152 



ANIMAL BIOLOGY 



toes, the 

 joints ; 



The pigeon has 



hind toe having 



of the three front toes, the 



inner has - joints (count 



the claw as one joint), the 



FIG. 285. LEG BONES 

 OF BIRD. 



middle has 



joints, and the 



outer toe has 



joints (Fig. 285). 

 Is the thigh of a bird bare or 

 feathered ? The shin ? The 

 ankle ? Where is the ankle 

 joint of a bird ? Do 

 you see the remains 

 of another bone (the 

 splint bone, or fibula) 

 on the shin bone of 

 the shank? (Fig. 285 



Questions: Which is the stiffest portion of the Or 286.) Why WOUld 



several joints in the 

 ankle be a disadvan- 

 tage to a bird ? 



FIG. 286. SKELETON OF BIRD. 



Rh, vertebrae; Cl, clavicle; Co, coracoid; Sc, scap- 

 ula; Si, sternum; H, humerus; R, radius; U, 

 ulna; P, thumb; Fe, femur; T, tibia. See Fig. 394. 



vertebral column ? How are the ribs braced against 

 each other ? Which is longer, thigh bone or shin ? 

 Compare shoulder blade with man's (Fig. 399) . Which 

 is the extra shoulder bone ? Compare tail vertebrae 

 with those of extinct bird, Fig. 290. 



