But there is another little sailor called the velella; unprovided with offensive weapons, though formed in most respects upon a model somewhat similar to that of the physalia, unguarded as the peaceful trader against the piratical attacks of a thousand enemies, its very race would soon become extinct, were it not for its unlimited increase.
Provided with a flat, transparent, oval scale of cartilage, for the support of a gelatinous body, it floats by specific levity, alone, for it has no air vessel—and employs its hundreds of stomachs for ballast. Another scale arising at right angles with the first and covered with thin membrane, supplies it with a sail. This unprotected creature serves as food for many predatory tribes, and of these, the most voracious is the barnacle. The flesh devoured, the scales still float for many days, mere wrecks of these gay vessels.
The velellæ are usually found in fleets, and to convey some idea of their numbers, I may state that on one occasion, when sailing before the western winds, beyond the southern latitude of the Cape of Good Hope, our ship encountered a group of globular masses of a pale yellow color swimming upon the surface and surrounded by fringes of an unknown substance. Each mass resembled the eggs of some great sea-bird, reposing on a nest of buoyant feathers. Taking them with a dip net, from the chains, we found the yellow masses to be globular cryptogamous plants, to every one of which adhered a group of barnacles, far larger than the largest I had ever seen before.[[1]] Many of these last were so intent upon demolishing their prey, that, even in leaving their native element, to fall into the hands of tyrants more dangerous than themselves, it was not always relinquished. Grasping in their horny arms the unfortunate velellæ, they continued grinding the soft jelly from the tougher cartilage, with an avidity and determination that reminded me strongly of the scene in Byron’s Siege of Corinth, where Alp, the renegade,
“Saw the lean dogs beneath the wall
Hold, o’er the dead, their carnival,
Gorging and growling o’er carcass and limb;
They were too busy to bark at him!”
This drew our attention to the source from which such plentiful supplies of food were obtained, and on examination, the ocean was found literally covered with the scales of the murdered velellæ, faintly distinguishable by their glistening in the sunshine, and interspersed with a few living specimens waiting their turn in the general massacre. We scooped them up by thousands; and for three long days the ship swept onward “dead before the wind” with the steady and scarcely paralleled speed of more than ten knots an hour, thus accomplishing a change of more than seven hundred miles in longitude, before the last remnant of this unhappy fleet was passed.
Though it is not pretended that these little sea-boats possess the phosphorescent quality, their numbers and the wide extent of their flotilla will suffice to render far less wonderful the vastness of those beautiful results of animal secretion which have furnished the subject of this sketch.
But there are other similar and more remarkable phenomena attendant on these brilliant night scenes, that can only be explained, either by supposing that myriads of these aquatic beings are endowed with a community of instinct, or, that the changes of the weather influenced them in such a way as to awaken all their luminous powers upon the instant, without the intervention of any mechanical disturbing cause, in the mere frolic mood of nature.