Microscopic Life in the Ocean at the South Pole, 565 



35. Symbolophora Microtrias. 38. Symbolophora tlexas. 



36. ... Tetras. 39. Synedra Ulna. 



37. ... Pentas. 



B. SILICEOUS PHYTOLITHARIA. 



40 Amphidiscus clavatus. 47. Spongolithis Heterononus. 



41. Spongolithis acicularis. 48. ... ingens. 



42. ... aspera. 49. ... neptunia. 



43. ... brachiata. 50. ... obtusa. 



44. ... Caput serpen tis. 51. ... vaginata, 



45. ... Clavus. 52. ... uncinata. 



46. ... Fustis. 



C. CALCAREOUS POLYTHALAMIA. 



53. Grammostomum diver gens. 



9. Samples from Cockburn's Island, the furthest limit of vege- 

 tation 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 condition. 

 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 numbers, 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 silice- 

 ous earthy element of the little invisible polygastric animals ap- 

 pears to form no inconsiderable part of the solid substance, which 

 by the death of generations goes to form earth and land. 



The following forms were observed : — 



SILICEOUS POLYGASTRICA. 



1. Eunotia amphioxys. 4. Rhaphoneis Scutellam. 



2. Pinnularia borealis. 5. Stauropiera capitate, 

 3- ... peregrina? 



J n 



