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THE AMERICAN NATURALIST [Vol. XL V 



be applied with great circumspection to the dinosaurs. 



It is frequently asserted that the pelvis and the limbs 

 of the diplodocus possessed analogous resemblances to 

 those of the elephant. In the pelvis these are confined, 

 I believe, to the great size and to the convex iliac crest. 

 In the sauropod the ilia are directed from front back- 

 ward; in the elephant almost transversely. The pubes 

 and ischia in the two animals are utterly different. The 

 acetabula are different in form, size and position. The 

 femora of the two animals are alike large and straight- 

 shafted. That of the sauropod, however, has no great 

 trochanterial process; and whether, as my critics con- 

 tend, only the inner angle of the proximal end of the 

 femur or, as I insist, the whole of the proximal end, is to 

 be regarded as the head of the bone, this head is very dif- 

 ferent from that of the elephant. The size of the radius 

 relatively to the ulna and of the fibula to the tibia is 

 very different in the two animals. The digits of the ele- 

 phant, in general, are far less reduced than those of the 

 sauropod. That the limbs of the sauropods were 

 straight like those of the elephant has been assumed; 

 but we are now discussing that proposition. 



On the outer border of the upper end of the femur of 

 Diplodocus is a rugose area which extends downward a 

 distance equal to one fifth the length of the bone, per- 

 haps somewhat more. This, or at least its lower end, 

 represents the trochanter major. According to Dr. v. 

 Huene's figures, this trochanter occupied about the same 

 level in the Triassic dinosaurs, but it was placed some- 

 what more on the dorsal surface of the bone. Osborn 

 represents this trochanter in approximately its correct 

 position, but not extended far enough downward, as is 

 evident from the photograph reproduced on his Plate 

 XXIV. Dr. Matthew speaks of this trochanter as a 

 4 'clearly marked rugosity around the proximal external 

 angle of the head." I find this rugose surface on other 

 sauropod femora. The upper half of a large femur in 



'Mem. Amer. Mus. Nat. Hist., I, p. 210, Fig. 14. 



