5 
The manus may be described as anisotridactyl, and in the inequality 
of the digits it is intermediate between the fore foot of Ornitholestes and 
that of Struthiomimus (compare Figures 1 and 2), though closer to the 
former than to the latter. 
The deeply grooved and keeled interphalangial joints are evidently 
for the purpose of confining the digits to an exclusive opening and closing 
movement, and this same articulation persists in the joints between the 
metacarpals and proximal phalanges, with the possible exception of this 
joint in digit III, which is still unknown. 
Figure 2. Left fore foot of Struthiomimus alius (Lambe). No. 5339, Am. Mus. Nat. Hist. 
A, Dorsal aspect; A 1 , palmar aspect; r, radiale; i, intermedium (?) coalesced with ce, centrale; 
Ci, C*, carpalia. One-third natural size. B, left fore foot of Ornitholestes hermanni Osborn. No. 
587, partly restored digit I from No. 619. Am. Mus. Nat. Hist. One-half natural size. Both 
figures after Osborn. 
The known phalanges are compressed, extremely long and slender, 
and highly pneumatic, as is so clearly indicated by their flattening due to 
post-mortem crushing. The walls of the bone are especially thin and 
bird-like, as in the known members of the Coelurid®. 
