43 2 MANUAL OF ZOOLOGY. 



consists of a femur, a tibia and fibula, a tarsus, metatarsus, 

 and phalanges ; but some of these parts are considerably ob- 

 scured by anchylosis. The femur or thigh-bone (fig. 170, A, /) 

 is generally very short, comparatively speaking. The chief 



Fig. 170. A, Hind-limb of the Loon (Colytttbus glacialis) after Owen : i Innominate 

 bone ; f Thigh-bone or femur ; / Tibia, with the proximal portion of the tarsus an- 

 chylpsed to its lower end ; r Fibula ; m Tarso-metatarsus, consisting of the distal 

 portion of the tarsus anchylosed with the metatarsus ; f / Phalanges of the toes. B, 

 Tail of the Golden Eagle : s Ploughshare-bone, carrying the great tail-feathers. 



bone of the leg is the tibia (/), to which a thin and tapering 

 fibula (r) is anchylosed. The upper end of the fibula, how- 

 ever, articulates with the external condyle of the femur. The 

 ankle-joint is placed, as in Reptiles, between the proximal and 

 distal portions of the tarsus. The proximal portion of the 

 tarsus is undistinguishably amalgamated with the lower end of 

 the tibia. The distal portion of the tarsus is anchylosed with 

 the whole of the metatarsus to constitute the most characteristic 

 bone in the leg of the Bird the " tarso-metatarsus " (m). In 

 most of the long-legged birds, such as the waders, the dispro- 

 portionate length of the leg is given by an extraordinary elon- 

 gation of the tarso-metatarsus. 



