STERNA OF OMNIVORA. 331 



more feeble in all its parts than the diurnal preyers 

 that, in a strictly natural system, they ought perhaps 

 to be wholly separated. The common owls have the 

 posterior edge of the sternum with notches, generally 

 two on each side, filled by membranous or cartila- 

 ginous matter, and they have the arms of the clavicle 

 or furcal bone straighter, and with its flat side placed 

 more in the direction of the strain than in the diurnal 

 birds of prey. This accords with the comparative 

 slowness of their flight, and the feeble and downy 

 character of their flying feathers. 



STERNA OF THE OMNIVOROUS BIRDS. 



The character of the sternum is much the same in 

 the greater part of those birds which form the otherwise 

 diversified order Passeres. They have the sternum 

 longer than broad, enlarged toward the posterior ex- 

 tremity, and with two deep notches toward the sides. 

 The keel is moderately produced, convex on its under 

 side, and concave to the front, which has a forked 

 process upon which the middle of the furcal bone 

 rests. ' The coracoid bones are longer than the 

 sternum, slightly bent, or coulter-shaped, with an 

 enlargement near the shoulder-joints, and narrowed 

 toward the extremities. The clavicle is long and 

 bent downwards at the middle, generally rather nar- 

 row, and united to the forked process of the sternum. 

 The scapular bones are long, bent downwards, pointed 

 at the extremities, but with an enlarged process on 

 the under sides near the middle of their length. The 

 following figure of the sternal apparatus of the jack- 

 daw may be taken as nearly the average of birds of 

 this character. 



None of the birds which have the sternum formed 

 in this manner capture their prey on the wing, or are 



