AXIAL SKELETON OF THE PELECANID. 321 
series with the side of the median ventral prominence beneath the heemal arch of more 
postaxial vertebree. The parapophysial process of the seventh vertebra is much smaller 
and less conspicuous than in the sixth vertebra, and is a little antero-posterior ridge of 
bone outside the postero-ventral part of the pleurapophysial lamella. 
Thus the ridges bounding the median subcentral groove in more postaxial vertebrae 
are catapophysial (¢. ¢. lateral hypapophyses), the parapophysis hardly reappearing as a 
small distinct process till the fifteenth vertebra. 
The diapophysis does not begin to appear as a more or less distinct, though small, 
postaxially projecting process till at the fourteenth vertebra. 
When the seventh vertebra is viewed dorsally, the hyperapophyses are seen to have 
advanced somewhat preaxiad from the ends of the postzygapophyses, which extend 
much outwardly and postaxially beyond them. 
The EIGHTH VERTEBRA, unlike the same vertebra in Struthio and Dromeus, presents 
very great differences from its preaxial predecessor. The latter differs strikingly from 
the sixth by the sudden appearance of a deep concavity at the postaxial margin of the 
neural arch between the long backwardly extending postzygapophyses; but in the 
eighth vertebra other and more remarkable characters suddenly appear, some of which 
are correlated with the backward extension of the postzygapophyses of the seventh 
vertebra (Plate LY. figs. 13-17). 
The eighth vertebra is slightly shorter than the seventh, and very slightly shorter 
than the sixth, fifth, or even the fourth vertebra, though it is longer than the 
third. j 
When the eighth vertebra is viewed dorsally the neural surface of its centrum is 
more exposed than in the seventh vertebra through the oblique cutting away of the 
preaxial part of its neural arch, which arch is deeply concave postaxially, even more so 
than in the seventh vertebra (fig. 14). 
The preavial articular surface of the centrum (fig. 16) looks preaxiad and somewhat 
dorsad (instead of almost entirely ventrad, as in the preceding vertebra), is very much con- 
stricted medianly, while each lateral and expanded part is very convex dorso-ventrally, 
and very slightly indeed concave transversely. ‘The preaxial opening of the vertebral 
lateral canal (v) opens above (dorsad) and postaxiad to this surface, instead of above and 
beside it as in the seventh vertebra; thus it is hardly seen when the vertebra is viewed 
preaxially, but is conspicuous when the vertebra is viewed dorsally—conditions pre- 
cisely the reverse of those obtaining in the seventh vertebra. 
The postaaial articular surface of centrum (fig. 17) expands more laterally ventrad than 
in the seventh vertebra ; and the whole surface looks postaxiad and not dorsad. Viewed 
laterally the vertebra is seen to be less bent ventrad at its postaxial end than in the 
seventh vertebra, and the postaxial end of the catapophysial ridge, or plate (which 
bounds the subcentral groove externally), is more sharply defined as a process. 
For the first time since the axis vertebra, the prezygapophyses are not carried pre- 
