the presence of the Gulf Stream, but only through the operation of collateral
conditions prevailing at great depths below tho current itself; and that fresh-
looking specimens were present in the digestive carities of Ophiocomæ brought
up from a depth of 1260 fathoms ;
2ndly. That the Ophiocomæ arrived at the surface in a living and rigorous
condition, adherent to that portion only of the sounding-line which had rested
on the bottom ; that the number captured affords presumptive proof of the gregarious
habit of the order having remained unaffected hy change of conditions ;
that the detection of ova and GloUgerinæ within their- cavities indicated a perfectly
normal state of their reproductive and nutritive functions ; that no superficial
or deep current capable of drifting them in a northerly or north-easterly
direction from any coast-line nearer than Newfoundland exists in this part of the
ocean, and, if it did, that it would not account for the most important phenomena ;
3rdly. That in certain deposits Annelid-tubes were found, the nature of which
proves them to have been constructed on the sea-bed, of material there accumulated
;
4thly. That a living Serpula, SpirorUs, and group of Polyzoa were brought
up, in a distant locality, from a depth of 680 fathoms;
othly and lastly. Taking into consideration the arguments adduced to prove
that the conditions which prevail on the deep-sea bed are not incompatible with
the maintenance of animal life, and the extreme improbability that the creatures
heretofore discovered at great depths are merely exceptional or accidental
examples ; it will, I think, be conceded that the presence of a living fauna in the
deeper abysses of the ocean has been fully established.
Assuming, then, that the creatures referred to were captured in the midst of
their normal haunts, the inquiry naturally suggests itself, AVheuce did they originate
I and are we to regard the localities in which they were found as their
genetic centres, or only as isolated colonies tenanted by species whose genetic
centres are to be looked for elsewhere 1 These questions can only be answered
by a further appeal to concomitant facts.
“ Every living race of plants and animals,” writes Professor Phillips, “ exists
in a province of space over which by natural conditions it has been diffused,
within which by natural conditions it has been restrained, and beyond which it
only passes by a change in these conditions. Thus one place of origin is indicated
for each species of plant and animal—one locality where it first appeared,
whether it still remain there confined to a limited region, or have wandered far
away without losing its prominent characters through length of time, change of
conditions, mixture with other races, or any of the innumerable incidents of the
‘ struggle for existence ’ ” *.
Bearing in mind the law thus comprehensively set forth, and connecting it
with the extraordinary fact that the Ophiocomæ, the Serpula, and the SpirorUs
of the deep soundings one and all belong to well-known littoral species-f, we are
irresistibly led to the inference that their acclimatization must have kept pace,
during a vast sequence of generations, with the changes going on in the portion
of the sea-bed inhabited by them, and, hence, that, under sufficiently favourable
circumstances, species may accommodate themselves to conditions differing so
widely from those under which they were originally created, that their subjection
to them under circumstances less favourable inevitably results in their extinction.
I have endeavoured to establish that an extensive area of sea-bed to the
southward of Iceland has undergone subsidence, partly on the evidence afforded
by the depths, and partly by that supplied from old charts and tradition.
The subjoined striking passage from Forbes’s admirable memoir “ On the
Existing Fauna and Flora of the British Isles ” will serve to show that, on geological
grounds alone, he arrived at a similar opinion :—“ Great as the changes
appear to be affecting the distribution of land and water during recent geological
periods, as compared with the present, assumed by me in this essay, I cannot but
express my conviction that future research will not only confirm these, but prove
that still greater took place during the epochs under inquiry. The phenomena
of the glacial formations, the peculiarities in the distribution of the animals of
that epoch, and the relations of the existing fauna and flora of Greenland, Iceland,
and Northern Europe are such as strongly to impress on my mind that the close of
the Glacial epoch was marked by the gradual submergence of some great northern
land, along the coasts of which the littoral Mollusks, aided by favouring
currents, migrated; whilst a common flora became diffused over its hills and plains.
Although I have made icebergs and ice-floes the chief agents in the transportation
of an Arctic flora southwards, I cannot but think that so complete a transportation
* ‘ Life on the Earth,’ by Professor Phillips. London, I860 : p. 24.
t The species are Ophiocoma gmnulata, Serpula vitrea, and Spirorbis nautiloides.