Glimpses of Ocean Life; Or, Rock-Pools and the Lessons they Teach

by John Harper

The use of these singular objects—by naturalists termed Pedicellariæ—is totally unknown. Some writers think they are an integral part of the Echinus, others describe them as distinct and parasitic animals. There is good reason to believe that the former will eventually be proved to be the correct explanation of the matter.

Its masticatory apparatus is not the least wonderful portion of the Sea-Urchin. The teeth, five in number, which may frequently be seen protruding from the mouth, are of extreme hardness, and of seemingly disproportionate length. They are not fixed in sockets as ours are, or they would be speedily worn away by their action on the shelled mollusca upon which the animal feeds, but fresh substance is added to each tooth as fast as it is worn away by use, as in the case of many gnawing animals. 'In order to allow of such an arrangement, as well as to provide for the movements of the teeth, jaws are provided, which are situated in the interior of the shell, and these jaws, from their great complexity and unique structure, form perhaps the most admirable masticating instrument met with in the animal kingdom. The entire apparatus removed from the shell consists of the following parts. There are five long teeth, each of which is enclosed in a triangular bony piece, that for the sake of brevity we will call jaws. The five jaws are united together by various muscles, so as to form a pentagonal pyramid, having its apex in contact with the oval orifice of the shell, while its base is connected with several bony levers by means of numerous muscles provided for the movements of the whole. When the five jaws are fixed together in their natural position, they form a five-sided conical mass, aptly enough compared by Aristotle to a lantern, and not unfrequently described by modern writers under the name of "the lantern of Aristotle." The whole of this complicated machinery is suspended by muscles from a frame-work fixed in the interior of the shell, and may often be picked up upon the beach, or still better exposed in situ in a dead Echinus, by those who would examine closely this wonderful piece of mechanism.'[18]

I have made two careful drawings of the jaws and teeth of the Echinus. No. 1 represents, as it were, the 'elevation' of the pentagonal pyramid above described, while No. 2 constitutes the 'plan' of the same object.

The Echinus sphæra, or common Egg-Urchin, may often be seen forming a curious ornament in the drawing-rooms of the "West End," and also in the dwellings of the poorer classes, who, according to some authors, boil it like eggs, and so eat it. Hence its popular title. Among the ancients the Echinidæ were accounted a favourite dish. 'They were dressed with vinegar, honied wine or mead, parsley and mint. They were the first dish in the famous supper of Lentulus when he was made Flamen Martialis. By some of the concomitant dishes they seemed designed as a whet for the second course to the holy personages, priests and vestals, invited on the occasion.'

[The illustration on Plate 10] was drawn from a living specimen, and gives a somewhat unusual representation of a Sea-Urchin. In general the spines alone are shown, but I have endeavoured to give the uninitiated reader some faint notion of the appearance which the suckers present when extended from the surface of the shell.

The young Urchin sat very quietly while I was engaged in taking his portrait, but continually extended crowds of his slender tubular legs in all directions, as above indicated, much to my gratification and apparently to his own.

In preparing a Sea-Urchin for a chimney ornament, the most important point is to remove the spines so as to let the tubercles remain entire. In performing this operation some little experience is necessary. Several times I attempted the process by aid of a pen-knife and a pair of pliers, but not with a satisfactory result. Having mentioned my difficulty to a friend, he laughingly asked me if I had ever heard of a certain pilgrim who, for some peccadillo he had committed, was doomed to perform penance by walking to Loretto's shrine with peas in his shoes? Of course I was acquainted with the story, but could not see what it had to do with Sea-Urchins, and told my brother naturalist so. Still smiling, he said, 'Do you remember the relief that was said to be afforded to the humorous rascal, both mentally and bodily, by boiling his peas?' Yes. 'Well, then,' was the reply, 'do you boil your Sea-Eggs, and you will find your troubles speedily cease.' I did as I was directed, and found the advice of great service; for, after being an hour or two in the 'pot,' the spines of the Urchin may be totally rubbed off by aid of a nail brush, or some such instrument. Moreover, the colour of the shell is improved, and the dental apparatus may be drawn out entire, with the greatest ease.

I may here take opportunity to mention, that the student who may think proper to act upon the hint above given, should not boil the Urchin too long, or the fleshy parts will become dissolved, and the entire shell fall into a multitude of fragments.

This unfortunate result actually happened on one occasion to a genial, clever friend of mine, much to his chagrin and my malicious delight.

There are several other species of Sea-Urchins whose forms are tolerably well distinguished by their popular appellations. Thus we have the 'Silky Spined Urchin;' the 'Green Pea-Urchin,'—the latter is the commonest and prettiest of all its kindred, its back being covered with a kind of powdery green, as is seen on the elytra of many beetles; the 'Cake-Urchin,' which from its flattened form may be regarded as a link between the Sea-Urchins and the true Star-fishes; the 'Purple Heart-Urchin,' and the pretty 'Rosy Heart-Urchin,' appropriately named from the brilliant crimson hue that its body presents during life.