DARWIN'S WANDER-YEARS 49 



recent species; on the effect of minute individual 

 peculiarities in preserving life under special circum- 

 stances ; and on the influence of insects and blood-suck- 

 ing bats in determining the existence of the larger 

 naturalised mammals in parts of Brazil and the 

 Argentine Republic. It was the epoch of wide collec- 

 tion of facts, to be afterwards employed in brilliant 

 generalisations : the materials for the ' Origin of Species ' 

 were being slowly accumulated in the numberless 

 pigeon-holes of the Darwinian memory. 



Among the facts thus industriously gathered by 

 Darwin in the two years spent on the South American 

 coast were several curious instincts of the cuckoo-like 

 molothrus, of the owl of the Pampas, and of the 

 American ostrich. A few sentences scattered here and 

 there through this part of the ' Naturalist's Journal ' 

 may well be extracted in the present place as showing, 

 better than any mere secondhand description could do, 

 the slow germinating process of the ' Origin of Species.' 

 In speaking of the toxodon, that strange extinct South 

 American mammal, the young author remarks acutely 

 that, though in size it equalled the elephant and the 

 megatherium, the structure of its teeth shows it to be 

 closely allied to the ruminants, while several other 

 details link it to the pachyderms, and its aquatic 

 peculiarities of ear and nostril approximate it rather 

 to the manatee and the dugong. 'How wonder- 

 fully,' he says, { are the different orders, at the present 

 time so well separated, blended together in different 

 points of the structure of the toxodon.' We now 

 know that unspecialised ancestral forms always display 

 this close union of peculiarities afterwards separately 



