I SKELETON 
NI 
Birds, and certain Petrels, but dwindles almost to disappearance 
in some flightless forms such as the Dodo, the Kakapo (Stringops), 
the extinct New Zealand Goose (Cnemiornis), and a good many 
Rails. The absence of a keel is characteristic of the other and 
smaller group of Birds, made up of the Ostrich, Rhea, Emeu and 
Fic. 2.—-Skeleton of the trunk of a Falcon. Oa, coracoid, which articulates with the 
sternum (St) at +; C7, keel of sternum; Fw (CZ), furcula (clavicles) ; G, glenoid 
cavity for humerus; S, scapula; Un, uncinate process; V, vertebral, and Sp, sternal, 
portion of rib. (From Wiedershein.) 
Cassowary, Moa and Kiwi, which from the resemblance the 
sternum thus bears to a flat-bottomed boat (7atis) are known as 
Ratitae. Whether keeled or not, the breast-bone affords a 
surface of attachment to the principal muscles of the fore-limbs, 
and its anterior end supports the coracoids, as in Fig. 2. Various 
processes are in most cases developed on the sides of the sternum 
itself, behind its junction with the ribs, especially towards the 
