BARNACLES,
Or, as they are sometimes called, Bernicles, belong to what naturalists term the class Cirrhopoda, sometimes spelled cirripeda, which appears to be derived from the Latin cirrus—a tuft or lock of hair curled, and pede—a foot; hence the term may be translated hairy-footed. Such of our readers as have seen the Common or Duck Barnacle, (Pentalasmis anatifera,) will at once understand the applicability of this term. Many a piece of drift wood comes to land literally covered with long fleshy stalks, generally of a purplish red colour, twisting and curling in all directions, and terminating in delicate porcelain-like shells, clear and brittle, of a white colour, just tinged with blue, from between which project the many-jointed cirrhi, or hair-like tentacles, which serve the purpose of a casting net, to seize and drag to the mouth of the animal, its prey, which consists of small mollusks and crustacea.
This is the Barnacle about which such strange stories are told by old writers, who affirmed that the Barnacle or Brent Goose, that in winter visits our shores, is produced from these fleshy foot-stalks and hairy shells by a natural process of growth, or, as some philosophers of our day would say, of development. Gerard, who, in 1597, wrote a “Historie of Plants,” describes the process by which the fish is transformed into the bird; telling his readers that as “the shells gape, the legs hang out, that the bird growing bigger and bigger the shells open more and more, till at length it is attached only by the bill, soon after which it drops into the sea; there it acquires feathers, and grows to a fowle.” There is an amusing illustration given in Gerard’s book, where the young Geese are represented hanging on the branches of trees, just ready to drop into the water, where a number of those that have previously fallen, like ripe fruit, and attained their full plumage, are sailing about very contentedly. It was part of this theory that the Barnacles were of vegetable origin, they grew upon trees, or sprung out of the ground like mushrooms; so we find in the works of an old poet named Du Bartas, these lines:—
“So slow Bootes underneath him sees
In the icy islands goslings hatched of trees,
Whose fruitful leaves, falling into the water,
Are turned, as known, to living fowls soon after;
So rotten planks of broken ships do change
To Barnacles. O transformation strange!
’Twas first a green tree, then a broken hull,
Lately a mushroom, now a flying Gull.”
The investigations of modern science have quite exploded this foolish notion; we now know exactly what transformations the Barnacle undergoes; strange enough some of them are, but it does not change into a Goose, although its specific name has reference to that bird, being derived from anas, the Latin for Goose.
The shell of the Barnacle is composed of five pieces joined together by membranes; four pieces are lateral, that is to say, they form the sides, the word comes from the Latin latus—a side; the other is a single narrow slip, which fills what would otherwise be an open space down the back between the valves; these parts of the shell appear to be somewhat loosely connected, so as to allow free action to the animal lodged within, which is enclosed in a fine skin or mantle. The mouth is placed at the lower part, near the opening, whence the cirrhi issue forth; this mouth is a curious piece of mechanism, being furnished with a horny lip covered with minute palpi, or feelers; there are three pairs of mandibles, that is jaws, the two outer ones being horny and serrated, that is jagged or toothed like a saw; the inner one is soft and membranous, that is, composed of little fibres, like strings, crossing each other, as we see what are called the veins in a leaf.
Much more might be said about the internal structure of the Cirrhopods, or Balani, as the Barnacle group is sometimes called, from the Latin Balanus—a kind of acorn. By some naturalists, the term is not applied to the stalked Cirrhipoda, like that we have been describing, but only to the sessile kinds, that is, those which set close or grow low; from the same Latin root comes the English word session—a settling. The coverings of these Dwarf Barnacles are sometimes called acorn shells; they are commonly white, of an irregular cone shape, composed of several ribbed pieces, closely fitted together with an opening at the top, closed by an operculum, or stopper.
These shells cover in patches the surface of exposed rocks, drift wood, and any other substance. Some of the mollusks affix themselves to the bodies of Whales, others form a lodgment in the hollows of corals and sponges. Once fixed they remain so during life, taking their chance of such suitable food as may come within their limited sphere of action. At an earlier stage of their existence, both their shape and habits are very different, being lively little creatures, swimming about hither and thither like water-fleas. They are about the tenth of an inch long, and of most grotesque appearance, having six jointed legs set with hairs, the whole being so arranged that they act in concert, and striking or flapping the water, send the little body along in a series of bounds; then the creature has two long arms, each furnished with hooks and a sucker, and a tail tipped with bristles, which is usually folded up under the body; its pair of large staring eyes are pedunculated, that is, set upon foot-stalks; it has a house on its back, like a bivalve shell, into which it can collect its scattered members when occasion requires. When of sufficient age to settle itself in life, and become a staid member of submarine society, it fixes itself to some convenient object, throws away its eyes as no longer useful, gets rid of its preposterous limbs, enlarges its house, and sits down to fishing in a small way for an honest and respectable livelihood.
A piece of timber covered with Stalked Barnacles, wriggling and twisting about like so many helmeted snakes, and waving their plume-like cirrhi, is a very curious sight. They sometimes attach themselves to ship’s bottoms in such numbers as to retard their progress through the water; they do not, however, bore into and destroy the timber, like the Teredines, or ship worms, to which we have alluded in our brief notice of the Pholadæ. The growth of Barnacles must be very rapid, as a ship perfectly free from them, will often return after a short voyage, with her bottom below the water line completely covered.
We give a representation of a group of these stalked mollusks, as they appear affixed to a piece of timber. This is the Common, or Duck Barnacle.
