On the Groups of the Falconidce. SI 9 



d'Arneriqvie of M. Buffon.* I believe this species still stands sin- 

 gle in the genus. 



Closely allied to Ibycter appears 



Daptrius, Vleill. 



founded upon a new species from Brazil, which the same authour 

 has denominated D. ater, and which he describes as differing from 

 the last only in the lower mandible being obtuse, instead of pointed, 

 and the cere being covered with hairs instead of being smooth. He 

 particularizes also the orbits of the eyes only, and not the cheeks, 

 as being naked, together with the throat and crop. It has been 

 frequently objected to M. Vieillot's views of arrangement, that he 

 founds his genera upon very minute and unimportant points of dis- 

 tinction. Although strongly inclined to the admission of all such 

 genera as are founded upon ostensible characters, for reasons which 

 I have stated at large elseAvhere+, especially in such groups as from 

 their extent require subdivision, I am nevertheless of opinion that 

 great caution should be observed in introducing genera, which em- 

 brace but one species ; such only being admissible as are decidedly 

 separated by inriportant characters. One great object aimed at in 

 the subdivision of a numerous group is the relief which is afforded 

 the student in his search after species, by the number of those 

 belonging to each genus being lessened. But no such relief is 

 gained where only a single species is cut off from the original 

 group, the points of examination being still the same in number ; 

 the examination of a new generick character being substituted for 

 that of the original specifick one. How far the two preceding genera 

 of M. Vieillot are sufficiently distinct from each other, or from the 

 remainder of the naked-cheeked Eagles it is not for me to hazard 

 an opinion, without the opportunity of more accurate examination 

 of the birds than is at present within our power, and a more perfect 

 knowledge of them, than a mere description affords us. It would 

 appear however that one group, at least, that of IbydeVy is suffi- 

 ciently distinguished from the other Falcomdce with the naked 

 cheeks, by the difference in its food and habits. The accounts 



* PI. Enl. 417. Gal. des Ois. pi. 6. 

 + Zool. Journal, No. II. p. 180. 



