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

l\lYAl\lA,] MOLLUSCA. 111 lcnglh, forming acntc anglcs, lhcir origi11 closc to thc cardinal hiatus, wil11 thc i1111cr limh continucd by a rib ~imilar to that 011 thc oppositc 1·al\'c. 1. LEl'TON SQUA~IOSUM, pi. XL, f. 7, Psammobia p1tnclun1, First Et!., pi. JG, f. 7; Lepton sr¡ua- 11w.mm, Turto11, Biv., p. G2, pi. (i, f. 1, 2, 3; Flcming, p, -1:!fJ; Sofo11 sr¡uamosus, Montagu, p. 5G5; Mato11 ami Tiackctt, I'· ·18. Shcll co111prcsscd, a littlc trm1s1·crscly clongatcd; both sidcs cqually roundcd ; pcllucid, thin, ami whitc; wholc surfacc col'crccl with miuutc ancl thickly stmlclcd puucturcs, having much thc appcarancc of shagrccn whcn vicwcd through a strong lcns; insidc smooth, glossy, whitc, with obscurc, longitu- dinal, radialing slril'C, cli\'crging from thc hinge. Lcngth four- tcnths of an inch; brcadth half an inch. First mct with in sand from Salcomb Bay; Turton mcntions Torbay; ami l'.lfr. Lyons found it at Tcnby. 2. LEPTON N!TIDUM. Leplon niticlmn, Turton, Biv., p. 63. "Shell glossy, slightly striatc transverscly. "Shell half the size of thc lasf, which it resemblcs in shape and hingc, but is of a lucid, palc, glossy horn-colour, without puncturcs. " From corallincs, in Torbay."-T1wton. GENUS 39.-MAGDALA,-Leach. Shell generally thin, transvcrsc, incquivalvc, incquilatcral, gaping at thc anterior sidc; hingc with a transvcrsc, heart- shaped, unattachcd platc-likc tooth, to which both valvcs are unitecl by a small cavity on which this laminar platc is seated, ancl fixccl by a ligamentary process; destitute of lateral teeth; ligament interna!. l. MAGDALA STRIATA, pi. XLIV, f.], 2, ami 10. lJlagclala striata, First Ed., pi. l l, f. !, 2, ancl 10; Alva Norwegica, Wood, Cat., p. 11; Fleming, p. 463; Mva pellit- cicla, 13rown, ·wernerian Mcm., II, p. 50-1, pi. 24, f. 1; Lvonsia sl1·iata, Turton, Biv., p. 35, pi. 3, f. 6, 7. Shell thin, subpellucicl, transversely oblong; hingc linc nearly parallcl; anterior side shortest, and well roundcd; posterior side truncatccl, gaping, and with the eclgcs rcflcctecl; from the base of the trnncation thc shell abruptly obliques, until it reaches the basal line; umbones not quite central, very obtuse, and straight; surfacc covcrcd with a thin, olivaceous epidermis, with pretty strong, concentric wrinklcs, which are more strongly developcd at thc sides, cspccially the truncated onc, whcre thcy are rugosc ancl sharp ; bcnealh thc epidermis the shell is thickly bcsct with fine, longitudinal, slightly wavecl stril'C, which is less strong towards thc disks of the valves; inside of a rich pearlaceous hue, exhibiting iridesccnt reflcctions. J ,ength about fh-c-cighths of an inch ; breadth an inch ancl a quartcr. First cliscovcrecl by Miss Hutchins, in Bantry Bay, lreland, has since been found at 'Narren Point; at Tcnby, Wnlcs; and the \Vcstern coasts of England. GENus 40,-MYATEI,LA-Brown. Shcll thin, transvcrscly oblong-ovatc, incquilatcral; hingc linc nearly parallel, truncatecl at onc sidc; hingc with a large, single, ercct, spear-shapcd tooth in one valve, rcstinrr upon a corrcs- ponding cavity in the cardinal region of thc 0~1cr rnl\'C; mar- gins smoolh ancl evcn. l. l\frATELLA MONTAGUI, pi. XL, f. 26, 27. Hiatella striata, First Ed., pi. 16, f. 26, 27; 1l1yatell11 stri- ata, Brown, Conch. Text Book, p. 1'12, pi. 16, f. 12 ancl 30; Alga stl'iata, Montagu, Linn. Trans., XI, p. 188, pi. 13, f. t A; L gonsia striata, Turton, Biv., p. 35. Shell trans1•ersely elongatccl, thin, semitransparent; umboncs short, obtusc, and situatccl ncarest the posterior or truncatecl side, which is shortest; anterior side rounded; whole surfnce covcred with a vcry thin, olivaccous epidermis, bcncath which the shcll is finely striatcd longitudinally, ami is of a pearly hue; inside smooth, pearlaccous, ancl cxhibiting nacrcd reflections. Length half an inch ; breaclth an inch. Discovcred in T enbay-bay, by l\'.lr. George Lyons. It is not withont considerable hcsitation that I havc institntccl this genus, but I think it impossiblc that so accmatc an obscncr as Montagu could describe the tooth of this shell as fixecl, if it had not been so. Our figures are copic<l from his. Dr. Flc- ming says he followed Turton in bringing together the syno- nims, but with considerable hcsitalion. GENUS 41.-MYA-Linnl'Cus. Shell transverse, nearly equivalve, gaping at both extrcmities, but widest at the posterior side; onc valve with a largc, com- pressed, clilated, hollow, spoon-shaped, perpendicular, vcrtically projccting tooth; thc opposite valve destitute of tccth; the cartilage placed in a narrow suture; two lateral, dislant, largc, muscular impressions, the anterior one narrow, and the posterior almost orbicular; pallial impression with a largc sinus; ligament interna!, large, ancl fixed in thc cavity of thc tooth in one valve, and to a large subumbonal cicatrix in the othcr. J. l\'.IYA ARENARTA, pi. XLV, f. l. 1lfva 1irenciria, First Ecl., pi. 10, f. 1 ; Montagu, p. 30; Donovan, II, pi. 85; Lamarck, V, p. 461 ; Turton, Biv., p. 32 ; Fleming, p. 463. Shell strong, transvcrsely oblong-oval, and modcrately con- vex; umbones rathcr large, prominent, nearly central, ancl not incurvecl; one side more ample and roundcd than the other, which is somewhat acuminated, and pointed at the cxtremity; e:dcrnal surfacc generally with concentrie wrinklcs and irregular striro, mostly of a brownish sand-colour, but diffcring consiclcra- bly from various localitics, as well as from the age of the shcll; one valvc with a broad, thick, perpendicular tooth, provided with a large spoon-likc cavity for the reception of the cartilagc, ancl anothcr smaller one by its side ; oppositc valve clcstitute of tccth; inside glossy, whitc. lnhabits many of the 13ritish and Irish consts, particulnrly at the mouths of rivers. 2. MYA TRUNCATA, pi. XLV, f. 2. llfya trimcata, First Ed., pl. 10, f. 2; l\fontagu, p. 32; Dono- van, III, pl. 92; Maton and Ilackett, p. 35; Turton, Biv., p. 31 ; Forbes, p. 54.