heart, in comparison with ours, is but half a one, as it merely serves to force the venous blood into the gills—whence the aërated blood does not flow back to the heart as with us, to be rapidly and strongly propelled through the body, but proceeds immediately to the arteries. Evidently only a cold blood could be formed under such circumstances. It may seem strange that, when fishes are taken out of the water, they die from want of air; such, however, is the case. Their delicate breathing membranes collapse in the atmosphere, the blood can no longer flow as before into the innumerable small vessels with which they are interwoven, and, by rapidly drying in the air, they soon entirely lose the faculty of breathing. Thus those fishes whose gill-cover has a large aperture, die soonest in the air, while those where the opening is narrow, and more particularly those species where the gills communicate with a cellular labyrinth containing water, which serves to keep them moist, are able to live a much longer time in the atmosphere.

It is owing to such a moistening apparatus that the climbing fishes (Anabas) live for days out of the water, and even creep up the trees at some distance from the shore, to catch the insects which serve them as food—a curious instance indeed of an animal seeking its nourishment in another element.

The Frog-fish of the Asiatic islands and the Southern hemisphere is not more remarkable for its hideous deformity than for its capacity of leading a terrestrial life. Not only can it live several days out of the water but it can crawl about the room in which it is confined, a facility which it owes to the great strength and the peculiar position of its pectoral fins, which thus perform the office of feet. The whole aspect of these grotesque-looking creatures, particularly in a walking position, is so much like that of toads or frogs, that a careless observer would at first be at some loss to determine their real nature.

A no less wonderful pedestrian is the Hassar (Doras costata), a South American fish, that marches over land in search of water, travelling a whole night when the pools dry up in which it commonly resides. It projects itself forwards on its bony pectoral fins, by the elastic spring of the tail, exerted sidewise, and in this manner proceeds nearly as fast as a man will leisurely walk. The strong scuta or bands which envelop its body must greatly facilitate its march, in the manner of the plates under the belly of serpents, which are raised and depressed by a voluntary power, in some measure performing the office of feet. The Indians say justly that these fishes supply themselves with water for their journey. If they find the pools and rivers everywhere dried up, they bury themselves in the mud, and fall into a kind of asphyxia or lethargy, till the rainy season recalls them again to life.

The hassar is also remarkable for a parental affection, almost unexampled among fishes. Sir Richard Schomburgk relates that it not only builds a complete nest for its spawn but also watches over it with the utmost vigilance till the young brood comes forth. In April, this marine artist begins to build his little dwelling of vegetable fibres, among the water-plants and rushes, until it resembles a hollow ball, flattened at the top. An aperture corresponding to the size of the mother leads into the interior. The parental affection of the fish is shamefully misused by man for its destruction. A small basket is held before the opening; then the nest is slightly beaten with a stick; and, furious, with extended fins, whose sharp points are able to inflict a painful wound, the poor hassar darts into the fatal basket.

SUBAQUEOUS LIFE—STICKLEBACKS AND NEST.

The black Goby (Gobius niger) also prepares a nest for its eggs. This fish inhabits the slimy bottoms of the lagoons near Venice, and burrows galleries in the clayey soil, where it spends the greater part of the year, protected against storms and enemies. In spring it digs more superficial dwellings among the roots of the sea-grass, to which the spawn attaches itself. The architect watches over the entrance of the house, opposing sharp rows of teeth to every intruder.

A similar care may be admired in the tiny Stickleback, which the celebrated ichthyologist, M. Coste, has often watched building its nest. After the fish has collected the materials, it covers them with sand, glues the walls with a mucous secretion, and prepares a suitable entrance. At a later period it becomes the bold and indefatigable defender of its eggs, repelling with tooth and prickles all other sticklebacks that approach the nest. If the enemy is too powerful, it has recourse to artifice, darts forth, seems actively engaged in the pursuit of an imaginary prey, and often succeeds in diverting the aggressor's attention from its nest. The River Bullhead is likewise said to evince the same parental affection for its ova, as a bird for its nest, returning quickly to the spot, and being unwilling to quit it when disturbed. It is believed, also, of the Lump-Sucker, that the male first keeps watch over the deposited ova, and guards them from every foe with the utmost courage. If driven from the spot by man, he does not go far, but is continually looking back, and in a short time returns. Thus we find among the inferior animals glimpses of a higher nature, which prove that all created beings form a continuous chain, linked together by one all-pervading and almighty Power.

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.

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.

Far more dreadful, from its gigantic size and power, is the White Shark (Squalus carcharias), whose jaws are likewise furnished with from three to six rows of strong, flat, triangular, sharp-pointed, and finely serrated teeth, which it can raise or depress at pleasure. This tyrant of the seas grows to a length of thirty feet, and its prodigious strength may be judged of from the fact that a young shark, only six feet in length, is able to break a man's leg by a stroke of its tail. Thus, when a shark is caught with a baited hook at sea, and drawn upon deck, the sailors' first act is to chop off its tail, to prevent the mischief otherwise to be apprehended from its enormous strength. An anecdote related by Hughes, the well-known and esteemed author of the "Natural History of Barbadoes," gives a good idea of the savage nature of this monster. "In the reign of Queen Anne a merchant-ship arrived at that island from England: some of the crew, ignorant of the danger of the recreation, were bathing in the sea, when a large shark appeared and swam directly towards them; being warned of their danger, however, they all hurried on board, where they arrived safe, except one poor fellow, who was bit in two by the shark, almost within reach of the oars. A comrade, and intimate friend of the unfortunate victim, when he observed the severed trunk of his companion, vowed his revenge. The voracious monster was seen traversing the bloody surface of the waves, in search of the remainder of his prey, when the brave youth plunged into the water. He held in his hand a long sharp-pointed knife; and the rapacious animal pushed furiously towards him. He had turned on his side and opened his enormous jaws, when the youth, diving dexterously, seized the shark with his left hand, somewhere below the upper fins, and stabbed him repeatedly in the belly. The animal, enraged with pain, and streaming with blood, attempted in vain to disengage himself. The crews of the surrounding vessels saw that the combat was decided; but they were ignorant which was slain, till the shark, exhausted by loss of blood, was seen nearer the shore, and along with him his gallant conqueror—who, flushed with victory, redoubled his efforts, and, with the aid of an ebbing tide, dragged him to the beach. Finally, he ripped open the stomach of the fish, and buried the severed half of his friend's body with the trunk in the same grave."

It is no uncommon thing for the negroes, who are admirable divers, thus to attack and vanquish the dreaded shark, but success can only be achieved by consummate dexterity, and by those who are armed for this express purpose.

Ordinary swimmers are constantly falling a prey to the sharks of warm climates. Thus Sir Brooke Watson, when in the West Indies, as a youth, was swimming at a little distance from a ship, when he saw a shark making towards him. Struck with terror at its approach, he immediately cried out for assistance. A rope was instantly thrown, but, even while the men were in the act of drawing him up the ship's side, the monster darted after him, and at a single snap took off his leg.

Fortunately for the friends of sea-bathing on our shores, the white shark, like his relation, the monstrous Hammer-headed Zygæna, appears but seldom in the colder latitudes, though both have occasionally been found on the British coast.

The northern ocean has got its peculiar sharks, but they are generally either good-natured like the huge basking shark (S. maximus), which feeds on sea-weeds and medusæ, or else like the Picked dog-fish (Galeus acanthius), of too small a size to be dangerous to man, in spite of the ferocity of their nature.

But the dog-fish and several other species of our seas, such as the Blue Shark (Carcharias glaucus), though they do not attempt the fisherman's life, are extremely troublesome and injurious to him, by hovering about his boat and cutting the hooks from the lines in rapid succession. This, indeed, often leads to their own destruction, but when their teeth do not deliver them from their difficulty, the blue sharks, which hover about the Cornish coast during the pilchard season, have a singular method of proceeding, which is, by rolling the body round so as to twine the line about them throughout its whole length; and sometimes this is done in such a complicated manner, that Mr. Yarrell has known a fisherman give up any attempt to unroll it as a hopeless task. To the pilchard drift-net this shark is a still more dangerous enemy, and it is common for it to pass in succession along the whole length of net, cutting out, as with shears, the fish and the net that holds them, and swallowing both together.