704 GEOLOGICAL SURVEY OF THE TERRITORIES. 
PIG AALIB \Y¥ ICs 
Fig. 52.—Lateral view of skull of Centrocercus, adult ¢, hyoid archremoved. Figs. 
54, 55, 58, 61, 64, 65, 66, 68, 69, and 70 are from the skeleton of the same specimen. 
Fic. 53.—Sternum of the chick, three or four days old; Centrocercus. 
Fig. 54.—Sternum of Centrocercus, viewed from below; adult ¢. 
Fig. 55.—Dorsal vertebre, lateral view, left side, from the same. 
Fig. 56.—Sternum of Centrocercus, ‘bird of the year” (two months old), showing 
development of this bone: 4, lophosteon; 5, metosteon; 6, pleurosteon. 
