40 
Philippine Journal of Science 
1919 
and are situated well back from the anterior limitation of the 
centrum on any particular vertebra; that is to say, there are 
no demifacets (Plate VI). 
There are no epipleural appendages on either the last pair of 
the cervical ribs or the last pair of the pelvic ones (Plate IV) ; 
and, while of no great size on the first pair of dorsal ribs and 
the leading pair of pelvic ribs, they are conspicuously long and 
massive on the ribs of all pairs constituting the midseries. Any 
of these, in articulation, overlaps the body of the next rib 
behind; and all of these processes, at least in adult life, are 
very extensively and firmly coossified to the rib to which in 
any case they belong. With respect to direction, they all point 
upward and backward. 
In the harpy eagle the basic portion of any one of these epi- 
pleural appendages is notably extensive, and occupies, in the 
case of the second pair to include the fifth, a large part of the 
posterior border of the rib — fully a third at least. There is a 
smaller pair of these apophyses on the last pair of pelvic ribs 
(Plate V). 
All the ribs in Pithecophaga, save the cervical ones, articulate 
with the sternum by means of costal, or sternal, ribs ; and there 
are no floating ones on the last pair as there are in the case of 
the harpy eagle (fig. 17). In our subject these sternal ribs 
increase in due proportion, in size and length, as we proceed 
from the first to the last pair; they are more or less massive, 
in keeping with the rest of the skeleton of this ponderous bird, 
and the last two pairs exhibit more or less upward curvature 
(Plate IV). 
Our white-headed eagle has the last pair of pelvic ribs more 
or less feebly developed. The thoracic pair, upon one side or 
the other, may be more or less aborted with respect to its length 
and not descend to meet the usually well-developed corresponding 
pair of sternal ribs in this bird. 
The pelvis and the caudal vertebrae. — When we come to ex- 
amine and compare the pelves of various species of eagles from 
different parts of the world, we are struck by the marked sim- 
ilarity of form and of characters among them. This applies 
with special significance to the pelvis as we find it in our pres- 
ent subject and in the harpy eagle. liere the different char- 
acters are of the most trivial description possible — so much so, 
indeed, that a detailed account of the pelvis of an adult Pithe- 
cophaga jefferyi would answer admirably for the same bone of 
the skeleton in the harpy. Upon comparing Plates IV and V 
of the present memoir, it would appear that the disposition of 
