1902.] OSTEOLOGY OF THE FALCOOTFORMES. 291 



In Catharistes the fission of the bar takes place much further 

 forward than in Cathartes, and the short superior segment is 

 abruptly truncated and roughly aiticulates with the aforesaid 

 maxillary process of the premaxilla. 



In Gypagus this infeiior limb remains much as in Cathartes 

 and Catharistes, but the superior limb now forms a shorter but 

 laterally compressed lamina with a hollow anterior border fitting 

 into the rounded posterior border of the maxillary process of the 

 premaxilla. 



In Pseudogryphus and Sarcorhamphus the short, laterally com- 

 pressed upper limb now forms a spatulate process, working in 

 oppositioiT. to a shallow depi-ession in the maxillaiy process of the 

 premaxilla. 



The gradual development of these peculiar articulations seems 

 to have gone hand in hand with tlie development of a nasal 

 hinge, formed by a deep notch hollowed out of the anterior 

 border of the lachrymal, for the reception of a " tooth- shaped " 

 process borne by the outer border of the nasal. This foi-ms the 

 hinge ; the necessary movement of the beak upon the skull is 

 aiforded by the elasticity of the nasal and premaxillary processes 

 lying mediad of the right and left notches. This hinge is most 

 perfect in Gypagus, Pseudogryjyhus, and Harcovliamphus, In 

 Catharistes the lachiymal is only barely pei-ceptibly notched. A 

 fui'ther study into the origin of structures like the pi'esent would 

 prove profitable. Ai'e they to be ascribed to kinetogenesis ? 



The composition of the quadrato-jugal bar, as revealed by an 

 immature skull of Cathartes, is intei-esting, and chiefly on account 

 of the large share which is borne by the maxilla. This, together 

 with the jugal, extends backwards as a long slender bar to 

 within a short distance of the quadrate articulation. The 

 Jugal terminates anteriorly to meet, and sometimes articulate 

 with, the maxillary process of the premaxilla, and apparently in 

 Pseudogryphus and Sarcorhamphiis, for instance, becomes much 

 broadened to make the articulation the more complete. The 

 quadrato-jugal appears to terminate at about the middle of the 

 inner aspect of the bar. A slightly older skull of Serjjentarms, 

 but still showing traces of sutures, agrees very closely with what 

 has just been desciibed in Cathartes. The great backward exten- 

 sion of the maxilla appears to be a Neognathine character. 



The AFandihle. 



The mandible of the Accipitres is truncated posteriorly, and 

 has a very long internal angular process. It very closely 

 resembles that of the Bubonine section of the Striges, so much 

 so as to requii'e very careful discrimination. In comparing 

 mandibles of these two gi'oups, it will be found that among the 

 Accipitres the two rami form a less open angle one with another, 

 and the ventral aspect of the internal angular process is not 

 marked by a median ridge. The lateral vacuity in the mandible 



