600 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 49. 



Radius. — The radius is more slender than the ulna, more cylindri- 

 cal, and a little shorter. Its relative proportions as compared to the 



ulna appear to be almost iden- 

 tical with the forearm of Hyp- 

 silopJiodon, except perhaps that 

 both elements in that genus are 

 more slender. The distal end 

 of the radius appears to have 

 articulated exclusively with the 

 radiale. The length of the left 

 radius is 149 mm.; width of 

 proximal end, 30 mm.; width of 

 distal end (estimated), 22 mm. 



Manus. — There are five digits 

 in the fore foot of Thescelosaurus. 

 These have the phalangial for- 

 mula 2, 3, 4, 3, 2, as determined 

 from the articulated foot shown 

 in figure 11. 



The carpus consists of five 

 elements, a proximal row of 

 three bones of about equal pro- 

 portions — the radiale, interme- 

 dium, and ulnare, and a distal 

 row of two elements. The lat- 

 ter are flattened, irregularly, 

 rounded elements that articu- 

 late with the proximal ends of 

 metacarpals III and IV and 

 probably represent carpaha 

 three and four as shown in fig- 

 ure 11. 



Phalangial formula of known Dinosau- 

 rian fore feet. 



Digits. 

 I. II. III. IV. V. 

 Thescelosaurus neg- 



lectusGilvixoTG... 2 3 4 3 2 

 Hypsilophodonfoxii 



Huxley 2 3 4 3 2 



Leptoceratops gra- 

 cilis Brown 2 3 4 3 1 



Camptosaurus dis- 



par Marsh 2 3 3 3 2 



Trachodon annectens 



Marsh 3 3 3 3 



bernis- 



FiG. 11.— Left fore tiMB of Thescelosautics neg- 



LECTUS GaMORE. T\TE. CAT. No. 7757, U.S.N.M. 



i NAT. SIZE. Palmar view op foot shown as Iguanodon 



found in situ. C, carpus; H, humerus; R, ra- sartensis Bou- 



Dius; M, Ulna. lenger 1 



3 



