. The biology of birds. Birds. THE PEDIGREE OF BIRDS 359 of the keel on the breastbone presents no difficulty, for it has disappeared in various " Carinate " birds, such as the has disappeared in various Carinate birds, such as the burrowing parrot called Stringops. Of course the argument. GLC Fio. 56.—Pectoral girdle and breastbone of an ostrich (Struthio). sc, scapula; CO., coracoid ; PC, precoracoid ; f., foramen; , the glenoid cavity with which the humerus articulates ; , the coraco- sternal groove; ST., the sternum or breastbone, without a keel, but convex outwards ;

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. The biology of birds. Birds. THE PEDIGREE OF BIRDS 359 of the keel on the breastbone presents no difficulty, for it has disappeared in various " Carinate " birds, such as the has disappeared in various Carinate birds, such as the burrowing parrot called Stringops. Of course the argument. GLC Fio. 56.—Pectoral girdle and breastbone of an ostrich (Struthio). sc, scapula; CO., coracoid ; PC, precoracoid ; f., foramen; , the glenoid cavity with which the humerus articulates ; , the coraco- sternal groove; ST., the sternum or breastbone, without a keel, but convex outwards ; R., sternal portions of the ribs. From a specimen. is not conclusive. It is possible that the Tinamous are not Ratitae, but very peculiar Carinatae which sprang from a primitive stock with dromaeognathous palate and distant affinities with the flightless Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Thomson, J. Arthur (John Arthur), 1861-1933. New York : Macmillan

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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbirds, bookyear1923