190 MR. W. P. PYCEAFT ON THE MOEPHOLOGT AND 



Furthermore, it agrees with the same in the nature of its relations with the pterygoid. 

 The palatine, in the part played by it with regard to the pterygoid and vomer, differs 

 but little from that of Rhea. Its chief difference consists in the fact that it is much 

 narrower from side to side, and that it terminates in a pair of spines, an outer and an 

 inner, instead of an outer pterygoidal only as in Rhea. The form of the palatine, as 

 a whole, will be described latter. 



In Dinornithidce, e. g. Emeus (PI. XLIII. fig. 3), the vomer takes the form of a 

 pair of perfectly distinct vertical laminae embracing the parasphenoidal rostrum. 

 They are continued forwards only for a very short distance beyond the level of the 

 anterior end of the posterior narial aperture. It differs from that of Rhea (1) in the 

 greater vertical extent of the paired laminae, (2) in that these are often free 

 throughout, and (3) in that there are no anterior horns running forward between the 

 palatine processes of the premaxilla and the maxillo-palatine. In Emeus, the palatine 

 processes send inwards a pair of flattened spurs to embrace the sides of the anterior 

 end of the vomerine plate. 



Posteriorly, the feet of the vomer suturate with the pterygoid exactly as in Rhea. 

 The relations between these bones and the palatine is also the same. Indeed, the 

 inturned under-flooring region of the palatine in Emeus is more strongly developed 

 than in Rhea, projecting backwards to the level of its pterygoidal spur. 



In Apteryoc the vomer is relatively short, and cleft from behind forwards for about 

 half its length. Its form and relation are described on p. 205. 



The pterygoid in Casuarius is, seen ventrally, an elongated, crescentic rod of bone 

 dorso-ventrally compressed, with convex surface directed towards, and partly resting 

 on, the parasphenoidal rostrum, and its concavity, for the most part, articulating with 

 the palatine. Anteriorly, it runs forwards along the inner side of the hinder limb of 

 the vomer — which is at this point wedged in between the pterygoid and palatine — and 

 terminating thereon in a sharp spine. Its proximal end articulates with the quadrate, 

 below the orbital process ; mesiad and anterior to this articulation is a second for 

 articulation with the basipterygoid process. Seen dorsally, the pterygoid is fusiform, 

 not crescentic, a large median tube overlapping that part of the palatine which on a 

 ventral view appears within a crescentic hollow. Thus the true shape of the pterygoid 

 cannot be seen without the removal of the palatine, which discloses the dorsal 

 overlapping lip. 



In Dromams (PL XLII. fig. 7) the form and relations of the pterygoid are simpler. 

 Its relative length is about the same, and it terminates anteriorly in a point. The 

 anterior region of its external lateral border is directed upwards in the form of a thin 

 vertical plate affording a sutural surface for the external vertical plate of the vomer. 

 The posterior region of this border is straight and affords attachment to the palatine. 

 Its internal, mesial border is convex, the convexity facing the angle between the 



