38 



PSOi'. D AECY AY. THOilPSON ON THE 



[Jan. li 



cus (fig?. 38, 39), and Melopsittacus (fig. 40, p. 39). Of these, the 

 last alone differs markedly from the others. The characters com- 

 mon to the rest are precisely the characters to which I have called 

 atfcenbioa in Aprosmictics, Polytelis, and PyrrJiulopsis ; that is to 

 say, to the Australasian forms described under the group Palce- 

 orniihince. In all, we find au incomplete orbital ring, a postfrontal 

 process scarcely represented by more than the raised border of the 

 orbit ; a squamosal process crossed at its base by a deep groove 

 above the meatus and in front of the suprameatal process. In 

 all, the auditory meatus is narrow and curved ; the intraorbital 

 vacuity is large (especially in Nijmphicus) ; the mandibular fenestra 

 is obsolete. In all, the base of the skull is flattened, the small tri- 



Kg. 38. 



Nympkious uvmensis. 

 Fis. 39. 



Auditory region of Nymphioiis uvcee^isis (enlarged). 



angular basitemporal plate being nearly on a level with the areas 

 at its sides. The squamosal region presents certain pecuHarities 

 in the several forms. In Platycercus, at least in Pennant's 

 Parrakeet, the groove above described at the base of the squamosal 

 is bridged by a well-developed ring of bone, extending from the 

 suprameatal process to a slight descending process or tubercle at 

 the base of the squamosal. In NympMcus- the groove is extremely 

 deep, and though the bridge of bone is not present, the two pro- 

 cesses are very well marked, that at the base of the squamosal 

 being extremelj'' conspicuous, la Neophema the postfrontal process 

 is at a minimum, the posterior border of the orbit running with 



