course of about a quarter of an hour, excited the slug to project the peculiar organ noted. By observing this organ as accurately as I could during the slug's brief exposures of it, and by cutting open the one dead slug, I satisfied myself, in a good degree, that this organ is white, horny, of the figure of the longitudinal half of a hollow cone, with the hollow upwards (so as to resemble a deep spoon), and that the slug, when informed of a worm's presence by the contact of its own head with a worm's body, projects this organ under the worm, to the flesh of which it adheres by a tenacious viscum, and perhaps, also, as the organ is hollow, by the aid of suction. It is projected and applied in an instant, and when applied, the action of a muscular structure, connected with its origin, draws it, and with it the worm, into the slug's mouth. The skin and parts of the head of the slug are then gradually turned in, as one would turn in the finger of a glove, or in the manner shown in Mr. Lukis's figure (fig. 39. c). Mr. Blair informs us, in VI. 43., that the T. scùtulum swallows worms (and occasionally a small slug) whole, and the introversive process mentioned (although the testacellus may not be able to employ introversively any very considerable portion of the upper part of its body) must avail it in swallowing worms which it happens to catch by either extremity. Mr. Blair has, however, seen (VI. 43.) "one firmly fixed to the middle of a large worm, the head of the slug being so buried in it that it appeared to be nearly cut in two." In the worm that had, as I have observed above, twisted itself out of the slug's mouth, I noticed, after it had twisted itself out, a piece of its flesh absent close beside the tip of the front extremity, and blood apparent there; and this, as I had not observed any defect in the worm when I applied it to the slug, I take to have been bitten out by the slug. This assumed fact, that quoted before it from Mr. Blair, and the likelihood that it is impracticable for the testacellus, whose body is somewhat slender, to swallow a large worm doubled, suggest that, although this slug may usually swallow earthworms, &c., whole, it occasionally, also, partakes of the earthworms piecemeal.

Mr. Blair thinks (VI. 44.) that the Testacéllus usually gets hold of the worms underground. However this may be, the animal seems to insinuate its head and neck easily, and not very slowly, into loose broken soil; and the slender attenuated form of the body, when extended, is not unfavourable to Mr. Blair's idea; and as the orifice, in the Testacéllus, for the admission of air, is at the posterior extremity, just under the outward edge of the shell, protected, as it were, by the eaves of the shell, fancy may imagine the shell designed to

keep the orifice clear of soil, while the animal progresses through this pulverulent material. [I have since seen that M. de Férussac has expressed, and more positively, both these ideas; and Mr. G. B. Sowerby, also, that on the remarkable power of extension and attenuation of body given to the Testacélli. Fig. 41. b shows their great power of contraction.]

Mr. Blair's remarks, in VI. 43., intimate that the Testacéllus does not hibernate; Mr. Lukis's facts, above, teach the same thing; and a couple of facts known to me point to the same conclusion. The Testacélli (of the species T. scùtulum, at least) seem to be, with regard to hybernation, in precisely the condition of the naked slugs, whose case has been so accurately described by G. J. in p. 116, 117. The fact told of a T. scùtulum, in VI. 44., from Mr. J. Sowerby, jun."; and that related above by Mr. Lukis, of a Testacéllus laying its eggs after being twenty minutes in a warm room, suggest that the Testacélli are, indeed, especially sensitive of variations in temperature.

Since the above remarks were written, we have striven to meet Mr. Lukis's wish for a statement of the diagnostics of the species of Testacéllus. Mr. J. D. C. Sowerby has, in relation to this object, supplied the following figures (fig.41.);

and we have transcribed, with his permission, from his copy of Baron de Férussac's Histoire Naturelle Générale et Particulière des Mollusques Terrestres Fluviatiles, the diagnostics there given of T. haliotídeus, Maugèi, and ambiguus; and from Mr. G. B. Sowerby's Genera of Recent and Fossil Shells, the one there given for T. scutulum, which is a species that was unknown to Férussac at the time that he published those here quoted from him.

T. haliotídeus Faure Biguet. Animal: Flavidum, rufum, vel griseum, maculatum aut immaculatum; tentaculis cylindricis. Testa: Övata postice acuminata, cornea, crassa, extus rugosa, intus nitida; clavicula [inner lip G. B. Sowerby] alba lata et plana.

* Since removed from among us by death. This most amiable and most promising young man died of a tubercular consumption, on February 7. 1834, aged 18 years. His loss to us all, and to science, is feelingly regretted by every one whom his uncommon modesty allowed to know him.

[a pallide lutescens, immaculatum Fér. Hist. vol. i. p. 94. t. viii. fig. 5. to 9.]

[It is this last condition of the species which is figured by Férussac, whose figures are copied in our fig. 41. a, b, c: a, seen from behind; b, as seen when contracted; c, the shell, as seen on the inside. In Sowerby's Gen., No.i., two views of the shell of this species are given, to contrast with those of T. scùtulum and Maugèi, there also exhibited. "T. haliotídeus is not uncommon in France." (G. B. Sowerby, in Gen.) It is a native of France and Spain. (Mr. Lukis, in p. 225.)]

T. scùtulum G. B. Sowerby. Testa ovata, antice paulum acuminata, extus plana, clavicula arcuata, elevata. The animal bears a near resemblance to that of T. haliotídeus, not having the double row of tubercles running from the head to the anterior part of the shell, so conspicuous in T. Mauge. G. B. Sowerby, in Gen., No. i., fig. 3, 4, 5, 6. [Of these figures of T. scùtulum, derived from an animal or animals taken in the neighbourhood of London, fig. 3. represents a front view of the animal; fig. 4., a view of the same animal when extended; fig. 5. (copied in our fig. 41. e), an outside view of the shell magnified; fig. 6. (copied in our fig. 41. d), an inside view of the shell magnified. If the Guernsey Testacellus (fig. 39.) be, as I have, in p. 226., conjectured it to be, of the species T. scutulum, then fig. 39. farther exhibits the animal, the shell, and the eggs of this species, and all of the natural size; and Guernsey may be added to the habitats of this species already noted in p. 224.] T. Maugei Férussac. Animal: Rufescens; maculis brunneis sparsis ornatis; tentaculis filiformibus; ora corporis aurantia. Testa: Ovatoelongata, fulva, exilis, striatula; spira elevata; clavicula angusta. Fér. Hist. vol. i. p. 94. t. viii. fig. 10. 12., Sowerby Gen. No. i. fig. 7. to 10.]

[The synonymes exhibited by Férussac, under T. haliotídeus and T. Maugei, teach that these two species had been more than once confounded. Our fig. 40. c, (repeated in VI. 45., and VII. 225., from the Encyc. of Agriculture, ed. 2. § 7706.), is wholly erroneous, as compared with Férussac's figures, in the matter of the part of the animal in which the lateral furrow is commenced. In Férussac's figures, the furrow is represented as commenced in this species (T. Maugei) just in front of the shell, and as carried thence to each of the two sides of the animal's body. Fig. 40. d is a view of the shell of this species, taken (as well as that of the animal c, though this too inaccurately) from an individual derived from Bristol; and fig. 41. f, g are views of the shell copied from Férussac's figure. "T. Maugèi is a native of Teneriffe; but [is] naturalised in a garden at Bristol." -G. B. Sowerby, in Gen.] T. ambiguus Férussac. Animal [unknown]. Testa: Depressiuscula, fragilis, subtiliter striata; pallide viridis; spira indistincta; apice occultata; apertura amplissima, simplici.

[Férussac has (in Hist. vol. i. p. 95. t. viii.) given two views of the shell, which are copied in our fig. 41. h, i. "We cannot consider De Férussac's ambiguus as a species, inasmuch as it has every appearance of being an internal shell [of some species of the family of slugs].". G. B. Sowerby, in Genera, under T. scùtulum.]

Férussac has consigned eight folio pages, and twelve figures besides, to the elucidation of the three species quoted from him but the greater portion of the descriptive matter is an exposition, in a generic manner, of the anatomy, faculties, habits, and manners of the Testacélli; that is, of the two species (haliotídeus and Maugèi), with the animals of which he is acquainted. He has, besides, in another part of his

work, namely, in his "Observations Générales sur l'Organisation et les Facultés des Pulmonés sans Opercule," in generalising on the conditions of the tentacula in various genera, spoken and analogised on the tentacular function of the lips in the genus Testacéllus. It is hence apparent that a rich store of facts and observations is already on record on these interesting animals; and, had we been earlier aware of this, we could scarcely have resisted quoting several of the more instructive of them. As it is, we can only thus refer to them *, and express our sincere regret that Férussac's excellent work is so rare in Britain; or, at least, in London. See V. 192.] J. D.

ART. V. Illustrations in British Zoology. By GEORGE JOHNSTON, M.D., Fellow of the Royal College of Surgeons of Edinburgh.

19. LYCO'RIS MARGARITA CEA. (fig. 42.)

THE body of this worm is from 4 in. to 6 in. long, contractile, semicylindrical, of the thickness of a large quill, and tapered towards the tail: it is of a brown colour, more or less deeply tinted with metallic green, particularly near the head and on the anterior margins or sides of the segments, and, in certain lights, is finely iridescent. A red vessel runs down the middle of the back, giving off to each foot a small branch, which is again slightly ramified; and a similar vessel may be traced along the flat ventral surface, which is marked with a central furrow, and stained in some degree with the opaque internal viscera. The head is square, with four small eyes; two placed on each side at the base of a conical projection, on

We must just notice the following: - M. de Férussac, in his "Observations Générales sur l'Organisation et les Facultés des Pulmonés sans Opercule," in speaking of the means given to various animals of this class for defending themselves from the heating and drying effects of the solar rays, mentions a manteau particulier which is given to the Testacélli. This, in his generic character of the Testacélli, is thus described:-" Manteau: simple, gélatineux, contractile, caché habituellement sous le test, divisé en plusieurs lobes susceptibles d'envelopper tout le corps par un développement extraordinaire, lorsque l'animal éprouve le besoin de se garantir de la sécheresse." Mr. J. D. C. Sowerby has seen one or more animals enveloped in this" manteau:" the body is then in its most contracted state. In the dead testacellus, of which we have spoken above, we perceived a starlike scar at a little distance from the front extremity of the body, which we avoided mentioning, for fear of being found in some error. On the organs of generation, however, Férussac has remarked, "Réunis ; orifice en arrière du grand tentacule droit:" and this remark, and the subsequent inspection of a preserved specimen at Mr. J. D. C. Sowerby's, assure us that the scar we had seen was this orifice.

42

a, L. margaritàcea, natural size; b, the head, magnified; c, a view of the proboscis from below; d, the feet, with the filaments and bristles.

which are articulated two longish papillæ : and beneath these, and exterior to them, there are two much larger papillary processes, terminated with a small knob-like point, which is entirely retractile within the lower portion. On each side of the head, originating from a common swollen base, there are four setaceous tentacula of unequal lengths. The mouth is somewhat inferior, wide and terminal, furnished with a short thick proboscis, divided into two portions by a circular fold, and capable of being extruded at pleasure: its point is armed with two curved serrated horny mandibles; and around these there are placed, on as many swellings, six distinct patches of small black horny prickles, the side patches larger than the others; two still smaller patches, on mammillary swellings, are situated just under the projecting lobe of the head; while, at the very base of the proboscis, we find a band of similar prickles, some larger than others, arranged in several irregular series. The whole surface of the proboscis is marked with pale longitudinal lines (muscles?), frequently anastomosing. The segment immediately behind the head is footless, and scored with faint whitish lines, or sometimes spotted; and oblique lines of the same kind may be seen, with a magnifier, on the sides of the other segments. These are very numerous, shorter than their breadth, smooth, and furnished with papillary feet, filaments, and setæ. The feet of the first two segments consist of only two fleshy papillæ, but all the rest have three arranged transversely: the papillæ are short, obtuse, and equal; and, at the base of the superior one, as well as under the inferior one, there is a tentacular nonretractile filament; while a small brush of setæ issues from the inner side, and near the root of each. These brushes are made up of a single strong black bristle and a considerable number of slender straight hairs, and can be pushed out or withdrawn at will. The tail is terminated with two short filaments.