PLATE 6. 



Crassostrea lugardi, sp. nov. 



FlG. I. Interior of lower valve, with striated ligament region, and large radially ribbed 

 muscular scar. For external view of same specimen see Plate 7, fig. i. 



Ostrea cf. marginidentata, S. V. Wood. 



FlG. 2. Outer view of a regularly contoured upper valve, with obscure radial striations. 

 FlG. 3. Interior of same specimen exhibiting the dentated margin. 

 FlG. 4. External aspect of an upper valve with deeply cut plicated margin. 

 FlG. 5. Interior of same showing marginal dentations. 



Plicatula polymorpha, Bellardi. 



FlG. 6. Exterior of a right valve of example with closed valves showing obscure striations 



in the furrows. 



FlG. 7. Ventro-marginal view of another specimen showing valvular folding. 

 FlG. 8. Interior of a right valve showing nodular sockets between the margin and pallial 



line. 

 FlG. 9. Interior of a left valve of another specimen, bearing nodulations. 



Nucula costaeimbricatis, sp. nov. 

 FlG. 10, Example with closed valves, x 2. 

 FlG. lOa. Sculpture of same, magnified. 



FlG. ii. Interior of another specimen showing the hinge teeth and minute marginal 

 dentations, x 2. 



