Page:Natural History, Mollusca.djvu/162

 its base. The mouth is fleshy, and contains a long slender tongue, armed with spinous teeth, for the rasping down of the sea-weeds, of which the food of these animals consists. This organ in the common Limpet is described as a narrow ribbonlike-body, fully three inches long, of nearly equal breadth throughout, except at the tip, where it is soft and somewhat dilated. The width of this singular appendage is not more than one-twelfth of an inch; but the surface is armed through its whole length, with three parallel rows of spinous teeth, pointing backwards. The teeth of the middle row are cut into four points, but those of the external rows, which are not exactly opposite to, or continuous with, those of the middle series, but alternate with them, are cut into two points only.

TONGUE OF LIMPET. (The upper figure represents a portion of the surface magnified).

"The first time," says Mr. Patterson, "we chanced to see this, we mistook it for some strange species of worm; but on examining several Limpets, the supposed worm was seen in all; and great was our astonishment when we discovered that we had, in every case, been looking at the