408 Annals of the Carnegie Museum. 



bones, as they occur in the Psittaci, have been described by a number 

 of anatomists, so their peculiar conformation is well known. Connnis, 

 as in most true Parrots, has both of these bones horizontally flattened 

 in front, where they are inserted above the hinder portion of the supe- 

 rior mandible to meet the lower part of the nasal sei)tum, Init not 

 the palatine of the opposite side. 



Proceeding backwards from this horizontal extremity, the palatine 

 is seen to contract, then immediately afterwards to form a broad, 

 oblong and vertical plate. This plate has a certain limited portion of 

 its antero-superior part curled towards the median line, where it meets 

 a corresponding edge of the fellow of the opposite side ; and the two 

 here form, by the assistance of the palato-pterygoidal articulation, the 

 usual longitudinal groove for the under edge of the rostrum. 



Behind this, the superior margin of the palatine plate is sharp ; the 

 posterior margin shows a deep notch, while the inferior margin of the 

 part of the bone is rounded, becoming in front continuous with the 

 dilated anterior end. 



Both the internal and external surfaces of these palatine plates may 

 develop processes and ridges for the better insertion of muscles, which 

 in life are thereto attached. A broad, spindle-shaped vacuity exists 

 between these palatines in front, while posteriorly the angle separating 

 their plates is somewhat less than the angle of divergence of the 

 pterygoid bones. 



These latter elements are long, nearly straight and cylindrical rods. 

 They are at some distance below the basis cranii, and in no Parrot, so 

 far as is at present known, do they develop basipterygoid processes. 

 Anteriorly, their heads are but slightly enlarged to articulate with 

 each other ; with the lower rim of the rostrum ; and with the palatines. 

 The maxillary i)Ortion of either of the infraorbital bars is inserted 

 by a somewhat horizontally flattened end, just within the posterior 

 edge of the beak, on a higher plane than the insertion of the palatines, 

 and at a point where 1 take the foot of the nasal to be. The remain- 

 der of the bar almost immediately becomes of a uniform calibre, and 

 at first being concave outwards, passes just beneath the orbital ring, di- 

 rectly downwards and backwards to its articulation with the quadrate. 

 At the cranial base we find a basitemporal area of small extent, tri- 

 angular in outline, bounded on all its sides by raised lines, and having 

 its apex directed anteriorly, terminating at the point where occurs the 

 naked and external double-tubed entrance of the Eustachian canals. 



