1899.] 



CRANIAL OSTEOLOGY OF THE PABROTS. 



19 



Chrysotis and the Macaws. The orbit is of remarkably small size, 

 its antero-posterior diameter being about equal to that of Psittacus 

 erithaats, and a little less than that of Eclectus cardinalis. The 

 squamosal process is large and flattened ; it runs parallel to the 

 postei'ior portion of the suborbital ring, and the temporal fossa 

 between is unusually deep and wide. The suprameatal process is 

 large, and overhangs a deep groove or hollowed plate of hone th.it 



Ym. 9. 



Stringops Tiahroptilus : part of the skull of a young individual, for 

 comparison with figs. 4, 5, 6. 



lies posterior to the quadrate articulation and above the auditory 

 meatus, roofing over the superior auditory recess ; it is comparable 

 to, though far smaller than, the remarkable area connecting the audi- 

 tory cavity with the hollowed surface of the squamosal in Nestor. 

 The anterior border of this bony plate forms a well-defined margin 

 to the quadrate articulation, which is thus very distinctly sepa- 

 rated from the auditory cavity. The auditory meatus is rounded 

 and wide open ; its posterior wall scarcely diminishes its aperture. 

 The basitemporal plate is on a level with the occipital condyle ; its 

 edges are formed by elevated ridges that run back to the nearly ver- 

 tical paroccipitals, and the lateral areas continued forwards from 

 these latter are sharply inclined. The intraorbital vacuities are very 

 large. The quadrate bone (fig. 10) is especially remarkable, and 



Yior. 10. 



Quadrate bone of Stringops. 



in it the Psittacine type of quadrate is imperfectly attained, 

 shaft of the bone is shorter and less vertical than usual, 



2* 



The 

 the 



