488 DR MURRAY ON THE DEEP AND SHALLOW-WATER MARINE FAUNA 



to show that deep-sea species had a world-wide distribution, as usually supposed. While 

 some deep-sea species present archaic characters, and others recall the fossils of the chalk 

 period, still deep-sea species do not represent such an old fauna as many shore and fresh- 

 water forms living at the present day, such as Ceratodus, Protopterus, Amphioxus, 

 Trigonia, Lingula, and Hdiopora. There appears to be little evidence from the Chal- 

 lenger's researches to show that the deep sea has been peopled since the earliest geological 

 times ; it is more probable that migration took place from the mud-line into the deep sea 

 at a not very remote geological period. The recent oceanographical researches show that 

 both in deep and shallow water there are large numbers of identical and closely-allied 

 species in the extra-tropical regions of the Northern and Southern Hemispheres which, so 

 far as at present known, are not represented within the intervening tropics, even though 

 in deep water the climatic conditions as regards temperature are the same. It will now 

 be interesting to inquire how far these general conclusions are supported by the foregoing 

 analysis of the results obtained within the Kerguelen Region of the Great Southern Ocean. 



The Challenger in the Kerguelen Region made seven hauls with the trawl and one with 

 the dredge in depths exceeding 1260 fathoms. This was probably the most productive 

 series of hauls obtained in deep water in any one region of the ocean during the whole 

 cruise of the Challenger. In 1375 fathoms, exclusive of Protozoa, over 200 specimens 

 of fishes and invertebrates were obtained belonging to 78 species ; in 1600 fathoms about 

 the same number of specimens were obtained belonging to 89 species ; in 1950 fathoms 

 over 150 specimens were procured belonging to 79 species; the total number of species 

 in the three hauls being 199. The number of species procured in these three hauls with 

 a small twelve or sixteen feet beam trawl is certainly very remarkable when we remember 

 that the depth is about two English miles. 1 



The total number of species of Metazoa obtained at the eight deep-water stations of 

 the Kerguelen Region in depths exceeding 1260 fathoms amounted in all to 272 species. 

 The total number procured in the other twenty-nine stations in the Southern Hemisphere 

 south of the tropic of Capricorn in depths over 1000 fathoms was 301 species, the average 

 per haul in this last case being only 10 "4 species, while in the first case the average is 34'0 

 species per haul. The twenty-nine stations are on the whole situated about seventeen 



1 Since the above was written a list of the species procured in three hauls with a trawl in shallow water (6 to 

 21 fathoms), off the west coast of England, has been published with the view of showing the large number of species 

 that may be captured in single hauls from the shallower zones of depth (Third Report of British Association Com- 

 mittee on the Marine Zoology, Botany, and Geology of the Irish Sea, Ipswich, 1895). The total number of species 

 procured in these three shallow-water hauls was 189, therefore less by 10 species than were procured in the three 

 deep-sea hauls above noted. The most marked (inference in the character of the species in these series of deep-water 

 and shallow-water hauls is the predominenee of Echinodermata in the deep sea and of the Mollusca in shallow water : 

 — 54 species of Echinodermata occurring in the deep hauls, while only 18 species are present in the shallow onea 

 and 40 species of Mollusca occurring in the shallow hauls, while only 26 species are present in the deep ones. This 

 comparison has been introduced with the view of calling attention to the large number of species in these deep hauls, 

 and not with the purpose of showing that in the deep sea species are more abundant than in shallow and shore 

 regions of the ocean. Though, as already stated, it is recognised that the total number of species present in the whole 

 area of depths less than 50 fathoms all over the world is greater than in deeper water, still we have good reason for 

 believing that in high northern and high southern latitudes the reverse holds good for depths less than 25 fathoms, 

 and that there may lie a larger total number of species in deep water than quite close to the land. 



