18 THE MAMMALIA. 



form, that is, upon the inexplicable sovereignty of 

 the idea of type. Even though parallel groups 

 s;;di as the repetition of different orders of the 

 Mammalia within the group of Marsupials, the 

 repetition of the habitus of the Bodents in the 



tivnra were observed and discussed, still the 

 ("uteuted zoologist did no more than enter these 

 observations into his hook; and remarks such as 

 those made by Goethe and d' Alton remained with- 

 out result. What position Darwin took as regards 

 the idea of convergence, has already been stated. 

 His school, too, endeavoured at first to account for 

 the homologies exclusively by inheritance, and, on 

 the other hand, regarded the effects of adaptation 

 almost wholly as differentiation. Even that 



mely interesting adaptation as a means 

 of defence mimicry and, moreover, the ease 

 win -re the species in danger finds immunity and 

 protection in feigning a resemblance with the 

 species not endangered, did not lead to any 

 generalisation of the- inquiry. Still, some striking 

 phenomena of convergence were observed, and 

 <>tln-r> that had long since been known, but not 

 carefully considered, were inquired into more 

 particularly. Among these is Fritz Mailer's 

 admirable analysis of the arrangement by which 



