STRUCTURE AND GEOGRAPHICAL DISTRIBUTION. 59 



(Anas Penelope and A. americana,) or the American 

 and the European Ked- headed Ducks, (A. ferina 

 and A, eryihrocephala,) which inhabit respectively the 

 northern parts of the Old and New World in summer, 

 and migrate further south in these same continents dur- 

 ing winter; while the Mallard (A. Boschas) and the Scaup 

 Duck (A. mar Ha) are as common in North America as in 

 Europe. What do these facts tell 1 That all these birds 

 originated together somewhere where they no longer occur, 

 and established themselves in the end within the limits 

 which they now occupy ? or, that they originated either in 

 Europe or America, where, it is true, they do not live all 

 together, but only a part of them ? or, that they really origin- 

 ated within the natural boundaries which they now occupy? 

 I suppose with sensible readers I need only follow out the 

 conclusions flowing from the last supposition. If so, the 

 American Widgeon and the American Red-headed Duck 



o 



originated in America, and the European Widgeon and 

 the European Red-headed Duck in Europe. But what of 

 the Mallard and the Scaup, which are equally common 

 upon the two continents 1 Did they first appear in Eu- 

 rope, or in America, or simultaneously upon the two con- 

 tinents ? Without entering into further details, as I 

 have only desired to lay clearly a distinct case before my 

 readers, from which the character of the argument, which 

 applies to the whole animal kingdom, may be fully 

 understood, I say that facts lead, step by step, to the 

 inference, that such birds as the Mallard and the Scaup 

 originated simultaneously and separately in Europe and 

 in America ; and that all animals originated in vast num- 

 bers, indeed, in the average number characteristic of their 

 species, over the whole of their geographical area, whether 

 its surface be continuous, or disconnected by sea, lakes, or 



