PLATE XIII. 



PlSIDlVAI CASERTANUJI (Poli). 



1. a, I. Posterior and dorsal view of a pair from Fitton Hall, Oldham, 



Lancashire. (" Pisidium jpusillam, var. grandis": T. Rogers 

 coll.) 



2. ft, b. of a pair from Swinton, Lancashire. (" Pigidium puriUum, large 



variety. J. G. Jeff." : T. Rogers coll.) 



3. ft, b. of a pair from Lagan Canal (2nd lock), Cos. Down and Antrim. 



4. ft, b. of a pair from Scarborough, Yorkshire. 



5. a, b. of a pair from Basaenthwaite, Cumberland. 



<i. a, b. of a pair from Lancaster. 



7. ft, b. of a pair from the Sebeto, Naples. 



8. ft, b. of a pair from Wniana, Roumania. (' P. fossarinum, Clcssin.") 



9. External right aspect of a pair from Manchester. ("P. fontinaJe, 



C. Pt'r., var. rosea, Scholtz " from 0. Boettger.) 



10. of a pair from Swiuton, Lancashire. (" P.fontina 7 e, var. cinereum 



[sic]," marked " J. G. Jeff." : T. Rogers coll.) 



11. of a pair from Scarborough, Yorkshire. 



12. of a pair from Swinton, Lancashire. (" P. pueillum, large variety, 



J. G. Jeff." : T. Rogers coll.) 



13. of a pair from Fitton Hall, Oldham, Lancashire, (" P. pusillum, 



var. grandis " : T. Rogers coll.) 

 ] 4. of a pair from Bath, Somerset. (" P. fontinale, var. pulcJiella, 



named by Mr. Jenyns" : T. Rogers coll.) 



] 5. of a pair from Addington, Surrey. 



10. of a pair from Gateshead, Durham. (" P. cinereum " : T. Rogers 



coll.) 



17. a-j. of a series of the " lake form " from Bassenthwaite, Cumberland. 



18. External left and right aspect of a pair from the type locality at Caserta, 



Italy. 



19. a, b. External right aspect of two pairs from Hendon, Middlesex. 



20. , b. of two pairs from North Wootton, Norfolk. 



21 . of a pair from Shirvvell, Devonshire. 



22. of a pair from Lancaster. 



23. of three pairs from Lochmaben, Dumfriesshire. 



24. ft. b. Posterior and dorsal view of a pair from V r estre Aker, Christiania. 



25. External right aspect of a pair from Coolkeeragh, Co. Londonderry. 



2.V*. ft-c. of three pairs from the Lagan Canal, Cos. Down and Antrim. 



2<>. a-d. of four pairs from Annadale, Co. Down. 



27. of a pair from Sicily. (" Galileja tenebrosa, 0. G. Costa " : 



R. Bellini.) 



28. of a pair from Vestre Aker, Christiania. 



2!>. of a pair from Mt. Majella, Italy. (" P. casertanum, var. lenti- 



cnlaris, Norm." : R. Bellini.) 



30. of a pair from the Sebeto, Naples. 



31. of a pair from Wniana, Roumania. ("P. fossarinum, Clessin.") 



32. ft, b. of two pairs from Naples. ("P. australe, Phiil." : R. Bellini.) 



33. of a right valve from Trancailla, Italy. 



*** The scale in millimetres under each figure, or series of figures, 

 shows the amount of magnificatum. 



