548 



PROCEEDINGS OP THE ACADEMY OF 



mere pierre-garin," Buffon and French authors. " Gemeine, oder Rothfiissiger 

 Meerschwalbe," Bechstein, Meyer and German authors. " Wilson's Tern," 

 Bonaparte, and most later American authors. 



Habitat. — Sea Coasts of Europe, part of Asia and America, ascending rivers 

 and bays to a considerable distance. 



This species has been so long known that any description of its characters, 

 or changes of plumage are unnecessary. Temminck says that the adults in 

 winter do not lose the black of the crown, "£lle est seulement plus terne." If 

 this be so, the species forms an exception to the general rule among Terns, 

 that at this season the front becomes nearly white, the crown variegated with, 

 black and white, or the black still further reduced to a circumocular fascia. 



Comparisons of this species with S. Forsteri and macroura, its most intimate 

 allies, will be found under the head of the former. 



The common Terns of Europe and America were considered identical by all 

 writers up to the year 1838. At that date they were separated by Bonaparte ; 

 and American authors, with the exception of Audubon, have generally followed 

 his example. I am little pleased to be obliged to refer to a European species, 

 an American bird which has been judged distinct by high authority, but such 

 a procedure seems unavoidable in the present instance. I am not aware that 

 any distinctive characters have ever been assigned to our bird. Bonaparte, in 

 instituting the species, gives no description, as, indeed, is the case with several 

 other species founded in the same work, with regard to which he appears to 

 have relied, for means of separating them from their European allies, rather 

 upon some theory of geographical distribution, than upon any discrepancies 

 presented by the birds themselves. 1 have very carefully compared a series of 

 skins from both continents, and neither in size, form or color, have I been able 

 to detect the slightest differences ; and consequently, until some one is more 

 fortunate than myself in detecting valid specific characters, I must refer the 

 American bird to the old Linnagan 5'. hirundo. 



Below are offered the detailed measurements of five American and European 

 birds, taken at random from a large series. It; will be observed that in no re- 

 spect do the dimensions of the birds from the two continents present greater 

 differences than are found in the various examples from either. 



^ A. — S. hirundo ex Europd. 



B. — S. hirundo ex America. 



* Inches and hundredths. 



[Dec. 



