in the Ocean at the South Pole. 
123 
35. Symbolophora Microtrias. 
30. — Tetras. 
37. — Pentas. 
B. SILICEOUS PHYTOLITHARIA. 
38. Symbolophora Hexas. 
39. Synedra Ulna. 
40. Amphidiscus clavatus. 
41. Spongolithis acicularis. 
47. Spongolithis Ilcteroconus. 
48. 
49. 
50. 
51. 
52. 
'ingens. 
neptunia. 
obtusa. 
vagimta. 
uncinata. 
42. -r- aspera. 
43 . — brachiata. 
44. — Caput serpentis. 
45. — Clavus. 
46. — Fustis. 
C. CALCAREOUS POLYTHALAMIA. 
53. Grammostomum divergens. 
9. Samples from Cockburn’s Island, the furthest limit of vegeta¬ 
tion at the South Pole, 64° 12' S. lat., 57° W. long. 
Off Cockburn’s Island (Cockburn’s Head) Dr. Hooker saw an 
Alga, as the lowest and furthest step of vegetation, with forms of 
Protococcus. The Alga is one of the Tetraspora allied to Ulva, 
which Dr. Hooker has reserved in order to describe more accu¬ 
rately : I have not recognised the Protococcus in its dried con¬ 
dition. This mass, however, is chiefly and equally peopled with 
and made up of Siliceous Polygastrica. An apparently unorganic 
sand, penguins’ feathers and excrements, the Ulva, and only five 
as yet distinguished species of siliceous Infusoria in great num¬ 
bers, form the mass sent over. The vegetable substances may 
indeed have disappeared by putrefaction. The excrement of the 
birds, like guano, might abundantly furnish solid matter; but the 
solid siliceous earthy element of the little invisible polygastric 
animals appears to form no inconsiderable part of the solid sub¬ 
stance, which by the death of generations goes to form earth and 
land. 
The following forms were observed :— 
SILICEOUS POLYGASTRICA. 
1 . Eunotia amphioxys. 4. lihaphoneis Scutellum. 
2. Pinnularia borealis. 5. Stauroptera capitata. 
3. — peregrins ? 
Two forms are new, two have been observed also at the north 
pole, and one is widely distributed. 
