chap, xiii.] THE AUSTRALIAN REGION. 391 



Marsupialia and Monotremata, found nowhere else on the globe 

 except a single family of the former in America. The Marsu- 

 pials are wonderfully developed in Australia, where they exist 

 in the most diversified forms, adapted to different modes of life. 

 Some are carnivorous, some herbivorous ; some arboreal, others 

 terrestrial. There are insect-eaters, root-gnawers, fruit-eaters, 

 honey-eaters, leaf or grass-feeders. Some resemble wolves, 

 others marmots, weasels, squirrels, flying squirrels, dormice or 

 jerboas. They are classed in six distinct families, comprising 

 about thirty genera, and subserve most of the purposes in the 

 economy of nature, fulfilled in other parts of the world by very 

 different groups ; yet they all possess common peculiarities of 

 structure and habits which show that they are members of 

 one stock, and have no real affinity with the Old-World forms 

 which they often outwardly resemble. 



The other order, Monotremata, is only represented by two rare 

 and very remarkable forms, Ornithorliynchus and Echidna, pro- 

 bably the descendants of some of those earlier developments of 

 mammalian life which in every other part of the globe have long 

 been extinct. 



The bats of Australia all belong to Old- World genera and 

 possess no features of special interest, a result of the wandering 

 habits of these aerial mammals. The Eodents are more interest- 

 ing. They are all more or less modified forms of mice or rats. 

 Some belong to the widely distributed genus Mus, others to four 

 allied genera, which may be all modifications of some common 

 Old- World form. They spread all over Australia, and allied 

 species occur in Celebes and the Papuan Islands; so that al- 

 though not yet known from the Moluccas, there can be little 

 doubt that some of them exist there. 



Birds. — The typical Australian region, as above defined, is 

 almost as well characterized by its birds, as by its mammalia ; 

 but in this case the deficiencies are less conspicuous, while the 

 peculiar and characteristic families are numerous and important. 

 The most marked deficiency as regards wide-spread families, is 

 the total absence of Fringillidre (true finches), Picidse (wood- 

 peckers), Vulturidse (vultures), and Phasianidae (pheasants) 



