Illustrations of the recent conchology of Great Britain and Ireland, with the description and localities of all the species, marine, land and fresh water

CONCIIACEA.] :MOLLUSCA. 97 This spccics is nol uncommon in lhc Frith of Forth, ami at Color Cols, ncar Tyncmoulh, Northumbcrland. In thc firsl cdition 11 ·c · ¡ 1 1 . . , conssc cree l 1c thrcc figures rcfcrrcd to ns d1sl111cl spccics bul . . . . . , on compnnng Ynnous spccsmcns, wc are IIOw mclmcd lo look upon thcm as mere variclics, Fig. i was lhought n dccidcd spccics by my late fricncl Dr. Lcn:h, allll who nnmcd il C'. co11 ve.i·iuscula, l\•ISS., p. 8. It is co 11 ssclcrnbly more comcx, with thc slrim fi11cr. _Fig. G wc callccl lhc C. oblir¡ua, from its obliquc form, all(l hcsng strongcr allll more inlln1cd than thc olhcrs. Gi,:--us 18.-CAPSA.-Lamnrck. Shcll trn11srcrsc, cquil'alve, incquilatera\; valves close ali ro~mcl; one valvc with two cardinal tccth, clivcrgcnt from a pomt closc to thc umbo; dcstilute of lateral tcelh; in the oppositc Yalrn 011e disti11ct, bificl, cardinal tooth, with two dis- t~11t, 11enrly obsoletc, lateral tceth; ligamcnt externa!, cntircly ssluatc 011 thc anterior sido of thc umboncs; two, not vcry clccply clelinecl muscular imprcssions in each valve; pallial im- prcssio11 with a large sinus. l. C,\l'SA C0~IPLANATA, pi. XXXIX, f. 10. Do11a:1: complafütta, First Ed., pi. 17, f. 10; l\fontagu, p. 106, pl. 5, f. ,1; l\'.Iaton and Rackctt, p. 75; Flcming, p. ,133; Turton, Biv., p. 125, pi. 7, f. 13, 14. Shcll subtrinngular, transvcrscly elongated; umboncs obtusc; smooth, ami cxtremely glossy; of a pale or goldcn-yellow, or faint lilac-colour, frcquently spottecl ancl blotchecl with reddish- brow11, or faw11; a broad, paler, generally immaculale ray cmanales at the umboncs, nnd terminales 011 the margin, which is frequently eclgecl wilh a fcnuginous shade; in somc specime11s faint i11clicntions of transverse striro are obscn•able by the aid of a lcns; inside smooth, extrcmely glossy, usually of a purple hue, frcqucnlly shadcd with goldcn-ycllow, or orangc-buíl~ especially 11car thc umbones, and somelimcs with . transverse zo11es of pale bluish-pmple; teeth small, cspecially the lateral ones; margin destitute of crenulations. This rare species is met with at Milton Sands; on the coasts of Devon, Dorset, Torbay, and Guernsey; and has been met with on the Irish coasts, at Connamara. 2. CAI'SA CASTANEA, pi. XXXIX, f. 12. Capsa castcmea, Turlon, p. 128, pi. 10, f. 13; Fleming, p. 434; Dona.1: castanect, Montagu, p. 573, pi. 17, f. 2; l\Iaton and Rackett, p. 77, Shell strong, tra'nsversely elongated; umboncs obtuse, slightly inílect.ed towards the anterior side; surface glossy, of a chcstnut- culour, with a fcw irregular, transverse, nearly obsolete wrinkles; an arcunted ray of darker chestnut emanates at the umbones, and terminales in thc base, from whence to the posterior sidc thc colour is paler than on the other parts of the shell; insidc smooth, glossy, and of a pale chestnut, with an indication of the cxternal ray on the margin ; hinge strong, with the teeth large, in proportion to the size of the shell; margin plain. Length a quarter of an inch; brcadth three-eighths, Found at St. Austlc's Bay, Cornwall, Penzance, and south coast of Del'onshire. 2n Section I I.-Shclls witlt one o,· two late,·al tecth. GENUS 19-DoNAX.-Linnrous. Shell t rnnsversc trigon ¡ • 1 . . r ' a, equsva ve, mequslateral; outer sur- 1ace gcnerally covered w"tl ti. l . 'd 1 1 a 1111, iorny epidermis; anterior s1 e for the must ¡>art thc ¡ t I f . . s 1or er; e l l'a]rn with two more or less d1st111ct, cardinal teeth . · n-1 t . 1 . . . . . ' ri., 1 1 a ve wsth only onc cardmnl t_oo_t_h, wl11_ch ss ge11crally cleft at its extremity; lateral teclh l·anablc, csther two or one very minut d . . . ' e, ª 11 rcmote; two large muscular smpresssons m cach i·alve and that f ti 1 . 1 • o 1c mant e wsth a arge posterior sinus; ligament externa!, and short. !n some species there are two lateral tecth, one of which bemg plac_ed 011. each ~ide of, and near to the primary teelh; o_nc rnlve 1s pronded mth a linear, posterior proccss, remotely s1tuated from the other lateral teeth, and between which a 11 d the margin of the shell, there is a groov.e for · the reception of t)ie other vall'e; the anterior lateral tooth can alone be dislin- guished, in each vah-c in other spccies, togethcr with the linear proccss; in sorne species there are two lateral teeth in osrn ~-alve, the P?sterior one more remole than thc anterior, whilc 111 the opposste valve therc are only slin-ht indications of them • J • b > ~ne 111 so'.ne species the lateral teeth are neady obsolcte. Thc hgamcnt 1s generally short, and in some i11sta11ces l'ery much so; the greatcr portion of it is situate anleriorly,"' but in most of t!ie specics a small portian of tite lignment is likewise placed behmd the bcaks. The shells of this ge11us are for the most part weclge-shnped. l. DoNAx TnuNcuLus, pi. XXXIX, f. 1 l. Dona,i: tnmculus, First Ed., pi. 17, f. 11; Pe1111a11t, p. 93, pi. 55, f. 45; Donovan, I, pi. 29, f. 1; Montagu, p. 103; Tur- ton, p. 123; Fleming, p. 433; Forbes, p. 46. Shell somcwhat compressed, tranS\'erscly oblong, inequila- teral, smooth, glossy; umbones small; very 1111ely striated lo11- gitudi11ally ; covered with a very thin epidermis, generally of a light yellowish hue, fasciated ancl radiated wilh 1rnrple, the radii ema11ating from the beaks, and terminating on the basal margin; sometimes quite plain; inside most frequently partaking of the colour of the exterior; teeth small, the lateral onc not very dis- lant from the cardinal ones; margins crenated. Found on most of the coasls of Grcat Britain and Ireland. 2. DoNAX nunnA, pi. XXXIX, f. 13, Dona.1: 1-ubra, llfontagu, Sup., P· 38; Turton, Biv., p. 127, pi. 10, f. 11 ; Fleming, p. 434. Shcll cuneiform, smooth, a11d semitransparent, considcrably truncated at one end ; umboncs prominent, but obtusc at thc points; surface of a reddish-ílesh or claret-colour, but freqnently only coloured near the umboncs; inside glossy, and usually of the same colour as the outside ; hinge with two tceth in cach valve, approximating towards the centre of the umboncs; mar- gin plain. Lcngth not an eighth of a11 iuch. lnhabits deep water on dilfcrent parts of thc coas!. Dr. Turton snys it is found abundantly in fine shelly sand al Tenby. • Coutrary to Lnmnrck, wo cousidcr tho sidc in which thc ligomcnt ¡ 5 situotc to bo tho a11terior sidc, ond it con only lcad to confusion to moko nn cxccption in tlús gcnus,