“When the sea retires, the presence of the Solen is indicated by a small orifice in the sand, whence escape at intervals bubbles of air. In order to attract them to the surface, the fishermen throw into the hole a pinch of salt; the sand immediately becomes stirred, and the animal presents itself just above the point of its shell. It must be seized at once, for it disappears again very quickly, and no renewed efforts will bring it to the surface a second time. Its retreat is commonly cut short by a knife being passed below it; for it burrows into the ground with such velocity that it is difficult to capture it with the hand alone. The fish itself is a kind of marine worm.” [Illustration: THE RAZOR FISH (_Solen ensis_).] But of the Acephalous Mollusca none are more important to man than the mussel and oyster, the pearl‐bearing varieties of which latter have been already considered. Both are familiar to every reader. The _Mytilus edulis_, the edible mussel of commerce, the “poor man’s oyster,” is provided with a byssus, a bundle of hairs or threads, by which it can anchor to the rock. In its natural state it is much less fitted for human food than when cultivated. Their civilisation, as it might be termed, dates back to the year 1236, when the master of a barque, an Irishman named Walton, was wrecked in the bay or creek of Aiguillon, a few miles distant from Rochelle. The exile at first supported himself by hunting sea‐fowl in the neighbouring marshes, where he also soon began, being an observant man, to notice certain peculiarities of mussel life. [Illustration: THE MUSSEL (_Mytilus edulis_).]