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

132 MOLLUSCA. waved; surface with regular, well defincd, divergent, longi- tudinal, moniliform strire, or presenting the appearance of two undulating lines intersecting each other, and faint lines of growth. Length a quartcr of an inch; breadth an eighth. Common in deep water, off Abcrdccn. GENUS 7 -HALIA.-Ri~o. Shcll subovatc, spirc short, convcx, obtusc, volutions rapidly diminishing, scparated by an impressed suture; body ,•ery largc, tumicl ; aperture largc, subovately-trigonal, acutc abovc, curvcd below, and terminating in a rather wide notch ; outer lip thin ; inner lip formcd by thc thin-cdged, sinous columella bcforc, dcstitute of an umbilicus. This genus to follow UTmcuLus, page 58. 1. 1-IALIA FLEMINGIANA. Ilcilia Flemingiana, Macgillivray, Moll. Ab., p. 189. Shell thin, brittle, glossy, sem_itransparcnt, subovate ; spirc consisting of thrce convcx volut1ons, separated by a distinct suture, and terminating in a vcry obtusc apcx; apcrture sub- ovately-trigonal, two~thirds of the cntirc lcngth, contracted abovc; outer lip with a thin margin, and forming thc fourth of a circlc; inncr lip sinous, its s1~pcrior half formcd by thc body- volution, thc inferior by thc thm flcxous cdgc of t hc columclla thc Jowcr cxtremity curvcd to the lcft in a short and rathc; widc canal; colour purc whitc. Lcngth upwards of half 311 inch ; diameter half its length. Found by Mr. James Smith, in dccp water, off Aber<lecn. GENUS PATELLA.--(Page 63.) 3. PATELLA l'ULYA, Müller, Zoo). Dan., I, pi. 24, f. 1, 2, 3. Patella Forbcsii, page 64. CLASS CONCHIFERA. GENUS PECTEN.--(Page 71.) l 6. PECTEN lsABEr,L,ll, Pecten Isabellcc, Macgillivray, n-Ioll. Ab., p. 225. Shell ovale, rouuda<l, nearly equivalve, slightly convax; having twenty-four slandcr, comprcssc<l, rounded ribs, with vary numcrous, thin-cdged lamcllre, which towar<ls the margin are clevated into triangular, comprcssed, acute spines; the interstices with transverse, scalar lamellre; ears very unequal, being in length as onc to two, with divergent sulci, trans \'ersely lamellate, and cchinated ; margins of the upper valves undcr lhe auricular process providcd with four conical spines, and a scl'ies is continucd on thc surfacc to the umbo, which is smooth ancl glossy ; colour white, lowcr valve tinged with pink. Length thl'ee-twclfths of an inch; brcadth somewhat lcss. "This most beautiful Pecten cannot be at ali confoun<led with Pcc:tcn vm·ius or Pecten niveus, to which it is allie<l in its mocle of echination!' Found by Profcssor Macgillivray, among Ascidire and coral- lines, from thc Aberdeenshirc coast. GENUS Moo10LA,-(Page 77.) 7. 1\100101,,\ BALLII, pi. XXXVII, f. 36. Shell _transver~ely oblong-ovatc; umbones placed very ncar to onc sacie ; a sl1ght groo,·e or furrow emanates from the um- bonc~, an'.l terminales in an oblique line on the margin of the ª'.~tenor_ stde, on wlti:h lhe colour is golden-ycllow; covercd ,rn1_1 ~ , ery glos~y, ohrnceous epidermis, wltich in certain Ji,-,hts exh1b1ts a metalhc lustre; inside hi,-,hly pearlaceous .· 1 ¡ t 0 . o , '" 1 rans- verse wrmkles towards tite cxtremity; tite surface exhibitintt golcl and copp_ery metallic rellections, aud stud<led with a num: bel' of small c1rcular pits, like those left by tite sm 11- . F I Y a pox. 01111 < at ougal, by Ilobcrt Ball, Esq. GENus CYCLAs.-(Page 93.) 5. CYCLAS CITRINA pi XXX"II f 37 Cl '., ,, , , . ' ge asjlavcsccns? l\lacgillivray, Moll. Ab., P· 246. Shcll vcry thin, subdiaphanous, and slightly clliptical; ,•ery veutricose, a little inequilateral, nearly hemispherical; umbones lal'ge, prominent, inflated, an<l rounclcd; covcrcd with a ratlter <lull citron-coloured epidermis, beneath wltich the surface is irregularly ancl strongly striatcd concentrically, witlt two or tltree lines of growth. Discovercd by Thomas Glovcr, Esq., of Smccllcy Hill, Man- chestcr, in the Leven, a little way below thc Lake of Win<lcr- merc, W'estmorlan<l. Length about two and a half eiglttlts of an inch. This shell differs from Cvclas cornea, in bcing more orbicu- lar, in thc umbones being much lat'ger, mot'e prnminent, ancl bulging, an<l it never attains so largc a size as that specics. GENUS P1s1DIUM.-(Page 94.) 7. P1S1DIUM JOANN!S. Pisidimn Joannis, Macgillivray, l\1011. Ab., p. 248. Shell transversely-ovatc, moderatcly convex, thin, glossy; both sides 1vell rounded; umbones tumid, obtusc, with smooth beaks, ancl placed nearest thc anterior side; whole surface with numerous, concentric strire, the inten·ening fnrrows broader, smooth, antl glabrous, with severa) well mal'kcd lincs of growth; hingc line a littlc arcuated; colour grcyish-yellow. Length two-twclfths of an inch; breadth two and a half twelfths. Found by l\fr. Leslie, in a clitch and pond of the Profcssor of Medicin~, an<l afterwarcls by Prnfcssor Macgillinay, in a ditch near the Lmks of Ol<l Abercleen, where it is l"ery abundant. 8. PlSIDIUM JENYl'(Sl!. Pisidium Jcnynsii, Macgillivray, Moll. Ab., P· 2,19; Pisidi11m pulchellum, var., Jenyns. _Shell transverscly ami obliquely ovale, somewhat tumid, very thm, ami glo~S)' · wit1 1 • J 1· · · · f - , 1 egu al', e 1st111ct, concentnc stn~, a ew m~rc conspicuous lincs of growth, ami vcry faint radiating stnulm · umbones t · J b • . . ' um1c, o lusc, cons1derably nearcr the ante- rior side, which forms about a third of the segmenl of a circlc,