Sclatter in 1857 recognised six zoogeographical regions on the basis of the distribution of terrestrial vertebrates, chiefly mammals. (i) The Palaearctic region (ii) The Ethiopian region (iii) The Indian region (Oriental) (iv) The Australian region (v) The Neotropical region (vi) The Neoarctic region The Palaearctic region includes the whole northern part of the Old World, i.e. whole of Europe, northern part of Africa and Asia, North of the Himalayas. Oriental region includes the whole of India, Ceylon, South China, Burma, Thailand, Malaya of Peninsula, Malayan Islands. The Palaearctic and Oriental regions are separated by Himalayan range.