ON RHAMPHORHYNCHUS BUCKLANDI 153 
from above downwards. Its contour is, roughly, that of a right- 
angled triangle with its apex directed backwards; and its lower 
edge passes into the sharp, outwardly concave ridge, into which the 
outer side of the posterior half of the coracoid is produced. An- 
teriorly, this lower edge rises into a rounded ridge-like tuberosity, 
as in the preceding species. 
The anterior end of the coracoid is produced for about half its 
‘depth into a process which appears to have been short, but whose 
extremity is covered by the adjacent humerus. So much of this 
process as can be seen is not more than ith of an inch long. At its 
‘superior angle, the outer surface of the anterior end of the coracoid 
is raised into a strong and prominent, somewhat sharp-edged ridge, 
which forms the lower lip of the glenoid cavity. 
The posterior extremity of the coracoid is fully half an inch wide, 
and is thicker in the middle than at either angle. The inner angle, 
again, is thicker than the outer, and more produced. The walls of 
the coracoid are as much as sth of an inch thick in the middle of the 
shaft ; so that its parietes are proportionally thicker, and its cavity 
less, than in the bones of the extremities, or of the jaws. This is 
intelligible when we consider that, in the absence of clavicles, the , 
‘coracoid must have sustained the thrust of the downward stroke of 
the fore-limb, and the concomitant strain of the pectoral muscles. 
Thus, the sternal end of the coracoid is, as in Birds, flat, ex- 
panded, and much wider than the middle, rounded part of the shaft 
of the bone, while its humeral end is thickened and elongated 
vertically. The plane of the sternal end does not form a right angle 
with that of the humeral end, but cuts it obliquely, passing upwards 
as well as outwards. 
The glenoid cavity is about }th of an inch long, and looks ob- 
liquely forwards and outwards, in the position in which the bone is 
figured ; but in all probability it looks backwards and outwards in 
the natural position. It is wider at each end than in the middle, 
and above than below; it is concave from above downwards, and 
‘convex from side to side. 
Superiorly, the humeral end of the coracoid passes into the 
scapula without any visible suture. The scapula becomes flattened 
from before backwards, above the upper edge of the glenoid cavity, 
where it has a width of about }th of an inch. Its general direction 
is at an angle of about 60° with the coracoid; but it is slightly 
curved, so as to be convex forwards and concave backwards. 
Its thickness is greatest along its axis; and both edges are thin. 
Its precise form and dimensions at its posterior end cannot be 
