PHENACODUS. 463 



The animal was probably omnivorous in its diet. It was not furnished 

 with any weapons of offense or defense pertaining to the osseous system, 

 so that it must have sought refuge in flight. The well-developed muscular 

 insertions of its limbs, and the digitigrade character of its step, indicate that 

 it may have had considerable speed. 



Distribution. — The bones of this species have been found wherever the 

 beds of the Wasatch Epoch occur, but most abundantly in Northern Wyo- 

 ming. From the Wind River Valley Mr. Wortman brought two specimens, 

 and ten from the Big-Horn Basin. 



Synonyms. — Two names have been given to supposed species which 

 may be identical with this one. These are P. omnivorus and P. trilobatus. 

 The latter is considered under the head of the dentition. The former was 

 founded on an inferior molar from New Mexico. It remains for future exam- 

 ination to ascertain its true position. 



Phenacodus hemiconus Cope. 



Paleontological Bulletin, No. 34, p. 179, Feb. 20, 1882. Proceed. Amer. Philos. Soc, 1881, Dec. (1882), 



p. 179. 

 Plate XXV e; fig. 16. 



Represented by the posterior two superior molars of an individual in- 

 termediate in size between the P. primcevus and P. puercensis. The poste- 

 rior molar is peculiar in the very rudimental character of the posterior inter- 

 nal lobe, which is reduced to a mere wart on the cingulum. The posterior 

 external tubercle is also rudimental, not exceeding the posterior inner in 

 dimensions. The anterior tubercles, including the intermediate, are well 

 developed, the internal exceeding the external. The cingulum is wide and 

 crenate, and is only wanting on the external base of the crown. The pe- 

 nultimate molar does not differ so much from that of P. primcevus, but the 

 two internal cones are not so deeply separated at their base. The tubercles 

 are all but little worn, and are conical in form, the external flattened on the 

 external faces. Enamel wrinkled. 



Measurements. 



M. 



Diameter8 0fM.ii^'''^*^'"''P°^'«"°' '^ 



I transverse 012 



Diameters of M. ill I '^'^^'^'■''P^st'^"'"' " '^l" 



t transverse 013 



