Dr. E. P. Wright on Deep-sea Dredging. 423 
LIV.—WNotes on Deep-sea Dredging. By Epw. PERCEVAL 
Wricut, M.D., F.L.8., Professor of Zoology, Trinity 
College, Dublin. 
Proressor HEpwArpD Forses refers, in his ‘ History of the 
European Seas,’ to “an abyss where life is either extinguished 
or exhibits but a few sparks to mark its lingering presence.” 
“Its confines,” he writes, ‘ are yet undetermined, and it is in 
its exploration that the finest field for marine discovery yet re- 
mains.” One sees here, as it were, the hope of some just pos- 
sible brilliant discovery contending in the author’s mind with 
a dark despair at finding anything beyond a mere spark of life 
in the great ocean depths, in the so-called azoic regions. Had 
the amiable author lived even until now, he would have 
known that many sparks of life are to be met with at depths 
undreamt of by him, and that the creatures which reside there 
are not so very much modified as he seemed to anticipate. 
The researches of Dr. Wallich, and the publication of the first 
part of his work on the North-Atlantic sea-bed, have thrown a 
great deal of light on this subject; a considerable number of deep- 
sea soundings are recorded or alluded to by him in his in- 
teresting volume. But, however valuable they may be, as 
affording us some slight knowledge of the formation of the sea- 
bottom at great depths, yet they have not given, nor are they 
likely to give us any indications of the animals, higher than 
the Rhizopods, living at these depths: I purposely pass over 
the occurrence of Ophiocoma nigra, O. F. Mill., as recorded 
by Wallich, as the bringing up of this species from the depth 
of 1260 fathoms was the result of accident. To afford us any 
certain knowledge of higher forms, recourse must be had, not 
to the sounding-line, but to the dredge; and even with it, it 
will only be after many a tedious and careful exploration that 
we can expect to arrive at any satisfactory results. It should 
not be forgotten how very small a surface is scraped by even 
the largest dredge; and as the deep-sea valleys lie at a con- 
siderable distance from the land, the examination of them, ex- 
cept with the assistance of a steamer, is only possible under 
very favourable circumstances. 
In the third or coralline zone of Professor Forbes, though 
animal life is abundant, yet plants become scarce; and in the 
fourth or deep coral zone, and at a depth of about 100 fathoms, 
the only vegetation met with consists of the lowly Nullipores. 
This latter zone, however, reaches to a depth that I am in- 
clined to place in our seas at about 150 fathoms, increasing 
another hundred fathoms at the Equator; and it is only below 
it that we come to a zone of which Professor Forbes knew 
