AXIAL SKELETON OF THE PELECANID^E. 317 



also antero-posteriorly shorter, and dorso-ventrally longer, not only than in Struthio, 

 but even than in Urom&us, if we omit from consideration the hypapophysis of the 

 axis of the latter (Plate LV. fig. 3). 



The odontoid process is smaller relatively than in Struthio. 



Viewed preaxially, the articular surface of the centrum is more concave, and its 

 ventral margin more convex. 



Postaxially, the articular surface of the centrum looks less dorsad and more directly 

 postaxiad. The transverse extent of its ventral margin considerably exceeds that of its 

 dorsal margin. The hypapophysis is continued more ventrad than in Struthio. 



VentraUy, there may or may not be two ridges diverging postaxiad from near the 

 preaxial margin of the ventral surface of the centrum. 



Laterally, the neural spine extends more dorsad than in Struthio, like that of 

 Drommis, but is longer antero-posteriorly than in the latter genus. The neural arch 

 extends much more postaxiad than in Struthio, so that one third of its whole antero- 

 posterior extent is postaxial to the postaxial end of the centrum. 



The hypapophysis extends more ventrad ; its preaxial margin is concave or concavo- 

 convex, and inclined gently ventrad and postaxiad ; its postaxial margin is almost in 

 a line with the postaxial margin (as seen laterally) of centrum. 



There is a small pleurapophysial lamella (at preaxial third of side of centrum) 

 enclosing the lateral vertebral canal, the small preaxial aperture of which is visible 

 when the axis is viewed laterally ; there is a slight interzygapophysial ridge, which may 

 be perforated ; but there is no transverse process. 



Seen dorsally, more of the neural surface of the centrum is visible than in Struthio, 

 owing to more of the preaxial part of the neural arch having been, as it were, obliquely 

 cut off. The prrezygapophyses are very small ; but the postzygapophyses are nearly as 

 large, relatively, as in Struthio. Each is concave from without inwards, convex antero- 

 posteriorly ; and they look ventrad and slightly externad. 



The hyperapophyses (hp] are small and inconspicuous. 



The postaxial margin of the neural arch is slightly concave ; its preaxial margin is 

 more concave, but without any median projection preaxiad. 



The THIRD VERTEBRA is much larger and half as long again as the axis. Its neural 

 spine is less high ; its neural arch is medianly notched postaxially ; and the much 

 elongated bony lamella enclosing the lateral canal is laterally prominent, and is evidently 

 the first appearance of a transverse process. It bears, postaxiad, a rudimentary styloid 

 process. It differs from that of Struthio in the greater extent of its antero-posterior 

 dimension compared with its transverse diameter (Plate LV. fig. 4). 



Preaxially, the central articular surface is hardly to be seen, since it looks almost 

 entirely veu trad. 



VentraUy, a hypapophysis may be seen projecting ventrad and postaxiad at the postaxial 

 end of centrum ; but it may be flattened on its ventral surface so as to present two lateral 



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