OSSEOUS SYSTEM OF AVES. 27 



is usually deepest, the processes on each side the mid one appear 

 as unequal, styliform, terminally expanded, prongs of a fork, the 

 outer prong being the shortest. The costal border is very short, 

 and is continued upon the costal process, which is long : the 

 manubrium is compressed and terminally dilated and deflected, 

 often perforated transversely by confluence of the short cora- 

 coid grooves. The fowls {Gallus), pheasants (Phasicmus), par- 

 tridges (^Perdix, Francolinus), quails (^Coturnix, Ortijx, Loph- 

 ortyx\ grouse ( Tetrao), exemplify the gallinaceous type of the 

 sternum. 



In the Turkeys {Meleagris)^ Pea-fowl {Pavo), and Kaleeges 

 (Polyplectron, Lophophorus, Oreophasis), the sternum is more 

 ossified, and the lateral processes are shorter and broader ; in the 

 Curassows {Crax, Ourax), they present the proportions shown in 

 fig. 14, A. In the Gangas or Sand-grouse {Pterocles^ Syrrhaptes), 

 the outer pair of notches are chiefly present, the inner pair 

 nearly obsolete ^ ; in the Tinamous ^ they are wanting, the outer 

 notches are of extreme length, and the whole sternum is reduced 

 to a trifid form, as in fig. 14, B. The sternum of Columha coronata 

 resembles that of the Curassow, with the median pair of notches 

 shorter and narrower. In Columha magnificat ^ the four notches 

 are more equal in size, and the whole sternum is broader. In the 

 Columha livia the median pair of notches are often converted into 

 small foramina. 



The transitional steps in the foregoing series from the type- 

 sternum of CralliiKB to that of the swiftest of the doves indicate 

 the natural character of the order Rasores. 



In diurnal Raptores the sternum is a large elongate paral- 

 lelogram, convex outwardly both transversely and longitudinally. 

 The manubrium is short and trihedral ; the lower border of the 

 keel is convex ; the front border concave ; their angle of union 

 rounded off. The instances where the sternum is entire have 

 been cited: in other birds of prey the arrest of ossification is 

 limited to very small parts of the hind border ; usually a fora- 

 men, rarely a notch (^SarcorampJius), on each side; one of 

 which may be filled up, wholly or partially. Eyton"* figures 

 two small notches on each side the posterior border in Hierax 

 hengalensis ; and both hole and notch on each side in Cathartes 

 aura. In the Nocturnal Raptores the sternum is relatively 

 shorter, the keel less deep, its lower margin less convex and not 

 thickened, the costal border is shorter. The posterior margin 

 usually presents two notches on each side, the outer one the 



' xiir. p. 2-28, fig. 109. - lb. p. 230, iig-. 110. ^ xiv. pi. 2 c. -■ lb. pi. 16. 



