184 Mr. Yarrell on the Anatomi/ of Birds of Prey. 



their feathers, are triangular in form, broad at the shoulders and 

 tapering gradually to the tail, the muscles of the thighs and legs 

 of great size; but these characters are less prominent in the hawks, 

 the bodies of which are more lengthened, the legs long and 

 slender, the pectoral muscles smaller, the wing rounded in form, 

 the fourth feather the longest, the wing primaries broad in the 

 middle, the inner webs overlapping the feather next in succession, 

 and emarginated towards the end. These two divisions of the 

 genus FalcOf although the latter are unequal to the former in 

 powers, are remarkable for their bold character and rapid flight, 

 their invariable mode of striking their prey on the wing, as well 

 as the instinctive knowledge by which they are directed to de- 

 stroy life, attacking the most vital part, and penetrating the brain 

 ■with their sharp hooked beak, either by one of the orbits where the 

 bone is very thin, or at the junction of the cervical vertebrae with 

 the occiput. 



On comparing the bones of our two British Eagles, the greater 

 power of flight appears to belong to the Jlhicilla, that of prehen- 

 sion to the Golden Eagle, but both exhibit various indications of 

 great strength. 



By an extended examination of the different species of Buzzards 

 and Harriers, it will be found, that the characters described as 

 necessary to produce rapid motion, decline gradually. The ster- 

 num decreases in size, the keel loses part of its depth, the clavicles 

 and furcula become more slight, while tlie form of the cranium, 

 the loose ruflled feathers of the neck, as well as the general downy 

 texture of the plumage, indicate the approach to the genus next in 

 succession. Of the bones of the different species of the genus 

 Falcoj generally, it may be added, that they are remarkable for 

 their strength, such as are cylindrical being furnished with nume- 

 rous transverse bony processes within the tubes, and the distribu- 

 tion of air throughout their internal cavities. The humerus is 

 supplied with air through several orifices upon its inner and upper 

 surface, and some difference will be found in the angle at which 

 this bone is articulated with the clavicle to accomplish the ascend- 

 ing flight of the skylark, in contradistinction to the precipitous 

 horizontal direction of the Falcons. The thigh bone is also sup- 



