34 
Smith, on Diatomacea. 
bundles of once encysted masses, still adherent after boiling 
in acid. The phenomena attending this encysting I hope to 
present to the Society at some future period, and its signi- 
ficance. 
12. Cocconeis, &c. 
13. Fragillaria capucina. — Contains small distorted Sy- 
nedra, and new Pinnularia ; also Gomphonema, No. 2, and sp. 
frustules. 
14. ^' Near centre run/^ five miles from Gambia. 
15. Synedra vitrea, Kiitz. ? 
16. Gomphonema. — Same as No. 3. 
17. Himantidium, kc. 
18. Meridion circulare. 
19. Pinnularia — nova ? — Eesembles Gibba and diver gens. 
20. Meridion constrictum. — Found stipitate. 
21. Synedra captata, &c. 
22. Collotonema vulgar e. — Encysted. 
23. Collotonema minutum. — Fluid. 
23* „ „ Dry. 
This remarkable object is found in great abundance in an 
iron spring, forming thick skins ; when fresh there is no 
difficulty in tracing tubular structure. The dry specimen, 
prepared by burning, will task the resolving powers of best 
objectives. I have been unable to " raise a ripple^^ on it ; 
it is on sufficiently thin glass to use xV^^ i burnt on the cover 
itself. Have found it conjugating. 
24. Stauroneis acuta, &c. 
25. Gomphonema olivaceum. 
26. Nitzschia linearis. 
27. Orthosira ovichalcea. — Formed, not only with walls, like 
Melosira varians, but with internal cells, as mentioned by 
Smith, S. B. D., in connexion with Mendior. This formation 
of internal cells, which may be observed in No. 30, and which 
occurs in Fragillaria capucina, is undoubtedly interpreted 
right by Mr. Ralfs, Microscopical Journal,^ vol. vi, p. 14. 
28. Mansfield. — Contains P. obturatum of Sull. 
29. Gomphonema, n. sp. — Found conjugating ; it resem . 
bles No. 2, but is smaller, and has double sporangise ; the 
specimen was prepared by burning, and a little circle scratched 
on the cover will point out conjugating specimens. I have 
named it provisionally paradoxum.^^ 
30. Meridion constrictum. — Developed into a straight fila- 
ment. Notice the nodules alternate at top and bottom. 
31. Meridion constrictum. — Prepared by burning. 
32. Gomphonema. — Same as No. 2. 
33. Meridion constrictum. — Distorted. 
