us to understand why the ocean never yields up its dead, and why, if tenanted by
living things as we now know it to be, dead creatures never rise up to the surface
to disclose the mystery of their past being. Decomposition may go on, but not
putrescence. The molecular constitution of the particles of animal matter may be
altered, and eventually, perhaps, their elements may enter into new chemical
combinations ; but, since no gaseous matter could be retained in a gaseous form
wdthin the cells or larger cavities of dead organisms, and the unfailing result of
endosmotic action would be to place in absolute equilibrium with the surrounding
medium every portion of the structure, no decrease of specific gravity can
occur to cause it to ascend from its position. The same conditions would apply
to living things originally formed to inhabit extreme depths, or acclimatized
through a vast succession of generations; for although minute differences of
specific gravity may exist between the fluid contained within their cavities and
the medium in which they reside, there is no ground for supposing such differences
to be greater than exist between the bodies of creatures constituted to live
in shallow water and the medium in which they sustain themselves. I f this
v iew be correct, it explains how it is that the submarine fauna remains as immutably
chained to the sea-bed under aU circumstances as the terrestrial fauna
remains chained to the surface of the earth. Here and there we detect the fossil
ized forms of oceanic creatures, some of which, in all probability, were denizens
of deep water; but under one set of conditions alone does the detection become
possible—namely, after the lapse of countless ages, during which sea and land
have exchanged dominions.
Again, we should bear in mind that the oceanic Rhizopods, although perhaps
more tolerant of change, in virtue of extreme simplicity of structure, than any
other tribe of creatures with which we are acquainted, are, for the same reason,
the least calculated to exhibit active vitality under sudden change. Under the
most favourable circumstances, and only after the lapse of considerable time, do
the shallow-w’ater forms when in captivity exhibit pseudo-cyclosis or extend their
pseudopodia. And hence, since it is in the last degree unlikely that those brought
lip from extreme depths should present these evidences of vitality, we must rest
content with collateral proofs. Fortunately these are of a very satisfactory kind.
The minute calcareous shells of the Foraminifera are the most frequent and
widely distributed organisms of the ocean. They occur in all seas in more or
less abundance. But there is one genus (namely, Glohigerina) which may be
regarded as essentially oceanic, since it is to be found in all latitudes, and at all
depths ranging from 50 to 3000 fathoms. Its seat of maximum development
is on the deeper areas of the sea-bed. There, like the sands of the shore, it
strews hundreds of square miles of surface, and apparently builds up vast
strata. The great superficial current of the Atlantic does not bear it away in
countless multitudes from tropical coast-lines, nor does the body of the ocean
itself constitute its habitation*. Nevertheless it is evident that there is an
intimate association between the Globigerina-deposits and the Gulf Stream; for
wherever we trace the one sweeping across the surface of the ocean, we are
almost sure to detect the other resting on the sea-bed; and where we fail to
trace the one, we almost as surely fail to detect the other. Thus, between the
Faroe Islands and Iceland, between Iceland and East Greenland, and for a considerable
portion of the direct route between Cape Farewell and Rockall, Glohi-
gerina is the prevailing form in the deposits; whereas between Greenland and
Labrador, along the belt traversed by the Arctic current, and in a southerly
direction along the coast of Labrador, it is either absent or occurs only in such
very limited quantity as to prove that the conditions are favourable to its increase
in the one case, and unfavourable in the other f .
I t is obvious that if the deposits were due to the subsidence of organic matter
transported by currents, instead of being formed of well-marked groups of species,
or (as is sometimes the case) almost exclusively of a single species, they w'ould
invariably consist of heterogeneous assemblages of minute organisms derived
partly from coast-lines, and partly from the oceanic regions previously traversed
* By sinking very fine gauze nets to considerable depths, 1 have repeatedly satisfied myself that
Glohigerina does not occur in the superficial strata of the ocean. On one occasion, a small bag was
drawn up through 700 fathoms of water, in a locality where Glohigerina abounded on the sea-bed.
without entrapping a single shell.
t I have only had one opportunity of noting the characters of the recent Foraminiferous deposits
of the southern hemisphere, namely, on the Agulhas bank to the southward of the Cape of Good Hope.
There, in 100 fathoms water, I foimd Glohigerina forming a nearly pure deposit (about 75 per cent.),
the area of which was marked by a definite boundary-line, depending probably on the current which
sets round the Cape from the eastward. This deposit differed in no respect from the deposits of tlie
North Atlantic, except in the less massive character of the shells. Hence it would appear th at mas-
3 increases with depth, or, as is more probable, th at it is a consequence of it.
T