Involute.] 



MOLLUSCA. 



17 



ones on the bodv, all of which are internally visible ; aperture suborbi- 

 cular, thickened within, but sloping to a thin edge on the outer lip ; pil- 

 lar lip broadly reflected on the columella, with a longitudinal groove in its 

 centre, and ending in an umbilicus. Length rarely a quarter of an inch ; 

 breadth more than half its length. Found in Falmouth Harbour, the 

 south coast of Devonshire, particularly at Salcomb, at low-water, attached 

 to algae. It is not uncommon in the Frith of Forth, and is to be met 

 with sparingly at Portmarnock, Ireland. 



11 T. Neritiformis, pi. X, f. 24._First Ed., pi. 46, f. 24. 



Shell strong, subconic, smooth ; spire very short, being about a fourth 

 of the length of the body, consisting of four well-rounded volutions, end- 

 ing in an obtuse apex ; body large, tumid, crossed by some obscure lines 

 of growth, its upper margin provided with a spiral shallow groove, which 

 continues throughout the volutions ; aperture subrotund, dark purplish- 

 brown within, pale fawn colour within the margin of the outer lip, which 

 is thin, and not continuous ; pillar lip glossy, white, or pale reddish-pur- 

 ple, broadly reflected on the columella, with a very slight subumbilicus 

 behind. Length nearly five-eighths; breadth upwards of three-eighths. 



We discovered this species, adhering to rocks below high-water-mark, 

 near Downpatrick, Ireland, where it is very plentiful. We at first mis- 

 took it for a variety of Nerita littoralis, to which it bears a considerable 

 resemblance. 



12. T.fabalis, pi. X, f. 38-39 First Ed., pi. 46, f. 38-39; Turton, 



Zoological Journal, II, p. 366, pi. 13, f. 10. 



Shell very small, smooth, subglobular, very obtuse, with two hardly 

 produced volutions ; body extremely large in proportion to the spire ; 

 aperture large, subrotund ; outer lip much expanded, and thin at the edge, 

 and extending high on the body ; pillar lip reflected broadly on the colum- 

 ella, from the centre of the aperture ; colour pale chestnut, with zigzag 

 markings of purplish-brown. Diameter about a line. 



Found on the rocks at Scarborough by Mr Bean. It is frequently co- 

 vered with a gray coating, which obscures the colour and markings, so as 

 to produce a chequered appearance on its surface. By the aid of a strong 

 lens it seems spirally striated. 



13. T. stridulus, pi. X, f. 33-34.— First Ed., pi. 46, f. 33-34 ; Monta- 

 gu, p. 306, pi. 10, f. 5; Maton and Racket, Linn. Trans., VIII, p. 172; 

 Turton, Brit. Fauna, p. 180; Turbo carinatus, Da Costa, p. 102, pi. 8, 

 f. 10; Cingula striatula, Fleming, Brit. Ann., p. 305. 



Shell white, with four or five strong turreted volutions, terminating in 

 an obtuse apex ; each volution flattened above, the upper ones being 

 nearly cylindrical ; body large in proportion to the spire ; the base of the 

 body provided with strong equidistant, spiral stria 1 , which, in the supe- 

 rior part of the body, assume the character of three strong, elevated, smooth 

 ribs, the superior one bounding the upper edge ; the other volutions with 

 two ribs each, which become obsolete towards the apex ; the furrows be- 

 tween the ribs are deep, and rounded at the bottom ; the whole shell co- 

 vered with strong, longitudinal striae, which is most conspicuous in the 

 furrows, and although interrupted by the ribs, produces a fine cancellated 

 appearance, more especially on the base of the body ; aperture suborbi- 

 cular, angulated at the upper part, between the body and outer lip, pro- 

 ducing a slight separation ; outer lip broad, smooth, and marginated ; inner 

 lip a little reflected on the columella above, but widening as it descends, 

 and is continuous with the outer lip. Length two-tenths of an inch ; 

 breadth not quite so much. 



Inhabits the coasts of Cornwall, and was found by Colonel Montagu 

 in sand from Falmouth Harbour, as also on the coast of South Devon. 

 We procured it from Weymouth, but in all these situations it is an ex- 

 tremely rare shell ; and is one of the most elegant of the minute British 

 species. 



14. T. aureus, pi. X, f. 23.— First Ed., pi. 46, f. 23. 



Shell strong, with four depressed, well-divided volutions, covered with 

 very strong spiral striae; aperture round, which, with the pillar lip, is 

 tinged with a golden metallic hue ; outer lip strong ; inner lip smooth, very 

 broadly reflected on the columella, and somewhat sharp at the base ; 

 colour of a deep brownish pink, with a golden metallic lustre. Length 

 and breadth about a quarter of an inch. 



Found at Seaton, Northumberland, by Walter C Trevelyan, Esq. ; 

 in the cabinet of Sir John Trevelyan, Bart. ; Wallington, Northumber- 

 land. 



subdivision II Shells Umbilicated. 



15. T. carneus, pi. X, f. 36-37 First Ed., pi. 46, f. 36-37. Lowe, 



Zool. Journal, II, p. 107, pi. 5, f. 12-13, and 13 b. magnified. 



Shell subglobular, semi-transparent, with four, rather strong, convex 



volutions ; the base of the body flattened j and furnished with regular ele- 

 vated rounded belts, continued to nearly the apex, and separated by 

 grooves ; these are rendered rough to the touch by the faint lines of 

 growth by which they are crossed ; spire short in proportion to the size 

 of the body, and terminating in a subacute apex ; aperture nearly round, 

 pearlaceous internally ; outer lip even, smooth, thin, and at its attach- 

 ment to the body, slightly reflected, forming a subsinus ; inner lip broadly 

 reflected above, until it teaches the large and deep umbilicus, from whence 

 it becomes narrow and straightish, w'th a gentle curve, slightly pointed 

 at its lower attachment to the body, where it joins the outer lip. The 

 whole shell is of an uniform yellowish flesh-colour, darker towards the 

 spire, lighter beneath and at the apex, and destitute of the metallic lustre 

 which is so remarkable in the Turbo margarita. It is provided with a 

 horny operculum. 



This shell is so nearly allied to the Turbo margarita, that it may easily 

 he mistaken for a variety ; but attention to the above characters will 

 render the difference obvious. 



Found on the Argyleshire coast by R. T. Lowe, Esq. 



16. T. margarita', pi. X, f. 28-29 First Ed., pi. 46, f. 28-29; Lowe, 



Zool. Journal, II, p. 107, pi. 5, f. 10-11, and 11, b. ; Fleming, Brit. Ann., 

 p. 299 ; Helix margarita, Montagu, Sup. p. 143 ; Laskey, Werneriau 

 Mem. I, pi. 8, f. 5. 



Shell rather strong, semi-transparent, subglobular ; body rounded, con- 

 vex at its base, and flattened, very large in proportion to the spire, which 

 is small, short, with three moderately inflated volutions, terminating in a 

 somewhat obtuse apex ; the whole shell covered with very faint, regular, 

 spiral striae, which, however, are not visible without the aid of a lens ; 

 aperture circular, a little angular at the upper extremity, where it is 

 slightly attached to the body, and nacreous within ; outer lip with its mar- 

 gin plain and entire ; inner lip broadly reflected above and narrowed, from 

 the large, open, and deep umbilicus ; colour of a livid bronze or pearla- 

 ceous lustre, with metallic reflections; operculum horny and rounded. 

 Diameter somewhat more than an eighth of an inch. 



Found at Dunbar, Frith of Forth ; at Gallanch, south of Oban, Argyle- 

 shire, and plentiful at Appin ; also on the south coast of Devonshire. 



17. T. olivaceus, pi. X, f. 30-31 First Ed., pi. 46, f. 30-31. 



Shell thin, olive coloured, pellucid, smooth, subglobose ; body large, 

 inflated; spire small, shoit, with three depressed volutions, terminating 

 in a moderately pointed apex ; aperture large, circular, standing out from 

 the body; outer lip thin, continuous with the inner lip above, which is 

 narrow, and a small circular umbiheus behind. Length two-tenths of 

 an inch. 



Found at Greenock by Stewart Ker, Esq. 



Genus 20 Trochus Linnaus. 



Shell conical ; spire elevated, sometimes abbreviated ; aperture 

 transversely depressed ; margin of the outer lip disunited from the 

 body at the upper part ; columella arcuated, more or less oblique at 

 the base; aperture provided with a horny operculum. 

 Subdivision 1 — Umbilicated. 

 I. T. Magus, pi. XI, f. 12-15 — First Ed., pi. 45, f. 12-15 ; Montagu, 

 p. 283 ; Pennant, Brit. Zool. IV, p. 126, pi. 80, f. 107; Donovan, Brit. 

 Sh. I, pi. 8, f. 1 ; Fleming, Brit. An., p. 321 ; Brown, Ency. Brit. VI, 

 p. 450; Turton, Brit. Fan., p. 177; Lamarck, VII, p. 15. 



Shell subconic, with five or six tumid, somewhat depressed volutions, 

 separated by a well defined, deep suture, terminating in a fine pointed 

 apex; each of the volutions slightly flattened ibove, with a series of ob- 

 lique tubercles along their margins, producing a somewhat undulated ap- 

 pearance; the margin of the base subcarinated and rounded beneath; the 

 whole surface covered with somewhat irregular, strong, spiral striae, and 

 crossed by very fine, oblique, longitudinal striae in the direction of the 

 lines of growth ; aperture compressed, angulated, inside pearlaceous, with 

 an open spiral groove, extending as far as can be seen ; umbilicus large and 

 very deep ; colour various, pale salmon, citron, yellow, or white, with 

 elegant, undulating stripes of pink, reddish-brown, or purplish-brown, and 

 sometimes spotted all over with the above colours, at other times, in re- 

 gular series of remote, square, or lozenge spots ; in some specimens the 

 upper edge of the volutions are ornamented by a series of dark brown 

 irregularly shaped markings ; size usually about an inch in diameter at the 

 base, and three-quarters of an inch in height; sometimes, though rarely, 

 an inch and a half broad. We obtained specimens measuring two inches 

 at the base, in the Kyles of Bute, Inchmarnock, and Lland of Arran. 



