AXIAL SKELETON OF THE PELECANIDA. 569 
canal, large and much pointed hyperapophyses, and with only slightly marked inter- 
zygapophysial ridges; fifth and sixth vertebrae not grooved beneath, but with a median 
ridge; postzygapophyses of seventh vertebra not more postaxiad than those of sixth; 
postaxial margin of neural arch of seventh vertebra not very concave, the first (pre- 
axially) deeply concave behind being that of the eighth vertebra; eighth vertebra 
about as long as the seventh, with no hemal arch, but with very prominent and rugged 
metapophyses, with styloid processes rather longer than in the seventh vertebra, and 
with prezygapophyses much more preaxiad, and postzygapophyses rather more post- 
axiad than the centrum. Ninth vertebra, and the first one which is at all pressed 
back preaxially; it is like the eighth of Pelecanus; its neural spine not so much 
developed as that of the eighth vertebra, and always with no hemal arch; its hy- 
perapophyses two very sharp lateral processes; its metapophyses sharp and long, but 
- not so much as those of Sula. ‘Tenth vertebra with no hemal arch; the post- 
zygapophyses of the eleventh vertebra fail, for the first time, decidedly to reach the 
postaxial end of centrum (therefore both zygapophyses fall short of antero-posterior 
limits of centrum); thirteenth vertebra with no hemal arch, but the catapophyses almost 
form one; a long median hypapophysis suddenly appears on the fourteenth vertebra ; 
fifteenth, sixteenth, and seventeenth vertebrae with large, median, plate-like hypapo- 
physes; postero-external angles of centrum of eighteenth vertebra drawn out into 
triangular processes ; nineteenth vertebra with a long narrow hypapophysis, and with 
its centrum laterally compressed; dorsa of tenth to nineteenth cervical vertebre not 
even much flattened, and therefore certainly not antero-posteriorly grooved; great 
lateral compression in centra of nineteenth to twenty-seventh vertebrae; sixteenth, 
seventeenth, and eighteenth vertebree expanded and flattened beneath in spite of the pre- 
sence of a hypapophysis; twentieth to twenty-fourth vertebre opisthoccelous; para- 
pophyses of second sacral vertebra not much, if at all, stronger than those of the first ; 
parapophyses of sacro-caudal vertebre rather suddenly bent dorsad. Tlio-caudal pro- 
cesses long and pointed; obturator-foramen oval, still longer than in Sula; sacro- 
sciatic foramina visible when the pelvis is viewed dorsally; transverse diameter ot 
pelvis, between its antitrochanteric processes, falling short of that of the most preaxial 
part of the ilia; each lateral acetabular fossa small, and shaped as a parallelogram; no 
supraacetabular fossa; pelvis very elongated; postaxial half of external margin of 
ischium strongly convex; ventral surface of conjoined ischium and ilium extensive ; 
ventral surface of ischium very strongly ridged; ischium, external to obturator-foramen, 
narrow. Pygostyle bent up dorsad, and shaped like the claw of a feline mammal. 
All the long vertebral ribs except the last with an uncinate process ; last sternal ribs not 
expanded proximally. Length of sternum exceeding its breadth but little more than 
in Pelecanus; lateral xiphoid processes rather broad, but pointed; pleurosteon much 
narrower dorso-ventrally than in Pelecanus, and with only four articular surfaces. 
