1899.] CRANIAL OSTEOLOGY OF THE PARROTS. 25 



auditory meatus in both is wide, and its posterior border concave. 

 The paroceipitals are prominent, pointed, and directed backwards, 

 without forming the transverse projection and ridge of Licmetis. 

 The basitemporal ridges run nearly continuously on to the par- 

 occipital, and the surface extei'nal to them is inclined outwards. 

 The shaft of the quadrate is very stout. In Qallocephalon the two 

 heads of the bone are only separated by a very narrow and shallow 

 groove. In both genera the angle of the mandible is rounded and 

 truncate. 



In Microf/lossa the squamosal process fails to join, though it pro- 

 jects a little way under, the suborbital ring ; it is exceedingly small 

 and pointed. The posterior or postorbital region of the suborbital 

 bar is very large and broad, and sends back a posterior lobe from 

 its lower angle. The temporal fossa is very small, scarcely larger 

 than in C. roseicapilla and much less than in C. leaclheateri. The 

 auditory meatus is wide open, its aperture approximately oval. The 

 paroccipital process is large ; looked at from behind its posterior 

 border is nearly vertical, but its angle projects somewhat poste- 

 riorly ; it is very little hollowed within, and the jugular foramen is 

 very small ; the basitemporal ridges run almost uninterruptedly 

 into the deeply compressed lower boixler of the paroccipital. The 

 articular facets for the quadrate are separated by a well- 

 marked groove, and are walled olf from the tympanic cavity by a 

 splinter of bone. The quadrate has two deeply separate heads, 

 the inner one scarcely half the size of the outer ; its other cha- 

 racters are those of the family ; the exti"a facet below the quadrato- 

 jugal cup is small and deeply marked. The angle of the shaft is 

 short and bluntly pointed ; the mandibular fenestra is obsolete. 

 In the skull the inner wall of the orbit is scarcely perforate in 

 front of the orbital foramen ; the jugal bone is notably expanded 

 at its anterior end. 



The skull of Calopsittacus (fig. 17) is similar to that of the 



Fiff. 17. 



Ccdopsittacus novce-hoUa ndics (enlarged). 



Cockatoos in having the orbital bar completed by junction both 

 with postorbital and with squamosal, which leave between a rather 

 elongated supratemporal vacuity. The auditory meatus is narrower 

 than in the Cockatoos, and its posterior and inferior notches are 



