388 University of California PuUications in Geology [Vol. 12 



PLIOHIPPUS EDENSIS, n. p. 



Type specimen. — A small, moderately worn upper cheek tooth from the right 

 side, Univ. Calif. Coll. Vert. Pal. no. 23331 (fig. Ill), Univ. Calif, loc. 3269. 



Bef erred specimens. — Premolars, nos. 23329, 23284, 23333 (figs. 113-115); 

 molars, nos. 23233 and 23207 (figs. 112, 117) ; M^, no. 23337 (fig. 116); and frag- 

 ment of jaw containing P* and M^, no. 23349 (fig. 118). All specimens in Univ. 

 Calif. Coll. Vert. Pal.; all from Univ. Calif, loc. 3269. 



Characters. — The moderate size, the long, narrow, curved crowns, 

 the thin, elliptically-shaped, and backwardly directed protoeone which 

 entirely lacks anterior projection. 



DescrixAion. — A comparison of the type specimen (no. 23331, fig. 

 Ill) and the directly referred specimens suggests that the type repre- 

 sents P^, the other teeth respectively three P%, an M^C?), an M^(?), 

 and an IM-. The type specimen is moderately worn (compare fig. 118 

 and tooth sections, fig. 117). The styles are light. The narrow, 

 elliptically-shaped protoeone is bent characteristically backward, and 

 is quite lacking in anterior extension. In moderately worn teeth the 

 protoeone tends to narrow in transverse diameter toward the rear of 

 the series. In worn teeth, such as are illustrated by the sections of a 

 molar (no. 23207. fig. 117) and and (fig. 118), the protoeone 

 is seen to retain much of its original form though tending to shorten 

 slightly anteroposteriorly and broaden transversely. The postproto- 

 eonal valley in the type specimen and in the referred molars is narrow 

 and without the accessory fold which occurs in the wider valleys of 

 the three upper third premolars. The lakes as compared with those 

 of the following type are of very moderate size, being smallest in the 

 molars; their margins are somewhat indented, especially in the more 

 slightly worn upper third premolars. 



Measurements of Teeth of Pliohippus edensis, n. sp. 



No. 23331 No. 23329 No. 23333 



Anteroposterior diameter of crown 23.7 mm. 25.8 mm. 25.9 mm. 



Transverse diameter of crown 23.2 24 21 



Length of protoeone of crown 8.2 9 8 



PLIOHIPPUS EDENSIS, subform A, PLIOHIPPUS SPECTANS-LIKE 



Type. — A large and slightly worn tooth from the right side, Univ. Calif. Coll. 

 Vert. Pal. 24039 (figs. 119a, 1196, 119c). 



Bef erred material. — A worn molar, Univ. Calif. Coll. Vert. Pal. no. 23328 (fig. 

 120); both teeth from Univ. Calif, loc. 3269. 



Additional material. — Second premolar, Univ. Calif. Coll. Vert. Pal. no. 23234 

 (fig. 122&), Univ. Calif, loc. 3269. 



