THE DEPTHS OF THE SEA. 
CalyAr Eisner: 
INTRODUCTION. 
The Question of a Bathymetrical Limit to Life.—The general Laws 
which regulate the Geographical Distribution of Living Beings.— 
Professor Edward Forbes’ Investigations and Views.—Specific 
Centres.—Representative Species.—Zoological Provinces.—Bear- 
ings of a Doctrine of Evolution upon the Idea of a ‘ Species,’ 
and of the Laws of Distribution.—The Circumstances most likely 
to affect Life at great Depths: Pressure, Temperature, and Absence 
of Light. 
THE sea covers nearly three-fourths of the surface of 
the earth, and, until within the last few years, very 
little was known with anything like certainty about 
its depths, whether in their physical or their biological 
relations. The popular notion was, that after arriving 
at a certain depth the conditions became so peculiar, 
so entirely different from those of any portion of the 
earth to which we have access, as to preclude any 
other idea than that of a waste of utter darkness, 
subjected to such stupendous pressure as to make life 
of any kind impossible, and to throw insuperable diffi- 
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