TRANSACTIONS OF MICROSCOPICAL SOCIETY. 
DESCRIPTION OF PLATES XI & XII, 
Illustrating Dr. Greville^s paper on New Diatoms. 
Series XX. 
Fig. 
1. — Plagiogramma elongattim, front view. 
2. — „ „ valve. 
3. — „ angulatum^ front view. 
4. — Cestodiscus Stokesianus. 
5. — „ pulchellus. 
6. — Aulacodiscus spa?'s?(s. 
7. — Gephyria gigantea, lower valve, front view. 
8. — „ valve, side view. 
9. — Rutilaria elliptica^ front view. 
10. — „ „ valve. 
11. — „ superba, front view. 
12. — „ 5, valve, side view. 
13. — Cocconeis armata. 
14. — Omphalopelta Moronensis. 
15. — Navicula excavata. 
16. — „ Eayptiaea, front view. 
17. — J, „ side view. 
18, 19. — ,5 permagna, very large, from Berbice. 
20. — „ „ small var,, from Berbice. 
21. — „ „ var. from Delaware River, U.S. (out- 
line of Dr. Lewis's figure). 
22. — „ Zanziharica. . . 
23. — „ Jamaicensis. 
24. — „ strayigulata. r " 
25. — ,, rimosa. 
All the figures are X 400 diameters. 
