Sinistral specimens of normally dextrally coiled shells, and dextral abnormalities of sinistral species, have always appealed to collectors on account of their rarity. Abnormally coiled shells, though never frequent, are less rare in some species than in others. Amongst freshwater shells sinistrorsity is most frequent in Lymnaea peregra, the inheritance of which has been studied by Boycott and others. King Lane pond, Leeds, used to be celebrated for sinistral peregra, and there are records from Tooting, Hale Moss, Scarborough, Durham, Woodhall Bridge and York. This abnormality is infrequent amongst freshwater snails: the following records are mainly culled from the Journal of Conchology. Viviparus viviparus: Bardsley, Lancashire (10:148, 18:329), R- Foss, York (22:170), London, Holocene (23:294). V. contectus: Beswick, Lancs. (11 '.22b, 12:68), Kessingland, Suffolk (19*^21). Valvata piscinalis: Budworth Mere, Cheshire (11:268), Hunstanton, Norfolk (7- 17^), Creswell Crags, 2 specimens, and a reference to one from Sunbury (4:145) V. antiqua: Dierden's Pit, Pleistocene, Kennard coll. Bythinella scholtzi (Amnicola taylori): Stockport canal, Reddish (15:283, 16:28). Lymnaea glabra: Scarborough (12:108, 191). L.stagnalis: Kenn Moor, Somerset (9:199), Doncaster (7:40). L.auricularia (13:26). Reversed coiling is also recorded for Physa fontinalis, Barnes Common (5:220) and. P.acuta (13:25), and for three species of Planorbis: P.planorbis, Wye, Kent (3:232), P.leucostoma, Tenby (11:235) and Sutton Coldfield (8:377, 384), and P.laevis, Aldeburgh (18:317).
Amongst land snails, sinistrorsity is most frequent amongst some of the larger Helicidae, such as Helix aspersa, H.pomatia, H.nemoralis (especially at Bundoran), H. hortensis and Helicella virgata. In some species it is unknown. The following records, mostly from J. Conch., are of rarer occurr¬ences. Acme fusca: N.W. Donegal (13s151)» Bristol (Jeffreys, British Conchology, 1:309), Tramore Strand, Donegal (16:80), Dingle C15•52; Irish Nat. 24:33^1 Broughton, Lincs. (20:158), Northfleet (24:27); some of these are subfossil. Succinea oblonga: S. Perthshire (7:367). Cochlicopa lubrica, Rugby (17-’33T. Pyramidula rupestris: A. S. Kennard, Proc. Malac. Soc. 16:110, no locality. Vertigo antivertigo: Southwell, Notts., Holocene (24:232). V. substriata: Shipley Glen, Yorks. (11:200). Pupilla muscorum: Abersoch, Caernarvon (11:11), Weymouth (24:19). Lauria cylindracea: Torquay (12:295), near Hexham (23:259)* Ena obscura: Danebury, Hants. (16:100). Helicodonta obvoluta: Ditcham (8:428, 12:13, 16:44). Helicigona lapicida: Linton (Taylor's Monograph, 3:391)- Arianta arbustorum: Buxton (5:225), Derbyshire (11:235), Maidwell, Northants. (11:330), Denford, Northants. (14:27), Uxbridge, Holocene (Taylor's Monog. 3;442). Trichia striolata: Haddon, Northants. (11:281), Peterborough (13:14), Chipstead, Surrey (22:94). T.hispida: King's Langley, Herts., Holocene (18:130), Thornton Dale, Pickering (19:14l, pi. 4, fig. 1), West Blatchington, Sussex (19:286), Scarborough (Naturalist, Spring 1953), Cambridge, Holocene, and Coldingham near Eyemouth (Taylor's Monog. 4:33)* Monacha cantiana: 13;25 (see also 16:40). Helicella caperata: Stanwick, Northants. (11:170), Woolacombe, Devon (13:20, l6:So), Lewes (13:45), Scarborough (12:249), North Devon (12:288), Frinton-on-sea (14:27)> Bassenthwaite Hause (8:158). H.itala: Northants. (13:26), Bundoran (9:265, 22:263), Water Newton, Hunts. (14:102); see Taylor's Monog., 4:132. Cochlicella acuta: Tenby (9:15'1) 211). Pune turn pygmaeum: Barnwell Abbey, Pleistocene (Taylor's Monog. 3:160). Discus rotundatus: Burnham Beeches (12:237)) Castleton, Derbyshire (18:329), Chiswick (8:170), Aghaderg, Loughbrickland, Co. Down (6:39); see Taylor's Monog., 1:108. Vitrea crystailina: Copford, Holocene, Kennard coll. Oxychilus draparnaldi: Coulsdon, Surrey (18:320). Retinella radiatula: Broughton, Lincs., Holocene, Kennard coll. P. nitidula: Saxlingham Thorpe, Norfolk (22:271).
Dextral Clausiliidae: Clausilia bidentata: Skipton (13:274, 22:263) Slammanan, Stirling (4:265), Lincolnshire (Arch. Moll. 60:47). C. dubia: Ingleton (22:263). Laciniaria biplicata: Cambridge (22:263).
The above records are only of British non-marine Gastropoda and make no claim to be comprehensive. Sinistral Vallonia pulchella is recorded from Poland (22:263), Oxychilus cellarius from Pennsylvania (7:388, Nautilus, Dec. 1893> 90) and Sweden (24:138), Zonitoides nitidus from France and Vitrina pellucida from Geneva; see Science Gossip, 1897:262.
A* E« Ellis