78 AVES. 



in other words, strongly arched, its branches standing wide apart 

 from each other ; in the Owls the branches are thinner, and the 

 whole furcula more Y-shaped ; this being the case in a still greater 

 degree in the Gallinac, where the process at the angle of union of 

 the branches is of very considerable size. In the Cuckoo the furcula 

 articulates with the keel of the sternum ; in the Stork and Heron 

 these parts are firmly united by syndesmosis, and in the Crane 

 by actual coalition. In some Owls, Parrots, and in the Rhamphas- 

 lidiae, the two branches are not united, and in some New Holland 

 Parrots (Pezoporus) the furcula is either entirely wanting, or in a 

 very rudimentary condition. The Brevipennes present peculiar 

 modifications of the scapular arch, for in them the scapula is very 

 narrow and small, the furcula is wanting or coalesces with the cora- 

 coid bones, which in the Ostrich are each perforated by a single large 

 opening, and in the Cassowary are represented by narrow bony plates. 

 In the Emeu a rudiment of the furcula is always present, and appears 

 in the Indian Cassowary as a mere hook-shaped process. The fur- 

 cula is entirely wanting in the Apteryx. 



The Humerus articulates by its broad head with the shoulder- 

 joint, to which it is attached by a loose capsular ligament and 

 several strong fibrous bands ; this articulating surface is commonly 

 formed by the coracoid bone and scapula. The humerus is in 

 many of those small birds which are considered powerful fliers, as 

 the Swift (Cypselus), Humming-bird, very short and broad, pro- 

 vided with processes, and in some degree resembles the scapula of 

 the Mole. In the Penguin it is, in common with all the bones of 

 the arm, quite thin and flattened; it is very large in the great 

 Birds of Prey, as Gypaetus, in the Ostrich at least it is much longer 

 than the bones of the fore-arm, but is small and rudimentary in the 

 Emeu. The two bones of the fore-arm are generally the longest in 

 large Birds of powerful flight. The ulna, which is of considerable 

 size and thickness, has usually a short olecranon at its proximal 

 extremity, while near to and in front of it lies the far more slender 

 radius. To these bones succeed two short bones, particularly large 

 in the Penguin, very rarely wanting, as in the Emeu and Apteryx, 

 and which represent, the bones of the carpus. The metacarpus is 

 always composed of a single bone, which consists however primarily 

 in nearly all birds of two distinct pieces, which at a later period in 

 their existence blend so completely together at their extremities, 

 that a large elongated space is left between them. The principal 

 bone is that which, corresponding in position to the radius, is turned 



