COMPARATIVE ANATOMY OF THE PELVIS. — In the different races of mankind, the pelvis, as influencing in a very great degree the form of the body, presents considerable varieties.
Camper, and afterwards Scemmerring, re marked that Negroes had more slender loins and hips than Europeans, consequent upon narrower pelves. Scemmerring gives a com parative measurement of the diameters of the brim in a Negro and an European of adult size. In the Negro, he found 3 in. llt lines, long or transverse diameter ; in the European, 4 in. 6 lines ; in the Negro the short or conjugate diameter was 3 in. 7-4- lines, and in the European, 3 in. 11 lines. From Camper's measurements, the long diameter was to the short one as 39 to 274, in an adult Negro, and as 41 to 27 in an adult European, who, nevertheless, was of much less stature than the Negro.
The measurements in the table on page 151, were taken in the dissecting rooms of King's College, from an adult male Negro 6 feet high. From the measurement of this pelvis, the antero-posterior diameters seem to pre vail in the Negro, and the whole pelvis to be smaller than in the European. This is seen remarkably in the limited breadth of the sacrum, (3 in. 9 lines), and in the ap proximation of the ischial spines (3 in.,) both much lower than the average European ; the latter, indeed, less than in the Chimpanzee. In fact, I have never met with an European sacrum so narrow as in the Negro above mentioned, especially in an individual so tall as 6 feet.
This difference is remarkably contrasted in the pelvis of O'Byrne, the Irish giant, in the Hunterian Museum, in which the iliac wings are remarkably large in compa rison with the true pelvis, and the sacrum very broad. The superior pelvic outlet is in this skeleton disproportionately larger than the inferior, the ischiadic tuberosities being nearly as close together as in ordinary sized pelves. This sudden narrowing of the pelvis has evident reference to the better sustaining of the viscera of the pelvis and ab domen.
It is supposed that in Negro women ge nerally, from the easy labours they undergo, there is much more proportionate pelvic ca pacity.* The dimensions of the pelvis of a Negress of small stature, contained in Bonn's Museum at Amsterdam, are given by Dr. Hull in his Second Letter to Simnzonds, as follows : At the brim, the conjugate diameter, 41 inches; the transverse, 41 ; the oblique, also 44- inches.
Fronn the inner extremity of the superior pubic minus, to the sacro-iliac joint )f the same side, 4* inches. At the outlet, the an tero-posterior diameter (measuring from the apex of the sacrum) was, 4* inches ; the transverse, 3i inches. The breadth of the sacrum was, 31 inches, and the length the same. The angle of the sub-pubic arch measured only 671°. In this pelvis also, al though a female, the prevailing size of the antero-posterior diameters, and the limited breadth of the sacrum and transverse dia meter of the outlet, as well as the exceedingly small expanse of the sub-pubic arch, are very remarkable, and are hardly accordant with easy labours, unless from the special adapt ation of the fcetal head.
Dr. Vrolik of Amsterdam, who devoted much attention to this subject, remarks, that the Negro male pelvis is contrasted widely from the female of the same race, in being strong, dense, and massy, while that of the female is light and delicate in appearance, although not presenting the transparent thin parts that the pelvis of the European female exhibits. But the Negro male pelvis given in the table is remarkably light, slender, and well formed for a man of so considerable a stature, and the centres of the ilia very concave, and as thin as in most pelves I have seen ; nor are the ischial tuberosities at all dispropor tionately large nor turned out, nor the pos terior superior iliac spines elevated. Vrolik points out also, as marks of degradation in type in the Negro female pelvis, the vertical direction of the ilia, their elevation at the posterior superior spines, and the approxima tion of the anterior iliac spines to the cotyloid cavity, together with the narrow transverse and antero-posterior diameters, the anterior sacral projection, the general elongation of the pelvis, and the greater acuteness of the sub pubic angle. This author considers these pe culiarities to resemble the formation of the pelvis in the Sinzice. But as far as I have myself seen, there are very few characters indeed, either in the Negro or Bushman pelvis, which assimilate to those of the widely-dif ferent pelves of the Chimpanzee or I.Tran.