The BUTTER-FISH, SWORDICK, or SPOTTED GUNNEL (Centronotus gunellus), belongs to this family, and is evidently one of the transitional species between the true blennies and those which are placed at the end of the family.

This fish is frequently captured upon our coasts, especially on the rocky shores, and is mostly found hidden under stones and seaweeds in the rock-pools left by the receding tide. The name of Butter-fish is very appropriate, and is given to it on account of the plentiful mucous secretion which is poured over its body, and which renders it so slippery that it can with difficulty be retained in the hand. It is quick and agile in its movements, and even if confined within the limits of the rocky pool, is not easily captured.

The body of this fish is much elongated and somewhat eel-shaped, the head is small, the muzzle blunt, and the dorsal fin is low and long, extending the whole length of the back. The ventral fins are very small. The colour of the Swordick is brown, in some specimens with a purple and in others with a golden wash. Along the base of the dorsal fin, and in some individuals upon the fin itself, are a number of bold black spots, each with a white streak on either side. A dark brown stripe is also drawn from the the lower jaw. The length of the Butter-fish is about six inches.

eye to

OUR last example of this family is the well-known VIVIPAROUS BLENNY, called also by the popular names of EEL-POUT, LUMPER, GUFFER, and GREENBONE, the last-mentioned title being given to it because, when boiled, the bones have a green hue.

As its name imports, the Viviparous Blenny lays no spawn, but produces its young alive, and able to shift for themselves. In one case, where a female fish of about fifteen inches in length was taken, the young were about four inches long. It is a very curious fact, that the size of the new-born young seems to depend upon that of their parent, the offspring of a Blenny of seven inches in length measuring only one inch and a half.

The flesh of this fish is tolerably good, but is not in very great repute, so that it is but seldom to be seen in the markets. According to the most careful observations, it appears to be less common in the south than in the north of England, and while it is plentiful on the Yorkshire coasts, is scarcely to be found upon those of Devonshire. In such cases, however, the apparent discrepancy is often attributable to the differing abilities of the observers, and not to the absolute abundance or scarcity of the species. It generally hides itself under stones or seaweed, preferring the large heavy algae called tang.

The body of this fish tapers gradually from the shoulders to the tail, in thickness as well as in depth, and when examined with a pocket magnifier, the surface appears to be studded with circular depressions. Its general colour is pale brown, and its length varies between six and sixteen inches.

PASSING by several small families, we come to a very curious fish, denominated the RIBAND-SHAPED VAAGMÄR, sometimes called the DEAL-FISH (Trachypterus árcticus).

This singular fish is remarkable for the extreme compression of the body, a specimen three feet in length not being thicker than an ivory paper-knife. The dorsal fin of this fish extends completely along the back, there is no anal fin, and the tail fin stands boldly erect, like the closed tail-feathers of a fan-tail pigeon. The general colour of the Vaagmär is silvery white, and the body is covered with very small scales. The dorsal fin is bright orange, sometimes being of a blood red, and the tail fin is of the same hue. On each side are two oval spots of blackish grey, set obliquely on the body. The length of this fish often reaches six feet.

It is one of the northern fishes, and is very seldom seen on our coasts.

A SPECIES even still more remarkable is, on very rare occasions, obtained on our coasts, but owing to the extreme fragility of its structure it is mostly deficient in some of its parts.

The OARED GYMNETRUS, or RIBBON-FISH (Regalecus Banksii), is also greatly compressed throughout its length, and is equally delicate with the last-mentioned species. It is chiefly notable for the very odd structure of the ventral fins, which are reduced to long slender filaments, much resembling in shape the long tail-feathers of the racket-tail humming-bird. This fish sometimes attains very great dimensions, a specimen in the British Museum measuring twelve feet in length. Its colour is silvery grey, mottled with dusky spots of varying depth, which are most conspicuous towards the head. The whole surface of the skin is plentifully studded with bony tubercles, and on the line of the abdomen each tubercle is furnished with a hooked point directed backwards. Along the lateral line runs a row of elongated flat scales.

In the next family, the tail is mostly armed with one or more bony spines or plates, small in the young, but increasing in size with the dimensions of the fish.

The SEA SURGEON is a good type of these fishes, and derives its popular name from the sharply pointed and keen-edged spine on the side of the tail, which cuts and wounds like a surgeon's lancet. The generic name signifying Thorn-tail is given to it in consequence of this structure. This species is found on the Atlantic coasts of Tropical America and Africa, and is tolerably plentiful in the Caribbean seas. The scales of this fish are very small, and the single spine on each side of the tail is movable and set in a longitudinal groove. Its food is of a vegetable nature.

In colour it is rather variable, but the ground tint is usually of a brownish hue, and the operculum has a black edge. In some specimens the end of the tail is marked with a

THE CLIMBING PERCH.

293

white band, which encroaches on part of the tail fin, and there is also a narrow white edge to that fin. There are in certain individuals a few darkish streaks drawn across the body, some black longitudinal stripes on the dorsal and anal fins, and in the young the sides are

marked with darkish waving lines. This fish sometimes attains a rather large size, a specimen in the British Museum being nineteen inches in length. The genus is rather comprehensive, containing between forty and fifty known species.

NEARLY allied to the surgeon-fish is a very curious species, called the UNICORN THORNTAIL (Naseus unicornis), on account of the singular structure of the forehead, which is modified in front into a long and horn-like protuberance, rather conical in shape, and projecting forwards in a line with the body. This horn is not to be seen in the young fish, and only attains its full dimensions when its owner has reached adult age. Sometimes the horn is longer than the snout, but in most specimens it is slightly shorter. Each side of the tail is furnished with two lancet-bearing plates, which are not movable.

This species is found from the Red Sea to Japan and Polynesia. Its colour is brownish grey, and the dorsal and anal fins are marked with longitudinal blue stripes. The largest specimen in the British Museum measures twenty-two inches in length, and its horn is three inches long.

THE extraordinary fish, called, from its habits, the CLIMBING PERCH, is a native of Asia, and is remarkable for its apparent disregard of certain natural laws.

This singular creature has long been celebrated for its powers of voluntarily leaving the failing streams, ascending the banks, and proceeding over dry land towards some spot where its unerring instinct warns it that water is yet to be found. There are several fish which are known to have this power; the common eel of England, for example, which has frequently been observed crossing the fields in its passage from one stream to another. I have even seen the cels creeping over rocks, and contriving, in some mysterious manner, to crawl along the flat horizontal surface of an overhanging rock as easily as a fly walks on the ceiling. But I believe that the eel only passes over moist ground, whereas the Anabas seems quite indifferent to such considerations, and takes its journey over hard, dry, and dusty roads, heated with the burning beams of the noonday sun, without appearing to feel much inconvenience from the strange nature of the transit.

Several species, of which the Anabas Scandens has been chosen as the best example,

possess this singular property of walking over dry ground, so that the old proverb of a fish out of water is, in these cases, quite inapplicable. Several instances of this remarkable propensity have been collected by Sir J. Emerson Tennent, and have been inserted in his valuable work on the Natural History of Ceylon. The following account is written by Mr. Morris, the Government agent in Trincomalee :

"I was lately on duty inspecting the bund of a large tank at Nade-cadua, which being out of repair, the remaining water was confined in a small hollow in the otherwise dry bed. Whilst there, heavy rains came on, and as we stood on the high ground, we observed a pelican on the margin of the shallow pool gorging himself: our people went towards him, and raised a cry of Fish! fish! We hurried down, and found numbers of fish struggling upward through the grass, in the rills formed by the trickling of the rain. There was scarcely water to cover them, but nevertheless they made rapid progress up the bank, on which our followers collected about two baskets of them at a distance of about forty yards from the tank. They were forcing their way up the knoll, and had they not been interrupted first by the pelican and afterwards by ourselves, they would in a few minutes have gained the highest point, and descended on the other side into a pool which formed another portion of the tank.

... As the tanks dry up, the fish congregate in the little pools, till at last you find them in thousands in the moistest parts of the beds, rolling in the blue mud, which is at that time about the consistence of thick gruel.

As the moisture further evaporates, the surface fish are left uncovered, and they crawl away in search of fresh pools. In one place I saw hundreds diverging in every direction from the tank they had just abandoned, to a distance of fifty or sixty yards, and still travelling onwards. In going this distance, however, they must have used muscular exertion enough to have taken them half a mile on level ground, for at these places all the cattle and wild animals of the neighbourhood had latterly come to drink, so that the surface was everywhere indented with footmarks in addition to the cracks in the surrounding baked mud, into which the fish tumbled in their progress. In those holes which were deep, and the sides perpendicular, they remained to die, and were carried off by kites

and crows.

My impression is, that this migration must take place at night or before sunrise, for it was only early in the morning that I have seen them progressing, and I found that those I brought away with me in the chatties appeared quiet by day, but a large proportion managed to get out of the chatties by night-some escaped altogether; others were trodden on and killed.

One peculiarity is the large size of the vertebral column, quite disproportioned to the bulk of the fish. I particularly noticed that all in the act of migrating had their gills expanded."

It is known of the Climbing Perch that the fishermen of the Ganges, who subsist largely on these fishes, are accustomed to put them into an earthen pan or chatty as soon as caught; and although no water is supplied to them, they exist very well without it, and live this strange life for five or six days.

On opening the head of this fish, the curious structure which enables it to perform such marvellous feats is clearly seen. Just within the sides of the head, the "pharyngeal " bones, i.e. the bones that support the orifice between the mouth and gullet, are much enlarged, and modified into a series of labyrinthine cells and duplications, so that they retain a large amount of water in the interstices, and prevent the gill-membranes from becoming dry. Some writers say that this fish is capable of climbing up the rough stems of palm-trees, in search of the water that lodges between the bases of the dead leaves and the stem, but this account is now held unworthy of belief. In the Tamoule language it is called Paneiri, or Tree-climber.

THE small genus Atherinidæ has a British representative in the SAND SMELT (Atherina presbyter), a pretty little fish, and one that is of great use to fishermen, both for sale and for bait.

It is extremely plentiful upon the southern coast, and in many places is sold as the true smelt, which it somewhat resembles in flavour and the peculiar odour as of cucumber. Owing to the small size of this fish the net is the usual mode of capture, the fashion of which varies according to the locality. On some coasts the net is about ninety feet in length and eighteen in depth, and is drawn along the sands by the united aid of one party in a boat and the other on the shore. In other places, however, it is circular and supported on an iron hoop. It is then baited with broken crustacea and lowered into the water. At intervals it is raised smartly to the surface, and the entrapped Sand Smelts removed.

The colour of the Sand Smelt is the palest pink, shining silvery white, which is drawn along the side. base of each pectoral fin are of the same white hue. and head are a great number of little black spots.

seven inches.

diversified with a broad belt of The cheeks, gill-covers, and the Upon the upper part of the back The length of the fish is from six to

We now come to the important family of the Mugilidae, of which the common GREY MULLET is a good example. In all these fish there are two dorsal fins, the first having four stiff spines. They are spread over all sea-coasts and fresh waters of the temperate and tropical regions. The mode of feeding is rather curious. These fish live chiefly on the soft organic substances that are found mixed with weed and sand, and in swallowing the food a considerable amount of sand is taken into the mouth. The fish, however, is furnished with a kind of self-filtering apparatus, by means of which the heterogeneous mass is raked and sifted, as it were, and the indigestible portions rejected.

The Grey Mullet deserves notice as being one of the most daring and ingenious of the finny race, and is, in fact, a very fox for artfulness. The idea of constraint is most obnoxious to it, and its instincts of freedom are so strongly developed that it endeavours to recover its liberty in the most extraordinary ways.

If, for example, it has been inclosed in a net, it will at once dart to the side and try to leap over the head-rope into the open sea. Moreover, if one fish succeeds in the attempt, the remainder immediately follow their leader, like a flock of sheep jumping over a hurdle. If the net is raised so high that the leap is impracticable, the fish tries to