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

104 MOLLUSCA. [ConDULACEA. hinge with an obscure, conic to~th in one valve, and a cavity for its reception in thc other, w1th an obscurc, ncarly obsolete tooth on cach sido of it. This is so nearly allied to Jl. minuta, that we should have considercd ita mere ,·ariety, but the total want of spines inclines us to think that il may be distinct. The figure wc havc givcn is from a specimen recently taken ali\'e at Dunbar; Turton gi,·cs as its locality Torbay ami Dublin Bay. GENUS 28,-Sl'HENIA,-Turton. Shcll transverso, incquivalve, inequilateral, general form flat- tish wedge-shapecl, gaping al the anterior end; hinge of the left valvc with an clevatcd, trans,·erscly dilated tooth, thal of thc righl valve with a concavc toolh, and small denticle behind it; destitutc of lateral teeth; two small muscular impressions in each valve; pallial impression with a large tonguc-shaped sinus, emcmating from lhe anterior side, and reaching nearly the mid- dle of tho vnlves; Jigament external. J. Sl'IIENIA BINGH,n11, pi. XLII, f. 17, 18, and 22. S¡,licnic, Bfoglu11ni, Firsl Ed., pi. 14, f. 16, l 7, 18; Turton, niv., p. 36, pi. 3, f. •l, 5, ancl pi. 19, f. 3; Fleming, p. 465. Shell lransvcrsely oblong-o,•ate, subcompressccl,wedge-shapccl, truncaled al Lho hinge, with Lhe superior margin frcquently a lilllo conlraclecl aboul Lhe micldle, gradually tapering towards the anterior encl, which is slight ly gaping, and subtruncate; um- bones rathcr prominent, with tl1cir beaks not quite opposite, bul clivnricating from each other; whole surfacc covered with a hrown, wrinkled epidermis, which extencls beyond thc anterior sido; insidc glossy, whitc, with a purplish tint; thc margin plain, ami sharp; the clcrnlccl tooth gradually diminishing, and ex- lending nearly half way along thc hinge line. Length a quartcr of au inch; breadth half an inch. Founcl among thc rocks nt Torbny, by Dr. Turton and Gen. Bingham, aftcr whom il was namccl by thc doctor. 2. SPIIENIA SWAINSONI, pi. XLII, f. 16, 23, 24. S¡,lwnia Swainsoni, Turton, Biv., p. 37, pi. 3, f. 3, and pi, )!), f. 2. Shcll trans,·ersely ohlong-oval, wedgc-shapcd; the anterior side ronml; nmhones nearly centrnl ; n concave tooth, lying hori- 1.outnlly, nnd pointing inw,mls. Length n quarter of an inch; hrcmlth abont half an inch. This spccies is somcwhat more O\'al in its form than the S. Binglwmi. Found alnong the rocks at Torbny. :t Sl'IIENIA DECUSS,\TA, pi. XLY, f. 3 . J1/g1i decussala, First Ed., pi. l O, f. 3; Montagu, Sup., p. 20, pi. 2S, f. l ; Fleming, p. 463; ó.. phenia dccussata, Turton, Biv., p. :!S. Shell suborbicular, slightly inílated ; umbones obtuso, rc- cur,·ccl, ami situalc nenrest thc posterior sicle; colour ycllowish- white, crosscd by rnther remole, conccntric riclges, which are dccussated by strong, regular, longitudinnl siria:-, forming tuber- cles nt the anterior end; insidc smooth, whitc; in one valve a broad, erect tooth ; in thc other a projecting lamina, with a small pit for thc rcception of thc tooth in the oppo~it c valvc. Lcngth not quite half an inch; breaclth somewhat more. Found in the Frith of Forth, hy Captain Laskcy. FAMtLY VI.-ConnuLACEA, Shell inequivalve, and for thc most part one valve somewhat larger than thc other; ligament placed intcriorly. GENUS 29.-PANDORA,-Bruguicrc. Shell free, thin, intcrnally pearlaceous, incquivalve, trans- vcrsc, inequilatcral; the anterior sidc the longer, subrostrated, and slightly gaping al its extrcmity; one valve llat, with two internal, anterior ribs, ancl with ils anterior margin turned downwards, providcd with a single, oblong, obtuse, cardinal or hinge tooth, situate behind thc ligamen!; the opposile valve concave, nnd dcstitute of tceth, but furnishcd with an indistinct cicatrice, on which the tooth of thc flat ,•alvc rests, whcn the shell is closed ; in cach vah•c are two distant, lateral, muscular impressions; Jignmcnt interna!, its sides loclged in, ami attached to an elongated cicatrice, which lics inclined to the anterior side of the valves; in somo spccies the cicatrix is produced into an clongated, divergent lamina, stretching from thc umbo towards the anterior sidc of thc shell, and terminating ncar the inner side of !he anterior muscular impression. l. PANDOltA ROSTRATA, pi. XLVII, f. 5, 12, 13. Tnttim, solc11oiclcs, First Ed., pi. 13, f. 5 ; Pamlom marga- ritacca, Turton, Biv., p. 40, pi. 3, f. 11, 12, 13, l 1 1; Panclo1·a i11((!q11ii;alvis, Fleming, p. 466; Solen pimw, Montagu, p. 566 ; Tellina incquivalvis, Montagu, p. 71 ; lb., Sup., P· 27 ; Dono- \'an, II, pi. 41, f. 1; Maton and Rackclt, p. 50. She\l transversely oblong and subovatc, thin, and brittlc; onc vahe nearly ílat, the cther moderntely com·cx; thc hingc linc of both valvcs arcuatcd; umboncs placed much to onc sido; posterior sid_e cxtcnding into a lengthened, obtuscly subtrun- catcd bcak; thc other sido short, ami rounclcd; surfacc cream• white, with a pcarly gloss, smooth in some specimens, but transvcrscly wrinkled in others; two tceth in both ,·alvcs, but deslitute of laleral ones; insidc whilc, and slight ly nacrcd; each valvc provided with n blunt toolh, running parallel from thc umbo, that in the com·ex valvc largest, and with an une,·en surface, thcse not inscrted, but stand by the side of each other, whcn thc ,·al\'Cs are closed. Length nearly half an inch; breaclth one inch; but sometimes considerably more. This spccies inhabits the sea at Dawlish, Guernsey; and in severa) places on thc Irish coast. GENUS 30.-ConnuLA.-Ilrugnicre. Shc\l incquivah·e, onc vahe being gencra\ly small ,\lid ílat- tencd, thc othcr largo and convex; subequilatcral, trnnsrerse, gencrnlly gibbose and closc; ench val re usually furnished with a single, conicnl, recur\'ed, ascending, pointccl tooth, al the side of which is a small concnve dcpression,-,·rry deep in somc species, which sen·es eithcr for thc rcrcption of thc ligament, or thc tooth of thc opposite rnlvc; two distant, lateral, so111c• what irregular, muscular impressions in each \'nl\'C; palli.11 impression posteriorly angulatccl, wilh n very smnll sinus; ligamenl interna!, fo:ecl to the tooth of the lcsscr rnl \'C, ancl inscrtecl in thc deprcssion by the sidc of thc tooth, in thc larger rnh·c.