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

26 MOLLUSCA. ['fRACHELIPODA brown beneath which the shell is often prettily mottle<l, che• quered with brown an<l white, or coverecl with zig-zag markings, and banded in sorne instances. This species is common on most of the Dritisl_1 and Irish coasts; adhering to stones and sea weed, between lugh and low water-mark. Fig. 22 represents the shell in its young state. GENUS 33,-NERITINA,-Lamarck. Shell thin, externa! surface generally smooth, and frequently covered with a strong, horny epidermis; spire mostly very short, sometimes nearly concealed, and at others obsolete; aperture semicircular; outer lip plain, sharp, and destitute of tecth or erenulations internally, but within the lower region of the aper- ture, it is provi<led with a somewhat elongate<l, transverse pro- minencc, which seems the fulcrum for the articulation of the operculum ; inner lip flattene<l, and reflected on the columella, an<l placed obliquely to the a.xis of the shcll; edge gencrally short, ancl dentatecl or crenulatcd; as the animal increases in dimensions, that part of the columellar lip is absorbed, which mnkcs it nppcar as having no columella; opcrculum tcstaceous, semicircular, closing the aperturc entircly, covered with a horny epidermis, ami provided internally al the lower e1úl with a tooth- like nppendage, which fils into a hollow betwcen the promincnee ami lip. 1. NERITINA !ILUVIA1'1LIS, pi . XVIII, f. l, 2, 3, and pi. XIII, f. ti, G~First Ed., pi. '13, f. 1, 2, 3. Nc1·itim, jfovicitilis, Turton, Man., p. 13, f. 12•1; Aldcr, Mag. Zoo!. ami llot., II, p. l li; Thompson, Ann. and M:ig. Nat. Hist., VI, p, 16; Lamarck, An.San. Vert., VI, pt..2nd, p.188; Fleming, Ilrit. An., p. 321 ; Ne1·itt, Jlttviatilis, Müll, Moll., II, p, l!H; Drnpcrnaud, Hist. Moti., p. 31, pl. 1, f. 1; Pfeiffer, I, l'· 1 OG, f. 37, 38, 3!); Fleming, Eclin. Ency., VII, p. 82; lb., 13rit. An., p. 321; Brard, p. 1!)•1, pi. i, f. !), 10, 12; Turton, Conch. Dic., p. 127 ; Nci·it-ina fontinali.~, Ilrard, 1-Iist. Conch., l'· l!)G, pi. 7, f. 11; Thcoclo,t·us Lutctianus, De Montford, II, p. 3¡; 1 ; Da Costa, Brit. Conch., p. 48, pi. 3, f. 8; Pcnnant, Brit. Zoo)., IV, p. 141, pi. 88, f. 1'12; Donovan, Ilrit. Sh., I, pi, 16, f. 2; 11-Iontagu, Test. Drit., p. •!iO. Shell subornl, subpellucid; body ver y large; spire extremely ~mall, oblique, ali(\ lateral, consisting of two well definecl rnlu- tio11$, ali() terminaling in a minutely small, slightly producecl apcx; apcrturc luniform ; outer lip thin, sharp at the edge ; pillar lip white, ílat, all(I very broadly rcflected on the columella; apcrture closcd by a t estaceous op<?rculum, of an orange-yellow l'olour; whole shcl\ covered with a brown or greenish epider- mis, bcncalh which thc surface is glossy and smooth, but longi- tudinal, minute wrinkles, are obserrnblc by the aid of a strong lcns; bcautifnlly slreaked, spottcd, or molllecl, with white a11Cl purplish-brown, <lccp umbcr, or palc brown, and in some in- stances with spiral Lamls of eithcr of those colours. Length thrce-eighths of an inch; brcaclth a quarter of an inch. Fig. 3 represenIs the operculum. Foull(\ in many of thc slow ruuuing ri,·ers ancl streams of Grcat Britain nnd Irehind aclhcriug to sloncs, ns lhe Thames, Humbcr, Tyue, mu\ Tweed in Euglaucl; the Liffey, Shannon, :md Ilresna in Irclan<l; ami the Forth, Tay, ancl Clnle in Scotlaml. · - FAMILY VII.-PERISTOMIDA, Shell conoid, or subdiseoi<l, with the margins of the aperture united; aperture protected by an operculum; fluviatile, and the animal having the power of respiring in water. GENUS 3•1.-PALUDINA~Lamarck. Shell ovale, or oblong; spire somewhat turreted; the volu- tions smooth, rounded, and subcarinated; aperture subrotund, ovale, or oblong, a littlc angulaled above, slightly moclified on thc inner side by the gibbosity of the body volution; lips unit.ed ali round, with acule edgcs; operculum corneus, with concentric lincs of growth, and provided with a sublateral nucleus. l. PALUDINA v1v1rAnA, pi. XIV, f. 71, 72.-First Ed., pi. 41, f. i 1, 72. Paludina vivipara, Lamarck, An. San. Vert., VI, pt. 2nd, p. 173; Ilrard, Coq. de Paris, p. 174, pi. i, f. 1; Fleming, Brit. An., p. 315; Alcler, Mag. Zool. ancl Ilot., II, p. 116; Thomp- son, Ann. and Mag. Nat. I-Iist., p. 17; Cgclosto-ma Vl'.vipanm1, Drapernaud, Hist. Nal. des Moll., p. 34, pi. 1, f. 16, 17; Tur- ton, l\fan., p. 113, f. 118; Brar<l, Coq. de París, p. 174-, pi. i, f. 1; Ilossmassler, f. 66; Hcli.i· vivipam, Monlagu, Test. Ilrit., p. 386; Ilrown, vVernerian Mcm., II, p. 527; Vivipan1sjluvio- ?'w11, De Montford, II, p. 24i; Paludina acliatin«, Sowcrby, Gen., f. l. Shell thin, subconic, oblong-ovate ; spire consisting of fü·e extremely rnntricose, abrnptly <liminishing volutions, separated by a dcep suture, ancl lcrminating iu an acule apcx; apcrture suborbicular, a little contracted above; pillar lip slightly reflect- ed, behind which is a subumbilicus; inside smoolh, bluish-white, the externa! bands shining lhrough; whole shell covered with an olive-green shining epidermis, beneath which the shell is white, with three spiral, clark brown bands on the body, and two on the superior volutions, which generally grow fainler as they ascend, until they become nearly invisible beforc reaching the apex; surface slightly wrinkled longitudinally, se,·eral of which are coarser than the others, marking the periodical growth of the shell; aperture protectecl by a thin horny operculum. In thc young condition the shell is subglobose, subpellucid, with thc bands rather obscure, ancl the volulions appear more flattene<l above than in the aclult state. Founcl in the Thames and other slow rivers, ancl sometimcs in poncls. Plentiful in a clitch near Southporl, Lancashirc. Occurs in a stream at Newtownarcls, County of Down, Irelancl. 2. PALUDINA ACIIATINA, pi. XIV, f. 68, 6!).-Firsl Ed., pi. 41, f. 68, 6!). Palmlim, acliatina, Lamarck, An. San. Vert., VI, pt. 2nd, p. 17,1; Ency. Meth., pl. 458, f. 1, a, b; Ilosstnassler, p. 10!), f. 66*; Turton, ?dan., p. 133, f. 119; Lymnw viviparn, Fleming, Dril. An., p. 31G; Cgclostoma achatina, Drapernaml, p. 3G, pi. 1, f. IS. Shell thin, oblong-ovate, ,·entricose; spire consisting of four or firn considerably inílate<l volutions, separatecl by a wcll dc- fined, dcep suture, ancl lerminating· in a rathcr ohtuse apcx; apcrlure suborbicular, slightly conlraclecl above, whilc withitt, with the externa! bands apparent; pillar lip a little reflected on the columella; onter lip thin, a1Hl sharp on the edge; whole shell coverecl with an olirnceous epidermis, benealh which il is provi<led wilh threc, clark re<lcfüh brown, spiral girdlcs 0 11 thc