ShuI'Kldt : OsTicoi.odv ok thk Psittaci 407 



convex vault of the cranium, and below, the lony; S(|u:imosal process 

 sejjarated from the sphenotic by a well-defined valley. 



The bony ear conch is circumscribed by rounded margins, while to 

 its under side a sharp vertical i)late is thrown down, the inferior rim of 

 which is the continuation of the occipital ridge behind, as in Ara and 

 C(r('(f///(f. 



As is well known, the characteristic feature of a paiTot's quadrate 

 bone is, that its mandibular facet is single, and placed in such a way 

 that its long axis is in the same straight line with the longitudinal axis 

 of the pterygoid ; to the possession of this narrow, convex, and long 

 facet Coniinis forms no exception. Above it, the body of the quadrate 

 is flattened from side to side, with a conical projection on its outer 

 aspect, i)osterior to its middle point, that has a pit at its apex to accom- 

 modate the apophysis on the inner side of the hinder extremity of the 

 quadrate-jugal. 



The orbital ])rocess of the quadrate is spiculiform and but moderately 

 developed, while the mastoidal limb of the bone rises as a stout sub- 

 cylindrical rod, with two convex articular facets at its summit. These 

 are divided by a notch, and the inner one of the two is very small, not 

 presenting more than one-tenth of the amount of articular surface the 

 outer one does. 'I'he pneumatic foramen is found near its most usual 

 place, on the inner and back part of the mastoidal shaft. 



\'iewing the skull now from above we observe that the narial aper- 

 tures can also be seen upon this aspect surrounded above by a few- 

 minute vascular foramina, the former being comparatively unusually 

 large in Cacatua. 



The cranio-facial hinge bordering the sujjerior mandible behind, is 

 found to be a transverse and depressed line extending all the way 

 across. 



Between the superior orbital perijjheries the frontal region of the 

 skull is smooth and nearly flat ; as we ])roceed backwards it gradually 

 becomes convex, to form the beautiful rounded vault of the cranium. 

 This flatness of the frontal region is very characteristic of the skull of 

 Ara militarius. 



A few perforating foramina are found just within the two edges of 

 the orbits in the frontal bones, being situated posteriori)- and above in 

 the Cockatoos and Macaws. 



Turning to the under side of the skull the most remarkal)le feature 

 that confronts us is the extraordinarily fashioned palatines. These 



