OSTEOLOGY OF BIRDS I3I 



and spongy, nearly rilling the space. Supraorbital part of a lacry- 

 mal somewhat shortened and pointed at its free extremity; with 

 out accessory piece. The descending limb of one of these bones 

 does not fuse with the pars plana, being hardly in contact with it. 

 Postpalatine of palatine broad, bent downward, and its hinder part 

 obliquely truncated from pterygoidal head outward and slightly 

 forward; the prepalatines are very narrow. A large vacuity in 

 either ramus of the mandible. Ossified ceratohyals of the hyoid 

 arches notably elongated. Four leading dorsal vertebrae fuse to 

 form one solid bone. Scapular process of a coracoid produced so 

 as to meet the clavicle of the same side when articulated. Sternum 

 2-notched, its manubrium not especially large, but the coracoidal 

 grooves markedly decussate. Mesial lip of bone on anterior border 

 of sternum to assist retaining the coracoids in their grooves when 

 articulated, present. Postpubic style of pelvis not interrupted. 



At the anterodistal end of the tibiotarsus the osseous tendinal 

 bridgelet is joined by a second short span at its upper border, which 

 comes downward and inward from the outer margin of the tendi- 

 nal groove. (Falconinae also possess- this character but apparently 

 none of the other subfamilies of the Falconidae.) 



Tarsometatarsus equals or is longer than the long diameter of the 

 skull. Its hypotarsus is composed of a central oblong process of 

 good size, and a rudimentary outer process, the valley between them 

 being very wide. Tubercle for tendon of tibialis anticus on the an- 

 terior aspect of the shaft as in Falconinae, as practically is also the 

 formulae of the comparative lengths of the phalanges of the digits 

 of pes. 



3 Pandionidae. Ossified nasal septum often incomplete above. 

 Supraorbital part of a lacrymal very much reduced and bears no 

 accessory piece; the descending limb of the bone fuses with the 

 outer border of the pars plana. Walls of Eustachian tubes very 

 deficient anteriorly, and they do not open in the mesial line. Upper 

 free ends of clavicles long and pointed. Scapular process of a 

 coracoid much reduced, and is transversely narrower than the much 

 flattened head of the scapula for whose articulation it is intended. 

 Xiphosternum hardly notched once upon either side of the carina. 



Pelvis remarkably broad and vertically somewhat compressed. 

 Postpubic style notably dilated toward its distal end, and ossifica- 

 tion is not interrupted in its continuity in fully adult individuals. 



Radial crest of humerus springs from the shaft completely below 

 the expansion of the proximal end of the bone. Length of ulna 



