PLATE XXIX. 



PISIDITJM niBEKNiccrM, Wcsterhmd. 



1. External right aspect of a pair 



2. a. b. } T , from 



' , ] Internal aspect of two pairs T , 



3. a, b. J , Lough 



4. Diagrammatic enlargement of the Hinge i Namaddra, 



5. a, b. Anterior and dorsal view of a pair | Co. Cork. 



6. External right aspect of a pair ) 



PISIDIUM MILIUM, Held. 



7. a-j. Internal aspect of five pairs of different ages, from 



Totteridge, Hertfordshire. 



8. a, b. Posterior and dorsal view of a pair from Comber, 



Co. Down. 



9. rt, b. of a pair from Criccieth, Carnarvonshire. 



10. a, b. of apposed valves from the Holocene at Gayfield, 



Edinburgh. 



11. a, b. of a pair from Ashridge, Hertfordshire, 



12. a, b. Internal aspect of a pair from Blythburgh, Suffolk. 



13. a, b. of a pair from llhosneigr, Anglesey. 



14. rt, b. of a pair from Sutton Coldfield, Warwickshire. 



15. a, b. of a pair from Lochmaben, Dumfriesshire. 



16. a, b. of a pair of valves from the Holoceno at Newbury, 



Berkshire, 



17. (i, b. of a pair of valves from the Holocene at Shand 



Street, Tooley Street, London. 



18. , 6. of a pair of valves from the Pleistocene at Swans- 



combe, Kent. 



19. Diagrammatic enlargement of the Hinge, 



20. a-e. External right aspect of five pairs of different ages, 



from Totteridge, Hertfordshire. 



21. of a pair from Blythburgh, Suffolk. 



22. =- of a pair from llhosneigr, Anglesey. 



23. -^ - of a pair from Comber, Co. Down. 



24. of a pair from Ashridge, Hertfordshire. 



25. - of a pair from Criccieth, Carnarvonshire. 



26. of a pair from Castle Rising, Norfolk. 



27. of a pair from Baguley Pit, Cheshire. 



28. a, b. External aspect of two valves from the Holocene at 



Shand Street, Tooley Street, London. 



29. ft, b. of two valves from the Holocene at Newbury, 



Berkshire. 



30. a-f of six valves from the Holocene at Gayfield, 



Edinburgh. 



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

 shows the amount oi magnification. 



