| OCR Text |
Show 1902.] OSTEOLOGY OF THE FALCONIFORMES. 297 is present in all the Accipitres. In the Falcons only does the anterior angle of the carina project forwards as far as the level ot the spina externa. Again, whilst in nearly all the other Accipitres the sternal ribs attach themselves along the whole outer border of the anterior lateral processes, in the Falcons the drstal third is ribless. In the larger Falcons the sternal plate is fenestrated posteriorly, but in the small forms-MeUerax, Pohohierax, MicrohieraX~it is notched. In Falcons, the coracoid Text-fig. 33. Cccr Left lateral aspect of the Sternum and Shoulder-girdle of Serpentarius serpentarius, showing the articulation of the furcula with the carina. ac. = acrocoracoid. cor. = coracoid. cs. = corpus sterni. H. = hypocleideum. car. = carina. f. - furcula. sr. = sternal rib. grooves overlap one another, and the spina externa is relatively long and pointed. The articular surfaces for the sternal ribs extend backwards as far as the middle of the sternal plate. The sternum of the Polyborince resembles that of the Falcons, but the spina interna is shelf-like instead of spiny, and the anterior border of the keel does not project so far forward. In the Buteonidse (Suschkin) the spina interna is not developed. The spina externa varies much in size. Generally, it n ay be described as a short stout tubercle; but in Accipiter it becomes a PROC. ZOOL. Soc-1902. V O L . I. No. X X. 20 |
