10 



In the Journal of the Linnaean 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 Linnrean Society, 

 pp. 100-107, gives a list of 1 Brachiopod and 38 Mollusks, hoth 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. G\vyu 

 Jeffreys, however, seems to think that some of the species may have readied 

 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 Echinoidea, 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 byway of the islands of the 

 North Atlantic, and the Mediterranean and the Indian Ocean, since the advent 

 of Flabellum laciniatum and Garyopliyllia 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 East 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. 

 Scbulze, the Ophiuroidea by Professor R. Koehler, the Mollusca (exclusive of 

 Cephalopoda) by Mr. Edgar Smith, and the Cephalopoda by Mr. E. S. 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. 



