368 INDO-PACIFIC REGION chap. 



discovered off Kerguelen are Neohuecinum and a sub-genus of 

 Struthiolaria (^Perissodonta) . 



B. The Indo-Pacific Region 



includes the whole of the coast-line of the Indian and western 

 Pacific oceans, from about East London in South Africa to the 

 north of Niphon (lat. 42°) in Japan, with the Red Sea and Persian 

 Gulf, the whole of the Indo-Malay Archipelago, Polynesia to the 

 Sandwich Islands in the north-east, and Easter Island in the 

 south-east, and Australia to Swan River in the west, and to 

 Sandy Cape and Lord Howe's Island in the east. It is especially 

 the resfion of coral reefs, which furnish so favourite a home of 

 the Mollusca, and which are entirely absent from the Atlantic 

 Region. 



(1) The Indo-Pacific Suh-region proper (which includes the 

 whole of this region except that part defined below as the Jap- 

 anese Sub-region) is by far the richest in the world. The 

 marine Mollusca of the Philippines alone (in some respects the 

 nucleus of the whole region) have been estimated at between 

 5000 and 6000 species, and Jousseaume estimates Red Sea 

 species at about 1000. Some prominent genera are very rich 

 in species. Garrett enumerates from Polynesia 81 species of 

 Conus^ 60 of which occur on the Viti Is., 21 on the Sandwich 

 Is., and only 14 on the Marquesas, where coral reefs are almost 

 absent; 82 species of Cypraea^ Viti Is. 44, Sandwich Is. 31, 

 Marquesas only 13 ; 167 species of Mitra (besides 29 recorded 

 by others), Viti Is. 120, Sandwich Is. 36, Marquesas 7. Of 50 

 existing species of Stromhus^ 39 occur in this region, and 10 out 

 of 11 JEburna. 



The following important genera are quite peculiar to the 

 region: Nautilus^ several forms of Purpuridae, e.g. Rapana^ 

 Magilus^ Rapa., Melapiiim^ and Ricinula ; Tudicla^ several forms 

 of Strombidae, e.g. Rostellaria^ Terebellum, Pteroceras, and 

 Rimella ; Cithara^ 31eIo, Neritopsis^ Stomatia^ Malleus^ Vulsella^ 

 Cucullaea^ Tridacna^ Hippopus^ Libit ina, Glaucomya^ Anatina, 

 Aspergillum^ and many others. 



The number of species common to the Red Sea and 

 Mediterranean is exceedingly small, some authorities even deny- 

 ing the existence of a single common species. The present 



