Troxell — Vertebrate Fossils of Rock Creek, Texas. 627 



The study of these specimens offers an interesting test of the 

 use of " ratios," by which the parts are separated into well 

 defined groups. Each bone is compared in as many dimen- 

 sions as possible with the corresponding part of Canis fami- 

 HarisJSo. 1077 of the Peabody Museum Osteological Collection 

 and its average is tabulated in the index list. 



Fig. 16. 



Fig. 17. 



Fig. 18. 



® ®&^^^^^ 



Fig. 16. Canis dims, proximal phalanx. Anterior, lateral, and posterior 

 views. One-half nat. size. 



Fig. 17. Canis dirus, tibia, posterior view. One-third nat. size. 

 r Fig. 18. Canis tcxanus, n. sp., holotype, ramus and dentition. One- 

 third nat. size. 



The largest animal, of which there are four parts (group I), 

 gives an average ratio of 151 per cent ; the second, group II, 

 which includes the type of C. texanus, n. sp., and seven parts 

 constituting the paratype, gives an average of 111: per cent. 



