In a paper on “The Index of the Pelvic Brim as a basis of Classification,” which I read in September at the meeting of the British Association in Aberdeen, and published in the Journal of Anatomy and Physiology, October 1885, I briefly referred to variations in the length and breadth of the sacrum in different races of men, and pointed out that in some races the length exceeded the breadth, and that in others an opposite relation prevailed. These differences may be expressed numerically by computing a sacral index by the following formula:

When the sacral index is above 100 the breadth of the bone is greater than the length, when the index is below 100 the sacrum is longer than broad. The following descriptive terms may conveniently express these differences in the relative length and breadth of the sacrum. As the Greek word ἱερον is the equivalent of the Latin sacrum, the term dolichohieric would signify a sacrum in which the length exceeded the breadth, whilst platyhierie would signify a sacrum in which the breadth exceeded the length.