DESCEIPTION OF PLATE VI. 
1. — Cocconeis placentiila. 
2. — Actinocycliis sedenarius ? 
3. — Triceratium striolatum. 
4. — Campy lodiscus bi-costatus. 
5. — Zygoceros Rhombus. 
6 a. — Odontidium Harrisonii ? 
6 h. — „ front view. 
7. — Rhaphoneis gemmifera. 
8. — fasciolata. 
9. — „ pretiosa. 
10. — rhombus. 
11. — Zygoceros Surirella ; front view. 
12. — „ „ side view. 
13. — Front view of Actinocyclus sedenarius, showing the undulations. 
14. — Side view of the same, showing the cellular markings. 
