Osteoiogical Studies of the Sub-Family Ardeitur. 23 
to outer xiphoidal processes, each of which point directly back¬ 
wards, and have simply rounded extremities. 
Evenly convex throughout, the sternal body shows but three 
pairs of lines upon this view — the pair of muscular lines of the 
pectoral muscles ; the subcostal lines ; and a pair, each one of 
which commences at the middle point of the inner border of the 
xiphoidal indentation, to be carried forwards and inwards to the 
carina, meeting the hinder ends of the pectoral lines. 
Anteriorly, we are enabled to see the under side of the point¬ 
ed manubrium, and the coracoidal beds, and gain some idea from 
the dissimilarity of the parts on the two sides of the former, of 
the method of decussation of the latter. 
The anterior third of the lateral margins of the body of the 
sterum show, also, upon this view the little rounded elevations in¬ 
dicating the position of the articular facets for the haeitiopophyses. 
The keel fails to reach quite to the end of the sternal body 
behind, but is brought far up in front, commencing imn> lately 
beneath the manubrium. . < 
Owing to the decussation of the coracoidal grooves ,,t depends 
upon which side of the sternum we view, as to how this part of 
the bone appears. In the drawing the right lateral view is pre¬ 
sented, and in this particular specimen the coracoidal groove seems 
to have a deep triangular notch in it. Had we seen it the other 
way, the groove would appeared as if it ran in one continuous belt 
around this anterior part of the bone. 
Upon this aspect, the manubrium is seen to project directly 
forward as a straight process. Below it, the anterior carinal mar¬ 
gin is sharp, being concave forwards above, and straight below. 
The carinal angle is rounded. Muscular lines are barely seen on 
the side of the keel, the surface here, as it is 011 the sternal body 
above it, smooth and polished, the bone becoming only slightly 
thicker anteriorly below the coracoidal beds. 
The keel is bounded interiorly by an elegantly curved margin, 
extending from the carinal angle to nearly the end of the sternum 
/pig. g). We are now better enabled to seethe hsemapophysial 
facets, with the deep concavities between each and its neighbor. 
As in so many birds, these interarticular cavities are the favorite 
sites of the pneumatic foramina, and they are seen to be numer¬ 
ous here, occupying the bottoms of the pits. For the rest of the 
border behind, it is sharp and continuous with the upper bor de 
