648 S. W. WILLISTON 
thickened posteriorly, the planes of its outer and inner surfaces directed 
a little inward anteriorly. The scapula narrows rapidly to within a 
short distance of the glenoid fossa, and then is widely expanded 
antero-posteriorly for the coracoids. That portion corresponding 
to the procoracoid of the allied reptiles is a little thickened, nearly 
flat, and directed. somewhat toward the visceral side. The lower 
anterior angle is nearly rectangular, and the mesial border of the 
whole bone is gently convex in outline, and is somewhat thinned. 
Posteriorly the rather narrow coracoid projects strongly backward, 
its narrowed extremity thickened and strongly curved toward the 
visceral side. ‘The deep glenoid cavity is directed upward, backward, 
and outward. Above, the thickened hind border of the scapula 
divides, inclosing between its two branches a rather deep non-articu- 
lar fossa. The anterior or external branch continues downward in 
the same plane and direction as the scapular border, ending in a sub- 
triangular, articular facet looking backward and outward. The end 
of the humerus lay in immediate apposition with this facet. The 
posterior continuation of the scapular border, the thicker of the two, 
curves inward and backward, in a strong, nearly semicircular sweep 
to near the extremity of the coracoid. Between these two divergent 
borders, there is a deep cavity or fossa, evidently no part of the real 
glenoid fossa, pierced by a large foramen or fenestra at its bottom. 
Just below the lesser ridge which bounds this fossa posteriorly from 
the glenoid cavity, running from the internal angle of the humeral 
facet upward and backward, and near its middle part, there is a 
second foramen, which opens on the convex surface of the inner side 
of the bone. A third foramen is seen below the humeral facet, open- 
ing on the inner side at the lower end of the vertical flexure. This 
must be the true supracoracoid foramen, through which the scapula- 
procoracoid suture doubtless passes. The true glenoid fossa is 
limited below posteriorly by a strong declivity. The inner surface of 
the scapula above, like the exterior, is nearly flat, the lower surface 
convex in front. Just back of the glenoid cavity and corresponding 
to the vertical margin of the outer side, the bone on the inner side 
turns abruptly outward, save on the lowermost portion, bounding in 
front a posterior cavity into which opens the supraglenoid and the 
supracoracoid foramina, above and below, as shown by the arrows in 
