Dr. E. P. Wright on Deejp-sea Dredging. 423 



LIV. — Notes on Deep-sea Dredging. By Edw. Perceval 

 Wright, M.D., F.L.S., Professor of Zoology, Trinity 

 College, Dublin. 



Professor Edward Forbes 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. MlilL, 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 NuUipores. 

 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 



