Glaucus; Or, The Wonders of the Shore

[Picture: Plate 2: 1. Cardium Rusticum, (tuberculatum). 2. Pagurus Bernhardi, in a Periwinkle Shell] That red capsicum is the foot of the animal contained in the cockleshell. By its aid it crawls, leaps, and burrows in the sand, where it lies drinking in the salt water through one of its siphons, and discharging it again through the other. Put the shell into a rock pool, or a basin of water, and you will see the siphons clearly. The valves gape apart some three-quarters of an inch. The semi-pellucid orange “mantle” fills the intermediate space. Through that mantle, at the end from which the foot curves, the siphons protrude; two thick short tubes joined side by side, their lips fringed with pearly cirri, or fringes; and very beautiful they are. The larger is always open, taking in the water, which is at once the animal’s food and air, and which, flowing over the delicate inner surface of the mantle, at once oxygenates its blood, and fills its stomach with minute particles of decayed organized matter. The smaller is shut. Wait a minute, and it will open suddenly and discharge a jet of clear water, which has been robbed, I suppose, of its oxygen and its organic matter. But, I suppose, your eyes will be rather attracted by that same scarlet and orange foot, which is being drawn in and thrust out to a length of nearly four inches, striking with its point against any opposing object, and sending the whole shell backwards with a jerk. The point, you see, is sharp and tongue-like; only flattened, not horizontally, like a tongue, but perpendicularly, so as to form, as it was intended, a perfect sand-plough, by which the animal can move at will, either above or below the surface of the sand. {67}