PLATE V. 



PrsiDiuM AMNICTJM (Muller). 



1. a, b. Posterior and dorsal view of a pair from the Regent's 



Canal, N.W. London. 



2. a, 6. - of a pair from the Thames at Hampton Wick. 



Middlesex. 



3. a, b. of a pair from the Bolton Canal, Lancashire. 



4. a, b. - Of a jmir 1 from the Pleistocene at Crayford- 



4. c, d. of ia right valve J Erith, Kent. 



5. , b. b"f a pair from the Cromerian at West Kunton, 



Korfblk. 



6. a, 6. of a pair from the Pleistocene at Barn well Abbey, 



Cambridgeshire: 



7. a, b. - of left Valve of " var. danubialis " from the Pleisto- 



cene at Crayford-Erith, Kent. 



8. a, 6. of right valve of the same from the Pleistocene at 



Grays, Essex. 



9. 0, b. of a left valve of a strongly striate example from 



the Pleistocene at Grays, Essex. (P. sulcatum, 

 pars, of S. P. Woodward's coll.) 



11. a-f. External left aspect of a sferies of different ages from the 



Thames at itampton Wi6k, Middlesex. 



12. a-d. of young shells frdm Newton Abbott, Devon. 



13. External right aspect of adult shell from the Regent's 



Canal, N.W. Londoh. 



14. External left aspect of adult shell from the Bolton Canal, 



Lancashire. 



15. External right aspect of adult snell from the Thames at 



Hampton Wick, Middlesex. 



16. from the Spandaiier Canal, Berlin. (" Var. eUngata") 



17. a-d. External right aspect of a series of different ages of 



* var. not>a, aul."j from St. Canzian, Croatia. 



18. - of adult shell from the Coin at West Bray ton, 



Middlesex-. 



ASTAKTOIDES, Bandbcrger. 



10. , b. Posterior and dorsal view of a left Valve from the 

 Pleistocene at Grays, Essex. (P. sulcatnni, pttrs, 'of 

 S. ^-. Woodward's coll.) 



*** Th^ sc^,le iri millimetres under each figure, or series of i 

 fchovrs thp anittnht of m^nifrcatioh. 



