112 
darkness. The presence of large and remarkably developed eyes in many. 
abyssal animals shows conclusively that Jight of some kind does exist on 
the floor of the ocean. seems absurd to suppose, as many scientists have, 
that the phosphorence of certain animals is a sufficient factor to produce the 
oahdnweg of such enormous and complicated eyes in a multitude of ae? 
sea specie 
= ae find in a general way that the physical conditions are much simpler 
more energetic in the depths of the sea than in the shallow w of 
ie = sil Region. The effect of temperature is marked in the wre 
of life over the warm and cold areas of the oceanic floor. The influence 
pressure, Taaettas darkness, and the quietness of the abyssal waters, is yet 
too imperfectly known to draw conclusions from. The sea bottom is very 
irregular, in some places being formed of bare rocks destitute of animal or 
vegetable life. Such a tract, rete is usually in the path of some power-— 
% current like the Gulf Str In other parts of the oceanic floot the 
fauna is found on the walls of sar ete th cliffs, and is here difficult to obtain 
with the appliances now in use. The greater portion of the bottom is coy- 
ered with a layer of solid matter, in condition varying from coarse gravel to 
the finest kind of mud. The gravels are chiefly confined to the Archiben- 
thal regions, while the true depths of the sea are carpeted with a viscid 
layer of the finest kind of calcareous mud or clay. 
Many animals flourish in a soft bottom, especially the pings fam- 
ily Nuculidze; others require some solid substance upon 0 
as a stone, piece of wood or the spine or test of some dead shieastlatel 
muddy regions where such objects are wanting, ne animals are also ab- 
o by the unfortunate ani- 
tom ; 
gee rs 0 
groups ch other © 
toa abr extent. is the bese of the sea this cared vero destraction is 
vom the — vi pater eyed emer with lavapegs of organisms — 
whic iharn the region to which tes 
belong to sh that ere byt Sie ce in any regions of the deep sea the - 
food supply is pao furnished to the aahiaala inhabiting the deptia: aor 
