32 



PROF. D AEC'Y W. THOMPSOlf ON THE 



[Jan. 17, 



plete, and in all these the postfrontal process is extremely reduced, 

 forming only a short protuberant edge as in Eclectus. In all the 

 squamosal process is well developed : it is especially long and 

 straight in Pacliynus, in which it nearly meets the prefrontal ; the 

 latter process is much shorter in Poeocephalus than in the other 

 two. In Pachymis the basi temporal ridges are faint, and the 

 surfaces external to them and extending back to the paroccipitals 

 are much flattened, the paroccipitals being directed backwards ; 

 there is no trace of descending maxillary processes. In Caiea the 

 basitemporal ridges are much stronger ; in all the basitemporal 

 plate is nearly on a level with the occipital condyle. The auditory 

 meatus is somewhat narrower and more notched above and below 

 than in Chrysotis, and the interspace betM'een it and the occipital 

 ridge is somewhat greater. The quadrate in Caica and Fachynus 

 has a high posterior prominence above and behind the socket for 

 the jugal, as in Conurus. The mandibular fenestra is large in 

 Caica, small or obsolete in the other tvk'o. 



Family Psittacinje. 



The skull of Ps. eritJiacus has been considered already. I have 

 also studied the skulls of Coracopsis vasa (fig. 27) and C. nigra, 

 and an imperfect specimen of Dasyptilus pecqueti (fig. 28). 



Coracopsis vasa. 



The skulls of these Parrots bring us face to face with the 

 problem of whether Coracopsis and Dasyjjtilus are rightly placed 

 in so close a relation to Psiitacus ; in other words, with one of the 

 dubious and crucial questions that osteology might suffice to solve. 

 1 cannot boast of being able to give a very clear answer to the 

 question, but it seems to me that the skull of Dasyptilus, and in 

 a minor degree that also of Coracopsis, differs in so many points 

 from that of Psittacus, that they go far to show that the little group 

 of Psittacince is very dubiously or improperly defined. 



In Coracopsis vasa the postfrontal process is almost obsolete, 

 forming a slight vertical ridge behind which rises the impression of 



