and they are amply furnished with the necessary weapons. The long flexible arms which encircle the head are set along their inner aspects, with numerous cup-like suckers, which the animal can fix to any object, and the adhesion is strengthened by a horny ring round the edge of each sucker often pointed with sharp curved teeth. (fig. 54. a.) "When

54

an animal of this kind approaches any body with its suckers, in order to apply them more intimately, it presents them in a flat or plain state; and when the suckers are thus fixed by the harmony of surfaces, the animal contracts the sphincter, and forms a cavity in the centre, which becomes a vacuum. By this contrivance, the sucker adheres to the surface with a force proportioned to its area, and the weight of the column of air and water, of which it conThe jaws, and a portion of the en- stitutes the base. This force, multiplied by the number of suckers, gives that by which all or a part of the feet adhere to any body. This power of adhesion is such, that it is easier to tear off the feet than to separate them from the substance to which the animal chooses to attach itself." (Cuvier, Comp. Anat., trans., i. 432.) It must, then, be a fearful thing, for any living creature, to come within their compass; for, entangled in the slimy serpentine grasp of eight or ten arms, and held by the pressure of some hundreds of exhausted cups, escape is hopeless, and the struggles of the hapless victim, by bringing its body into more rapid contact with the suckers not yet applied, only accelerate its fate.

larged part of the foot, of Loligo sagittata,

The digestive system of this tribe is less uniform in structure than, from the sameness of their food, we might at first suppose; but, in sketches of the very general character to which I limit myself, I pass over the peculiarities of tribes, to notice little beyond what is common to the class. The mouth, formed by a puckered fold of the skin, is placed at the base, and in the centre of the circle formed by the arms, and is armed with two powerful corneous jaws, having a vertical motion: they are fashioned to the resemblance of a parrot's bill (fig. 54. b), and are well adapted to tear their prey piecemeal, or crush the hard shell, especially when, as in the Naútili, their tips are hardened and calcareous. Between the jaws lies the tongue, adherent to the platform of the mouth, VOL. VII.- No. 41.

EE

but capable of being unrolled to a slight extent, and having its surface roughened with many rows of small sharply pointed tricuspidate, or semi-tricuspidate teeth, set in close and regular array, which can be erected at will, so as in some measure to grate down the food, previously to its transmission to the gizzard, and they greatly facilitate its descent by their direction, and by their motion backwards and forwards. In the mouth, the food is mixed with the saliva, which is secreted by one or two pairs of large glands. The gullet is a narrow membranous tube, of nearly uniform calibre throughout in the Loligo

55

56

The stomach of Lollgo vulgàris.

(fig. 55, 56. a), and penetrating the substance of the liver before it enters the gizzard; but, in the Octopus, the gullet is only bound to the surface of the liver, and at the point of

attachment swells out into a large membranous crop, of the appearance of which, in the Octopus ventricòsus, at least, I cannot give you a better idea than by comparing it, both in size and position, to the bulb of a small retort. The gizzard (fig. 55, 56. b) is a thick muscular organ, like the gizzard of a fowl, and strongly corrugated internally in a longitudinal direction: immediately beyond it, in the Sèpia and Octopòdiæ, is situated a curious spiral appendage, laminated on the inte rior, into which the bile is poured; but in the Loligo, instead of this spiral cæcum*, and, as it were, to compensate for its deficiency of a crop, there is a very large membranous and somewhat cylindrical bag (fig. 55, 56. c), on the posterior and upper part of which we trace vestiges of the spiral structure, for there a fatty substance is so disposed as to assume that form, having the outer edges cut in a deeply serrated manner (fig. 55, 56. d). I have found this bag always filled with a grumous fluid, and it is undoubtedly the organ in which digestion is principally effected and completed; for it not only receives the bile, but is itself, or the spiral part of it, supposed to furnish a secretion analogous to that of the pancreas in higher animals. The aperture between the gizzard and this cæcum is oblique and valvular, and another adjoining aperture leads to the intestine (fig. 55, 56. † e), which, like the œsophagus, winds upwards along the surface of the liver to terminate in the funnel, which is the common vent of all the excrements. The liver is very large in all the genera of this class, and must furnish a copious supply; but, besides this, and the secretions of the other accessary organs to good digestion, Sir E. Home believes that the inky fluid is intended also to have some effect upon the lower portion of the intestinal canal, to enable this to extract from its contents "a secondary kind of nourishment" (Comp. Anat., i. 369. and 393.); an opinion not very probable in itself, and with but a few fanciful analogies in its support.

"It may with greater propriety be denominated the duodenum, as it performs some of the offices of that part of the gut in the higher orders of animals. This stomach is conical, closed at the distal extremity, and performs about a turn and a half, like a spiral shell. Its inner surface is covered with a ridge, which traverses it in a closely spiral direction.”— Fleming, Phil. Zool., ii. 424.

In reference to these figures, it may be observed that they are copied from nature; a remark which seems necessary, since they differ entirely from Sir E. Home's figure of the stomach of Loligo vulgàris, or the Sèpia Loligo of Linnæus. Sir Everard's figure appears to have been taken from a species of Octopus.

ART. IV. Observations on some British Sérpulæ.
By the Rev. M. J. BERKELEY.

In an interesting notice of Sérpula tubulària Mont., by Dr. Johnston, in p. 126., a doubt is expressed whether S. tubulària Mont. and S. vermicularis of Authors have not been confounded in an article in the Zoological Journal, iii. 229. The truth is, that, at the time the article in question was prepared, my text-book for British conchology was Dr. Turton's Conchological Dictionary, as being the most recently published work upon the subject; and, throughout, where S. tubulària is mentioned, the species so named in that work is intended, which is not the same with S. tubulària Mont., but is S. triquetra Mont. Test. Brit., pt. 2. p. 511. (Tùbus vermicularis Ellis, Corall. t. 38. f. 2.), but not Mont. Suppl. p. 157., which is the true S. triquetra. Though I was well acquainted with the several allied species and their distinctive characters, I confess freely that I was not then aware of the identity of Montagu's S. tubulària, with S. arúndo Turt., and, in consequence, supposing Turton's species to have been first described by him, adopted his name.

The following synonymes, which I find written on the back of the rough copy of the article above mentioned, I shall beg leave to subjoin, as they may possibly be useful to others in the study of the common British species, whose nomenclature has been most unfortunately confused, though, at the time the Supplement to the Testacea Britannica was published, the species were well known to Montagu. The only alteration I shall make is the one suggested by Dr. Johnston, of the propriety of which there can be no doubt; viz., that the older name of Montagu should be preferred to the more recent one of Turton. I am quite satisfied, on a careful examination of Turton's descriptions, that he had in view the species figured in Ellis, quoted above, for his S. tubulària, and the S. tubulària Mont. for his S. arúndo. If not, the very common species of Ellis is altogether omitted; or, if S. vermiculàris of the Conchological Dictionary be supposed identical with it, the almost equally common species with a double infundibuliform operculum, figured by Müller, Zool. Dan., t. 86. f. 7-9. I shall only add to these observations, that S. tubularia Mont. ought certainly to be placed in a different genus from S. vermiculàris, &c., being altogether destitute of an operculum. According to the principles of Cuvier's Règne Animal, it belongs to the genus Sabélla, and is one of the rare instances in which a shelly tube occurs in that genus.

This has been proposed in a paper printed in No. xx. of the Zoological Journal, but not yet published.

The following are the synonymes alluded to above:

Sérpula (Sabélla nob.) tubulària Mont.; Sérpula tubulària Mont. Test. Brit. pt. 2. p. 513., Johnst. Mag. Nat. Hist. vii. 126.; Sérpula arúndo Turt. Conch. Dict.p. 155., Berk. Zool. Journ. v. 3. p. 229., Tab. Supp. xviii. f. 2.

Sérpula Múlleri nob.; Sérpula vermiculàris Mont. Test. Brit. pt. 2. p. 509., Mont. Supp. p. 157. (with reference to Zool. Dan. t. 86.), Turt. Conch. Dict. p. 152.

var. b. Lam. An. sans Vert. t. v. p. 362.

I am obliged to designate this species, which is characterised by the double infundibuliform operculum, by a new name, as, in the confusion of synonymes, I know not that there is any which can be unobjectionably applied to it. The name now proposed will have the advantage of calling attention to the figure of the animal in Zoologia Danica, and thereby prevent any confusion which might arise from the similarity of its shell to that of any other species. I have received from the Western Hebrides a species exactly resembling this as regards the testaceous covering, but furnished with two double infundibuliform opercula. Though the animal was preserved in spirits, it was so decayed that, unfortunately, I could not trace the connection of the opercula with the branchial fringe, and, therefore, do not venture to propose it as decidedly distinct. Sérpula vermiculàris Linn.; Sérpula vermiculàris Lam. An. sans Vert. t. v. p. 362.; Tùbus vermiculàris Ellis, Corall. t. 38. f. 2.; Sérpula triquetra Mont. Test. Brit. pt. 2. p. 511. not Suppl. p. 157.; Sérpula tubulària Turt. Conch. Dict. p. 154. f. 84.

This species is distinguished from the following, in every stage of growth, by its corneous striated operculum. It is seldom found above the ordinary low-water mark.

Sérpula triquetra Linn.; Sérpula triquetra Mont. Supp. p. 157. not Mont. Test. Brit. pt. 2. p. 511., Turt. Conch. Dict. p. 152., Sow. Genera of Shells; Vermília triquetra Lam. An. sans Vert. t. v. p. 369. This is perhaps the most common of all the British Sérpulæ. The operculum, which is testaceous, is very variable. Specimens occur in which the testaceous coating is a mere pellicle: but in this case there is no difficulty in distinguishing it from the foregoing species, as it is destitute of the beautiful radiating striæ. Other forms of the operculum are described by Montagu, in the place quoted above, and figured by Sowerby in his excellent Genera of Shells.

King's Cliff, Wansford, Northamptonshire,

July 19. 1834.