AXIAL SKELETON OF THE PELECANIDZ. 343 
Tue Ixivum. 
This bone extends over the last and part of the penultimate dorsal vertebre; and 
ossification of fascia extends to the preaxial end of the last dorsal vertebra but two, 7. ¢. 
the twenty-second vertebra. 
Seen laterally, the preacetabular part is less convex dorsally, convex preaxially, and 
concave postaxially at its ventral margin. 
There is a faint indication of an ilio-pectineal process, and a rudimentary posttro- 
chanteric process (figs. 1 & 2, st). There are marked antitrochanteric processes (af). 
The postacetabular part of the ilium has its dorsal margin convex, sloping down 
ventrad behind the last sacro-caudal, and giving out a short, postaxiad, slightly dorsad 
process (the ilio-caudal process), which, however, may belong rather to the ischium, 
This process is greatly extended, and becomes a long pointed process, in some species, 
as before stated. It is never so wide and massive as in Pelecanus. The dorsal margin 
of the sacro-sciatic foramen is more concave ; and the foramen is longer. 
Tue Pupis 
is like that of Pelecanus, but extends even more postaxiad relatively, and its preaxial 
part is less bent and convex ventrad. It is somewhat incurved mediad and very much so 
distally. 
Tue Iscuium 
has its external smooth antero-posterior groove rather deeper and narrower than in 
Pelecanus, but quite distinct ; the process (fig. 2, ps) in which its inferior boundary ends 
preaxially is rather more prominent and distinct. The internal groove is longer, nar- 
rower, and in a sigmoid curve (Plate LX. fig. 3, g). 
The postaxial expanded part of the ischium is smaller; and its postaxial margin 
slopes more preaxiad and ventrad, and probably develops the ilio-caudal process pro- 
jecting postaxially at about where it joins the ilium. 
The ventral surface of the ilio-ischium postaxiad to the sacro-sciatic foramen (mediad 
of the ridge bounding the ventral ischiatic antero-posterior groove medianly) is a smooth 
expanse, as also in Pelecanus; but it is here less concave. 
Tue Riss, 
There are seven long vertebral ribs, and six or seven sternal ones, 
THe VERTEBRAL Riss. 
They increase slightly in length to the fifth or sixth, and expand generally somewhat 
distally, especially the fourth, fifth, and sixth. The first four! have long uncinate 
processes, which arise more dorsad as we proceed postaxiad. They are a good deal 
flattened and expanded towards the middle of their superuncinate part. 
) Five sometimes—e. g. in 11863, o, and p, College of Surgeons. 
