510 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.49. 



The ulnare is not known. Carpale two is apparently represented 

 by the small flattened ossicle that was found attached to the proximal 

 end of mtc. II (fig. 7c), of the right foot which is in close apposition 

 to the outer anterior border of the intermedium. A detached bone 

 found near the left manus is regarded doubtfully as representing Cg. 

 It is elongated in one diameter with angularly rounded surfaces. 

 There is no clue as to the position it occupied on the foot, if indeed 

 it represents such an element. Its longest diameter is 31 mm., with 

 a least diameter of 1 1 mm. 



Metacarpus. — The complete metacarpus in Allosaurus apparently 

 consists of three elements, there being no trace in either foot, of mtc. 

 IV which is present in the manus ^ of Ornitholestes Jiermani Osborn. 



Mtc. I is a short heavy bone with a deeply grooved distal end that 

 is turned inward away from the central axis of the foot. The articular 

 facets extend well upward on both front and back aspects (fig. 7d), 

 rising about equally above these surfaces of the shaft. The lateral 

 pits are moderately shallow, the outer one being the better defined. 

 Viewed from above the proximal end is subtriangular in outline with 

 a shallow concave articular end. This surface is opposed in the articu- 

 lated foot by the radiale and intermedium, the former only touching 

 shghtly the hinder internal corner, the remaining surface being closely 

 apphed to the intermedium, as shown in the right foot, where these 

 bones were found articulated. Mtc. I articulates closely on its upper 

 half with mtc. II (fig. 2), resting in a broad shallow depression on the 

 side of that bone. Mtc. II is an elongate bone, having an expanded 

 subquadrangular proximal end, rather a slender, angular rounded 

 shaft, and a less expanded but broadly grooved distal extremity. 

 The articular surfaces of the distal end of this bone are continued 

 backward in the form of two lateral condylar-like facets, which are 

 separated by a deep and moderately broad notch. The external one 

 is the larger of the two. The inner border of the proximal end is 

 beveled off, forming two facets of unequal size for the articulation 

 of the intermedium. The remaining proximal surface is smooth 

 though sloping toward the outside of the foot. Mtc. Ill is reduced, 

 being the weakest element of the metacarpus. Although present 

 with both feet, it was detached in both instances. The character 

 of the surfaces appears to indicate, however, that in position it 

 has a weak articulation with mtc. II on the postero-external angle 

 as shown in figure 2. Unlike the other metacarpals, the distal 

 articular end is not grooved but is smoothly rounded (fig. 7a). The 

 posteriorly directed facets are weakly developed, but are separated 

 by a shallow groove as in mtcs. I and II. 



Phalanges.— The phalangial formula is 2, 3, 4. All of the digits, as 

 shown in figure 7, are terminated with latterly compressed, sharply 



> H. F. Osborn. Bull. Amer. Nat. Hist., vol. 19, 1903, pp. 462, 463, figs. 2 and 3. 



