1887] Variation of the Human Shoulder-Blade. 633 
35° or 40° in man, presents great differences, as is shown by the 
appended wood-cuts. I give no measurements, as the difficulty 
of making accurate ones is quite out of proportion to their value. 
The difference is in part, but not wholly, due to the development 
of the surface at the lower part 
of the axillary margin for the 
teres major.*. This muscle arises 
from the dorsal surface of the 
bone, but there is almost always 
a slight projection at this point 
from the anterior border, and 
occasionally it is developed into F: 
a projection of considerable size. ; 
_ Broca states that this is more 
common in negroes. I have no i 
opinion to offer on this. point, 
but I believe that this process 
does not stand in direct ratio to 
the size of the muscle. It is 
well marked on a very delicate . 
scapula (Fig. 5), and on the other Hei 
hand there is a large surface to 
this muscle with hardly any projection on a remarkably sharp 
bone (Fig. 4). An analogous: case is the third trochanter, the 
_occufrence of which, in my opinion, is quite uninfluenced by 
muscular development. The surface for the ¢eres major projects 
out very strongly in the lower Simiidz, Cebas, and Chrisothrix, 
according to Mivart. Its occurrence in man is probably (as in 
the case of the third trochanter) the appearance of a peculiarity 
of lower forms. The lower angle, however, varies considerably 
apart from the influence of this process. 
~ The vertebral border (Fig. 2).—The most common form of 
scapula presents a line slightly curved at the lower part, and . 
then straight as far as the root of the spine, from which point it 
inclines slightly forward till it ends at the upper angle. The for- 
__ward inclination of the upper part, though varying in degree, is, 
so far as I know, constant, but the rest of the line varies much. 
Sometimes it is almost straight, sometimes the whole border of _ 
_ the bone is convex, sometimes the border below the spine is con- __ 
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