Page:Natural History, Mollusca.djvu/301

 the razor-fish feels the salt, it thinks the tide is coming in, and therefore rises in its hole.

"If the Solen be taken out of its hole and placed upon the sand, it immediately prepares to rebury itself. It stretches out its foot to full length, and then bends it so as to use the extremity as a sort of auger. When the end has sunk into the sand, it draws up its shell, which, first oblique, and afterwards perpendicular, soon becomes immersed and rapidly disappears. M. Deshayes, during his Algerian researches, observed a remarkable instinct of S. marginatus to swim when desirous of changing its locality. When it finds itself on ground too hard to be penetrated by its foot, it fills the cavity of its mantle with water, and then contracting and closing exactly at the same time its siphonal orifices, elongates its foot; then recontracting that organ, it ejects the water with force from the tubes, and thus propels itself after the manner of a cuttle-fish for a foot or two forwards. Then if it finds the surface favourable, it bores and buries itself, but if not, it makes another leap to try its chance anew."

(Gapers.)

A large assemblage of genera of small importance, presenting considerable variation in external form and appearance, but having much more in common, may, in a work such as the present, be conveniently associated under the above title, the more especially as they are united in one family by M. de Blainville. He has named the group Pyloridea,