86 THE COLLECTION OF OSTEOLOGICAL MATERIAL FROM MACHU PICCHU. 



brazing strip, by which the upper and lower sections were united, projected widely into the 

 interior nearly all the way around. A tentorium of this description being abnormal to the 

 Hominidcc, the projecting portion of the strip was removed by tools made especially for 

 this purpose. The control skull then gave excellent results, but the labor of cutting adrift 

 the detrimental portion of the brazing strip exceeded that of preparing a natural skull and 

 gauging it with distilled water. 



On Table II will be found measurements taken from several of the best-preserved pelves, 

 the system followed being modeled closely after that so successfully used by Sir William 

 Turner in the Challenger Report. As will be seen in the photographic views of three of 

 the pelves (Plates XXIX, XXX and XXXI), Turner's method of mounting the pelvic bones 

 before measuring has been adopted, a thin piece of wash-leather being introduced into each 

 sacro-iliac joint to represent the substance of the sacro-iliac cartilages, while the pubic 

 symphysis is filled in by folds of leather approximating the corresponding cartilage in 

 thickness. In order that the method of computing the indices of the pelvic bones may be 

 perfectly clear, Turner's definitions are here repeated: 



Breadth-Height Index is the relation of the maximum breadth and height of the entire 

 pelvis to each other, and is computed by the formula '^^'ff ^ ^i^° ' 



Obturator Index expresses the relative height and width of this foramen, and is obtained 



b)' the formula transverse diam. X loo. 

 -^ vertical diam. 



Pelvic or Brim Index is the relation of the conjugate diameter to the transverse. It is 



computed by the formula conjugate diam. X loo . 

 '■ transverse diam. 



Iliac Index is the relation of the height-length to the breadth of the ilium obtained by the 



formula bl^_><J9o. 



height-length 



Pubo-innominatc Index is the relation of the length of the os pubis to the breadth of the 



innominate bone, and is computed by the formula P"biclengthx loo . 



innominate breadth 



Innominate Index. — The height-length of the innominate bone being the same as the height 

 of the pelvis, the relation of the breadth of the bone to its height is computed by the formula 

 breadth X lOO. 

 height-length 



Ischio-innominate Index is the relation of the length of the ischium to the height-length of 



the innominate bone or pelvic height, and is computed by the formula :!£!H?U£5StiL^J29. 



'■ ° ^ ^ pelvic height 



Sacral Index is computed by the fomuila br£idjl^Xjoo. 



length 



The photographs of skulls and pelves were taken at a distance of two meters, measured 

 between the lens of the camera and the Basion of the skulls in the one case, and between 

 the lens and the center of the object in the other. At this distance, the camera records very 

 nearly the true form of the skull; in fact the discrepancy between a photograph so taken 

 and a stereographic tracing is almost negligible. 



