A Year at the Shore

by Philip Henry Gosse

Look at this old valve of a Mactra. Like hundreds more that you may pick up at high water-mark, it is perforated by a tiny hole near the hinge, so smooth and so perfectly circular, that you would suppose a clever artisan had been at work drilling the massive stony shell with his steel wimble. No such thing: the Dog-whelk has done it: this is the breach which he so scientifically effected in the fortress; and hence he sucked out the soft and juicy and savoury flesh of his miserable victim.

In order to understand his plan of operations, let us put down our captive, and see him crawl. He is not long before he begins to march, on his broad oblong foot, which, as you observe, is cream-coloured, elegantly splashed and speckled with dark-brown. But before he moves he thrusts out a long cylindrical proboscis from the front of his head, which he carries high aloft and waves to and fro; and this organ, we see, fits into the deep notch in front of the shell. This proboscis is his drilling-wimble.

THE DOG-WHELK’S DRILL.

This organ is itself a study. Long as it is when extended, it can be thoroughly drawn within the body; and there it forms two fleshy cylinders, one within the other, exactly like a stocking half turned on itself. There are proper muscles attached to its walls, and to the interior of the head, by extremities which are branched in a fan-shape, so as greatly to strengthen their insertions; and these, by contraction, draw the one portion within the other. Then there is a broad hoop of muscle, which, passing round the inner cylinder, by contracting pushes it out, and lengthens it. Within the interior of this latter there is a long narrow ribbon of cartilage, which is armed with rows of sharp flinty points, turned backwards; and this tongue or palate, as it is variously called, is the Dog-whelk’s weapon.

We cannot induce the Whelk to attack his prey just when we please; but he has been detected in the operation, and I will describe it. With his broad muscular foot he secures a good hold of the bivalve, and having selected his point of attack, in general near the hinge—a selection which probably looks more at the superiority of the meat within than at any peculiar facility in the perforation—he brings the tip of his extended proboscis to the point, so that the silicious teeth can act on the shell. Hard as is the calcareous shell, it is not proof against the flint; for, without any solvent excretion, the aid of which some physiologists have been ready to suppose, these glassy points, grating round and round as on a pivot, soon wear away the substance, and gradually bore the tiny aperture which exposes the sapid morsel.

Continuing our researches, we find, deep in a rocky pool under a tuft of weed, a shell of a peculiar form, because of the enormous expansion of its outer lip. It is known as the Pelican’s-foot,[7] from the resemblance which this lip with its diverging ribs bears to the webbed toes of a water-fowl. This, too, is a carnivorous species; and though it is somewhat rare to detect the animal moving, even though kept alive in captivity, yet by carefully examining this one in its deep pool, before we disturb its equanimity, we can just see the proboscis protruding from the wide square notch in the shell, and discern that it is rather prettily coloured, being marked with spots of opaque white on a rose-coloured ground.

This species is interesting from the changes of figure which it undergoes in its progress from youth to maturity. While young the shell is simple, with no trace of the expanded lip; and it is only at mature age, and rather suddenly, that the shell makes its remarkable growth into these far-projecting points and angles, the augmented thickness of which is, moreover, at least equally conspicuous with the expanse.

THE COWRY.

But far more remarkable changes take place in the growth of the shell in a family of signal beauty, of which I discern a specimen in yonder cavernous hollow. The family I speak of is that of the Cowries; and this individual represents the only species that is indigenous to our seas—the little Furrowed Cowry.[8] Let us pause awhile to admire it, for it is one of the very loveliest of our marine animals.