A large area in Indonesia is named Wallacea after Wallace, but where did this word originate? According to Ernst Mayer (1944) the term was coined by Dickerson et al. in 1928. Wallacea is a biogeographical transition zone between the Australian region to the east, and the Oriental region to the west.
The mammals of the Australian region are mostly marsupials (e.g. kangeroos and cuscus), whilst the Oriental region only has placental mammals (like tigers, elephants and rhinos). The islands in Wallacea contain a mix of Australian and Oriental animals. For more information see http://en.wikipedia.org/wiki/Wallacea
Wallacea, the heart of Indonesia. It encompasses islands which never had dry land connections to the main land masses of either the Australian region or the Oriental region. Consequently it has few animals which find it difficult to cross stretches of open ocean (e.g. land mammals, land birds, or freshwater fish of continental origin). [From Wikipedia]
Dickerson, R. E., Merrill, E. D., McGregor, R. C., Schultze, W., Taylor, E. H. & Herre, A. W. C. T. 1928. Distribution of life in the Philippines. Philippine Bureau of Science [Manila], Monograph No. 21: 322 pp.
Mayr, E. 1944. Wallace's Line in the light of recent zoogeographic studies. The Quarterly Review of Biology, 19(1): 1-14.