30 



PEOF. D AECY W, THOMPSOIf ON THE 



[Jan. 17, 



postfrontal process is in both cases very small, while tlie squamosal 

 one is of large size. The auditory meatus is narrow, especially in 

 Myopsittacus. A mandibular foramen is present and large in By'oto- 

 garys, absent in the others ; the ramus of the mandible is in both 

 longer and its angle less truncated than in the Conures. The 

 nares in Brotogerys are even larger than in the Conures, and 

 separated by a very narrow bridge of bone ; in Myopsittacus, on 

 the other hand, they are unusually small and wide apart. 



Eamily Pionin^. 



Of this group I have studied Chrysotis cestiva (fig. 22), PacJiynus 

 hracliyurus, Pionus menstruus and P. maxhniliani, Caica melano- 

 cephala (fig. 24, p. 31), and Poeocephalus fuscicajnllus (fig. 26, p. 31). 

 Of these, Ohrysotis and Pionus are markedly different from the rest. 

 In Chrysotis the orbital ring is complete, by the fusion of the pre- 



Fic. 22. 



Ghry&otis astiva. 

 Ym. 23. 



Quadx'ate bone of Chrysotis cestiva. 



oi'bital and postorbital processes, and the bar thus formed is strong 

 and broad, and forms with its lower border an abrupt descending 

 angle opposite to the extremity of the squamosal processes, which 

 closely approaches it. The latter is broad and massive, and similar 

 in shape to that of Conurus ; the temporal fossa between the post- 

 frontal and squamosal processes is deep, but unusually narrow. 

 The auditory meatus is wider, its superior and inferior notches are 

 broad and rounded, and the ridge separating it from the quadrate 

 articulation is low and indistinct. The probtic articular surface is 



