May 31, 1901.] 
trum are removed from the sun’s rays by 
absorption, leaving the green rays only. 
He comes to this conclusion from a study 
of the colors of the animals of the deep 
sea, which demonstrate, in his opinion, the 
presence of light of some kind. He appar- 
ently assumes that this light comes from 
the sun, and resorts to the explanation just 
referred to to prove its presence in the 
oceanic depths. 
We shall see presently, I hope, that it is 
not necessary to assume the presence of 
sunlight at the sea bottom in order to meet 
the demands for light revealed by a study 
of the coloration of its inhabitants. 
The bottom waters, then, are almost 
freezing cold, subject to tremendous pres- 
sure, moved by slow currents creeping from 
pole to equator, supplied with sufficient 
oxygen to sustain animal life, and devoid 
of sunlight. Could a more uncomfortable 
and altogether forbidding habitat be con- 
ceived of for an animal population? Cer- 
tainly not, from our standpoint. But it 
must be remembered that we are neither 
fishes, nor mollusks, nor jelly-fishes ; and 
that everything depends upon being used 
to environment. A practical application of 
this fact would result in the saving of a lot 
of otherwise wasted sympathy in human 
as well as zoological affairs. 
Let us now turn our attention briefly to 
the topography of the sea bottom. It may 
be said, in general, that there are few 
abrupt changes of level; that the ascents 
and descents are gradual, and that there 
are few areas which, if laid bare, would 
present anything like the broken contours 
of a mountainous region. In areas adja- 
cent to continents and archipelagoes the 
topography is often considerably broken, 
but away from the land masses the sea 
bottom is, ordinarily, as level as a western 
prairie. Few, if any, bare rocks are to be 
found, except where recent submarine vol- 
eanic explosions have torn up the subjacent 
SCIENCE. 
845 
strata, or the cooling lava has encrusted 
the bottom. Practically the entire sea bot- 
tom is covered to an unknown depth by a 
soil that varies with the depth in a defi- 
nitely determinate manner. This soil, like 
that of the upper world, is organic in its 
origin, being composed in large proportion 
of the remains of a few species of very wide- 
spread forms, individually minute, but col- 
lectively of stupendous bulk. These ani- 
mals belong almost exclusively to the Pro- 
tozoa, or one-celled forms, and largely to 
the class Rhizopoda. They are of immeas- 
urable importance from a biological stand- 
point, furnishing, as they do, the food basis 
for all marine life. As a type of these or- 
ganisms Gilobigerina bulloides stands forth 
preeminent, a form of exquisite beauty of 
structure, being like a series of minute 
chalky spheres, exquisitely sculptured, from 
which radiate many and almost infinitely 
slender and delicate spicules which serve 
to support the living animal on the water, 
which, in places, is rendered of a reddish 
color by the hosts of these Rhizopods. It 
has fallen to the lot of but few naturalists 
to examine these creatures in a living and 
perfect state, as the slightest touch will rob 
them of their beautiful spicules and cause 
the living protoplasm to retreat within the 
hollows of the spheres. Minute and fragile 
as they are, the skeletons of these animals, 
and of others equally small, cover at the 
present time many millions of miles of the 
sea bottom, and in times past were the 
main element in building up the mighty 
chalk deposits of the world. 
If we were to run a line of soundings 
from the continent of North America east- 
ward to the mid-Atlantic, we should find 
that the bottom could be easily divided 
into three regions on the basis of the soil, 
as I have termed it, covering everywhere 
the actual rocks. For the first few miles 
the bottom would be covered with débris 
of many kinds from the adjacent land. 
