630 Troxell — Vertebrate Fossils of Rock Creek, Texas. 



ratios are quite constant and again there is a great variation, — 

 significant of the specific differences in the two types com- 

 pared. 



Group I. 



Description 



Phalanx 



Length 



Prox. diam. trans. 

 Prox. diam. ant.-post. 

 Distal diam. trans. 

 Distal diam. ant.-post. 

 Shaft, diam. trans. 

 Shaft, diam. ant.-post. 



Speed index 



L 

 W 



Fossil 



Ratio 



Recent 



No. 10079 



No. 1077 



No. 145 







4-3 



143 



3-0 



1-6 



160 



1-0 



1-3 



144 



0-9 



1-4 



175 



0-8 



1-0 



167 



0-6 



1-2 



171 



0-7 



0-9 



180 



0-5 



3-58 



163 



4-29 



Tibia 



No. 41 







Length 



26-2 



119 



22-0 



Width, prox. trans. 



5-6 



137 



4-1 



Distal ant.-post. diam. 



3-6 



171 



2*1 



Shaft, trans, diam. 



2*2 



137 



1-6 



Shaft, ant.-post. diam. 



2-6 



173 



1-5 



Shaft, distal trans, diam. 



4-2 



150 



2-8 



Speed index 



W 



Rib 



Across tubercle 

 Radius of curvature 



P 3 



Antero-posterior diameter 



11 



No. 354 



1-4 

 9-5 



No. 12 



1-8 



148 



127 



158 



143 



150 



15-0 



1-1 



6-0 



1-2 



Group II. 



Description 



M 1 (Large) 



Ant.-post. diam. over middle 

 Grinding surface, transverse diam. 



Fossil 

 No. 10058 



No. 83 



1-3 



1-2 



Ratio 



118 

 133 



125 



Recent 

 So. 1077 



1-1 



0'9 



