AXIAL SKELETON OF THE PELECANID#, 371 
seventeenth vertebra; postero-external angles of centrum of eighteenth vertebra ex- 
tensive, and extending more preaxiad than in Phalacrocoraz. Nineteenth vertebra with 
a small hypapophysis; centrum not at all laterally compressed, but ventrally flattened. 
Dorsa of tenth to fourteenth vertebree form a longitudinal groove; great lateral com- 
pression in centra of twenty-second to twenty-sixth vertebre; seventeenth to twenty- 
first vertebrae flattened beneath; twenty-second to twenty-fifth vertebra opisthoccelous ; 
parapopbyses of second sacral vertebra not stronger than those of first; parapophyses 
of sacro-caudal vertebre rather suddenly bent dorsad. Ilio-caudal processes long and 
pointed ; obturator-foramen shorter and rounder than in the three preceding genera ; 
sacro-sciatic foramina hidden when the pelvis is viewed dorsally, because of the length 
of the transverse processes of the sacro-caudal vertebre, which extend the ilium so 
much outwards on each side; transverse diameter of pelvis between its antitrochanteric 
processes falls short of that of the most preaxial part of the ilia; lateral acetabular fosse 
small and triangular; no supraacetabular fossa; pelvis rather short; postaxial half of 
external margin of ischium strongly convex; ventral surface of conjoined ischium and 
ilium rather extensive ; ventral surface of ischium very slightly ridged; ischium, ex- 
ternal to obturator-foramen, broad. Pygostyle much laterally compressed and dorso- 
ventrally curved. All the long vertebral ribs with an uncinate process, except the 
last rib; last sternal rib not expanded proximally. Length of sternum exceeding its 
breadth but little more than in Pelecanus; lateral xiphoid processes narrow, long, and 
pointed ; pleurosteon much narrower dorso-ventrally than in Pelecanus and with only 
four articular surfaces. 
CHARACTERS OF THE PELECANIDA. 
Cervical vertebre 15-18, cervico-dorsal 1-3, together 17-20; dorsal 5 or 6, prelumbar 
22-26, lumbar 3-5, together 8-10; cervical to lumbar inclusive 25-30, lumbo-sacral 
1—3, lumbar and lumbo-sacral 5—7, sacral 1—3, sacro-caudal 4-8, caudal 5-8, sacral to 
caudal inclusive but without pygostyle 13-18: total 40-49. Vertebral ribs 6-9; sacral 
ribs 5-7. A sudden change of form arising in either eighth or ninth vertebra, such 
vertebra being pressed back postaxiad at its preaxial end, and having both the vertebra 
in front and behind it bent dorsad from it; neural arch of seventh or eighth vertebra 
suddenly deeply concave at its hinder margin, save in Plotus; median hypapophysis 
always to seventeenth vertebra, and possibly present from fourteenth to twenty- 
seventh vertebra; always a complete, or nearly complete, hemal arch to two or 
three vertebra, and generally complete from tenth to thirteenth vertebra, sometimes 
from eighth to fourteenth; metapophyses often long and pointed; atlas generally 
with an odontoid foramen, sometimes with an odontoid groove; neural spine promi- 
nent in seventh to ninth vertebra:; postzygapophyses fail to attain the postaxial end 
of the centrum, for the first time, in from eighth to twelfth vertebre; twentieth to 
VOL. X.—PART Vil. No. 8.—August 1st, 1878. BE 
