CREODONTA. 307 



Measurements. 



M. 



Length last four superior molars 022 



Length Pm. iii 0065 



Length Pm. iv 0085 



Width Pm. iv 0050 



anteroposterior OO.'iS 



transverse 0088 



oblique external '. 0072 



Diameters M.ii^^"t<'^°P''^"^™'' 0027 



( transverse = 0055 



■rx. . ■ i- • nr ■< anteroposterior 007 



Diameters interior M. i < ^ 



< transverse 005 



_. , • i. • 111 ..(anteroposterior 0055 



Diameters inferior M. ii < ' 



( transverse 003 



Depth of ramus at M. ii (squeezed) . 010 



The peculiar characters of the last inferior molar distinguish this species 

 from its congeners. The last superior molar is relatively smaller than in 

 the D. protenus. In size this species is equal to the D. dawkinsianus, and 

 is smaller than the D. leptomylus. As already remarked, the inferior denti- 

 tion approaches that of Oxycena. A slightly-increased development of the 

 anterior cusps of the last (second) inferior true molar would give two infe- 

 rior tubercular sectorial molars, as in that genus. The superior dentition is, 

 however, totally different, for there is no approach in the first true molar to 

 the sectorial type characteristic of the Oxycenidce. It is dedicated to the 

 distinguished geologist, Dr. F. V. Hayden. 



Puerco epoch of New Mexico; D. Baldwin. 



DiDYMICTIS ALTIDENS Cope. 



Bulletin U. S. Geol. Surv. Terrs., vi, 1881, Feb. 26, 190. American Naturalist, 1880, Oct. 746. 



Plate XXV a, figs. 13-14. 



This species is represented in my collection by the jaws of four indi- 

 viduals in a fragmentary condition. One of these supported the last five 

 inferior molars ; in others the inferior molars are separate from the jaws. 



