128 
Prof. Ehrenberg on Microscopic Life, Sj-c. 
coast, namely, tbe Astasia oceanica, which Von Chatnisso had 
observed; all other accounts were imperfect and useless. By the 
new materials the number of species is increased nearly 100. 
7. The hitherto observed oceanic microscopic forms are chiefly 
siliceous-loricated animals with some calcareous-shelled. Do 
these numerous forms derive the material of their shells from 
the bottom of the sea ? This question becomes daily more 
interesting. 
8. Siliceous, and calcareous-shelled minute living forms are 
not only mixed up with the muddy sea-bottom, but they them¬ 
selves form it. They live even to a depth of 270 fathoms, and 
consequently support a pressure of water equal to 50 atmospheres; 
the whole influence of this does not indeed bear upon their organic 
tissues when they are locally fixed, but when they move from the 
bottom upwards or reversely; yet it does not appear to have acted 
on the drawn up specimens. Who can doubt but that organic 
beings which can support a weight of 50 atmospheres may support 
100 and more. 
9. The supposition, that in great depths, above 100 fathoms, 
there is no fresh nutriment for organised beings of any kind, has 
become untenable. 
10. Life and temperature in the depths of the ocean are, in 
their variable relation, the points which at present deserve especial 
attention. 
11. The showers of meteoric dust, or supposed ashes, have at 
present been proved to be, even in the case where they fell 380 
sea-miles from land, of organic and terrestrial origin. 
12. It is not perishable Protococci or Ulvce or Lichens that 
principally constitutes the organic covering and soil of the ulti¬ 
mate islands in the Polar Sea; but the living creatures that form 
the first layer of solid earth are invisible, minute, free animals of 
the genera Pinnularia, Eunotia, and Stauroneis with their siliceous 
loricte. Several species from the North Pole and the South Pole 
are identical. 
