PLATE XII. 



Ianthina. Moats on ocean. 



Fig. 



1. I. COMMONIS, Lamk.—Eelix Ianthina, I.fragilis, etc.— Cornwall, 



Bristol, etc. ; oceanic, C. Sides depressed. 



2. I. BRiTANNiCA, Leeck. Reeve.— ■Ixeh.uA, Cornwall, etc., Mr. 



Darkly coloured, not compressed. 



3. I. PALLIDA, Harvey. — /. jiatula.—C\aie, Rr. as Brit. 



4. I. EXiGDA, Lamk, — Cornwall, Clare, etc., Mr. 



Nbeitina. In rivers. 



5. N. FLUviATiLis, Linn.— N./ontinalis.— Thames, Trent, Humber, 



etc., Scotch lakes, Cc. 



BiTHiNiA. In ponds. 



6. B. Leachii, S/iepp. (Turbo.) — B. ventricosus, Paludina acuta, aimi- 



lis, etc. — Rivers S. Brit., Mr. Narrow, with rounded whorls. 



7. B. TENTACULATA,Z*»«. (Helix.) — T. nucleus, Paludina impura, etc. 



— Fresh-water, throughout Brit. Oval. 



Paludina. In ponds. 



8. P. LiSTEEi, Forbes and Hanley. — Helix vivipara, etc. — Lakes and 



ponds generally, Mc. Whorls more separate, umbilicus larger 

 than P. vivipara. 



9. P. VIVIPARA, Linn. — Pal. achatina, etc. — ^Thames, etc., C. 



Valvata. In ponds. 



10. V. PISCINALI3, Mutter. — Nerita, Turbo, Cyclostoma fontinalis, ob- 



tusa, thermalis, etc. — Fresh-water, C. Subglobose. 



11. V. OEisTATA, Mailer. — F. planorbis, ^ic. — Many loc, Mc. Or- 



bicular. 



LiTTOEiNA. On the sea-shore. 



12. 13. L. EUDis, Dmiov. (Turbo.) — L. littoreus, etc., L. ni^ro-Uneatus 



(var. f. 13). — British shores generally, Cc. 

 14, 15. L. LITTOREA, Linn. (Turbo.)— L. vulgaris, etc. — British shores 



generally. The common eatable Winkle. 

 16,17. L. TENEBROSA, Mont. (Twr^o). — British shores generally, C. 



Not thickened at bottom of mouth hke L. rudis. 

 18. L. PATULA, Jeffreys. — L. labiata, L. jugosa, etc. — Common on 



our shores. 



