10 
In the Journal of the Linnzean Society, Zoology, Vol. xii, (1874-76) the 
same author gives (p. 108) a list of shore-fishes common to the West Indies, 
the Mediterranean, and Japan. 
Again, Dr. Gwyn Jeffreys in the same Journal of the Linnean Society, 
pp. 100-107, gives a list of 1 Brachiopod and 88 Mollusks, both littoral and 
bathybial, that are common to Japan and the North Atlantic (including the 
Mediterranean Sea). These are exclusive of several species noted by other 
authors, and quoted in the said paper, as common to the two regions. Dr. Gwyn 
Jeffreys, however, seems to think that some of the species may have reached 
these two remote regions from a common arctic centre of distribution. 
In his Report on the “Challenger” Cephalopoda, p. 224, Mr. W. E. 
Hoyle makes special mention of the occurrence of a Mediterranean species in 
the Malay Archipelago and Pacific, and briefly refers to the possibility of a 
former connexion between the Mediterranean Sea and the Indian Ocean. 
Finally, the Geographical Distribution Chapters and Tables of the 
“Challenger” Reports are very instructive in this connexion, especially the Table 
of the Geographical Distribution of the Lchinoidea, by Professor A. Agassiz. 
It appears to me that our facts do necessitate the existence of a direct and 
open-sea connexion between the West Indian Seas—by way of the islands of the 
North Atlantic, and the Mediterranean—and the Indian Ocean, since the advent 
of Flabellum laciniatum and Caryophyllia communis; and that the analogy of 
the Alpine floras may fairly be used to explain the occurrence, under similar 
conditions, of identical species in seas so remote as those of the West Indies 
and Andamans. In other words, the corresponding species from the Hast and 
West Indies may be regarded as the remnant—preserved under corresponding 
conditions—of the fauna of the single old sea basin, or series of basins of geologi- 
cal speculation. 
But, apart from other possible explanations of the occurrence of this large 
proportion of Atlantic deep species in the Indian Seas, the correctness of our 
identifications of species may be questioned. 
It is therefore necessary to state that the Hexactinellid sponges, including 
those mentioned in the foregoing lists, were identified by Professor F. E. 
Schulze, the Ophiuroidea by Professor R. Koehler, the Mollusca (exclusive of 
Cephalopoda) by Mr, Edgar Smith, and the Cephalopoda by Mr. E. 8. Goodrich ; 
the Holothuroidea by Dr. J. H. Tull Walsh; the Echinoidea and Crustacea by 
the late Professor J. Wood-Mason, Dr. A. R. Anderson (the present Naturalist 
to the Survey) and myself; and the Corals, Asteroidea and Fishes by myself. 
As regards my own identifications, five are based on comparisons of speci- 
mens from both the regions in question and three more on “ Challenger” 
duplicates from the localities mentioned in Tables IV-VI: the others depend 
upon figures and descriptions. 
