LIMPITS.
Among the rocks of the British coast, there are no shells more frequently met with than those of the Common Limpit, Patella vulgata; they lie scattered about like so many little empty cups, each having, on the death of the mollusk, fallen from the rocky cavity in which it was embedded, and which was just large enough to contain it. Here the animal attaches itself so firmly by its fibrous foot, which is hollow in the centre, and acts like a sucker, that it is almost impossible to loosen its hold otherwise than by inserting something thin, like the blade of a knife between it and the stone. By this power of adhesion, the Limpit is protected from the violence of the waves, and also from its numerous enemies, aquatic birds and animals, which have a relish for its flesh. Still vast numbers are used as food, both by man and the inferior creatures, so that the means of defence furnished to the Limpits of the rock, are not always sure. “The peasantry of the western isles of Scotland,” we are told by Miss Pratt, “look to the Periwinkles and Limpits, which abound on the rocks, for their daily meal, often for long seasons, subsisting almost entirely upon this humble food. In the Isle of Skye, the inhabitants are often, at one time of the year, without any other source of provision.” Then comes the Sea-gull, and the Duck, and the Pied Oyster-catcher, to feed on the poor little mollusk, the bill of the latter bird being admirably adapted for loosening its hold on the rock.
Patella in Latin signifies a salad-dish, a knee-pan, and several other domestic utensils, of a broad shallow make, and hence we find the plural form of the word applied to the Limpit family, whose shells are of such a shape. Members of this family are found on all rocky coasts, except those of the Arctic seas; on Tropical rocks they grow to a large size, and form a valuable article of food. A very curious piece of mechanism is the tongue of the Common Limpit, it is from two to three inches long, and has a spoon-like extremity, so that it looks, when extended from the mouth, like a small snake; if examined through a microscope, it is seen to be armed throughout its whole extent with rows, four deep, of sharp hooked teeth, and between each row are placed two others, which have three points, and are set in a slanting position; the use of this arrangement we cannot at present determine, but no doubt it has a perfect adaptation to the wants of the animal.
There are shell-fish called Key-hole Limpits, which belong to the genus Fissurellidæ, from fissura—a cleft or slip, from whence comes also fissure. All the members of this genus are distinguished by the aperture at the top of the shell, shaped like a key-hole, which is situated exactly over the breathing organs, and serves as a channel for the water necessary for respiration.
Frequently upon the fronds of the large olive sea-weeds may be found a tiny shell shaped something like that of the Common Limpit; it is of an olive green colour, with blue streaks, and is called, from its clearness, the Pellucid Limpit, P. pellucida. There is also another much like it in appearance, which naturalists call P. lœvis. To the labours of these little mollusks, according to Dr. Harvey, may be partly attributed the destruction of the gigantic Algæ, (sea-weed.) Eating into the lower part of the stems, and destroying the branches of the roots, they so far weaken the base, that it becomes unable to support the weight of the frond; and thus the plant is detached and driven on shore by the waves.
“And so the forest tall that groweth,
Underneath the waters clear,
Does the little woodman mollusk,
Level every year;
From small causes, great results—
Teaching you to persevere.”