222 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



15. Acetabulo-symphysial width. Width between the posterior margin of the acetabulum and 

 the symphysis pubis. 



16. Sacral length. Vertical length of the 5 sacral vertebrae. 



17. Sacral breadth. Maximum breadth of first sacral vertebra. 



18. Width of sacrum at brim. Width of the superior strait at the reunion of the anterior lace 

 and the base. 



19. Inferior width of sacrum. Width of the sacrum below (at the interior part of the auricular 

 surface). 



4 33. THE COLUMNAR OR PILASTER FEMUR, F&MUR A COLONNE. 



We have studied this peculiar form of the femur, not by classifying the bones according to 6 

 different degrees as first recommended by Broca, but by finding an index as he later advises. (See 

 Tables LXIX to LXXIII.) In order to obtain this index we took two transverse measurements of 

 the diaphysis at its center one antero-posterior, the other lateral; we multiplied the former by 

 100 and divided the product by the latter as directed by Topinard.* Our results, therefore, may 

 be compared with a table given by Topinard. Our maximum index is 147.61. Our average 

 indices are for 66 right femurs, 114.74, for 65 left femurs, 116.94, and for 131 femurs of both sides, 

 115.83 (Table LXXII). In 15 series which Topinard gives us, representing ancient and modern 

 Europeans, Negroes, New Caledonians, and anthropoids, but three are higher than the Sahuloan. 

 These are: 1 nameless femur, 158; 1 femur from Cro-Magnon, 128, and 5 femurs from the Grand 

 Canaries, 117.5. These series are all so small that they can not be compared with ours to good 

 advantage. Indeed, Topinard has no series approaching ours numerically; his highest is 20 

 African negroes. We are not, then, able to judge with any degree of exactness where the Sala- 

 doans stand among the various human races and the lower orders of animals in respect to lateral 

 compression of the shaft of the femur, and prominence of the linea aspera; but we may safely say 

 that few, if any, races of men possess these peculiarities to a more exaggerated degree, and that 

 few if any are further removed in these particulars from the anthropoids. Whatever, then, are the 

 causes which produce the pilaster femur, they may be sought among the Saladoans. 



It has been often observed among other races that the pilaster femur and the flattened tibia 

 are associated features, and the Saladoans offer no exception to tliis rule. The flattening of the 

 tibia is perhaps more remarkable among them than the lateral compression of the femur. We 

 have some evidence, too, that, in this series at least, these features are associated in a direct 

 though not symmetrical or constant ratio. This is shown in Table LXXIII, in preparing which we 

 have selected 5 skeletons whose tibiae showed the lowest indices, i. e., the greatest lateral com- 

 pression, and 5 other adult skeletons whose (normal) tibiae exhibited the highest indices and the 

 least lateral compression. For these 10 skeletons we have presented- side by side the tibial and 

 femoral indices, and computed averages for the two groups separately. It will be seen by con- 

 sulting the table that the low tibial indices are accompanied by high femoral indices, and vice 

 versa; in other words, the lateral compression of the femur is in a general way proportionate to 

 the lateral compression of the corresponding tibia. Since the lateral diameter is employed as the 

 dividend in computing the index of the tibia, and the antero-posterior diameter is so employed in 

 the index of the femur, the indices of these bones bear an inverse relation to one another, i. e., the 

 narrower laterally the tibia, the lower the index; the narrower the femur, the higher the index. 

 These observations lead us to the conclusion that whatever causes operate to produce the platyc- 

 nemic tibia operate as well to produce the pilaster femur. Under the next section ( 34) we con- 

 sider these causes with regard to the tibia, because in that connection we fancy we can discover 

 their operation more plainly. 



$ 34. PLATYCNEMIA, OR FLATTENED TIBIA. 



There is probably no single series of bones in any collection which offers better advantages 

 for the study of platycnemia than the bones of the Salado. They belong to a race apparently 

 very homogeneous, whose general habits of life are well understood, and they present this peculiar 



* Op. tit., p. 1019. 



