I90I.] 



O shorn and Granger, Limbs of Sauropoda. 



203 



distinguished by the deep groove upon its anterior face ; the 

 lower articulation of the humerus indicates that the limb was not 

 greatly flexed at the elbow in the standing position, a fact in 

 keeping with the great weight of the anterior portion of the body. 

 In an uncrushed humerus the ulnar condyle is also well defined ; 

 the ulna, however, extends around and behind the radius. 



Proximally the radius articulates on the anterior outer side of 

 the humerus with the radial condyle ; it fits in the broad anterior 

 groove of the ulna, which 

 element supports the entire 

 posterior as well as the inner 

 portion of the humerus, 

 while the radius supports 

 the anterior and outer por- 

 tion only. The analogy of 

 these elements with the 

 fore limb of the elephant is 

 obvious, because in both 

 the proboscidian and dino- 

 saurian the ulna is a stouter 

 element than the radius, as 

 shown by reference to the 

 respective circumferences 

 of the shafts, namely : 



Diplodoctis . No. 594 No. 5S8 



mm. mm. 



Ulna = 285 2go 



Radius = 255 265 



The shaft of the radius 



also crosses that of the ulna 



completely, as in the elephant and other ungulate mammals. On 



the posterior face of the radius, in its upper fourth, is a stout 



tuberosity for the ligaments and muscles connecting this bone with 



the ulna. Distally, the radius and ulna present approximately 



equal facets for the carpals. 



Two carpals were found entirely out of position, making it 

 difficult to determine their homologies ; the larger of these appa- 

 rently belongs to the opposite side and, as the evidence is con- 

 flicting, reference must be made to another fore limb, No. 588, 

 described below. 



Fig. 3. Fore limbs of Sauropoda. 

 A. Complete fore limb of Moro- 

 saurus^ Amer. Mus. Coll. No. 

 332 ; B. Humerus of Diplodocus, 

 Amer. Mus. Coll. No. 342 ; C. 

 Humerus of Brontosaurus^ Amer. 

 Mus. Coll. No. 280. All from the 

 Bone Cabin Quarry, jj nat. size. 



