PLATE XXI. 



Limn^us. In and near fresh-water. 

 Fig. 



1, 2. L. pereger, Miiller {Buccinum.) — Helix, Turbo, Bulimus, and 

 L. pulris, infiata, teres, lutea, limosa, ovata, vulgaris, marginata, 

 intermedia, lacustris, etc. — Springs and ponds, Cc. 



3. L. stagnalis, Linn. {Helix.) — Buccinum, Turbo, etc., stagnalis, 



fragUis, and major, etc. — Ponds, etc., not so generally as "No. 1, 

 '%, C. 



4. L. palustris, Miiller, {Bucc.) — Helix and L. frag His, fontinalis, 



stagnalis, etc. — Ditches, ponds, etc., C. Whorls more nume- 

 rous and less rapidly enlarged than No. 3. 



5. L. auricularius, Linn. {Helix.) — L., Helix, Bucc, Turbo, Buli- 



mus a., patulus, etc. — Near London, Swansea, etc., Mc. Aper- 

 ture very wide, and outer lip partially reflected. 



6. L. acutus, Jeffreys. — L. auricular ins, var. B. M. — Oban, Clumber 



Lake, Bloomfield, Kent, It. Apex sharp and tapering; aperture 

 smaller than No. 5. 



7. L. truncatulus, Miiller, {Bucc.) — H,B.,a.nd L.truncatus,fossarius, 



minutus, limosus, etc. — Partly amphibious, generally diffused, C. 

 Small, spire equal to body. 



8. L. glabek, Miiller, {Buccinum.) — H, B., and L. octanfracta. pere- 



grina, elongata, octona, leucostoma, etc. — Fresh and brackish 

 marshes, Stafford, Somerset, York, etc., E. Spire longer than 

 aperture. 



9. L. involutus, Harrey. — Amphipeplea i. — Lake near Killarney, 



Belfast, Er. Spire almost covered. 



10. L. glutinosus, Miiller, {Buccinum.) — Helix, Amphipeplea, and L. 



— Windermere, etc., Mr. Oval. 



11. L. Burnetti, Alder. — Lakes in Dumfries and Breconshire. In- 



flated ; spire flat ; colour opaque-amber. 



Physa. In and near fresh-water. 



12. P. HYPNOR.UM, Linn. {Bulla.) — Helix, Physa, Limncea, and Aplexa 



turrita and marmorata. Pools and lakes, Brit, generally, C. 



13. P. eontinalis, Linn. {Bulla.) — Turbo, Planorbis, Bulimus, and Ph. 



adversus, bulla, bulloides, and fluviatilis. — Brit, pools, lakes, 

 and ditches, C. 



Ancylus. In fresh-water. 



14. 15. A. PLUviATiLis, Miiller. — Patella lacustris. — Running streams, 



on stones and plants generally, C. Oval, apex turned to left. 



