Anutomy of Acantliidositta chloris. G15 



The exact limitations between the maxilla and pre-maxilla 

 cannot be made out; but this portion of the jaw is long and 

 slender, triangular at its base, and has a flattened culmen 

 and a slightly sinuous free edge. There is the faintest 

 possible trace of a notch at the tip of this beak. 



The maxilla, indistinguishably fused with the palatine, 

 bears unusually long and slender maxillo-palatine processes, 

 formed apparently by the backward production of the infero- 

 internal angle of the maxillo-palatine plate — that is to say, 

 these processes appear to spring from the point where the 

 quadrato-jugal bar enters the maxilla. The processes are 

 continued backwards so as to terminate mesiad of the large 

 and spongy antorbital plate in the form of a strap-shaped 

 blade with a rounded free end. 



In the quadrato-jugal bar no separate elements can be 

 distinguished. 



The vomer is of considerable size, and presents a pair of 

 long limbs and a broad deeply notched free end. Anteriorly, 

 for nearly half its length, it rests upon the maxillo-palatine 

 processes. 



The palatines send downwards from their dorsal border a 

 deep concavo-convex plate, the concavity inwards. The free 

 edge of this plate at the articulation of the pterygoids forms 

 a deep blade-shaped keel. From the convex surface there 

 runs forwards a long slender shaft to fuse with the maxilla, 

 and this shaft may be regarded as prolonged backwards into 

 a short spur, the " transpalatine process." 



The pterygoids are moderately long, sigmoidally curved 

 bones having a slipper-shaped free end, which is applied to 

 the sides of the basisphenoidal rostrum. .The palatines 

 articulate by an oblique joint with the outer border of this 

 elliptical " foot," which apparently represents the hemi- 

 pterygoid. 



Comparative Remarks. 



The skull of Acanthi do sitt a appears to agree most nearly 

 with that of the Synallaxine birds ; in some particulars, 

 indeed, this resemblance is ypvv striking. As I shall shew 



