SOUTHERN FAUNA. 



237 



host of congeners, one and all alien to the population 

 predominant in America, and indicating importation 

 probably in the Tertiary period; unless it be assumed, 

 with Riitimeyer, " that irnplacental mammals were cre- 

 ated out of Australia as well as in it." 



Among the first to be mentioned are the wingless 

 birds, that is, those which are anatomically and syste- 

 matically connected, and which we now find scattered 

 over continents and some of the larger islands. The 

 cassowary of New Holland and America, the extinct 

 giant birds of Madagascar and New Zealand, the 

 African ostrich, which has advanced from the south 

 northwards, cannot have originated in their present 

 isolation. The same considerations are forced upon 

 us by the mammals named Bruta by Linnaeus, and 

 by modern zoologists termed Edentata, by reason of 

 their imperfect dentition, among which, accepting the 

 latter definition, must be included the Ornithorhyncus, 

 or duck-mole of Tasmania. These duck-moles incon- 

 testibly occupy the lowest grade among the mammals 

 now extant; but the other true Edentata are no less alien 

 to the higher orders, and their occurrence in South Amer- 

 ica on the one hand, and in South Africa and South Asia 

 on the other, as well a,s the impossibility of tracing them 

 from a common centre in the northern hemisphere, points 

 to the vanished land of the south, where perhaps the 

 home of the progenitors of the Maki of Madagascar may 

 also be looked for. 



" Or," says Riitimeyer, " does the hypothesis of a 

 Polar land, once possessing an abundance of animal life, 

 partly covered by the ocean and partly by a coat of ice, 

 appear an unfounded assumption to us who now witness 



