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

32 MOLLUSCA. [TnACHELIPODA two or threc volutions, wcll dividcd by the suture linc; some- what largcly umbilicate above and bclow; body volution pro- vidcd with transvcrsc spinous ribs, forming a regular eres! round thc centre of thc sidcs; apcrture slightly o,•ate; outcr lip con- tinuous ali round. Diametcr the tenth of an inch. Not unfrcqucnt in ponds and ditches, adhering to aquatic plants. Scction 11.-Volutions ca,·inated. 5. PLANORDIS CARINATUs, pi. XIV, f. 35, 36, 37.-First Ed., pi. 41, f. 35, 36, 37. Plano,•bi11 ca1·inatu11, Müllcr, V crm., II, p. 157; Drapernaud, p. '1G, pi. 21, f. 13, 14, ami 16; Pfcill'er, p. 76, pi. 4, f. 5, 6; Brard, p. 150, pi. 6, f. 3 ; Turton, Man., p. 106, f. 87; Alder, Mag. Zoo!. and Dot., II, p. 113; Thompson, Ann. and l\fag. Nat. Hist., VI, p. 35; Heli:i; complanata, Montagu, T est. Drit., Sup., p. 146, pi, 25, f. 4; Hcli.i· pl,mate1, Maton and Rackett, Linn. Tr., VIII, p. 189, pi. 5, f. 14; Heli.i- pla1101·bis, Linné, Syst. Nat., I, p. 1242. Va,·iety l. Púmorbis clisciformis, Jell'rcys, Linn. Tr., XVI, p. 521; Alder, Mag. Zool. ancl llot., II, p. 113; Plcmorbi$ lutcsce11s, Jell'rcys, Linn. Tr., XVI, p. 385 ; Planorbis plcmatus, Turlon, Man., p. 110, f. 92; 1-fcU:i: cai·iiwta, l\fontagu, Test. 13rit., ¡,. 451, pi. 25, f. l. Shell pale horn-colourcd, subpcllucid; with six rapidly in- creasing volutions, with a promincnt obtuse keel on their outcr cdges, almost 0nt above, somewhat convex, ancl grndually bevil- ling oíl' towards the outer edge bcneath, the outcr volution smldcnly increasing in sizc, ancl the hinder parts of cach volu- tiori rather convex; aperture ohliquely angular, contracted to a point bcncnth; providcd with a slight central umbilicus. Din- meter abont half an i11ch. This shcll mny be distinguishccl from thc Pla1101·bis rna1'gi- 11atus by the under side of the YO)utions bcing less inílated, ancl hy their gradually bevilling off to the oul~r edge. In old shells thc volutions become more inílated. This species is frequently covered with n thick brownish coating. It is nlso liable to mon- strosities, Sheppard, in the Linncan Transactions, vol. XIV., page 157, describes one with thc YO)utions apart, similar to the Scalcu·ia preciosa. Founcl in stagnnnt waters in many parts of Great Dritain allll Irdnnd. 6. PLANORlllS MAnGtNATus, pi. X IV, f. 49, 40, •11.-First E1I., pi. 41, f. 39, 1 10, 41. I'lcmorbis mm-ginatus, Drapernaud, p. 45, pi. 2, f. 11, 12, nn~ 15; Drard, p. 152, pi. 6, f. 5; Rossmassler, Icon., II, pi. 2, f. a9; Aldcr, Mag. Zoo). ami Dot., II, p. 112; Turton, i'lfan., P· I0i~ f.~¡; Plc'.1101·bis complcmatus, Turton, Man., p. 108, f. 88_; l•lemmg, Ilrit. An., p. 278; Heli.r plcmorbis, Pennant, llnt. Zoo)., II, pi. 83, f. 123 ; l\faton and Uackett Lº 1·. V , mn. ,., I_H, p. 1_88, pi. ~• f. 13; Hcli.i· complana/11, Montagu, T est. Bnt., p, •l;i0, pi. 2a, f. -1; Planorbis 11mbilicatus, Müller, Vcrm., 11, P· 160 ; J effreys, Linn. 'fr., XVI, p. 38-1. lt is subject to thc following ,·arietics. Vm•icl!J l. Siclcs wicqucrl,fmgilt·, 1111cl gloss!J, Planorbis tm-giclus, Jefi'rcys, Linn. Tr., XVI, p. 3S3. !l I:m·:ct!I 2•. l'lanorbis rhombeus, Turton, l\lan., p. 1OS, f. ·O, l lcmo1·b1s Shcppcmli, Lcach, i\loll., p. ¡.¡9; Plww1·bis Drape,·11<1lcli, Jell'reys, Linn. Tr., XVI, p. 306; Hcli.7: Dra- pcnialdi, Sheppard, Linn. T rans., XIV, p. 158. Vai·icl!J 3. Destitutc of et lccel. Shell' of a brownish horn-colour, scmitransparcnt, slightly striatcd transvcrsely, Jlat, or somewhat concave nbove, subum- bilicated below; with five or six rapidly increasing, Jlat volu- tions, with a strong carina above, and vcntricose and roundccl to the margins beneath; apcrturc rhombic, with the front rounded. Thrce-quarters of an inch in diameter. Found in stagnant watcrs. This is to be distinguished from P. cai·iiwtus by its being thickcr, ami the volutions more roundcd, ancl more convex b cncath 011 thc margins; in its more roundcd aperturc; and in thc kecl being less promincnt. The young shell is more rhomboidal, with the eclges consi- clerably thicker in proportion to its sizc, :md is describcd and figured by Turlon as a distinct species, undcr the name of Pla- 11orbis rlwmbcus. A remarkublc monslrosity of this sp_!)cies was found by l\fr. Thomas Stephcns, in the poncl of thc Collegc Dotanic Garden of Dublin; ami is in thc cabinet of my respccted friend lVI. J. O'Kelly, Esq., of Hochestown Housc., near Cabintcely, Ireland. Pinte XIV, f. 38. I figuree! ami described this monstrosity in the ,verneriau lVIcmoirs, vol. II, p. 528, pi. 24, f. 1 O, uncler the name of Helfa· cocldca. It is thus dcscribccl :- " Shell of a dark horn-colour, with scven tapering, roundccl volutions; the three ncxt thc apex are twistcd like a cork- ~crcw, and t erminate in n sharp point ; the five lower volutions slope gradually to a carinated riclge, which commences in the centre of thc oútcr margin of the lip, ancl loses itsclf in the fifth volution, giving the volutions · the appenrance of being ílat at bottom; volutions slightly wrinklecl obliqnely across; apcrture somewhat angulatecl, oval, ami n little compressccl; lip vcry thin, at~d re ílcctecl on the columella at the base, where it is pro,·idccl w1th a dccp a111I wide umbilicus." Turton clescrihcd a111I copied my shell, i11 his Conch. Dict., ~nder the namc of Hcli.i· tm·cbm; and in his l\Ianuel, irnblished m 1831, followed me, in the first eclition of this work in con- nectiug it with Planorbis mai'gi11<1t1cs. ' 7, PLAKonms VOHTEx, pi. XIV, f. 4,1, 45.-First Ed., pi. -11, f. 42, 43. P lcmorbis vo1·tc.i:, l\liiller, V erm., II, p. 158, var. a; Draper- uaucl, P· ,14, pi. 2, f. 4, 5 ; Brarcl, p. 154, pi. 6, f. 9; Lamarck, An. San. V ert., VI, p. 15,1; l'feiffcr, p. i9, pi. 4, f. ¡ ; Hoss- masslcr, P· 10,1, pi. 2, f. 61; Jcll'rcys, Linn. Tr., XVI, p. 382; Turton, l\fan., p. 109, f. 91; Alder, Mag. Zoo!. ami Bot., II, ¡,. 1 ;3; r:orbes, Mal. l\Ion., p. 13; Thompson, Ann. ami l\Iag. Nat. H1st., VI, p. 50; Plrmorbis compi·cssus, l\lichaud, Compl., Jl· 81, pi. 16, f. 6 and S ; llcli.i· i·ortc.t·, Linnú, Syst. Nat., I, p. 12,~2 i Montagu, Test. Brit., p. 45,1, pi. 25, f. 3; Drown, W er- nennn_Mem.,_ II, p. 52-1; IL., Ency. Drit., Gth Ed., VI, p. 458 ; Dono,an, 13~11. Sh., pi. 39, f. 1; Flcming, Drit. An., p. 278. ,lion.~fro.~tt!J. Tlu: «pcrlm·c: pi·ovidc:cl u·ith « thicke11cd inlcl'- 11al 1·ib, l\Iichancl Com 1 80 1 l 6 f . • ' P ·• P· , P • , • 3, 4, :, ; Hossmasslc r, Icon., I, p. 105, f. G2. She\1 hrownish ho •I . . . rn-co OUI, t ransparcnt, rery thm, llattcncd nbo,·e, ami a httle concn . 1 1 . 1 . . . . •\ e JC ow; mt l s1x or se,·en gradually mcreasmg, obhquely a1ul lrans\'erscly striate<l ,·oluti ons, com·1•x