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

l :--,·01.UTE.] l\IOLLUSCA. 31 P· 85; A_mple.rn h!Jp1101·um, flcming, I3rit. An., p. 276; Lim- nea turnia, Sowerby, Genera, f. 1 O; 1Vautct h!Jp1101·11m, Lench, Moll., P· ~ ~2; Plano1·bis t1writ11s, l\füller, Verm., II, p. 169. Shell s1111s!rnl, elongntecl, subcylindrical, Ycry smooth, glossy, ami !rnnsparent, of a clark greenish horn colom; bocly about half the length of thc shcll; spirc consisting of four or fhe well di\'ided, and lapcr volutions, lcrminaling in an acule apex; aper- turc ovnle, narrow, conlraclecl abovc, ami roun<led beneath; pillar somewhat sinuated. Fouml in clitches, stagnnut pools, ami lakes in many places of Grent Britain nnd Ireland. · GE:-ius 40,-PLANORDis.-Müller. Shell discoidal, umbilicatc; spirc dcpresscd; apex always dis- tinct; Yolutions heterostrophe, or revolving from right 'to left, convolYing always on the same plane, and apparent on bolh sides; apcrture obloug, lunate, or subquadrate, its breadth being nearly equal to its lcngth, ancl somctimes greater; outer Jip thickcne<l, expanded, and its under part always extended for- wards; umbilicus very wide; destitule uf an operculum. Section I.- Volut·ions devoicl oJ et ca,·ina, ?'Otmded on both sicles ; spfre slightl!J concave. 1. PI,ANonms conNEus, pi. XIV, f. 31, 32, 33.-First Ed., pl. -11, f. 31, 32, 33. Plcmorbis corne1,s, Drapernaud, p. 43, pi. !, f. 42, •13, 44; Pfoi!fer, p. 77, pi. 4, f. 3, 4; Lamarck, An. San. Vert., VI, ¡it. 2nd, p. 152; Brard, p. 147, pi. 6, f. 1, 2; Je!freys, Linn. Tr., XVI, p. 383; Fleming, Brit. An., p. 277; lb., Eclin. Ency., VII, p. 69; Alcler, l\iag. Zool. aud Bot., II, p. 112; Thompson, Ann. and i\fag. Nat. Hist., VI, p. 34; Sowerby, Genera, f. 1 ; Turton, Man., p. 112, f. 95 ; Rossmassler, !con., II, p. 14, pi. 7, f. 113; Plano,·bis pmpm·eus, llfüller, Verm., II, p. 154; Plan01·bis simili.s, p. 166, young shell; Heli.i· cornea, Donovan, Brit. Sh., II, pi. 39, f. l; Montagu, Test. Brit., p. 448; Brown, \Vernerian Mcm., p. 524; lb., Ency. Brit., VI, p. 458; Heli.1; nanct, Pennant, !hit. Zool., IV, p. 133, pi. 83, f. 125, the young shell; p. 134, f. I 26, the adult. Shell dextral, clcpressed; spire consisting of four rapirlly climi- nishing volutions, cleeply cliYiclecl by the suture, sunk below the level of the outer, or body volution, and coiled upon its apcx, which gradually sinks, ancl forms a concavity, or nmbilicus; under surface nearly flat, ancl cxposing the whole \'Olutions of the spire ; entire body rouncled on the sides ; the shell trans- versely striated, and sometimes with sorne wrinkles, across the volutions; aperture nearly equilateral, sublunated, ancl oblique; outer lip thin; inner lip reflectecl on the columella, forming a continuous line with the peristome; colour, rufous or chestnut above, pule yellowish-brown or bluish-grey beneath . Diameter generally an inch, but often to be met with an inch ancl a quarter. In thc young condition, the volutions are provided with fine spiral stri:c. Found in slow rivers and stagnant ditches in England ancl Ireland. 2. Pl,ANonn1s ALnus, pi. XIV, f. 52, 53.-First Ed., pi.•11, f. 52, 53. Planorbis albus, Müller, Verm., II, p. 16-1; Pfci!fcr, p. 80, pi. ,1, f. 9, 1 O; Leach, l\Ioll., p. 156; J effreys, Linn. Tr., XVI, p. 387; Fleming, Eclin. Ency., VII, p. 69; lb., Brit. An., p. 278; Turton, Man., p. 114, f. 97; Alder, Mag. Zoo}. ancl Bot., II, p. 113; Forbes, Mal. Mon ., p. 13; Thompson, Ann. ami Mag. Nat. Hist., VI, p. 48; Pla1101·bis hispidus, Drapernaud, p. 43, pi. 1, f. 45, 46, 47, •18; Lamarck, An. San. Vert., VI, pt. 2nd, p. 154; Brard, p. 159, pi. 6, f. 6, 7; llelfa: alba, Mon!agu, Test. Brit., p. 459, pi. 25, f. 7; Brown, Wernerian l\Iem., II, p. 524; lb., Ency. Brit., VI, p. 458. Va1·iet9 I. S/wll smootli, shini11g, ancl white. Plano,·b-is glaber, Je!freys, Liun. Tr., XVI, p. 3-:l7, Shell dexlral, thin, pale yellowislHrhite, subpcllucicl, deprcs- sed; body volution very large, rounclecl on the sides; spire consisting of four rapidly clecreasing rnlutions, which are equally convex both above and below; the apex of thc spirc somewl1at sunk, forming a sub umbilicus, ancl the nndcr surface more concave; whole externa} surface covered with fine, clernted, close-set, transverse, and spiral striro, proclucing a reticulatecl appearance, which are providecl with dicidous bristles; aperturc very large, sublunale, somewhal higher thau wicle, clasping thc bocly Yolution; outer lip thin, a little oblique; pillar lip white internally, spread on thc columella, ali(\ conlinuous with the margin of the outer lip. When rccent it is covered with a fine pilous epidermis. Found principally in stagnant waters, ponds, and clitches, and by no means a plentiful species. 3. PLANonms L,r-:v1s, pi. XVIII, f. 7, 8, 9. Planorbis laJvis, Alder, Catalogue, Sup. Trans. Ncwcnstlc Nat. Hist. Soc., II, p. 337; lb., l\fog. Zoo). ami llot., II, p. 113. Shell smooth, semitransparent; volut.ions equally com·ex both aborn ancl bclow; bocly volution rounded on the sides, large; spire consisting of two or three small, compact, rounded volu- tions; whole shell wich nearly obsolete lines of growth, ancl of a brownish horn colour; aperture sublunated, or nearly circular. Discovered by Joshua .Alder, Esq., Newcastle, in a pond on Holy Island, and has also been met with by him and the Ilev. W. Mark, at Whitby, Northumberland; ancl has bccn founcl nt Belfast by William Thompson, Esq. 4. PLANORDIS rnnmCATUs, pi. XIV, f. 46, 47, and pi. XVIII, f. 11~First Ed., pl. 41, f. 46, 4 7. Plano,·bis imbricatus, llfüller, Verm., U, p. lú5; Drnper- . naud, p. 44, pi. 1, f. 49, 50, (i 1 ; Pfciffcr, p. 84, pi. 3, f. 15 ; Brard, p. 163, pi. 6, f. 10, 11; Je!freys, Linn . Tr., XVI, p. 388; Alder, Mag. Zoo). and Bot., II, p. 114; Turton, Man., p. 11, f. 95; · Forbes, Mal. Mon., p. 13; Thompson, Ann. and llfag. Nat. Hist., VI, p. 49; Pl<tno,·bis nautila1ts, Fleming, Eclin. Ency., VII, p. 69; lb., Brit. An., p. 278; Tu1·bo nau- tileus, Brown, Ency. Brit., VI, p. 457; lb., Wcrncrian Mem., II, p, 522; lleli:1: nautileus, Walker, f. 20, 21; Montagu, Test. Brit., p. 464, pi. 25, f. 5. Va1·iet9 1, pi. XVIII, f. 10. Shell c011siderabl9 smalle1·, with the imbricated laminal mo1·e distant. Plano1·bis c1·istatus, Drapernaud, p. 44, pi. 2, f. 1, 2, 3 ; I'fci!fcr, p. 8,1; Alder, l\:Iag. Zoo!. and Bot., p. 114. Va1·iet!} 2. J,Vith the lamÍl!Cll quite obsolete. Shell considerably depressed, pellucid, of a grecnish or black- ish horn colour; sidcs of the bocly rounded; spire consisting of