60 MANTJAL OF THE MOLLUSC A. 



CHAPTER II. 



GEOGRAPHICAL DISTRIBUTION OF THE MOLLTJSCA. 



It is one of the most familiar facts in Natural History tliat 

 many countries possess a distinct Fauna and Flora, or assem- 

 blages of animals and plants peculiar to themselves ; and it is 

 equally true, though less generally understood, that the sea 

 also has its proyinces of animal and vegetable life. 



The most important or best known of these provinces are 

 indicated on the accompanying map ; different names, in some 

 instances, and different letters and numbers, being employed to 

 distinguish the marine from the terrestrial regions.* 



The division of the surface of the globe into natural history 

 provinces ought to be framed upon the widest possible basis. 

 The geographical distribution of every class of animals and 

 plants should be considered in order to arrive at a theory of 

 universal ajoplication. 



The most i:)hilosophical division of the globe into natural 

 provinces has been by Swainson in 1835, and by Dr. Sclater in 

 1857. The last has been adopted by several naturalists. It was 

 based upon a consideration of the distribution of birds, and has 

 been extended to fishes and amphibia by Dr. Giinther. It 

 might be extended to moUusca. In Dr. Sclater's scheme the 

 world is divided into six regions, viz. (1) Palcearctic region: 

 this comprises Europe, North Africa, Asia Minor, Persia, Asia 

 north of the Himalayas, North China, and Japan ; (2) Ethiopian 

 or Western Palteotropical region, includes Africa south of the 

 Atlas, Madagascar, Mascarene, Arabia ; (3) Indian or Middle 

 Paleeotropical region, including Asia south of the Himalayas, 

 Ceylon, Burmah, Malacca, Southern China, Philippines, Borneo, 

 Java, Sumatra, and adjacent islands; (4) Australian or Western 

 Palasotropical region : Australia, New Guinea, New Zealand, 

 and the Pacific Islands ; (5) Nearctic or North American region : 

 Greenland, and North America as far as the centre of Mexico ; 



* The author regrets that, on account of the expense, this map appears without tlie 

 .■advantage of coloui's. He would recommend those who are sufficiently interested in 

 the subject to colour then- own copies, distinguishing the sliores of the marine provmces 

 bj' the following tints : — 



Blue. 1. Arctic province ; 15. Magellanic. 



Green. 2. Boreal ; 11. Aleutian ; 5. Aralo-Caspian. 



Orange. 3. Celtic. 



Purple. 4. Lusitanian ; 10. Japonic; 12. Calilornian; iS. iTans-Aaanac. 



Yellow. 6. W.African; 8. Indo-Pacific ; 13. Panamic ; 17. Caribbean. 



Ixike. 7. S.African; 9. Australo-Zealandic ; 14. Peruvian; 16. Patagonian. 



I 



