THE STRUCTURE AND LIFE OF BIRDS CHAP. 



Fig. 2.— Skeleton of Fowl (after Marshall and Hurst). 

 a, acetabulum ; at, atlas vertebra ; ax, axis vertebra ; cl, clavicle ; cm, carpo- 

 metacarpus ; co, coracoid ; cr, cervical rib ; n i, 2, 3, 4, digits ; dr, dorsal rib; 

 he, femur; hu, humerus; hy, hyoid bone that supports the tongue ; il, ilium; 

 is, ischium ; k, keel of sternum ; mc, 1,2, 3, metacarpals; MT, first metatarsal; 

 pb, pubis ; py, pygostyle ; r, radius ; rc, radial carpal ; sc, scapula ; si», spine ; sr, 

 sternal piece of rib; tm, tarso-metatarsus ; tt, tibio-tarsus ; u, ulna; uc, ulnar 

 carpal ; up, uncinate processes. 



