114 R. 8. Lull — Cretaceous Armored Dinosaur, 



position. The character of the proximal radial facet 

 would indicate a rotatory movement as well, but whether 

 the distal end of the ulna would bear this out is of course 

 impossible to ascertain from the present material. The 

 insertion of the biceps muscle on the radius is clearly 

 indicated. 



Wlanus. — Marsh speaks of the manus in some detail; 

 I find, however, but few bones Avhich through a process 

 of elimination may have pertained to the manus, as the 

 remainder seem to be those of the nearly complete pes. 

 There are two complete metacarpals, apparently the 

 second and fourth, and fragments of one, probably the 

 third, as it was in contact with the second. Some of the 

 scattered phalangeal elements may also be of the hand 

 but they are difficult to place. If these bones really 

 pertain to the hand, they are exceptionally long, as the 

 entire ones, though more slender, are fully equal in this 

 dimension to their apparent equivalents in the pes, 

 differing in this regard from Stegosaurus, but if Baron 

 Nopcsa's restoration (1905, pi. 12) be correct, resembling- 

 the proportions of the Wealden Polacanthus, which in 

 many respects is similar to the form under discussion 

 (see under generic comparisons, infra). 



Metacarpal III has a subtriangular proximal face with 

 a rounded rugose area on the outer side. Distally the 

 articular end is semi-cylindrical, dilating somewhat 

 externally. The mid-shaft section is subtriangular, with 

 rounded faces. The shaft bears two low tuberosities on 

 the posterior oblique face. Metacarpal IV is somewhat 

 more slender and has a short proximal phalanx in 

 articulation therewith. An ungual is also present, and 

 while its form may be somewhat attenuated, due to 

 erosion of its lateral margins, it seems to have been much 

 more claw-like than were those of the pes. 



Measurements of Metacarpals. 



mm. 



Metacarpal II 



Length over all 125.6 



Max. diameter, proximal end 57.6 



Max. diameter, distal end • 65 



Max. diameter, mid-shaft 38.3 



Length of entire digit ca. 245 



Metacarpal IV 



Length over all 123 



