n8 



NEW YORK STATE MUSEUM 



So much for the skull proper, and passing next to the hyoidean 

 arches of Pandion, it is to be observed that the fused or coossified 

 ceratohyals have the exact form of a capital letter H and the 

 broadened part of the first basibranchial fills the hinder recess of 

 this when articulated in situ, sending forwards beneath an osseous 

 lip that underlaps the transverse bar. Posterior to this the first 

 basibranchial is still broader, being produced transversely, either 

 way, as a stumpy process, upon the posterior recess of which, upon 

 either side, articulates a thyrohyal. Urohyal or second basibranchial 

 is long comparatively, and completely fuses with the one we have 

 just described. The thyrohyals are much as they occur in the Fal- 

 conidae generally. 



Some 13 or 14 sclerotal plates ossify in either eyeball, arranged 

 in the usual circlet. Each one, as a rule, is semiflat and quadri- 

 lateral in outline, becoming gradually deeper and somewhat wider 

 as we pass from the front of the eye, backward. 



Nineteen vertebrae, freely movable upon each other, are found 

 between the skull and pelvis ; and they all appear to be pneumatic, 

 with perhaps the exception of the atlas. Pneumaticity also is a 

 character of the 13 vertebrae that form the pelvic sacrum, but the 

 six tail vertebrae and the pygostyle are all nonpneumatic. Among 

 the points of interest in these bones are the extraordinary post- 

 zygapophyses of the fourth to include several of the succeeding 

 cervical vertebrae which are immensely long, and arched forwards 

 in the most peculiar manner. Parapophyses are poorly developed 

 in this part of the column, while the mid dorsal vertebrae are very 

 deep, and have long hypapophyses. The carotid canal does not 

 close in, in the cervical region, though the lateral vertebrarterial 

 canals are very prominent features. There are three pairs of cer- 

 vical ribs, none of which connect with the sternum by costal ribs, 

 nor do they usually bear unciform processes. These latter are large, 

 with dilated ends in the four pairs of true dorsal ribs, but only 

 occur upon the leading pair of the two pairs of sacral or pelvic ribs. 

 Both these last connect with the sternum by means of their haema- 

 pophyses. Sacral and dorsal ribs are both characteristically broad 

 and thin, and their epipleural appendages coossify with them. Hav- 

 ing a form much as we find it in other Accipitres, the pygostyle is 

 only peculiar in being pierced at its lower part transversely by a 

 small foramen, and this passes through, from side to side, an antero- 

 posterior fissure that occurs at the lower part of the 'bone behind. 



