Page:Popular Science Monthly Volume 7.djvu/45

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"Important objections, however, at once suggest themselves to this view. How can animal life be conceived to exist under such conditions of light, temperature, pressure, and aeration as must obtain at these vast depths?

"To this one can only reply that we know for a certainty that even very highly-organized animals do continue to live at a depth of 300 and 400 fathoms, inasmuch as they have been dredged up thence; and that the difference in the amount of light and heat at 400 and 2,000 fathoms is probably, so to speak, very far less than the difference in complexity of organization between these animals and the humbler Protozoa and Protophyta of the deep-sea soundings.

"I confess, though as yet far from regarding it proved that the Globigerinæ live at these depths, the balance of probabilities seems to me to incline in that direction. And there is one circumstance which weighs strongly in my mind. It may be taken as a law that any genus of animals that is found far back in time is capable of living under a great variety of circumstances as regards light, temperature, and pressure. Now, the genus Globigerina is abundantly represented in the Cretaceous epoch, and perhaps earlier.

"I abstain, however, at present from drawing any positive conclusions, preferring rather to await the result of more extended observations."

Dr. Wallich, Prof. Wyville Thomson, and Dr. Carpenter, concluded that the Globigerinæ live at the bottom. Dr. Wallich writes in 1862: "By sinking very fine gauze-nets to considerable depths, I have repeatedly satisfied myself that Globigerina does not occur in the superficial strata of the ocean." Moreover, having obtained certain living star-fish from a depth of 1,260 fathoms, and found their stomachs full of "fresh-looking Globigerinæ" and their débris he adduces this fact in support of his belief that the Globigerinæ live at the bottom.

On the other hand, Müller, Häckel, Major Owen, Mr. Gwyn Jeffries, and other observers, found that Globigerinæ, with. the allied genera Orbulina and Pulvinulina. sometimes occur abundantly at the surface of the sea, the shells of these pelagic forms being not unfrequently provided with the long spines noticed by Macdonald; and in 1865 and 1866 Major Owen more especially insisted on the importance of this fact. The recent work of the Challenger fully confirms Major Owen's statement. In the paper recently published in the proceedings of the Royal Society, from which a quotation has already been made. Prof. Wyville Thomson says:

"I had formed and expressed a very strong opinion on the matter. It seemed to me that the evidence was conclusive that the Foraminifera which formed the Globigerina ooze lived on the bottom, and that the occurrence of individuals on the surface was accidental and exceptional; but, after going into the thing carefully, and considering the mass of evidence which has been accumulated by Mr. Murray, I now admit that I was in error; and I agree with him that it may be