THE MOLLUSCA OF TOEEES STEAITS. 151 



The whole of this area is contained witliia the great Indo-Pacific 

 Marine Province, as proposed by S. P. "Woodward, 185G, though 

 the merging of that Province with the Australian is, speaking from 

 the molluscan point of view, hazily defined only and, naturally, 

 gradual. This Province is the largest by far, and likewise the 

 most prolific in marine life of all, and though almost unwieldy, 

 it should nevertheless, in our opinion, be still further extended 

 so as to iuclude Southern Japan, treated by Woodward and all 

 who have followed him, as well as by Agassiz, as part of a 

 separate region. The Indo-Pacific Province would then extend 

 from the East coast of Africa, north of the Tropic of Capricorn, 

 to the lied Sea, Persian Grulf, and Arabian Sea, round the whole 

 coasts of India and its adjacent islands, southwards so as to 

 include Madagascar, Mauritius, Bourbon, to Malaya, the Ea::*t 

 India Islands, and China coasts as far as, and inclusive of. 

 Southern Japan, also taking in tropical Australia, and finally the 

 Pacific Islands with Hawaii. Though so vast, we cannot see how 

 with advantage this tract can be lessened or modified ; and one 

 is strengthened in this view when the distribution of many of 

 the tropical Marine Mollusca is considered. The range, for 

 instance, of the most abundant, e. g., Cyprcsa helvola, L., Nassa 

 arcularia, L., or Terebellum suhulatum, L., being that of the 

 Province, even extending beyond its limits into the subtroj)ical 

 waters of Natal, or of Queensland and New South Wales. 



Many of the species in the following Catalogue have this 

 wide distribution ; and with reference to this fascinating subject, 

 it may be not out of place to refer briefly to the instructive 

 remarks made by Prof. E. von Martens, when enumeratino- 

 the Mollusca of the Mergui Archipelago *, a few years since. 

 He mentions that out of nearly four hundred specie?», only 

 one (^Natica unifasciata, Lam.) was known to have occurred 

 in the New World, besides three, also found on Atlantic shores, 

 and even these were species liable to spread by means of drift- 

 wood and other agencies. 



There can be little doubt that an unusually large number 

 of endemic foims occur in the region bounded north-westward 

 and noithward by the Philippines and Ladrone Islands, west- 

 ward and to the east by the Arafura Sea and New Caledonian 

 archipelago respectively, the Torres Straits forming part of its 

 southernmost boundary. 



* Journ. Linn. Soc, Zool. vol. xxi. p. 157 (1889). 



