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

CoNCl!ACEA.] MOLLUSCA. 99 :i. LuctNA LEUCOMA, pi. XXXIX, f. 29. Lucina leucoma, Tmto11, n·1\' 113 1 - f 8 L · ., P· , p , 1, • ; 01'/)JCS leucoma, Fleming, p. 430. Shell somewhat oblique, orbicular, slightly produccd an<l angnlar on lhc anterior side, ami gencrally a littlc flexous under the beaks ancl on lhc opposite sidc; umbones pro- minent, with a curvalurc under them; exterior surfoce of a chalky-white, with regular, crowded, transvcrsc, raised slri::c, all(I deeper wrinkles; crossecl by extrcmely fine, closc-set, lon- gitudinal lincs. Turlon, on whosc authority wc givc this shell, says he ha3 remarkecl in some specimens a small remole tubercle ou each side of the hinge, resembling obscuro lateral leeth. Inhabits Torbay, the Dritish Channel, an<l Guernsey. GENUS 22.-CnYPTODON.-Turton. Shell lransvcrsely subglobose, equi,·alve, nearly equilateral, closecl; umbones unequal, nearly central, beneath them a large, deep, clongatecl, cordiform lunule; hinge of thc right vah·e with a single, irregularly-formccl, crect, triangular tooth, which fits cxtcrnally into a small cavity below thc umhones in the opposile valve, and a narrow lateral cavity, for the reception of a triangular, flat, hollow, lateral tooth of the other valve, which is provicled also wilh an ill-clefinccl, nearly flal, primary tooth; bolh vah-es wilh a large, double, muscular impression on one sicle, and small single ones on the other si<le ; pallial impression destilute of a sinus, and situale low in thc ralves; ligament interna!, a small porlion only being visible through the seam ; an elongated, poinlecl lunule, hollow at the side ancl elevatecl in the centre, invests the entire Jenglh of the cartilage slope. 1. CnYPTODON FLExuosus, pi. XXXIX, f. 4, 5. L1tcilwjle.1,·uosa, First Ecl., pi. 17, f. •1, 5, 6, 7; Fleming, p. ·1·12; Cr!Jplodonjlc:1:uosus, Turton, Iliv., p. 121, pi. 7, f. 9, 10; Telliiu, Jlc.n,osa, Monlagu, p. 72; Ilrown, vVernerian Mem., II, p. 508; Venus sinuosa, Donovan, II, pi. 42, f . 2; Bcqua11ia jlc.rnosa, Leach, MSS., p. 9. Shell sublriangular, subglobose, thin, pellucicl, fragile, whitc; umbones small, slightly innectecl, ancl uncqual, lhat of the right valve smallcst, thc other rcsling on thc cavity above the pri- mary looth of the opposile valve; benealh them a large cordate lunule, with an clongatccl lunule on thc carlilage side, pointecl at bolh encls; a sulcus emanales from lhe umbones in bolh rnlves, running nearly parallcl with the cartilage, lerminating al one sidc, wherc it fonns a prclty large sinus, or flexure, at lhc eclge; wholc surfacc mocleratcly glossy, remotely and rather irrcgularly slrialecl conccntrically; hinge wilh a single, crect, triangular toolh in one valve, ami a flat, nearly obsoletc one in thc olhcr; insicle smoolh, glossy, white, cxhibiting slightly nacrecl rcflcclions, ami sorne inclicalions of longituclinal raclii; margins plain, and very acule. Figs. 6 ancl 7 is a varicty of this shell, figuree! by Donovan, which clilfers from any specimens wc havc seen. This intercsting little shell is met wilh, allhough very spa- ringly, on most of thc Brilish :me! Irish coasls. GENUS 23.-AncoPAGIA~Leach. Transvcrsc, equh·ah·c, inequilateral; right \'al\'e subdepres- sed; ~unboncs very small, ncarly slraight; with lwo primary lcclh m both 1•all'es, each of the lar,,er ones cleft · left ,·all'C • b > w1th lwo remole, lateral tcelh, lhat on thc anterior side lar"c, wilh a sinus betwixt it and the margin, for the reccption \r thc latera~ l~oth of _the. opposite 1·alve; muscular impressions lar~e; palhal 1mp_rcs,1on mterrupled by a broacl, tongue-shapcd, ~bhque, perpendicular, _nearly central sinus, clcfined by a decp, irregular groove; margm very hroacl, ami very glossy, as far as lhe pallial impression ; ligamenl subextcrnal. 1. AncorAGIA CRASSA, pi. XL, f. 8. A1·copagit, cmssa, First Ed., pi. 1 G, f. 8; Leach, MSS., p. 9; Tellinn crassa, Pcnnant, IV, p. 87, pi. 18, f. 28; Montagu, p. 65; Brown, Wernerian Mem., II, p. 508; Flcming, p. •13G; Forbes, p. 46; Turton, Iliv., p. 109, pi. 7, f. 2; Tellina 1·igicla, Dono\'an, III, pi. 103. Shell strong, thick, somewhat oblique, lransvcrsely ~ub01·atc, a little subtruncalccl on lhe extremity of thc cartilagc side, ancl slightly inequirah•e, lhe left onc bcing the larger, ali(( consider- ably more com•ex lhan the other, which is nrnch more com- pressecl ; umbones small, beaks short, ancl ralher obtuse, placed consiclerably off the centre towarcls lhc cartilage sicle, ancl poinl- ing lo thc opposile sicle; bcneath lhem a rathcr narrow, deep, elongatecl, lanceolalc lunule; colour white, cream-whitc, or palc sulphur-ycllow, rarcly skin-colourecl or pale sulphur-yellow; somclimes plain, but more frequcnlly beaulifully rncliated, with broacl ancl narrow, variously disposcd, rays of palc red, llesh- colour, or recldish-purple, which are always more clislinctly definccl towarcls their bases ; whole surface co\'erecl wilh nume- rous, strong, pretly regular, concentric slriro, becoming wiclcr as lliey approach thc base, lhesc are crossecl by numcrous, inclis- linct, shallow, longitudinal stri::c, which can only be seen by the aid of a slrong lens, and are most perceptible in thc inlersticcs helwcen thc lransvcrse slri::c, and inlerruptecl al inlervals by a fcw dislinct linos of growth ; a ralher broacl sinus exlencls from thc mnboncs towarcls thc base, on the posterior sicle of the right valve, wilh a corresponcling ridge on the oppositc valve; insidc very glossy, bluish-white, rich golclen-yellow, or in sorne of a heautiful rose-colour, or cleep recl; somelimcs slrenked nnd blolchccl in a 1•ery handsome manner; hinge with two carclinnl teeth in each vah•e, onc of which is cleft, ancl two strong, elon- gatecl, lateral teelh in both valves; a littlc way below thc pallial sinus are, gcnerally, a fcw irregularly disposccl, shallow punc- lurcs; margins plain, with a slighl groo,•e on the eclgc of thc lcft valve, for the reception of the eclge of the olher valve. This intercsting species is an inhabitant of most of thc Brilish ancl Irish coasts. 2. AncoPAGIA OVATA, pi. XL, f. 9, 10. Arcopagfo ovata, First Ecl., pi. 16, f. 9, 1 O. Shell strong, thick, lransverscly ovale, suboblique, onc valve convex, ali(( somewhat largcr lhan the other, which is compres- sed ; umboncs placee! ncarer onc side, small, ancl rathcr blunt; of a pale slraw-colour; coverecl wi1h strong, conccntric, rather regular slri::c, which fccl rough to thc touch, with inequidislant lines of growth ; deslilute of a lateral sinus, or riclge ; sid('s more uniformly rounclecl tl111n in thc forcgoing species, and without the slight truncation; hingc with n large bificl, ancl a