Peterson and Gii.more: Elosaurus Parvus. 



493 



<lc 



versely, and sujieriorly it presents a regularly 

 convex surface, and a well-defined head for 

 articulation with the sca])ula. The deltoid 

 crest is prominent, but in both humeri it is 

 turned oblicjuely outward thus forming much 

 less of a concavity on the anterior surface, 

 see Fig. 2, than is found in the humeri of 

 other Sauropoda. Medially the shaft is con- 

 stricted and a cross-section would be nearly 

 circular. I'he ulnar condyle has a flat rugose 

 surface while the internal or radial condyle is 

 slightly concave, the two being separated by 

 a well-defmed groove on the anterior face. 

 See ^i;, Fig. 2. 



Measurements. 

 Greate.'^t length of humerus, 225 mm. 8| inches. 

 Greatest breadth of humerus, 



proximal end, 104 " 4^^ " 



Greatest breadth of humerus, 



distal end, 80 " 3^ " 



U/na. — The ulna as in the other Sauropoda 

 is apparently the stouter element of the fore- 

 arm. On the anterior side the proximal end 

 has a well-defined groove in which the radius 

 fits. See Fig. 3. On the distal internal side 

 is a flattened, slightly rugose surface for the 

 attachment of the radius, which element cros- 

 ses from the front to the side of the ulna, as 

 has been .shown previously by Hatcher^ and 

 Riggs.'' laterally the proximal end is greatly 

 expanded (see Fig. 3), but the ulna tapers 

 down to a somewhat rounded distal extremity. 

 The proximal end of the ulna supports the en- 

 tire posterior and exterior portions of the humerus, thus enclosing ex- 

 ternally and posteriorly the proximal end of the radius, while the radius 

 articulates only with the internal or radial condyle. 



3 Hatcher. Forelimb and Manus of lirontosaurus. Annals of the Carnegie Museum, 

 Vol. I, pp. 356 et seq. 



* r^'gS'^- Foreleg and Pectoral Girdle of Morosaurus, Pub. Field Columbian 

 Museum Cieulogical Series, Vol. I, No. 10, p. 278. 



Fig. 2. Anterior view 

 of right humerus of £/o- 

 saurus piDi'iis (No. 566'), 

 ^ natural size, u.c, ul- 

 nar condyle; r.c, radial 

 condyle; (/.r. .deltoid crest; 

 g., groove separating ulnar 

 and radial condyles. 



Y\G. 3. Proximal end 

 of right ulna of E/osaunts 

 parvus (No. 566), one half 

 natural size. rg, radial 

 groove. 



