The male and female skeleton may be said to differ, not only in the whole combination, or in the general impression, from a comparative survey, but also in the form and properties of the individual parts. The bones of the female are generally smaller, more delicate, and the muscular impressions, and asperities are less distinctly marked on them. The articulations are smaller, and the shaft or body of each cylindrical bone is more slender in comparison with the articular ends; the frontal sinuses are smaller, and the superciliary arches less prominent; all the bones of the face are more slender; the figure of the alveolar circle is more elliptical in both jaws; whereas in the male it is more circular. The differences, however, are in many cases very equivocal, since they may occur in the male as well as in the female skeleton; in the former, where the individual has had a feeble constitution, and never used active exercise; while in the latter, hard labour will frequently confer upon her bony structure the masculine contour which we have described as generally belonging to the male skeleton. The only decisive marks, therefore, by which a female skeleton can at once be distinguished, are to be found in the structure of the pelvis, and arise from the obvious cause of the female possessing a proper frame to become a mother. The pelvis of a female, at and below the _linea innominata_, formed by the lower part of the inside of the _ileum_, and ridge of the _pubes_, is much more capacious, from side to side, than in the male. The entrance or brim of the cavity is also more oval, the greatest diameter being from side to side. In the male it is more triangular, and the greatest diameter at the brim is from the fore to the back part; there is not much difference in the breadth of a male and female pelvis, belonging to individuals of nearly the same height, if measured from the anterior part of the spine of the _ileum_ to the corresponding part of the opposite side; the difference in breadth is chiefly confined to the basin-like part of the cavity. The _symphysis pubis_ is broader in the female, and the angle underneath it is much more obtuse, the space between the descending rami of the pubes is consequently larger. The _sacrum_ is broader, less curved, and turned more backwards; this also adds to the capacity of the cavity. The _os coccygis_ is more moveable, and much less bent forwards so that it does not project so much into the pelvis. The _tuberosities_ of the _ischia_ are farther distant from each other, and from the _os coccygis_; and as these three points are farther asunder, the notches between them are consequently wider, and there is of course a much greater space between the _os coccygis_ and _pubes_; and lastly the whole _pelvis_ is less massy, but more capacious and shallow in the female structure.[45] There are, moreover, some striking peculiarities to be discovered in the structure of the thorax, which if not equally satisfactory with that derived from a comparison of the _pelvis_, deserve serious attention. The whole thorax is shorter in the female, larger above as far as the fourth rib, narrower below; more moveable, less conical; more convex in front; more distant from the _pelvis_, the interval between the last rib, and the _os innominatum_ being greater; less prominent anteriorly, so that when the trunk is supine, the _symphysis pubis_ is the highest point in the female, whereas in the male subject, the thorax is the most elevated; the sternum is also shorter in the female, ending at the plane of the fourth rib, while it reaches to the plane of the fifth in the male; the clavicles are likewise less strongly curved, so that the _scapulæ_ are thrown backwards; the female _scapulæ_ are, moreover, smaller, slenderer, flatter, and have acuter angles than those of the male.