374 COMPARATIVE ZOOLOGY. 
of the food. Carnivores have a wider range than herbi- j 
vores. 
Life diminishes as we depart from the equator north j 
or south, and likewise as we descend or ascend from the 
level of the sea. 
The zones of geography have been divided by zoolo¬ 
gists into narrower provinces. Five vertical regions in 
the sea have been recognized: the Littoral, extending be¬ 
tween tide-marks; the Laminarian, from low water to 
fifteen fathoms; the Coralline, from fifteen to twenty 
fathoms; the deep-sea Coral, from fifty to one hundred 
fathoms; and the Bathybian, from one hundred fathoms 
down; but since life has been found to extend to great 
depths in the ocean—as great as three thousand fathoms 
—these divisions are of little importance. Every marine 
species has its own limits of depth. It would be quite as 
difficult, said Agassiz, for a Fish or a Mollusk to cross 
from the coast of Europe to the coast of America as for a 
Reindeer to pass from the arctic to the antarctic regions 
across the torrid zone. Marine animals congregate mainly 
along the coasts of continents and on soundings. The 
meeting-place of two maritime currents of different tem¬ 
peratures, as on the Banks of Newfoundland, favors the 
development of a great diversity of Fishes. 
Every great province of the ocean contains some repre¬ 
sentatives of all the subkingdoms. Deep-sea life is diver¬ 
sified, though comparatively sparse. Examples of all the 
five invertebrate divisions were found in the Bay of Bis¬ 
cay, at the depth of two thousand four hundred and thir¬ 
ty-five fathoms . 198 
Distribution in the sea is influenced by the temperature 
and composition of the water and the character of the 
bottom. The depth acts indirectly by modifying the 
temperature. Northern animals approach nearer to the 
equator in the sea than on the land, on account of cold 
