1899.] CRA^'IAL OSTEOLOGY OF THE PARROTS. 37 



not overhaug the quadrate, but is excavated to form a deep Lotcb, 

 which espoties the head of the quadrate boue. In all these forms 

 the intraorbital tissure is large, tlie descending processes from the 

 hiuder border of the maxillae are large also, the inner head of the 

 quadrate is quite distinct, and the mandibular fenestra is obsolete. 



Fig. 36. 



Jgujjornis roseiccq^illus. 



In all, the auditory aperture is much narrowed, by the forward 

 growth of the posterior w all of the meatus ; this takes place to 

 the greatest extent in Polytdis and Aprosmictus, in which last the 

 aperture is reduced to a curved slit. The basiteraporal triangle is 

 very small in Pyrrhulopsis, and well dehned from the areas at its 

 sides ; the paroccipital processes, looked at from behind, are nearly 

 vertical ; in Aprosmictus they are more horizontal, and the lateral 

 areas are accordingly more on a leAel with and less defined from 

 the basitemporal ; in PoJytelis the same tendency is still more 

 displayed. 



In Ac/apornis the orbital ring is incomplete and the postfrontal 

 extremely small, as in the forms last described. There is a notch 

 at the base of the squamosal process, but the latter is not separated 

 by a groove from the suprameatal ; the conformation here is more as 

 in Edectus. The auditory meatus is narrow, and the intraorbital 

 vacuity very large. The mandibular fenestra is large also. The 

 quadrate is very delicate in form; its two heads are fused, its 

 shaft is very slender, and its anterior process small. 



Family Platycercin^e. 



Of this group I have examined skulls of Flatycercus (fig. 37), 

 Nanodes (Lathamus) discolor, Neophema jpulcliella, Psephotus, Nymphi- 



Fig. 37. 



Flatycercus eleyans. 



