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It is very interesting to watch the modus operandi of these quiet labourers; and the curious observer, who desires a distinct view of their operations, ought so to contrive matters that their advancing tube should come in contact with the sides of the aquarium. They then continue alike industrious; but frequently, as if to economise labour, the growing edifice is reduced to the segment of a cylinder, the transparent glass supplying the defective portion: in this manner, whatever passes within is sufficiently exposed. A Sabella, previously carrying on its operations in a watch-glass, will sometimes avail itself of the transparent side of a jar in the same manner. The greatest activity is always displayed during the warmest weather.

These animals quit their tubes when the water becomes vitiated, and sometimes without any such reason; seeming to suffer little inconvenience from the want of them.

Their food is unknown; nevertheless, they are easily preserved, specimens having been found to live thirteen months in confinement.

CHAPTER XXX.

AMPHITRITE VENTILABRUM- THE FAN AMPHITRITE.

"Unheard by them the roaring of the wind,
The elastic motion of the waves unfelt;

Still, life is theirs, well-suited to themselves,
Nor yet unuseful."

FROM the depth of 60 or 70 feet beneath the surface of the sea, a black leather-like tube is sometimes dredged up, affixed by the lower extremity to some solid foundation. Its position is erect, gradually enlarging upwards from a very narrow commencement. It frequently resembles a reed or vegetable stem of stunted growth, furrowed by age, with portions of the bark injured below by decay, but fresher and smoother above, where visibly more recent and entire. On the whole, when clear and perfect, this submarine product bears the narrowest resemblance to a tube of caoutchouc manufactured by human art.

On plunging this artificial-looking tube into a vessel of fresh sea-water, a few air-bubbles first escape from its orifice, and then the tip of a variegated pencil is seen gradually protruding, which suddenly unfolds as a splendid plume composed of many feathers (Pl. V. fig. 7). Let the slightest shock be communicated, and the whole instantly collapses and disappears

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within the tube almost before its image has faded from the eye.

The head or anterior portion of the animal, which may be called the plume (though truly the branchia), is disposed in two vertical fans, so arranged as to form a complete funnel. In large specimens it exceeds thirty lines in depth, and is decorated with the most brilliant colours, brown, red, green, purple and gold, exhibiting a truly gorgeous spectacle.

Two triangular, pointed, brown and green antennulæ arise near the bottom of the funnel, and below there are two external fleshy lobes or trowels, with an organ like a tongue or scoop between them.

The mode in which this lovely Annelide constructs its tube is exceedingly curious. We will suppose a specimen with its plume fully expanded in a jar filled with its native element: in this condition, if a drop of liquid mud be dropped from above into the water so as to disturb its cleanliness, the animal immediately begins to rouse itself, and all the thousands of cilia that fringe its branchial plumules are discovered to be in vigorous activity, collecting, by their incessant action, the diffused muddy particles into a loose mass, which is soon perceived visibly accumulating in the bottom of the funnel. Meantime, the neck or first segment of the body, rising unusually high above the orifice of the tube, exhibits the two trowels, previously alluded to, beating down the thin edge as they fold and clasp over the margin, like our fingers pressing a flattened cake against the palm of the hand. During these operations, the muddy materials are seen descending between the roots of the

fans, towards the trowels; while another organ, perhaps the mouth, is also occupied, it may be, in compounding the preparation with adhesive matter. As the bulk of the muddy mass diminishes, the activity of the worm abates; it is soon succeeded by repose, and then the tube is found to have received evident prolongation.

From the observations of Sir John Dalyell, it appears that the branchial fans of the Amphitrite, when lost or mutilated, are, notwithstanding their complicated structure, speedily reproduced and rendered again efficient.

AMPHITRITE BOMBYX. The Silk-worm Amphitrite.

The general structure of this Annelidan resembles that of the Amphitrite last described, both in the worm-like organization of its body, and in the luxuriant plume of branchiæ affixed to its anterior extremity, as also in the circumstance of its inhabiting a sheath or tube. This sheath, however, instead of being constructed of foreign materials, is entirely made up of an animal gluten, resembling silk, without any earthy particles being incorporated in its substance. The total length of this Amphitrite is about 3 inches, whereof the plume, composed of about sixty branchiæ, constitutes a third, while the body consists of sixty or seventy segments (Pl. V. fig. 8).

The plume is proportionately larger and more luxuriant than that of the Amphitrite ventilabrum; it is finely variegated with different shades of brown and yellow-orpiment orange is the colour which pre

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dominates on the body. This animal dwells in a tube surpassing its whole length, which is not of mechanical construction, but is formed by a spontaneous exudation from the entire surface of its body. When originally produced, this tube is as clear as crystal, completely displaying through its transparent walls the shape of its occupant: it seems indeed altogether made up of a silk-like secretion, and becomes quite opake with age. The secretion whence this tube is derived must be very copious, as several of them are sometimes secreted by the animal, one after another.

The Amphitrite Bombyx is a timid creature, and impatient of light. On the slightest shock, the plume collapses, and the animal at once retreats into its abode, closing the orifice of the sheath; but if left for a little time undisturbed, it again ventures to issue forth, rising slowly upward, as if to avoid deranging the order of its feather-like branchiæ.

These elegant Annelidans have been observed, in confinement, to spawn abundantly, covering the bottom of the aquarium with quantities of ova mixed up with a thin gelatinous matter. Spawning, indeed, continues during most of the summer, more especially during the months of May and June; but all attempts to rear the young progeny have hitherto proved abortive, and a most interesting problem yet remains to be solved, by ascertaining the earliest aspect under which the juvenile Amphitrite makes its appearance when first liberated from the egg.

When disappointed, however, in our inquiries concerning one interesting subject, it is gratifying to find satisfactory illustrations of another.