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

84 MOLLUSCA. [AnCACEA, Inhabits thc Mint, ncar Kenclal. Rossmasslcr is wrong in supposing that this varicty bclongs to thc form R oiss!Ji. 1 am indebted to the kindncss of !\fas Ellcn T. Thomson, of Stricklandgale, and Thomas Gough, Esq., surgeon, Kcndal, for specimcns an<l a knowledge of this ,•aricty. Variel!J 4. AncUATA, pi. xxx,• f. 3. Shell small, subdcprcssed, thick; hingc line consiclerably arcuatecl ; ligament promincnt; basal line grcatly curved; car- dinal tooth in one valve vcry largc; lateral sinus arcuatecl, and broacl as it retires from thc cardinal toolh; muscular impressions deep. Found in the river Dcrwent, Dassenthwaite, Cumberland, a little way bclow· Ousc Bridge. Variel!J 5. ÜLIVACEA, pi. xxx,• f. l. Small ; substancc of thc shell thick, rather infi alcd; hingc linc ncarly parallcl; basal linc with a fl exure, ancl a vcry little arcu- atecl ; valves wi th a slighl ly hollowecl, longitudinal, graclually widening furrow, from the umbones to thc basal margin; outer snrfacc olivaceous, with irregular, transverse furrows; umboncs much dccorticalcd, which extcnds ncal'ly to thc dorsal extrc- mity of thc valves ; insidc of a dull ficsh-colour, slightly nacrcd towarcls the 1lorsal sicle; lceth small, distinctly tripartitc in thc loft valvc, a1HI vcry srnall ancl single in the other. This vcry curious variety was discovered by Thomas Glo\"cr, Esq., of Smcdlcy 1-Iill, in thc Leven, a littlc way below thc lnke- of '\Vindermerc, Wcstmorcland. FAMll,Y IL-AncACEA. Shclls prol'idcd wi1lr numcrous small primary tccth, disposcd in a st raiglrt or intcrruptcd linc in ench rnh·c. Gmrns 4.-Nucu1,A.-LamarcR. Shcll cquivalrn, inequilatcral, transvcrsc, o,·al, trigonal, or obloug; generally co,·crcd with an epidermis ; hingc linear, narrow, cli\·ided inlo two 1mrts by :rn obliquc, procl ucccl, nearly central pit, wl,ich is dcslincd for the rcception of thc ligamcnt, thc one anterior and the other po,tcrior; lateral tecth 0 11 ca.ch sidc numcrou~, acnt c, cleratcd, somcwhat rccun·ccl, those of thc opposilc ,·aire locking int o thc intcrvcning spacc,; umboncs contiguous, :me\ not scparatcd by an intcn ·cning arca.; two simple muscular impressions; mantlc imprc,sion dcstitule of a sinus. Scction I.-Shclls oblong-ovalc. 1. Nucu1,, nosTnATA, pi. XXXIII, f. 1G. N11c11l<, 1·oslrata, Firsl Ed., pi. 25, f. 16; A 1·ca ,·ostmta, Ency. 1'foth., pi. 30!), f. i, a, b; 1'Iontngu, Sup., p. 55, pi. 27, f. i ; Turton, Couch. Dict., P· 11 ; l b., Brit. Di,·., p. 1 iS; La- marck, VI, pi. 1st, p. 58. Shell lrans,·crscly olilung-o\"ate, s0111cwhat com·ex, a.llll rather thin; smaller sidc produced int o an arcuatecl, lieak-likc form, which is proYided with threc transn:rsc ribs ; umbones nearly central, apprnximate, somewlrnt inclincd to thc smaller side; ext crnal surfocc pale horn-colourcd, ami a little glos,y, with strong, regular, undulating, diagonal striro, which makc an alirupt, angulaled turn across the ribs of the beak, tcrminating whcre the ribs of thc beak commence; lhese a.re crossed by extremely minute, irrcgula.r, transvcrse strim, which, howc\'cr, can only be seen by the aid of a strong lens, a11Cl appcar more like thc scratchcs of a file than striro; tceth strong, regular, mHI angulated, thosc on each sicle of the hingc pit with their m,gular sidcs turnecl towards it ; inside \'ery glossy a.nd white. Lcngth nol quite half an inch; brcaclth threc-quarlers. Found off St. Abb's H cad, Frilh of Forth, by Ca.ptain Las• key; and I met with an o<ld \'alve at Holy Island. 2. NucuLA MINUTA, pi. XXXIII, f. 18. 1Yac11fo minuta, First Ed., pi. 25, f. 18; Turlon, lliv., p. 178; A ,·cci ?11i1111lll, Montagu, p. 140; Drown, , vcrnerian l\Icm., II, p. 512; Ana caudata, Dono1·an, III, pi. 78; A1·e<i modiolus, Walkcr, p. 23, f. 81. Shell lransrnrscly oblong-ovale; a.nterior sidc procluced into an angulaled, arcualecl beak, which is squarc at thc point ; posterior sido roundecl; umboncs small, poinlcd, a1Hl turned lowards the anterior side, with a small spindfo-shaped dcprcs- sion under them, reaching lo the point of the bcak, and being indcntcd, gi,·es a. refiexcd appearnnce; tceth numerous, sharp, a.nd prominont; externa! surface yellowish or pa.le oliYe-grcen, coYcrcd with fine, distant, regular, trans,·ersc strim, and three or four concentric riclgcs, according to thc agc of the shell; insidc smoolh, glossy, :,.nd of a bluish-white or palo purple; margin plain. Length thrcc-cighths of a.n inch ; breadth some- wha.t more than half an inch. Found a.t Sandwich; Tenby; Dulilin Tiay a.nd Portmarnock, Irelancl; ami Fri th of Fort h, Scotlancl. 3. NucuLA onL0NGA, pi. XXXIII, f . 17. N11c11fo obsolcl<t, Firsl Ed., pi. 25, f. 17. Shell oblong-ovalc; anterior sidc producccl inlo a straight, but slighlly narrowcd bcak, with two sha.llow furrows running from thc apex lo tire point, which is slightly rounded; posterior sido roundcd ; umboncs slraight, vcry blunl, ami placed near the posterior side; exterior surface c,f a clark olive-green, with nearly ohsolctc, transversc striro; tccth strong, regular, promi- nent, an<l triangular; cartilagc cavity spoon-shaped, and sloping clownwarcls; inside smooth, an<l white; muscular imprcssions large; a slight groom cmanating below the umbones, termi- nales 011 the nmrgi11 a.t the hcaked side. Length upwarcls of half an inch; breadth upwards of scvcn-eighths. Discovercd by Stcwa.rt Kcr, Esq., a.t Greenock, and on thc bcach of thc opposite shorc, whcre it is not uncommon. •1. NucuLA TnuXCATA, pi. XXXIII, f. t !). 1Y11c1ila frrmcata, Firsl Ed., pi. 25, f. 1 !). Shell c,vate, somewhal bcakcd at its anterior sidc a.bo \"e, with an obliquc tnrnca.tion below the projecting point; umboncs rather prominent, rounded, ancl nearly central ; oulsidc of a dark olive-green, bcsel with numerous, extremely fi ne, closc, considerably undulatccl, transYerse slri,c, a.nd with exceeclingly fine, minute, longitudinal stri:c, which ca.n only be scen by thc aicl of a lcns; insiclc smooth, whi tc; hingc with about thirty sharp, clc,·a. ted, and somewhat imbrica.led tecth; cartilagc sockct ne:irly round, sloping downwarcls, ancl almost concealcd below the umbones. Length nol quite half an inch; brea.dth about thrcc-quart crs. D isco\'ered by Stew:irt Kcr, Es<¡., al Grccuock, a.nd ncar Anlencaple, wherc it is not uncommon.