SUGGESTIONS FOR RELIABLE HYPOTHESES 175 



higher types were developed from the lower. 1 A fact 

 it is that with the exception of forms introduced by 

 man and of such species as, like mice, bats, and seals, 

 can easily make their way from island to island, 3 no 

 other mammalian orders were found in Australia. What 

 is remarkable, however, in this connection is the circum- 

 stance that the Marsupials assume the most varied modes 

 of existence and suitable construction of the body : 

 there are flying marsupials, which resemble the flying 

 squirrel ; root and plant-eaters i.e. the Wombat 

 (similar to the Marmot) ; insect-eaters with the jaw 

 of the Sorex ( ? Shrewmouse) or Hedgehog ; Carnivora 

 for instance the marsupial Marten with the typical 

 equipment of the order of Carnivora ; springers e.g. the 

 Kangaroo (like the Steppe mice). 



All are Marsupials in other respects, however, con- 

 structed precisely like the representatives of the other 

 mammalian order, whose mode of existence they pursue. 



The significance of these facts appears close at hand. 

 The present forms, which obviously, as regards every- 

 thing connected with a quite special mode of existence, 

 are constituted to one end (einseitig), do not give the 

 impression of original animals, since these, according 



1 That the Allotheria of the Trias which are considered as being the 

 first Mammals are the ancestors of the higher orders, is in the meantime 

 a simple assumption. They are also ' unfortunately very imperfectly 

 known ' (R. Hertwig : Lehrbuch, p. 590). According to Deperet the 

 remains cannot well be otherwise considered. 



2 R. Hertwig : Lehrbuch, p. 591. The Marsupials are confined, except 

 the South American Kangaroo Rats, to Australia; earlier in the 

 Secondary and Tertiary periods they existed in Europe and North and 

 South America, 



