PLATE 16. 



Pago 

 Fig. 1. StROPHODONTA CONCAVA 96 



1 a. A ventral valve which is carinate along the centre. 



1 6. A dorsal view showing the area of both valves, etc. 



1 c. A profile of specimen fig. 1 b. 



1 d. A large ventral valve which is less convex than the usual forms and somewhat undulated 



or sub-plicated on the margin. 

 1 e. The exterior of a dorsal valve, showing the extension of the cardinal process above the 



hinge line. 

 1/. The interior of the specimen flg. 1 e, showing the muscular impressions, cardinal process, 



crenulated hinge line, etc. 

 1 g. A profile of the same, showing the geniculation in front, and the muscular scar. 

 1 h. The interior of a ventral valve, showing the area and muscular impressions. 



