6 
Comparative Measurements of Phalanges of Manus 
— 
Chirostenotes 
pergracilis. 
No. 2367, Geol. 
Surv., Can. 
Struthiomimus 
altus, No. 5339, 
Am. Mus. Nat. 
Hist. 
Ornitholestes 
kermanni *, 
Nos. 587-619, 
Am. Mus. Nat. 
Hist. 
Mm. 
Mm. 
Mm. 
Digit I 
Length of phalanx 1 
63 
110 
30 
“ “ 2 
44 
65 
30 
Digit II 
Length of phalanx 1 
65 
40 
41 
“ « 2 
72 
90 
44 
“ “ 3 
62 
85 
39 
Digit III 
Length of phalanx 3 
44 
75 
26 
<« K 4 
36 
80 
30 
Total length of digit I, exclusive of metacarpal 
107 
175 
60 
Total length of digit II, exclusive of metacarpal 
199 
215 
124 
Total length of digit III, exclusive of metacarpal 
128‘ 
215 
70 
In size and in several of its structural features the manus is inter- 
mediate between the Morrison Ornitholestes and the Belly River Struthio- 
mimus. In the inequality in length of the digits, the elongation of the 
proximal phalanx of digit II, and the presence of strongly recurved unguals, 
this foot resembles Ornitholestes. On the other hand, in the elongation of 
me. I and the proximal phalanx of the pollex, which results in a considerable 
lengthening of that digit, it approaches the proportions found in Struthio- 
mimus. 
The manus of Chirostenotes pergracilis is essentially a raptorial foot, 
though in its degree of specialization it does not appear to have advanced 
as far as in the highly specialized Struthiomimus . Though the foot, as a 
whole, approaches Ornitholestes, the answer to the question whether Orni- 
tholestes may be considered directly ancestral to the group which includes 
the present form must await the discovery of more complete Upper Creta- 
ceous specimens. 
The relationships of C. pergracilis are evidently with the light-limbed, 
slender-jawed Coelurid group of theropod dinosaurs as characterized by 
Matthew and Brown. The peculiarly specialized manus with long, slim 
phalangials, with the distal ends of metacarpals deeply grooved and with 
compressed strongly curved unguals, all indicate the affinities of this form 
to be in the family Coeluridae to which it is now referred. 
Description of Referred Specimen 
No. 343, Geol. Surv., Can., consists of considerable portions of both 
dentaries, containing roots of functional, and a few complete germ, teeth. 
Collected by C. M. Sternberg, 1917. 
Locality: Sec. 30, tp. 20, range 11, W. 4th mer., 2\ miles south of the 
mouth of Little Sandhill creek, Red Deer river, Alberta. 
1 Estimated. 
s Measurements taken from Osborn’s figure of manus. 
