Page:Natural History, Fishes.djvu/94

80 serve them as organs of touch, endowed with a sensibility to impressions that are indispensable in the situations where they haunt, as bottom feeders.

About two hundred and sixty species are enumerated in the Family, of which just one tenth part are European.

To this Family belongs a genus of fishes containing many well-known inhabitants of our coasts and rivers, the Sticklebacks (Gasterosteus). We have seven species, all of them of small size, some of which are familiar to every truant schoolboy by their abundance, their pigmy dimensions, their armature of spines and plates, their vivacity and boldness, and the beautiful tints of green, crimson, and silver, with which they are frequently adorned.

These little fishes, however, present other claims to our attention; for they afford additional examples of an instinct which has been considered almost if not quite unknown in the Class to which they belong, that of nest-building. The habits of one of these species, which appears to be the commonest of the Three-spined Sticklebacks (G. trachurus) have been described by a careful observer in a little-known periodical, called "The Youth's Instructor;" and his account carries its own guarantee of correctness with it. "In a large dock for shipping on the Thames," observes this writer, "thousands of these fish were bred some years ago; and I have often amused myself for hours by observing them. While multitudes have been enjoying themselves near the shore in the warm sunshine, others have been busily engaged in making their nests, if a