coat forms two loose folds around the circumference, from the innermost of which the tentacula arise; and the inner coat is probably a continuation of the outer reflected upwards; but it is not a simple membrane, since several laminæ can be perceived to cross the body. The white crucial bands adhere to this inner envelope: they are not muscular, but very probably belong to the generative system. I consider the plumose processes at the oral aperture as subservient to respiration, partly because of their position, and partly because of their folded structure; intended, as it appears to me, to expose the largest possible surface to the action of the water.

This Medusa is a luminous species. It gives out a copious light of a whitish colour when the water in which it swims is agitated, or when it comes into contact with foreign bodies. In the possession of this wonderful property it resembles the Medusa hemisphærica, described and figured by Dr. Macartney in the Philosophical Transactions for 1810, p. 267.; but differs otherwise in too many particulars to permit us to consider it as the same species. If the readers of this Magazine will turn to the figure of the Medusa hemisphærica, given in Vol. III. p. 313. fig. 82. e, they will perceive that our animal is vastly larger; has much fewer tentacula pendent from its circumference; has a more produced peduncle, which, instead of being divided into four equal "tentacula, covered with little cups or suckers, like those on the tentacula of the cuttlefish," is not divided at all, but provided with plumose appendages. With these differences I think myself justified in describing it as a distinct species, which I have taken the liberty of naming in commemoration of my friend Mr. William Baird, surgeon to the Berwickshire East Indiaman, and the author of several interesting papers in this Magazine [Vol. II. p. 208., Vol. III. p. 308., Vol. IV. p. 475. 500.], two of which are descriptive of luminous animals: and Mr. Baird deserves the compliment the more, as, in fact, one of the Medusa described by him, but not named, appears to be this species in an early stage of its existence, for it was only about the size of a small pin's head.

The character of the species may be thus given:

1. D. hemisphærica. Hemispherical, crossed in an arched manner with four opake lines; margin of the umbella undivided, surrounded internally by a row of pale brown spots, and numerous small tentacula; central process divided into four segments covered with suckers. Medusa hemisphærica, Macartney in Phil. Trans. 1810, part ii. p. 267. tab. xv. fig. 5, 6.; Loudon's Mag. Nat. Hist., vol. iii. p. 313. fig. 82. e. Gerydnia hemisphærica, Flem. Brit. Anim. 500. Hab. Coasts of

VOL. VI. No. 34.

Y

Britain in autumn.

Kent. Macartney.

Herne Bay, upon the northern coast of

2. D. Baírdii.-Hemispherical, crossed in an arched manner with four white bands; margin of the umbella undivided, spotless, encircled with about thirteen tentacula; central process furnished at the aperture with four plumose appendages. Medusa, Baird in Loudon's Mag. Nat. Hist., vol. iii. p. 312. fig. 81. h.-Hab. Straits of Banca, W. Baird. Berwick Bay, G. J.

Berwick upon Tweed, October 12. 1832.

13. SIGA LION Bo'a. (fig. 42.)

I OFFER, for the first time, to British naturalists, a native representative of Sigàlion, a genus of annulose worms established by MM. Audouin and Milne Edwards, for such spe

a, Sigalion Boa, of the natural size; b, a scale enlarged; c, side view of a foot magnified.

cies of the aphrodite family as have a greatly elongated body, and cirrhi to all the feet. One species is indicated by Cuvier in the Règne Animal, vol. iii. p. 207.; but, as the name only is given, I cannot say in what respects it agrees or differs with the one now figured. (fig. 42.)

The body is long, linear, flattened, slightly tapered towards the tail, the anterior extremity obtuse and somewhat rounded. Back covered with two rows of close scales of an ash colour; but, as some of the scales are often paler or whitish; the body then appears piebald. Mouth inferior, furnished with a re

very

tractile proboscis, about an inch long, cartilaginous, cylindrical, marked with a pale line along each side, and some fine transverse lines, armed near the apex with four triangular, acute, horny teeth, placed round at equal distances; and exterior to these there is a series of corneous serrated plates, which form, in fact, a circular saw at the entrance. Palpi two, setaceous, simple, half an inch long, arising above and at the sides of the mouth. Head minute, concealed by the rounded anterior pair of scales, without eyes, terminated in front with three short setaceous two-jointed tentacula, the central one larger and longer than the others. Scales overlapping, kidney-shaped, convex, roughish, cinereous; the concealed portion white, the outer and larger margin fringed with delicate hairs and some short anomalous processes: there are probably not less than two hundred scales on each side, and they are affixed each to a fleshy process, from the outer end of which a tentacular filament is extruded, equal to the feet in number, and placed exactly above them. Feet extremely numerous, fleshy, cylindrical, obtuse, bifid; the upper branch terminated with a brush of long unequal hairs, and the under furnished with two rows of shorter bristles. Base of the foot armed with a spinous fleshy process, and with a small tubercle. Between the branches of the feet there are some processes like those on the edges of the scales. The hairs of the upper branch are setaceous, roughish, multiarticulate, non-retractile; those of the under are in part retractile, and have a curious claw-like joint at the end; in some short, in others long and sharply pointed. Tail terminated with two short filaments. Ventral surface pale, perlaceous, marked down the middle with a red vessel. Length, when at rest, 7 in. or 8 in.; when extended, not less than 10 in. or 12 in.

Sigalion Bòa lives under stones, at low-water mark; and, in some parts of Berwick Bay, is found abundantly. When placed in a basin of sea-water, it appears sluggish; but it burrows in loose sand with much rapidity, being enabled to do so by the play of its innumerable feet. I much wonder what can be the use of the jointed claw-like bristles of these organs: even a probable conjecture does not occur to me. The worm is the Goliath of its race, and, I fear, the tyrant also; for its unprepossessing appearance seems to indicate a cruelty of disposition which the dreadful structure of its mouth confirms: so that I doubt not that, like the giants of our early story-books, he delights in blood, and makes his prey of every unwary worm that enters the same furrow, or shelters under the same stone.

Young individuals are generally of a light grey colour. I have described the cranial tentacula as being three in number, but I am not certain that the description is very accurate : sometimes I can see one only, and sometimes I think I can

ART. V. An Enumeration of the Land and Freshwater Shell Snails met with in some Rambles in Norfolk and Derbyshire; with a passing Mention of some other Natural Objects observed. By the Rev. ANDREW BLOXAM.

Sir,

DERIVING much pleasure, a feeling doubtless partaken by many other of your subscribers, from the short rambling notes of Rusticus of Godalming, and other similar correspondents, I venture to send you a short notice of the different objects of natural history which have lately fallen in

my way.

SHELL SNAILS AND SOME PLANTS MET WITH IN NORFOLK.

Being a resident at Harleston, in Norfolk, during part of the spring, I was astonished to find such multitudes of snailshells as are to be met with about there, so far more numerous than I have seen in the midland counties, where I have hitherto chiefly resided. The way in which I account for their being so numerous is, 1st, the nature of the soil, which affords plenty of calcareous earth, which, I believe, is necessary for the construction of their shells; and, 2dly, the formation of the fences [generally of hawthorn], which afford protection to them during the winter; the quickset being placed on banks of earth, which are frequently raised two or three feet above the level of the fields, and abound in holes, into which the snails creep; and thus they are free as well from the intrusive attacks of the peering thrush and blackbird, as also from the severity of the season.

The Common Snail (Hèlix aspérsa; the names are taken from Turton's valuable little Manual of British and Freshwater Shells, which contains excellent coloured engravings of each of the 126 ascertained species) I found huddled together in troops of forty or fifty, fixed upon each other at the operculum, by means of a thick glutinous substance which the animal has the power of secreting; a large shell having sometimes three or four thus adhering to it. The snail

seemed to be drawn within the shell often half an inch or more. I generally found their nests in the hollow stump of a tree or large thorn, and often discovered traces of an enemy among them, as there were dozens of broken shells in snug and cozy spots, where one or perhaps a pair of thrushes had been regaling themselves with a treat. The variety, in colour, size, and marking, was great, as scarcely two were similar to each other.*

The Girdled Snail (Hèlix nemoralis) I found but sparingly crawling out on the fine days in April, when the bank lay exposed to the warm rays of the sun.

In addition to these, I found Hèlix hortensis, arbustòrum, on low grounds near the river; carthusiana, very common; ruféscens, caperàta, ericetòrum, nìtens, radiàta.

Of Freshwater Shells, I found, on a bank of sand in the river Waveney, below Shotford Bridge, the following different species: they had been left there by the floods, and several land shells were also among them. I collected these: Cyclas córnea, ámnica, and pusílla; A'nodon cýgneus, Mýsca pictòrum, Succínea amphibia and oblónga; Planórbis carinàtus, marginàtus, vórtex, córneus, contortus, and fontànus; Limnèus auriculàris, péreger, stagnàlis, palustris; Physa fontinàlis; Valvàta obtùsa, spirórbis, planórbis; Paludìna vivípara, achátina, impùra, símilis; A'ncylus lacustris. Also these

* The Rev. Thomas Image, of Whepstead, near Bury St. Edmunds, has a collection of selected varieties of the shells of Hèlix aspérsa, nemoràlis, and perhaps other species. They are admirably cleaned and preserved, and mounted or fixed, singly or in pairs, according to size, on little square wood blocks or pavements (between two and three inches square, and perhaps more than half an inch thick), with a white or coloured ground, I have forgotten which, with which Mr. Image has paved the floors of the drawers in which he keeps these snails' shells. The shells were arranged in lines of (I think) the length, not breadth, of the drawer, and yet (I also think) in à quincunx order. Of each variety there was a row, and the varieties were of this kind: of Hèlix aspérsa, a row of shells devoid of the black band; a row with the black band present in a broad state; a row with it, in a narrow state; a row with (if I have not forgotten) two black bands present, &c. Of Hèlix nemoralis I have forgotten every thing, save that the shells looked bright and beautiful, but as the bands or "girdles on this pretty shell are very various, numerous distinct varieties might, and may, be at pleasure collected. I was surprised at the wide distinctness of the varieties of H. aspérsa, although, in gardening practice, I had killed thousands of individuals of it; which fact may show how instructive are conspective displays of many individuals of any kind of natural object. Mr. Image is much devoted to the study of objects of nature, especially of fossil remains, and of the last and other subjects has a rich collection of specimens, all which he was so kind as, with the greatest patience and pleasure, to show me, when I once called on him.-J. D.