Figs. 1-9. 
PLATE 32. 
Spirieera diyaricata .. 
Page 
213 
1. An imperfect dorsal valve of this species. From the Corniferous limestone. 
2-6. Ventral, dorsal, profile, front and cardinal views of a large and very perfect specimen, from 
the shales of the Hamilton group. 
7. An enlargement of the surface, showing the bifurcating plications and the concentric striae. 
8. Still further enlargement, showing the rugose character of the concentric striae. 
9. The cast of a ventral valve, from the Corniferous limestone. 
