416 Scientific Intelligence. 
and there is one which can certainly be identified with a form 
lately discovered by Mr. H. B. Brady in a clay-bed of the Carbon- 
iferous limestone. 
The question now arises, whether—as there must have been 
deep seas in all geological periods, and as the changes which mod- 
ified the climate and depth of the sea-bottom were for the most 
What is the source of nutriment for the vast mass of animal 
life covering the abyssal sea-bed is a question of the greatest bi- 
many of them are known to feed. Given the tozoa, everything 
else is explicable. But the question returns,—On what do these 
Protozoa live? 
On 
hypothesis has been advanced that the food of the abyssal 
is derived from Diatoms and other forms of minute 
rily living at or near the surface, may, by 
8, carry , Sa to the animals of the sea-bed 
re. Our examination of the surface-waters, 
ce of such micro- 
