M. R. Thorpe — New Fossil Carnivora. 477 



Art. XXXy. — Two Neiv Fossil Carnivora; by Malcolm 

 Rutherford Thorpe. 



[Contributions from the Othniel Charles Marsh Publication Fund, Peabodj 

 Museum, Yale University, New Haven, Conn.] 



Pliocyon marshi, gen. et sp. nov. 



(Figs. 1-3.) 



Holotype, Cat. No. 10043, Y. P. M. Eight lower jaw. Pliocene (Eat- 

 tlesnake), near Cottonwood, John Day Valley, Oregon. Collected in 1874 

 by L. S. Davis. 



Distinctive characters. — Dental formula I2, Cj, P2, M2 ; 

 ramus long and slender; angle heavy and rugose; P^ 

 small and adjacent to C ; P4 with prominent posterior 

 tubercle and heel ; Mj very large, with robust protoconid, 

 prominent metaconid, and low hypoconid medially 

 situated on the talonid; paraconid large and high. M2 

 long and stout, gradually decreasing posteriorly in width ; 

 symphysis short ; canines close together ; mental foramen 

 beneath anterior root of P4 and another below the anterior 

 part of the diastema behind P^ ; I3 in front of C ; nearest 

 part of C alveolus but 4 mm. from symphysis. 



Dimensions. 



mm. 



Ramus, length, C alveolus to condyle, inc 125 



Tooth row, length, C alveolus to Mo alveolus, inc 79 



M, alveolus, length . 14.5 



Ml, length 22.5 



Width 10 



P4, length 13.8 



Width 8 



C alveolus, ant.-post. diameter 13.5 



Transverse diameter , 8 



Depth of ramus below protoconid of M^ 26 



Depth of ramus below middle of Pm diastema. 20,5 



Geologic horizon. — This specimen was collected about a 

 mile west of Cottonwood, on the East Fork of the John 

 Day Piver. The enclosing matrix was soft tuff, lying 

 between the basal conglomerate and the capping rim rock 

 of rhyolite, about 3 feet below the lower edge of the latter 

 according to a letter written to Professor Marsh by L. S. 

 Davis, dated Camp Watson, March 15, 1874. This forma- 

 tion is the Rattlesnake of Merriam, and is of middle 



