CH. l] DISTRIBUTION OF TORTOISES. 39 



range. The Testudinse is by far the largest family of the 

 Chelonia ; Mr Boulenger divides it into 20 genera, 

 containing between them 113 species which are cos- 

 mopolitan with the exception of Australia and Papuasia. 

 Eleven of these genera are Oriental in distribution. 

 Three are American only. One, Pixys, is confined to 

 Madagascar. Two are confined to Tropical and Southern 

 Africa. Three have a wide range over both the Old and 

 the New World ; among these is the genus Testudo which 

 includes the gigantic tortoises of the Galapagos and the 

 Mascarene islands. The last family is exclusively marine 

 and may therefore be left out of consideration. 



The Pleurodira contains, as already said, three families. 



The Pelomedusa^ have a curious distribution ; its three 

 genera, Sternothwrns, P el o medusa, and Podocnemis being 

 found respectively in Tropical Africa and Madagascar, 

 Africa and Madagascar, South America and Madagascar. 



The family Chelydida3 contains eight genera. Of these 

 five are South American ; two range through Australia and 

 New Guinea, while one, Elsei/a, is only Australian. The 

 family Carettochelydida3 contains but a single genus 

 and species found only in the Fly river in New Guinea. 



The Trionychoidea includes only one family which is 

 made up of six genera. Of these three are East Indian, 

 two tropical African, while the remaining genus Trionyx 

 ranges through Africa, Asia and North America. 



It is obvious from the above summary which I have 

 made complete, owing to the advantage of having 

 Mr Boulenger's list, that South America is the principal 

 home of the land and fresh-water tortoises. The American 



