THE INTERNAL SKELETON. 189 
its upper end a small concave surface, called the glenoid, into 
which fits the upper end of the bone of the upper arm or root 
of the wing. The other division is called the clavicular 
process, because it articulates with the clavicle. 
The coracoid is not represented by any distinct bone 
in ourselves, but only by a curved process jutting out from 
our blade-bone. This has been compared to a crow’s beak, 
whence it was named “ coracoid” process, and this has led to 
the name bestowed on that bone of the bird which corresponds 
with this process in ourselves. 
The scapula or blade-bone is another constant element of the 
limb-girdle, which has received from it the denomination of 
“scapular” arch, It answers to our “ blade-bone,” but is very 
different in shape, being a long, narrow, curved bone flattened 

SnHoULDER-GIRDLE OF A Birp (after Parker). 
ce, Coracoid (its lower end abuts against the sternum—here removed) ; c/, 
the clavicles (merrythought); se, the scapula—the rounded glenoid 
surface, for the head of the humerus, is indicated in the scapula close 
to the junction of the latter with the coracoid. 
from without inwards, like a small bony sabre passing back- 
wards over the ribs but quite detached from them. It is, how- 
ever, rather broad in the Penguins. At its lower end the 
scapula may be said to bifurcate ; part of it forms a concave 
glenoid surtace which unites with that so named in the coracoid, 
to form the ‘‘glenoid cavity” for the reception of the upper 
arm-bones. The other bifurcation forms a process called the 
acromial process, which gives attachment to the clavicle. 
The scapula may anchylose with the coracoid, as in the Ostrich. 
In that and a few other Birds the long axis of the scapula may 
be nearly in a line with that of the coracoid, but in almost all 
other existing species they make an acute, right, or only a very 
slightly obtuse angle. 
