EXPEDITION OF TEE CHALLENGER. 



35 



"Important objections, however, at once suggest themselves to this view- 

 How can animal life be conceived to exist under such conditions of light, tem- 

 perature, 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 

 higlily-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 ProtophyUi of the deep-sea soimdings. 



" I confess, though as yet far from regarding it proved that the Gloligerinm 

 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, tem- 

 perature, and pressure. Now, the genus Gloligerina is abundantly represented 

 in the Cretaceous epoch, and perhaps earlier. 



"I abstain, however, at present from drawing any positive conclusions, pre- 

 ferring rather to await the result of more extended observations." ' 



Dr. TTallich, Prof. Wy ville Thomson, and Dr. Carpenter, concluded 

 that the Glohigerinm live at the bottom. Dr. Wallich writes in 1862 : 

 " By sinking very fine gauze-nets to considerable depths, I have re- 

 peatedly satisfied myself that Glohigerina does not occur in the super- 

 ficial 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 Glohigerinm " and their debris^ he adduces this fact 

 in support of his belief that the Glohigerince live at the bottom. 



On the other hand, Miiller, Hiickel, Major Owen, Mr. Gwyn Jefl^ries, 

 and other observers, found that Globigeri?iw, v^ith. the allied genera 

 Orhulina and Pulmnidina. sometimes occur abundantlv at the surface 

 of the sea, the shells of these pelagic forms being not unfrcquently 

 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 i^roceedings 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 i^<?ramii/era which formed the 

 Gloligerina ooze lived on the bottom, and that the occurrence of individuals on 

 the surface was accidental and exceptional ; but, after going into the thing care- 

 fully, 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 



' Appendix to "Report on Deep-Sea Soundings in the Atlantic Ocean," by Lieutenant- 

 Commander Joseph Dayman, 1857. 



2 The "North Atlantic Sea-Bed," p. 137. 



3 Preliminary Notes ou the Nature of the Sea-Bottom procured by the Soundings of 

 H. M. S. Challenger during her Cruise in the Southern Seas in the Early Part of the Year 

 1874." (Proceedings of the Royal Society, November 26, 1874.) 



