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

INVOLUTE,] MOLLUSCA. 36. 1-Iimx nADIATULA, pi. XVIII,* f. 5, G. Ileli.t· rndiat,tla, Alcler, Cat., p. 12, No. 50; lb., l\Iag. Zool. and Ilot., II, p. l0i; Jeffreys, Linn. Tr., XIII, p. 511; Thomp- son, Ann. ami l\Iag. Nat. Hist., VI, P· 33 ; IíeliJ: striatula, Gray, l\focl. Hep., 1821, p. 239; lleli.1: b1·cuipes, Turlon, l\Ian., p. G5, pi. 5, f. 50. Shell pellucid, diaphanous, horn-coloured, depressed ; spire but little elevated above the body ,·olution, and consisting of thrcc volutions, which are particularly flat at thcir junction; body largc, in proporlion to thc spirc; upper parts covcred. with regular, continuous, longitudinal stria!, and prodncing a radiated appearance; base smooth, with a moderately sized umbilicus. This is an cxccedingly minute species, its diameler hardly exceeding the twentieth of an inch. Its habitat is in wet mossy ditches, and in clamp wooded localitics, Distinguished from thc young of H. zonites, by the great flatncss of the volutions at thcir lower side, and by thc striro being more regular and decided. This shell occurs in many parts of Britain. Mr. Thompson gives as localities, Dovcdale, Derbyshire; the Falls of Clyde, Lanarkshire; and Ballantrae, Ayrshire; and in lreland, he says it is widely distributcd, namely, Lonclonderry, near Dublin, Downshire, Antrim, Tyrone, Cork, and Qucen's County. 37. HEux cnYsTALLINA, pi. XVIII,* r. 7, 8. Hclix Cl'!Jslallina, l\1üller, Verm., II, p. 23, No. 223; Pfeiffer, I, p, 46, pi. 2, f. 36 ; Drapcrnaud, p, 118, pi, 8, f. 13 to 28 ; Gray, Med. Ilep., 1821, p. 239; Alder, l\fog. Zoo!. ancl Bot., II, p. 108; Turton, Man., p. 58, f. 42; Jelfreys, Linn. Tr., XIII, p. 341 and 511; Thompson, Ann. ami l\fag. Nat. Hist., VI, p, 34; Rossmassler, VIII, p. 37, pi. 39, f. 531, va,·.; Hefü: vit1·ea, Brown, Edin. Journ. Nat. and Geo. Science, I, p. 12, pi. 1, f. 12, 13, 14; Zonites Cl'!JSlalli,ws, Leach, Mol!., p. 105. Shell thin, depressecl, of a very glossy, crystallinc, grccnish- white colour; spire with five well dcfined, gradually dccreasing volutions, terminating in an cxtremely small, hardly-raised apex; base of the shell a little convex, providecl with a small, but deep umbilicus; aperture semi-lunate, and enveloping the body. Diameter three-sixteenths of an inch. This spccies may at once be distinguishcd from its con- geners, by its extremely glass-like aspect, the number of its volutions, and in the body one being but little thicker than the lowcr volution of the spire. The H. C'l'!JSiallina is not uncommon in many parts of Eng- land. It. was first founcl in Scotland by my est.ecme<l friencl James Gerard, Esq., who cletected it in an ole! wall at Corstor- phinc Hill, near Edinburgh; wherc I afterwards found it. Thompson says it is generally distributed in I reland, occurring in moss, under stunes, and upon decaying wood, bi;th in wet :md dry si tuations. He adds, "Sorne adult specimens which I have collected have had but tluee and a half volutions, instead of four ancl a half or five, the ordinary number." I have great doubts of these last mcntioned being really the JI. Cl'!fslallina, as one of its strongest chara_cters is, the number of its volutions, in which it is only equallcd by thc following spccies. 38. HELIX EXCAVATA, pi. XVIII,* f. 9, 10. Hcli:i: e.1:rav11ta, Bean; Alder, Cat., p. 13, No. 53; lb., Mag. Zoo!. and Bot., II, p. 107; Thompson, Ann. and Mag. Nat. o Hist., VI, p. 34; Heli.1: lucida, va1·., Turton, Man., p. 57, pi. •1, f. 39; Hcli.1: nítida, J effreys, Linn. Tr., XIII, p, 339 ancl 511. Shell subglobosc, lransparent, diaphanous, shining, yellowish horn-colourcd, and covcred with longitudinal, irregular wriu- kles; body \'ery large; spire subdcpressed, small, consisting of four or five well rounded, close-set volutions, terminating in an obtuse apex; base considerably inflated, and provided with a largc a11d <lecp umbilicus, in which may be scen the inside of the volutions, nearly to the apicial one; aperture slightly lunate, or nearly round. Diameter about a quarter of an inch. Disco1•erecl near Scarborough by Mr. Bcan, all(l has been found by l\'Ir. Alcler in Northumberl:m<l; ancl Thompson says he has sP.en but one Irish specimen, which was procurecl nt Dunscombe ,vood, near Cork, by Miss King, of Cork. Its favouritc habitat is timbcr which has been cut clown, all(I under decayed wood. 39. HELIX PURA, pi. XVIII,* f. 11, 12. Ilcli.v pura, Alder, Cat., No. 46; lb., Mag. Zool. :tll(I Bot., II, p. 108; Thompson, Aun. ami Mag. Nat, Hist., VI, p. 32; Turton, Man., p. 59, the dcscription only; Hcli.v 11itidula, vm·. /3, Jelfreys, Linn. Tr., XIII, p. 511. Val'iet9 l. Sltell palc lioni-colourcr:l. Alder, Mag. Zoo). and Bot., II, p. 108. Shell nearly white, depressed, somewhat pellucid, and glossy, a little striated, or wrinkled; body large; spire smnll, with three volutions, placed somewhat oblique; base considerably flattened, provided with a largc and dccp umbilicus; base nel'cr opaque. Diametcr between a fifth and sixth of an inch. This shell differs from H. crystallina in being larger, more convcx, ancl less glossy; the volutions are not so closely set, the body somewhat largcr in proportion to the spire, with a larger umbilicus, and cspccially in the fine, regular striro, of which the H. Cl'!JSiallilla is destitute. Found near Newcastle-upon-Tyne by J oshua Aldcr, Esq., and as far as is known, rather a local spccies in England; in Ireland, according to Thompson, it is rathcr widely sprcad; its usual habitat being among moss, in sheltered situations. I found it near Cabinteely, County of Dublin. The ycllowish horn-coloured \'nriety is most commonly met with. Sub-Gcnus 8,-Tlllco.vos'l'o,,rA.-Ffrussac. Shell sub1liscoidal; 1pc:c dcp1·csscd; base umbilicatcd; apc,•- tm·c trigo11al; outc1· lip denticulated; epidermis fo,· thc mosl pa1·t hispid. 40. HELIX ODVOLUTA, pi. XVIII,• f. 13, 14. Hcli:1: obvoluta, l\1üller, V crm., II, p. 24; Hcli:i: liolosc,•icea, Drapernaud, p. 112, pi. 7, f. 27 and 29 ; Brard, p. G2, pi. 2, f. 16, 17; Pfeilfer, 1, p, 41, pi. 2, f. 28; Hossmassler, I, p. 70, pi. 1, f. 21; Férussac, Prod., p. 38, No. 107; Lindsay, Linn. Trans., XVI, p. 765. Shell reddish-brown, planorbiform, depressed both above and below, and largcly umbilicatcd; spire concave, ancl consisting of five uarrow volutions; apcrture triangular; thc outel' lip re-· flexcd, pale red, and provided intcrnally with a small, bluntcd tooth. Diameter five-eighths of an inch.