30 



PROF. D AECY W. THOMPSON ON THE 



[Jan. 11 



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

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

 Myopsittacus. A mandibular foramen is present and large in Broto- 

 gerys, 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 Brotoyenjs 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. 



Family Pionin^. 



Of this group I have studied Chrysotis (estiva (fig. 22), Pacliynus 

 hracliyurus, Piotms tnenstnius and P. niaximiliani, Caica melano- 

 cephala (fig. 24, p. 31), and Pceocephalus fuscicapilhis (fig. 26, p. 31). 

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

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



Fig. 22. 



Chrysotis mstiva. 



Fig. 23. 



Quadrate bone of Chrysotis isstiva. 



orbital 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 Conurxis ; 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 prootic articular surface is 



