vo.. xvu. (2) GERVILLI^ AND PERNA ^35 



EXPLANATION OF PLATE XXVIL 



Figs. la-d. Perna oxoniensis sp. nov. 



ifl right valve— exterior ib right valve— interior 



ic left valve-exterior id left valve-interior 



Perna-Bed. Neeeran Beds, Bell-Inn Quarry, Enstone, Oxford- 



shire. 



Fig. 2. Gervillia enstonensis sp. nov. 



Fossil-Bed (14), Nesran Beds, Bell-Inn Quarry, Enstone. 



Figs. 3a and b. Gervillia richardsoni sp. nov. 



Bed 18 (probably), Nesran Beds, Sharp's Hill Quarry, near 

 Hook Norton, Oxfordshire. 



All the specimens are in Mr L. Richardson's collection. 

 The figures are -95 natural size. 



