60 MAirUAL OF THE MOLLTJSCA. 



CHAPTEE II. 



GEOGRAPHICAL DISTRIBUTION OF THE MOLLUSCA. 



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

 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 provinces 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 application. 



The most philosophical 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 mollusca. In Dr. Sclater' s scheme the 

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

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

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

 or Western Palseotropical region, includes Africa south of the 

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

 Palaeotropical region, including Asia south of the Himalayas, 

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

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

 Palseotropical 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 ; 



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

 advantage of colours. He would recommend those who are sufficiently interested in 

 the subject to colour their own copies, distingiiishing the shores of the marine provincea 

 by the following tints :— 



Blue. 1. Arctic province ; 15. Magellanic. 



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



Ornn/je. 3. Celtic. 



Purple. 4. Lusitanian; 10. Japonic; 12. Califomian; 18. Trans- Atlantic. 



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



Lake. 7. S. African ; 9. AustralO'Zealandic ; 14. Peruvian ; 16. Patagonian. 



