40 Philippine Journal of Science wis 



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 vertebrss. — 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. Here 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 



