On a new genus of Falconidaz. 69 



feathers being marked on the inner web by an abrupt emargina- 

 tion near the apex : while the tarsi also display the character of 

 the same group in having the acrotarsia reticulated. The bird thus 

 exhibits a striking modification of form, at once partaking of 

 the chief of the respective characters of both the Hawks and 

 Falcons; with the former of which it may in addition be observed 

 that it agrees in its general form, and with some of the latter, 

 particularly the beautiful group of lerax ccerulescensy in its colours, 

 and in the general distribution of them. To the latter group 

 indeed it has a striking resemblance, and might perhaps be re- 

 ferred unconditionally to it, could we pass over the important 

 character of the untoothed bill. In characterizing new forms, 

 I wish to perpetuate those names, as far as they are applicable, 

 which are preserved in classical writers. These of course should 

 be affixed to groups, to which they may be supposed to have 

 formerly applied. But there are cases where we can not hope to 

 find new forms suited to old names ; as for instance among the 

 Falconidce, where it is not likely that we shall meet with an 

 European new form to suit an ancient unappropriated raptorial 

 epithet. Here it is allowable I presume to look beyond the 

 ancient boundaries for an appropriate subject; and the bird 

 before us, although a New World species, I shall invest with an 

 Old World name. 



GAMPSONYX. 



Rostrum breve ; mandlbulis integris ; naribus rotundatis. 



AlcB breves ; remige secunda longissima, tertia secundx fere 

 aequali ; primas et secundae pogonio interno fortiter prope apicem 

 emarginato. 



Cauda mediocris, aequalis. 



Pede* mediocres; tarsis reticulatis, acrotarsiis infra genu usque 

 ad medium plumatis. 



SwAiNsoNii. G. superne cineraceo-niger, suhtus albus; f route, 

 gents, abdominis laieribus, plumisque femoralibus auraniiacis, 

 macula pectorali utrinque nigra. 

 Rostrum nigrum. Dorsi plumae, scapularesque cineraceo-^ 



nigrae, ferrugineo-maculata;. Latus mferms torquesqixe nuchalis 



