336 strigintE. 



Beyond this membrane it is not our business at present 

 to penetrate. 



In the eagles and hawks generally, the structure is 

 similar, the form of the external aperture varying from 

 oblong to circular. Thus, in the peregrine falcon and 

 sparrow hawk, the same parts are seen, the external 

 rim being merely thinner. Among ^^^ 

 these birds, however, there is a group ^^J^^ ^^^ 

 which exhibits a decided diflFerence /^TTcN. 

 in the appearance of the parts. The common har- 

 rier, Circus cyaneus, which presents so great a re- 

 semblance to the owls, as already mentioned, has the 

 external ear of an oblong form, and very large size, 

 compared with that of other hawks. It is about half 



an inch in length, and beset round the thin edges with 

 slender recurved feathers. It is divided in a manner 

 longitudinally into two portions by a process of the oc- 

 cipital bone covered with skin, its anterior part being 

 sunk, and exhibiting a longitudinal slit four-twelfths of 

 an inch long, which is the opening of the meatus. 

 From its inferior margin proceeds downwards and for- 

 wards to the base of the lower jaw a narrow curved 

 space of bare skin, more than half an inch long ; along 



