. The natural history of birds . its underside, and concave to the front, which has a forkedprocess upon which the middle of the furcal bonerests. The coracoid bones are longer than thesternum, slightly bent, or coulter-shaped, with anenlargement near the shoulder-joints, and narrowedtoward the extremities. The clavicle is long andbent downwards at the middle, generally rather nar-row, and united to the forked process of the scapular bones are long, bent downwards, pointedat the extremities, but with an enlarged process onthe under sides near the middle of their length. Thefollowin


. The natural history of birds . its underside, and concave to the front, which has a forkedprocess upon which the middle of the furcal bonerests. The coracoid bones are longer than thesternum, slightly bent, or coulter-shaped, with anenlargement near the shoulder-joints, and narrowedtoward the extremities. The clavicle is long andbent downwards at the middle, generally rather nar-row, and united to the forked process of the scapular bones are long, bent downwards, pointedat the extremities, but with an enlarged process onthe under sides near the middle of their length. Thefollowing figure of the sternal apparatus of the jack-daw may be taken as nearly the average of birds ofthis character. None of the birds which have the sternum formedin this manner capture their prey on the wing, or are 332 JACKDAW. very rapid fliers, though they are all birds of con-siderable power of flight. They are, however, all,at the same time, birds which are tolerably active on their feet; and the large notches in the sternum,. Jackdaw. posteriorly towards the sides, enable them to makeuse of their feet, by the flexure of this part of thesternum, while the average production of the sternalcrest or keel admits of tolerably powerful muscles forputting the wings in motion. They are so numerousand so diversified in their habits, that no one typecan be properly expressive of them all, but their gene-ral character is that of uniting habits on the wing andon the ground in nearly equal proportions ; and uponcomparing their sternal apparatus mth those of thebirds of powerful wing and the ground birds, it will SWIFT. 333 be found to partake of the characters of both. Thedifferent powers of wing in these birds are in a greatmeasure dependent upon the form and distribution ofthe feathers. STERNA OF THE FISSIROSTRES. The birds which belong to this order are all feederson the wing; but upon comparing their sternal appa-ratus we find more difference between the diurnal andnocturnal feeders t


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