XII JAPANESE SUB-REGION — AUSTRALIAN REGION 369 



author, from an examination of the shells dredged by Mac- 

 Andrew at Suez, regarded 17 species as common, and Mr. E. A. 

 Smith has confirmed this view with regard to 8 of the species in 

 question.^ The MoUusca occurring in Post-pliocene beds at Suez 

 show that Mediterranean species lived there in comparatively 

 recent creological times. 



The opening of the Suez Canal appears to have already 

 induced several species to start on their travels from the Mediter- 

 ranean to the Eed Sea and vice versd. Two Ked Sea species 

 {Mactra olorina Phil., Ifytilus variabilis Kr.) had in 1882 estab- 

 lished themselves at Port Said, while two Mediterranean species 

 (Fholas dactylus L., Solen vagina L.) had reached Ismailia.- 



(2) The Japanese Sub-region consists of the Japanese Islands to 

 Niphon, together with Corea and a stretch of adjacent mainland 

 coast of unknown extent. The warm Kuro Siwo current, sweep- 

 ing up between Luzon and Formosa, permits tropical species to 

 extend much farther north than on the opposite shores of America, 

 where a cold polar current keeps them back. A certain number 

 of species, however, are common to the two shores of the Pacific, 

 and a few circumpolar species occurring on our own coasts reach 

 Japan, e.g. Trophon clatliratus, Puncturella noachina, Mya arenaria, 

 Modiola modiolus, Lasaea rubra, and Nueula tenuis. 



Among the characteristic genera are Fusus, Siphonalia, Colum- 

 barium, Hemif'usus, Bapana, Chlorostoma, Pleurotomaria, Haliotis, 

 and Cyclina. 



C. The Australian Region 



includes the Australian coast-line from about Swan R.^ (lat. 

 32° S.) to Sandy Cape (lat. 25° S.), Tasmania, New Zealand, and 

 the adjacent islands (except Lord Howe's I.). 



(1) Tlie Australian Sub-region proper (wliich consists of the 



1 A. H. Cooke, Ann. Mag. Nat. Hist. (5) xviii. (1886) p. 380 f ; E. A. Smitli, 

 P. Z. S. 1891, p. 391 f. 



^ C. Keller, Neuc Denksch. Schw. Gesell. xxviii. 1883, pt. 3. 



^ According to Tate {Trans. Roy. Soc. S. Austr. 1887-88, p. 70), 'Australian' 

 species predominate at Freemantlc (32°), but Tenison-Woods (/. Roy. Soc. N. S. Wales, 

 xxii. p. 106) holds that the tropical fauna extends as far south as Cape Leeuwin (34"), 

 and that the Australian forms are not predominant until the extreme south. 

 Tenison-Woods regards Cape Byron (31°) as the limit of the tropical fauna on the 

 east coast, while some characteristic tropical genera reach Port Jackson, and a few 

 (e.g. Cypraea annulus) Tasmania. 



VOL. Ill 2 B 



