1st. The oval form.—The superior opening of an egg-shaped figure, narrow in front, broadest near the sacro-iliac symphysis, and again narrowing to the sacral promontory. The antero-posterior diameter smaller than the transverse. The ilia moderately distant, and obliquely placed ; and the convergence of the walls of the true pelvis downward, also moderate. The sacrum moderate in breadth, length, and vertical curvature. The ischial tuberosities placed rather backward, and the spines widely distant. The sub pubic angle neither very acute in the male, nor the arch very prominent in the female. Of this type, he makes two varieties, — viz, the oval or male-oval, and the round-oval or female-oval; the male variety of form being sometimes found in the female. Of this form he gives three specimens :—one of an Euro pean male; one, very large, of a Botocundo male; and one of the round or cross-oval form, in an European female pelvis, broad and shallow, with the transverse diameter 5 in., and the conjugate 3 in. 10 lines. The pelvis of the Australian female, given in the table, belongs to the round-oval form, and that of the male Tahitian to the male-oval fortn.
2nd. The round form, distinguished by the round or cross-formed superior opening, by the vertical sides, less anterior direction of pubes, and less projection of sacral pro montory, making the conjugate of nearly the same extent as the transverse diameter. Of this form he gives five specimens, all females : — one European, two Negresses, one Hot tentot, and one Javanese.
3rd. The square or four-sided form, dis tinguished by the great breadth of sacrum and horizontal flattening of pubes. The transverse diameter greater than the conju gate, but the superior opening forming nearly a square. Of this form are six specimens :— one of an European female ; two of Javanese male, and one of a female of the same race, and two Mestizos.
4th. The cuneiform, or oblong form.— Su perior opening laterally compressed and ob long ; sacrum very narrow ; pubis with great anterior direction, so as to unite at an acute angle ; with the conjugate greater than the transverse diameter. In the female, this form snakes some approach to the oval shape. Of this form he gives eight specimens : — one of an European female, which has this shape very well marked, the conjugate diameter being 4 in. 9 lines ; one of a female Boto cundo ; one of a Negress ; one of a Negro ; one of a Kaffir ; and three others from Von Scemmerring's collection. The pelves of the Bushman and Negro, given in the table, belong to this form.
M. Weber's conclusions drawn from these specimens are, that though the oval shape is most common in Europeans, the round shape in the American aborigines, the square shape in the Asiatic or Mongolian races, and the oblong in the Negro races ; yet that none of the characters laid down by Vrolik are con stant, nor belong exclusively to any particular race, but that deviations from the usual form in any race present characteristics which gene rally belong to other varieties of the human species.
The coincidence between the prevailing form of the skull and that of the pelvic brim in these classes of the human race is worthy of especial remark, and influences ma terially, as before mentioned, the adaptation of the fcetal skull to the pelvic passage during labour. After the form of the skull, that of the pelvis is perhaps the most characteristic of race of any in the body, because of its great influence upon the shape of the trunk ; and yet, from Weber's researches, it would appear that it is not sufficiently so to constitute a greater distinction than that of variety, and is not exclusive enough in its peculiarities to es tablish separate generic classifications of the human species.
In the Sznzia, and those even which most closely approach in osseous conformation the human race, as in the genera Pithecus and Troglodytes, the form of the pelvis is suffi cient, at a glance, to distinguish them even frorn the Bushman and Australian, which have been seen to present all the pelvic pecu liarities of the higher varieties of humanity.
An inspection of the foregoing table will at once show this in the pelvic dianzeters. It will be seen that the antero-posterior dia meters in the Chimpanzee, Uran-utan, and Gibbon prevail greatly over the transverse ; that the depth both of the whole and the true pelvis is much greater.than in the human pelvis ; and that the sacrum Is much narrower, espe cially in the Chimpanzee, and the ischial spines more closely approximated. The, sacro-ver tebral angle, too , is remarkably increased, es pecially in the Chimpanzee (160°), the sacrum being placed much more nearly in the direc tion of the whole spinal column, and having a less vertical, as well as a much less horizontal curvature, with no sacral promontory in the Chimpanzee, and little in the Uran; while the coccyx is straighter, and placed more in the line of the spinal column, and its tip is ele vated above the level of the upper border of the symphysis pubis, so that the whole of the sacrum and coccyx is seen in front view. (See fig. 92.) This high position of the coccyx is owing partly to the shortness of the sacrum, which is composed of three large flat vertebrm, all entering: into the formation of the sacro-iliac joint, ancl united by ankylosis to two of the four coccygeal pieces in the Uran, and to one only in the Gibbons. In the Chimpanzee, however, there are four sacral vertebrx, all articulating laterally with the ilia, and the anterior sacral foramina are very small. The coccyx is composed of five vertebrm.