THE PIGEON 



409 



over the shoulder to its insertion on the upper side of the 

 humerus, which it raises. The perching mechanism is 

 also interesting. The flexor tendons which curve the 



Fig. 299. — The fore-limb and hind-limb of a bird compared. 

 — From Thomson. 



//., Humerus ; R ., radius ; U., ulna ; r. t radiate ; «., ulnare ; C, distal 

 carpals united to carpo-metacarpus ; CC, the whole carpal region ; 

 MC.f., metacarpal of the thumb ; /., phalanx of the thumb ; MC.II., 

 second metacarpus ; //., second digit ; MC.III,, third metacarpus ; 

 ///., third digit. F., femur; T.T., tibio-tarsus; Fi., fibula; Pt., 

 proximal tarsals united to lower end of tibia ; dt. , distal tarsals united 

 to upper end of metatarsus, forming a tarso-metatarsus (T.MT,); 

 T., entire tarsal region ; MT.I., first metatarsal, free ; I.-IV., toes. 



toes round a branch are so arranged that they are 

 tightened by the bending of the metatarsus on the tibia 

 in perching, so that the bird does not fall even_when 

 it is asleep. 

 27 



