454 ON THE MEALY LINNET. 



and Europe. Should there be any, however, still disposed to regard these as 

 mere varieties superinduced by the long-continued influence of external cir- 

 cumstances, we have only to recede another step, and place in juxta-position 

 - the Buboes, Woodcocks, and Bitterns, of the two Continents ; and after them 

 any two species of the same genus, however dissimilar, and whether inhabiting 

 different or the same localities. Or the (Jttestion may be fairly propounded, how 

 the European Sparrow Hawk comes to be represented by more than one closely- 

 allied species in the corresponding latitude of America, and the Kestril of that 

 continent by more than one analogous species in Europe ? — But as no one, in 

 fact, now hesitates to admit all the above-named species as really distinct — inas- 

 much as the contrary opinion is quite untenable — we may forthwith proceed to 

 the other extremity of the scale, and examine the claims of more intricately 

 approximate races to be ranked as species. 



The remarkable parallelism subsisting between a large proportion of the 

 American and European birds is too obvious to have escaped the notice of the 

 most cursory observer. It obtains, less or more, throughout every group which 

 is common to the two continents ; and abounds in instances tending to support 

 the theory for which I contend. Thus, of twelve transatlantic species pertain- 

 ing to the typical primary division of the Ardeidce, or Heron family, corresponding 

 to the genus Ardea, as defined by Temminck, six are represented by as many 

 analogous races in Europe, and may be opposed to them, commencing with the 

 most diverse ; those on the left being the European species, and the right their 

 American representatives. 



Botaurus stellaris. B. lentiginosus. 



Ardea cinerea. A. herodias. 



Ardeola minuta. A. exilis. 



Egretta garzetta. E. candidissima. 



Egretta alba. E. leuca. 



Nycticorax Gardenii. N. Gardenii ? 



Of the remaining species, the elegant European Purple Heron (Ardea purpurea) 

 can only, as belonging to the same restricted genus, be opposed to the magnificent 

 White Heron (A. occidentalis) : and the abnormally structured Egretta russata 

 and E. ralloides to the two dark-plumaged Egrets E. ccerulea and E. rvfescens ; 

 though the former also deviate from the pure unsullied white adult garb which 

 distinguishes the numerous typical representatives of the subdivision to which 

 they pertain. The fauna of Europe is deficient in species to counterbalance the 

 Ardea (?) virescens, Egretta (?) Ludoviciana, and aberrant Nycticorax violacea, 

 — of which the last-mentioned, as also the Bittern of America, have been met 

 with in England, wherefore the occurrence of a solitary instance or so of Nycti- 

 corax Gardenii (?) of the American dimensions (to be presently noticed) on this 



