the individual. The number taken is amazingly great. As a basis for the calculation, let us take our own fishery, and let us estimate the boats engaged in the capture of fish that esteem the lug-worm a favourite food, at the number of twelve only (we have, in reality, seventeen so engaged at present); and let us further suppose that each boat baits one line, with its 700 hooks, daily with the lug, and, for the short period of six weeks per annum, and this low estimate will give an annual consumption of 302,400 worms! Now, again, multiply this great host by the numbers used in each of the fisheries that are carried on in almost every bay and creek of our island, and it will take a very long series of figures indeed to express the enumeration-such as sets the mind to wander vaguely amidst creations that are to it innumerable." Four or five species of Arenicola, or sand-worms, are found natives of Britain.

The TEREBELLIDE, which follow the worms just mentioned, are typical specimens of the order Tubicola, or Sedentaria. These worms inhabit consistent sandy tubes, open at both ends, which they form themselves. The body of the species of the family is generally nearly cylindrical in shape, without a well-defined head. Springing, however, from the buccal segment we see numerous filiform extensile tentacula placed on the crown, or on a lobe above the mouth, or on each side near the mouth beneath the lobe. In some of the genera the dorsal margin of the post-occipital segment is furnished with a transverse row of stiff golden bristles. The tubercles which represent the feet, and which bear setæ, are almost always disposed in two rows; the dorsal, armed with setaceous bristles; the ventral, with a single or double series of hooks or uncini (Tab. IV., Figs. 4, 5). The branchiæ are generally very much branched, rarely filiform, usually placed laterally, seldom in the medio-dorsal line, and confined to the two or three anterior segments.

The Annelides belonging to the genus Terebella are destitute of the stiff bristles. The tentacles which crown the head, or buccal lobe, are very long, filiform, very extensile, furrowed below, and roughish with mucous granules, and the branchia are in one, two, or three pairs. The tubes which these animals form are of a membranous nature, coated with broken shells, gravel, or sand, cylindrical in form, erect or free, and open at both ends. In some of the species found on our shores, this tube is as large as a swan's quill, and is easily distinguished by a peculiar tuft of branched arenaceous fibres, with which its orifice is armed. It stands erect in the mud, buried to a considerable distance, and extends from six to twelve

inches in length. In some, the tentacula and branchiæ are coloured, and present an agreeable appearance in the water as they move waving about. One species, the Terebella textrix, or the "Weaver," is peculiar in forming a real cobweb, "as distinct," says Dalyell, "as that of the spider, with which it covers itself, and which, also frequently, if not always, serve to support its spawn."

The genus, Pectinaria, is distinguished at once by the front of the animal being armed with a transverse row of stiff bristles, like the teeth of a comb; from which resemblance it derives its name. The species, of which there are two, or perhaps, three, natives of Great Britain, inhabit tubes, consistent in texture, free and unattached, of a conical shape, widely open at both extremities, and composed of agglutinated grains of sand, and generally quite even on the surface.

The most common British species is the Pectinaria belgica, which lives in a straight tube, corresponding almost exactly to the size of the animal. This stands immersed in the sand, in a perpendicular position, and from its upper wide end, the animal projects the head with its many tentacles which are in continual movement. These are described as being shortened, and lengthened, and twisted about at will in search, apparently, for fit grains of sand to construct or extend the tube; a process which is very curious and interesting. "This creature," says Sir John Dalyell, "constructs a very delicate tube, as thin as paper, exclusively of the grains of sand agglutinated together in an extraordinary manner. The thickness of the side does not exceed a single grain, each lies in its proper place, and the whole is lined with the slightest silken coating. The sand being collected at the orifice of the tube, its tenant, chiefly by means of the tentacular organs, selects those which are appropriate, and applies them to use. This is done only through the night, all the additions being made at the orifice, and as the animal grows, the shape and dimensions of the tube being an inverted conic frustrum, result from the successive growth of the body." The Pectinaria belgica is generally from two to two and a half inches long though occasionally it exceeds that length. The spines on the head are of a golden bronze colour, and the branchiæ a bright vermilion.

The SABELLARIÆ are distinguished from the Terebella by their head being provided with a number of peculiar bristles, generally arranged in a double or triple circular series. The post-occipital segment is cleft, as it were, into two similar halves, each fringed with about forty tentacular organs which are extremely flexible,

apparently cartilaginous, and, when examined by the microscope, appear serrated on their margins. The body of the animal is of a somewhat cylindrical shape, and composed of two distinct portions; the upper is divided into segments which are provided on each side with feet armed with setæ and uncini, or hooks; the posterior portion is in form of a slender appendage without segments or feet, usually folded upon the body.

The species inhabit eccentric-looking but massy tubes, composed of pieces of coarse sand, or fragments of shells, cemented together by means of a glutinous matter secreted by the animal, forming irregular masses impacted, generally, amidst the roots of sea-weeds (Laminaria), or fixed in heaps upon old shells. They are, in most cases, flexuose in shape, and about an inch or an inch and a half in length. The aperture of this tube is open and circular, somewhat expanded at the margin, but closed up at the bottom. There are two or three species found on our shores, one of which, the English Sabella (Sabellaria Anglica), was described many years ago by Ellis amongst his species of corallines. As he says, the tubes are of a dark sandy colour, of a brittle texture, rather light than heavy, and porous on all sides. The animal itself is said by Sir J. Dalyell, to be timid, lively, and active; to be never tired of working, though night is its chief season for constructing its dwelling. The tentacular organs are those employed by the animal for selecting the grains of sand and adapting them to the precise spot wanted, where they are fixed by means of the glutinous secretion mentioned above. The interiors also are lined with a silky looking substance, the produce of the same secretion. The Sabellariæ are oviparous, and the ova are laid during the summer, from spring to the end of autumn. Sir J. Dalyell tells us that these ova are generally purple in colour, with a darker nucleus within a gelatinous sphere. "A specimen of the animal," he says, "having been injured in the third week of October, by separating a congeries of tubes, a vast quantity of purple ova issued from the root of the cleft (on the anterior or post-occipital segment). The parent itself was coloured by the presence of the ovarium, for by this organ are these creatures greatly affected during the season of propagation; they become brown or dingy white, from a fine ruddy colour, when the spawning season is over. On removal to a watch-glass, the same specimen continued discharging thousands of ova, all of a beautiful colour and regular ovoidal form."

The SABELLE (belonging to the family Serpulida), differ much from the worms last mentioned; they are often described under the

name of Amphitrite, but the former is the original name given to them by Savigny. They are very beautiful animals, as far as the fan-shaped branchial plumes on their head is concerned. The first time Mr. Gosse found a Sabella, he exclaimed, when he saw it unfold its plumes, "Oh, what a magnificent creature! I thought, as I gazed delighted upon it, that it excelled in beauty any of the marine worms I had yet found." "This plumous crown," he continues, "seemed as if it would well become the head of some noble cacique, or the lord of one of those isles in the distant east, which are the depositaries of earth's most precious things." The body of these worms is distinctly annulated, and the head is marked by a four-lobed, everted, cartilaginous collar. The branchiæ arise from the front, and consist of a pair of large fan-shaped rays composed of many fringed parallel filaments, united together on a cartilaginous base. The mouth is situated in the centre between these branchia, at the bottom of a regular funnel formed by them, and frequently has two small setaceous tentacula on each side. It is, besides, furnished with two small, fleshy lobes, which Sir John Dalyell, who first noticed them, calls "trowels," having between them another organ which he describes as a tongue or "scoop." The two or three first segments of the body are not possessed of feet, but the succeding segments of the thoracic portion of the body have setigerous feet, with a series of uncini to each. The abdominal portion of the body has a pair of setigerous feet also on each segment, with a similar series of uncini, which, however, in this part of the body, reverse the position they had on the thorax. The animals live in soft and flexible cylindrical tubes, sometimes tapered at the base, made of fine mud, smooth externally, and coated with a fine membrane interiorly.

A very handsome species, and one of the most common found on our coasts, is the "Fan Sabella" (Sabella penicillus), Plate IV., Fig. 3.

The animal is from twelve to fifteen inches in length, and as thick as a common goose-quill. It is of a brownish orange-colour, and composed of numerous segments. There is no proper head, but the anterior extremity is furnished with branchia which form "a pair of remarkably elegant, large, fan-shaped tufts, of a strawyellow colour, beautifully spotted and banded with brown, yellow, orange, green, and red, and about two inches in height; each tuft consists, in an ordinary specimen, of more than thirty (sometimes as many as eighty or ninety) filaments, densely fringed, and united together by a common cartilaginous membrane at the base."

The

cilia of the fringe are simple, and the uncini or hooked seta are arranged in such a way "as to resemble the denticles of the tongue of a zoophagous mollusk." The bristles which their feet bear "are of a golden yellow, collected into a cylindrical fascicle; and as each bristle is thickened or kneed where the point begins, the apices of the whole are made to converge and form a conical termination." The tube in which this worm lives is long, flexible, and cylindrical; smooth outside, the mud or fine sand of which it is constructed being cemented by a kind of glutinous secretion. In some of our creeks and tidal rivers these animals abound in immense numbers, and on the coast of Essex they are known to the fishermen by the name of "Hassocks." When dredging in the river Roach, I have often come upon banks where they existed in hundreds of thousands, and appear in masses of large extent growing erect like a standing field of corn.

Sir J. Dalyell gives us a very interesting account of this fine species under the name of Amphitrite ventilabrum. He describes it in great detail, and the formation of its tube is given with graphic accuracy. The little organs which he calls "trowels," and the "scoop," are extremely useful in this construction, and the operation is thus given us by Dr. Johnston: "To catch and collect the muddy material necessary for the work, the branchial fans are spread out into a semicircle, so that when the two are brought into contact a wide funnel is formed. Once in the funnel the muddy matter is forced down the rachis of the filaments by the play of the ciliary fringes, and brought within reach of the singular organ at the base of the funnel by which the mud is selected and applied, just as a mason would lay lime on with his scoop, and then mould and smoothen it with his trowel." These organs, described above, receive the pellets of mud which the animal mixes up "with an adhesive secretion, furnished, probably by the collar of the cephalic segment and by the organs just mentioned. It is thus rendered consistent and tenacious, and fit to be employed in raising the edge of the tube. To that position the material is raised by the tongue and trowels, aided by a general elevation of the head; and it is fashioned into shape by the same scoop and trowels curved over the exterior circumference as far as they can be stretched, and smoothed and polished by their motions, while clasping it with their pressure. And thus the tube is built up." When clear and perfect, says Dalyell, this tube bears the narrowest resemblance to a tube of caoutchouc manufactured by human art.

The branchial plumes are the most striking part of the structure