AXIAL SKELETON OF THE PELECANIDA. 359 
spine is much more extended antero-posteriorly, while its hypapophysis is much reduced 
(not being larger than in Phalacrocorax), but still extending postaxiad of the centrum. 
The rib-like styloid process is still shorter and more notched preaxially; while the 
lamella of bone enclosing dorsally the lateral vertebral canal is still more antero- 
posteriorly extended, and also more outwardly. The ventral surface of the centrum is 
flattened and much broader than in the sixteenth vertebra, while its external margins 
are developed with lateral catapophysial ridges. 
The EIGHTEENTH VERTEBRA (Plate LVIII. figs. 37 & 38) is like the seventeenth, except 
that the neural spine is still more elongated antero-posteriorly, and dorsally flattened, 
and the hypapophysis still more diminished, the centrum still more flattened beneath, 
and its lateral ridges more developed. While the lamella enclosing the lateral canal 
dorsally is as large, there is ventrally but a slender osseous bridge, the point of junc- 
tion between which and the dorsal plate is the last rudiment of the styloid process. 
THE CERVICO-DORSAL VERTEBR. 
In the NINETEENTH VERTEBRA, compared with the eighteenth, the transverse processes 
extend less outwards and are inclined more postaxiad, and the lateral hypapophysial 
ridges are more developed, while the root of the median hypapophysis extends further 
preaxiad (Plate LVIII. figs. 39 & 40). 
Compared with the nineteenth vertebra of Phalacrocorax, the transverse processes 
extend much less outwards, the hypapophysis is much more postaxially situated, and 
more inclined postaxiad distally. The centrum is very much less laterally compressed, 
and very much more flattened ventrally, with lateral hypapophysial ridges much more 
laterally extended; these ridges cannot be parapophysial, because the heads of the ribs 
articulate dorsally tothem. The postaxial articular surface of the centrum is much more 
extended transversely; and the prezygapophyses are relatively as well as absolutely 
smaller. 
In the TWENTIETH VERTEBRA (Plate LVIII. figs. 41-43), compared with the nineteenth, 
the lateral hypapophysial plates (or catapophyses) are still more developed externad, 
being conspicuous lamellar processes. They do not, however, now reach to the post- 
axial end of the centrum, but only project out from its preaxial half. The median 
hypapophysis is shorter dorso-ventrally ; but its root now extends to the preaxial margin 
of the centrum. The postaxial surface of the centrum is less extended transversely. 
Compared with the twentieth vertebra of Phalacrocoraa, the median hypapophysis is 
very small and postaxiad, while the centrum, instead of being greatly compressed 
laterally, is extremely flattened ventrally with great lateral hypapophysial processes, 
the distal ends of which begin to incline somewhat ventrad. ‘The outline of the post- 
axial articular surface of the centrum is more quadrangular, not rounded, and is less 
concaye. Its sides are concave from the outward extension of the postaxial ends of the 
lateral hypapophysial ridges. 
