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

ÜSTUACEA,] MOLLUSCA. 69 <lucecl in the mid,lle; ll'hole surface invesled with fine lonr.ifu- <linal, 1li1-crgent strirc; perforation a little trianr.ular. Le~!!lh ne;ll'ly an inch and a quarter; breaclth one inch. 0 - This spccimen ll'US casl ashore at Teignmouth. It is doubtful ll'hether this is a true Ilritish specics. GENUS 2.-OnmcuLA.-Cul'ier. Shell inequivalve, nearly orbicular, compressecl; generally irregular in form, a<lherent, fl at, ami altachccl by means of a fibrous substancc, passing through an orifico near the centre of the lower Yalvc; uppcr val ve patclliform, its vcrtex posterior, or ncarly central ; cach vah•c prol'i<lecl wilh four muscular im- pressions, two of which are largc, approximale, ami silualc near t.he centre, an<l two smallcr an<l more <listan!, placed near the posterior margin; those of the lower ,·aire not so well <lefinecl as thc olhcrs; conliguous to the inner extremity of the orífice therc is an obtuso teslaceous process; <lcslilute of hinge t eeth, or a ligament. l. OnmcULA NonvEGICA, pi. XXII, f. 9, ami pl. XX, f. 21, 22. Orbicula No,·vegica, First Ecl., pi. 37, f. 21, 22, and pi. 34, f. 9; Lamarck, VI, pt. 1st, p. 242, G. B.; Sowcrby, Linn. Trans., XllI, p. 468, pl. 26, f. 2; Stark, Elem. Nat. l·Iist., II, p. 75; Disc:iiw Ost?-eoiclcs, Lamarck, VI, pt. 1st, p. 237; Fleming, Urit. An., p. 376; Stark, Elem. Nat. Hist., p. 76; Turton, Brit. Biv., P· 238; Patclla anomala, Müllcr, Zool. Dun., I, p. 1'1, pi. 5, f. 1 lo 7; Patclla clistorta, Flcming, Edin. Ency., VII, p. 65, pi. 204, f. 4; :ilfontagu, Linn. Trans., XI, P· 195, pi. 13, f. 5. Shell subquadrangular, somcwhat irregular in shapc, and ruggecl in thc margin; upper valvc patelliform, convex, con- ccntrically wrinkled by thc lines of growth, with a wart-likc subcentral protuberancc ; of a du\1 ycllowish-brown colour ; undcr valvc quite flat, vcry thin, and adhcring its whole cir- cumfcrcnce lo submarine stoncs, ami othcr substances; inside bluish-white, and miuutcly granulatcd; furnished with four muscular impressions. Founcl in decp water at Zetland,.and is not uncommon in thc Clydc, particularly in Rothesay Bay. FAMILY 11.-ÜSTRACEA. Ligament placed eithcr interiorly, or nenrly so; shcll irregu- lar in form, foliaceous, an<l somctimcs papyraceous. Sun-D1V1s10N I-Ligamcnt placed interiorly; shcll thin, papyraceous. GENUS 3-ANOMIA,-Linnrous. Shell inequivalve, irregular, operculatcd; under vahe ílat- tened, with a large circular or ovale pcrforation nenr the hingc, with its edges turned back, through which protrudcs a testacc- ous, or bony, straight, cl1iptical operculum or plug, with a dilnted base, by which the shell adheres to extraneous bodies; upper valve the larger, concave, an<l entire; liga111e11t large, transverse, interna!, and placed within the upper valve, at the umbo, and to a promincnt, expanding appendage in the dcpressed vnlve; lower valrn with a single, orbicular, nearly central, muscular s imprcssion; upper ralrn with three impressions, situate con- tiguous to each other, the largest is next the base of tite shell, which is connected by means of its musclc with the plug, allCI tite other two are also connected, by the meclium of their muscle, with tite single impression in tite lower, or ílattened valvc. l. ANO~II,\ EPlllPl'IU~I, pi. XXII, f. 1 ali(! 4. Anomia Ephippium, First Ed., pl. 34, f. 1 ancl ,1 ; Linné, p. 1150; Lamarck, VI, pt. 1st, p. 226; Pennant, p. 109, pi. 62; Montagu, p. 155; Dono1•a11, I, pl. 26; i\Iaton ami Uackett, p. 102; Brown, Ency. Brit.• p. 422; lb., Ency. Edin., p, 548, pi. 54, f. 3 ; lb., Wcrnerian Mem., p. 514; Fleming, p. 395 ; lb., Edin. Ency., p. 9S; Forbcs, p. 38; Turton, Biv., p. 227, pl. IS, f. 1, 2, 3. Shell suborbicular, subpellucid, irregularly wnved an<l wrin- kled; generally of a palc ycllowish-white 011 tite outside, ami of a shining pearly lustre within, reflecting various hucs, according to the play of light; one valve convex, the olher ílat, with a prctty large perforation near the hinge, through which protrudcs a thick tcstaceous plug, by which the shell is aílixe<l to extrane- ous bodies. This specics is not uncummon in our seas, attached to oysters and othcr extraneous bo<lics; oftcn assuming the form uf thc substancc to which it is attached. Very curious speci111ens are frcqucntly found adhering to the Pecten opc1·c11lm·is ami Pecten ma:1:imus; thesc take the impression of the ribs and markings of those spccies, ami produce a very bcautiful appcar:mce. The A. Bphippium abound~ in Lough Strangford, Irelnn<l, of a vcry largc sizc, adhering to Oysters. 2. ANOMIA UNDULATA, pi. XXII, f. 2, 3. Anomia mufolata, Firsl Ed., pi, 3•1, f. 2, 3; Linn. Gmelin, p. 3346; Montagu, p. 157 and p. 580, pi. 4, f. 6; Ency. Melh., pi. 18•1, f. 5, 6; Malon and Rackett, p. 103; Flcming, Brit. An., Jl· 395; lb., Edin. Ency., p. 98; Brown, Ency. Brit., p. 422, pl. 153, f. 9; lb., \Vernerian Mem., p.¡¡ 14; lb., Conch. Text Book, p. 110, pi. 14, f. 2; Forbcs, p. 39; Turton, Brit. Biv., p. 230; Ost?-ca striata, Da Costa, p. 162, pi. 11, f. 4 ; Dono,·an, pi, 45. Shell strong, ílat, sometimcs thin, and pcllucid; generally of a suborbicular, or slightly elongatcd form; externa! surfacc with numerous, strong, rib-like strirc, emannting at the smnll, pointcd, flattened umbo, which is placed a little within thc margin, nnd radiating towards tite sides and base of thc shell, which is gene- rally slightly crenulatcd; upper vah·e a little roun<led; lower ,•alve flat, with a very large, oblong-ovalc perforation, <lestined for thc passage of a testaceo!]S plug, by which the animals adhcre to marine boclics, on onc side of which is a triangular concave space, finely striate; outside dirty green; inside almost always of a clcar glossy green, which is more intense towards thc centre; margin of a bluish, iridescent hue; thc plug ter- minales in a thin oval layer, strongly striated transvcrsely, and crossed by fine longitudinal lines. Found on stones, shells, &c., within low water-mark, on many of our shores; wc may particularise Soulh Dcvon, Salcomb Bay, rocks at Torbay, the Frith of Forth; Callinn Bay and Rathgar- mont, Lough Strangford, Ircland. 3. A NO~II,\ SQUAMULA, pi. XXII, f. 5. Anomia squamula, First Ed., pi, 34, f. 5; .Pennant, p. 109, No. 71; Da Costa, p. 167; Montagu, p. 156 an<l p. 561;