A CHAPTER on marine fishes will not be considered out of place in an "Introduction to the Natural History of the British Coasts," or "The Sea Side Book," and, accordingly, a few pages are here devoted to a notice of those marine species most in request for the table, with reference to their relative value as an article of food; their numbers; variety; cheapness; edible and nutritious qualities; when best in season; and the various modes by which they are captured.

Geographers assume that more than two-thirds of the surface of the globe is covered with water, and Fishes, as a Class, are probably more numerous than Birds.

The external form is very variable, and too well known to require particular description. The Mac

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SCALES OF FISHES.

kerel may be quoted as one of the most elegant in shape, as well as perfect in its adaptation, to the element in which it moves, but the external figures of several species have been accurately measured and studied by naval architects for models of vessels, as speed or tonnage might be the power required.

The surface of the body is, in most instances, covered by scales, which vary considerably in size, number, and thickness, according to the species. Each scale is attached to the skin of the fish by its anterior edge, and in arrangement they overlap each other. They exhibit in their structure both radiating and concentric lines, or striæ. If examined with a lens of sufficient magnifying power, the straight or radiating lines indicate the situation of minute tubes conveying a fluid, by which the substance of the scale is nourished. The concentric lines mark the edges of the laminæ forming the scale itself, the outermost line being the edge or margin of the last layer deposited on its inner surface, and the number of these lines become greater as the fish advances in age, thus marking the growth. The row of scales along the side of the fish, forming the lateral line, in addition to the structure common to the scales on the other parts of the body, are pierced in their centre by a tube which allows the escape of the mucous secretion produced by the glands underneath them. The scales may be considered as defending the skin of the fish from the

SCALE OF GREY MULLET.

PERIODICAL MIGRATIONS OF FISHES.

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action of the water in which it resides, and it is observed that those species in which the scales are small, are furnished with the largest quantity of protecting mucus or slime.

The membranes of the fins are thin, and more or less transparent, supported by slender, elongated portions of bone, of variable degrees of flexibility. The names given to the different fins have reference to the particular part of the body to which they are attached. The principal organ of motion in fishes. is the tail, assisted by the simultaneous action of the pectoral and ventral fins. The economy of Nature is conspicuous in the habits of fishes. Some always swim at or near the surface, others about mid-water, and many close to the bottom: all parts of the water are alike occupied, and some peculiar qualities and powers are found to belong to each of the species, thus affecting by choice these different stations in the water.

By a portion of the older Ichthyological writers, fishes were supposed to perform, like some birds, certain periodical migrations, making long voyages from north to south at one season of the year, and the reverse at another. It does not seem to have been sufficiently considered, that, inhabiting a medium which varied but little either in its temperature or productions, locally, fishes are removed beyond the influence of the two principal causes which render a temporary change of situation necessary. The law of Nature which obliges them to repair to the shallower water of the shores at a particular season, ap.

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MODES OF TAKING FISHES.

pears to be one of those wise and bountiful provisions of the Creator, by which not only is each species perpetuated with the greatest certainty, but a large portion of the parent animals are thus brought within the reach of man, who, but for the operation of this law, would be deprived of many of those species most valuable to him as food. It may be observed further, that as there is scarcely a month throughout the year in which the fishes of some one or more species are thus brought within the reach of man, a constant succession of wholesome food is spread before him, which costs him little beyond the exercise of his ingenuity and his labour to obtain.

The modes of taking fish are very variable, and the practice of capturing them by hooks and spears is probably of very remote antiquity. Nets appear to have been first used in this country about the year 678, when the peasantry on the coast of Sussex were first instructed in the use of nets by Bishop Wilfrid ;* some of the nets in use at the present day are, however, more immediately the subjects to be here described, as well as the modes by which they are successfully worked.

The trawl, or trawling-net, more generally used than any other on those parts of our coast where the ground surface is of sand, or otherwise smooth, has a beam of eighteen or twenty feet in length, the extent of the beam being the breadth of the mouth of the net, the length of the net is from three to four times the length of the beam. In the representation of this # 66 Origins and Inventions," by W. Pulleyn.

net here given, the rope that runs through the block is called the trawl-warp, and is the only connection

between the boat and the net when the net is overboard. The ropes passing obliquely backward from the block to the ends of the trawl-beam are called the bridle, and serve effectually to keep the open mouth of the net square to the front as the net is drawn along over the ground by the boat. The trawl-beam is four inches in diameter, and is supported at the height of twenty or twenty-four inches above the ground by a heavy frame of iron of a particular form at each end of the beam, called the trawl-heads, which assist by their weight to sink the net and keep it on the ground. The upper edge of the netting is attached along the whole length of the beam; the lower edge is fastened along a heavy rope called the groundrope, and follows, on the ground, considerably behind and below the advanced straight line of the beam, forming the portion of the circle seen through the upper surface of the net in the representation. This sort of net is only adapted for taking those fish that live upon, or very near, the bottom. When drawn

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