T,6S INDO-PACIFIC REGION chap. 



discovered off Kerguelen are Neohuccinuvi and a sub-genus of 

 ^S';^?^ uthiolaria {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 Eed 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 Eiver in the west, and to 

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

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

 Mollusca, and which are entirely absent from the Atlantic 

 Eegion. 



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

 whole of this region except that part defined below as the 

 Japanese 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 Eed Sea 

 species at about 1000. Some prominent genera are very rich in 

 species. Garrett enumerates from Polynesia 8 1 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 

 Elur7ia. 



The following important genera are quite peculiar to the 

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

 Magilus, Bapa, Mclapium, and Bicinula ; Tudicla, several forms 

 of Strombidae, e.g. Bostellaria, Terehellum, Pteroceras, and Bimella ; 

 Clthara, Melo, Neritopsis, Stomatia, Malleus, Vulsella, Cucullaea, 

 Tridacna, Hippopus, LiUtina, Ghmcomya, Anatina, Aspergillum, 

 and many others. 



The number of species common to the Eed Sea and 

 Mediterranean is exceedingly small, some authorities even deny- 

 ing the existence of a single common species. The present 



