304 ZOOLOGICAL GARDENS. 



appearance. In the latter respect, as well as in several 

 of their technical characters, they are truly vulturine ; 

 while in many points of structure, in their air, and in 

 their habits, they seem to approach more nearly to 

 the Eagles, and especially to the genus Morphnus of 

 M. Cuvier. 



Although we have for the present referred these 

 birds to the genus Polyborus, we are not by any means 

 disposed to consider them as actually forming part of 

 that group. We are rather inclined to believe that 

 they will hereafter be found to be typical of another 

 nearly allied subdivision, which, however, we do not 

 conceive ourselves entitled to establish upon the mere 

 inspection of the living birds. They present, as far 

 as we have yet been able to examine them, the following 

 generic characters. Their beak is deep, elongated, and 

 nearly similar in form to that of the Caracara, but 

 much more compressed or flattened at the sides ; its 

 upper surface is arched for the greater part of its length, 

 the extreme point terminating considerably below the 

 extremity of the lower mandible, which is embraced 

 within it, and the opening being long, straight, and 

 without dentation. The nostrils are placed transversely 

 near the fore part of the naked cere, and are long-oval 

 in their form ; instead of being, as in the Caracara, 

 removed to near the upper edge of the beak, sloping 

 obliquely downwards and forwards, and having the 

 appearance of an iri'egular slit. The naked space of 

 the cheeks is less extensive, and less defined at its 

 edges, but entirely surrounds the eyes, which are placed 

 in both birds almost on a level with the general surface 

 of the head. In the birds now under consideration the 

 head is narrower and less flattened above, and the neck 

 more elongated ; both which circumstances, as well as 

 the somewhat downy character of the feathers by which 

 these parts are covered, tend to increase their resem- 



