DORSIBRANCHIATA-THE SEA-MOUSE.

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tric circles of gilded hairs, and ending in a head surmounted by a branching crown, which reflects rainbow colours. The whole resembles a bed densely covered with fairy flowers of strange shape and delicate struc

ture.

Such are some of the commoner kinds of Tubicolar Annelides; those of the Dorsibranchiate order, which we commonly meet with in dredging, are still more beautiful, and some of them are among the most splendidly coloured objects that the animal kingdom presents to us. The rainbow tints of the humming-bird, and the metallic lustre of the gayest beetle, have their equals in many of the members of this family of worms. If we are free from associations of disgust at the worm-like body, we cannot help being struck with the beauty of its clothing, or the really graceful motions of these little animals, gliding like serpents among the crevices of rocks and shelly masses, or half swimming half crawling along the bottom of a rock pool. Naturalists, struck with their beauty and grace, have assigned to them the names of nymphs, as Nereis, Euphrosyne, Eunice, Alciopa, Aphrodita, and others. Our British seas furnish examples of many of these genera, but, as yet, the several species have not received, from British naturalists, that close attention which they deserve, and a monograph, illustrated by figures, is much wanted for their elucidation.

A great variety of species, varying in size and form, may be observed in dredging. One of these, which seldom fails to attract the dredger's notice by the lustre of its coat, though its frequency may cause it to be thrown

back as of no value, is the Sea-Mouse or Aphrodita (Halithea) aculeata, which is frequently met with in dredging over muddy ground. The body of this creature is oval, three or four inches in length, or sometimes more, soft, dull grey, clothed with a fine silky substance on the back, and thinly covered with small hairs which reflect rainbow colours. The sides are broadly margined with several rows of stiff purple spines, among which are long silky hairs half an inch to an inch in length, of metallic lustre, and reflecting the most brilliant prismatic colours. Oranges and greens of the richest tints are the most abundant. Under the silky hairs of the back are concealed fifteen pairs of scaly plates, one of which is affixed to each ring of the body, and covers over the branchial organs or gills. The under surface is smooth, transversely divided into about forty rings or segments. Each segment is produced at the margin into a short fleshy lobe or oarlike body, armed with a triple row of stiff spines. These oars, or feet, (for they answer partly the purposes of swimming, partly those of crawling,) may be contracted at the will of the animal into conical lumps, and the spines may be wholly withdrawn, each within its proper sheath. The spines are curious microscopic weapons, each armed with barbed teeth like those of a fish-spear, capable of inflicting a severe wound on any soft body.

No one can have thrown down the dredge many times, on almost any sort of ground, and failed to bring up one or other of the various animals called Starfishes, whose name sufficiently indicates their form. Sometimes the dredge comes up literally filled with these creatures,

LILY STONES, OR ST. CUTHBERT'S BEADS.

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thousands being brought up in a single haul, as if the bottom were formed of a living bank of them, or as if we had disturbed a submarine hive in the process of swarming. The countless myriads of living starfishes which thus cluster together may serve to explain to us the profusion with which similar animals, whose remains are now found in rocky strata, were dispersed through the waters of the early world. But, while we have this similarity in relative quantity between the modern races and those of ancient days, we find in this, as in most other cases, a complete change in the types most common at different periods of the world's age. The animals which represent our Starfishes in early strata have wholly perished from the modern waters; and the very type of structure to which they belonged has nearly become extinct, and is now confined to a very few species. In the seas which once flowed over the British Islands there lived a race of Starfishes whose bodies were affixed, like flowers, to a slender stalk, composed of numerous shelly plates, disposed like the bones in a vertebral column, and connected together and rendered flexible by the fleshy coat of the animal. This stalk was fixed to some foreign body, and thus the Starfish remained at anchor, ready to seize upon any animal which came within the length of its tether, but, unlike its modern representative, unable to pursue its game to any distance. The petrified remains of these curious animals are commonly called Lily stones, or Encrinites, and the joints of their stem are known by the name of "St. Cuthbert's beads." Whether they became, at any period of their life, free from the stalk, and capable of independent motion, is

134

YOUNG FEATHER-STARS.

uncertain, as we have no living species to tell the tale; and, to judge by the remains found in a fossil state, it does not appear probable. The modern seas of Britain furnish us with but a single species of the family Crinoidea, the group to which the Lily Stars of early times belonged; and it is not a little curious that this species, though it afterwards becomes free, swimming about like any other Starfish, is in its infancy affixed to a stalk perfectly analogous to that of the Encrinite. When first detected, in this young state, it was, indeed, sup

PENTACRINUS EUROPEUS.

posed to be a distinct animal, and believed to be the pigmy representative of the Lily Star. Subsequent observations have shewn that the little creature is merely the young of the Featherstar (Comatula rosacea), the only living Crinoid Starfish in the British seas.

Young Feather-stars, or, as they were called, Pentacrinus Europeus, are found affixed to the stems of various zoophytes. They are about half an inch or three quarters in height, with a body more or less resembling (according to its age) the perfect Comatula,

fixed to a column consisting of several pentagonal joints,

attached by an expanded base to the zoophyte. The column is perfectly flexible, and can be moved at the will of the animal in any direction. Mr. J. V. Thompson, who originally discovered this curious little creature, subsequently succeeded in tracing its development until he found the lily-shaped body had acquired most of the characters of the youngest Comatula which he could procure in a free state, and was thus led to the conclusion, which the observations of other naturalists have since confirmed, that the supposed Pentacrinus was merely the young of the Comatula, or Feather-star.

The Feather-star itself is certainly the most beautiful of our Starfishes, but must be seen in a state of life and activity, as it rises in the dredge, to have all its beauties appreciated. Like so many of its kindred, it is exceedingly fragile, breaking up shortly after it finds itself in captivity, so that it can rarely, even with the greatest care, be brought to shore in an uninjured state. The body is small, clothed on the back with dense jointed filaments, and having five long slender arms cloven nearly to the base, and thus looking like ten, each branch being closely feathered with slender processes a very elaborate structure. The whole body is of a deep rose-colour, and resembles, when its arms are expanded, a beautiful living flower, every part of which seems alive with independent motions. It would be vain to attempt in a woodcut to give a just impression of such an object, and mere description can afford but a feeble notion of its wondrous beauty. The Feather-star is found all round our coasts, and is frequently brought up in from ten to twenty fathoms water, attached to different kinds

of