PLATE XIV. 



PlSlDIUM CASERTANUM (Poli). 



1. ft, b. External aspect of two opposite valves from the Holocene 



at Gayfield, Edinburgh. 



2. of left valve from the Cromerian (peat) at "VVesfc 



Runton, Norfolk. 



3. a-e. of a series of left valves from the Holoceie at 



Dagenham, Essex. 



4. a-x. - of a series of valves showing variation, from the 



Pleistocene at Swanscombe, Kent. 



5. a-l. from the Pleistocene at Grays, Essex. 



6. a-e. from the Holocene at Newbury, Berkshire. 



7. a-p. from the Pleistocene at Crayford-Erith, Kent. 



8. rt-7i. - - from the Pleistocene at Clacton, Essex. 



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

 shows the amount of magnification. 



