30 



ISLAND LIFE 



PART I 



the Andes ; and the birds-of-paradise, consisting of nine- 

 teen or twenty genera and about thirty-five species, almost 

 all inhabitants of New Guinea and the immediately 

 surrounding islands, while a few, doubtfully belonging to 

 the family, extend to East Australia. Among reptiles the 

 most striking case of restriction is that of the rough-tailed 

 burrowing snakes (Uropeltidse), the five genera and 

 eighteen species being strictly confined to Ceylon and the 

 southern parts of the Indian Peninsula. 



The Disirihttion of Orders. — When we pass to the larger 

 groups, termed orders, comprising several families, we find 

 comparatively few cases of restriction and many of world- 

 wide distribution ; and the families of which they are 

 composed are strictly comparable to the genera of which 

 families are composed, inasmuch as they present examples 

 of overlapping, or conterminous, or isolated areas, though 

 the latter are comparatively rare. Among mammalia the 

 Insectivora offer the best example of an order, several of 

 whose families inhabit areas more or less isolated from the 

 rest ; while the Marsupialia have six families in Australia, 

 and one, the opossums, far off in America. 



Perhaps, more important is the limitation of some entire 

 orders to certain well-defined portions of the globe. Thus 

 the Proboscidea, comprising the single family and genus of 

 the elephants, and the Hyracoidea, that of the Hyrax or 

 Syrian coney, are confined to parts of Africa and Asia ; 

 the Marsupials to Australia and America ; and the 

 Monotremata, the lowest of all mammals — comprising the 

 duck-billed Platypus and the spiny Echidna, to Australia 

 and New Guinea. Among birds the Struthiones or ostrich 

 tribe are almost confined to the three Southern continents, 

 South America, Africa and Australia ; and among 

 Amphibia the tailed Batrachia — the newts and 

 salamanders — are similarly restricted to the northern 

 hemisphere. 



These various facts will receive their explanation in a 

 future chapter. 



