1921] Frick: Faunas of Bautista Creek and San Timoteo Canon 401 



the average of these teeth might be considei-ed as greatly worn, and 

 on that ground referred to the smaller of the two foregoing typical 

 series, were it not : ( 1 ) for the presence of other greatly worn molars 

 already referred to that section; and (2) for tooth no. 23296 (figs. 

 148a-1486), which though long-crowned and comparatively little worn, 

 illustrates the same characters seen in the other narrow teeth. Tooth 

 no. 24228 (figs. 149a^l49&) shows a tendency to the even, oval form in 

 the valley bounding the protoconid of the of the teeth described 

 under subform A of P. osborni, from which it otherwise differs abso- 

 lutely through lacking: (1) the great development of the fold between 

 the protoconid and hypoconid; (2) the anteroposterior elongation of 

 the metaconid-metastylid column; and (3) the great degree of flatness 

 of the exterior faces of that more advanced tooth type. 



LOWER CHEEK TEETH OF PLIOHIPPUS, indeterminate 



Teeth of remarkably small size, and of uncertain form. 



Material. — A premolar, no. 23292 (fig. 153); molars, nos. 23517 and 23290 

 (figs. 154, 152); and a last molar, no. 23227 (fig. 155). All from general Univ. 

 Calif, loc. 3269. All in Univ. Calif. Coll. Vert. Pal. 



Figs. 152 to 15'5. Pliohippus, indet. sp. Lower cheek teeth of very small size. 

 Fig. 152, molar, no. 23290; m, outer view, X %; occlusal view, X 1. Fig. 153, 

 premolar, no. 23292, outer view, X %; m, occlusal view, X 1; n, cross section, 

 X 1. Fig. 154, molar, no. 23517, outer view, X %; m, occlusal view, X 1. Fig. 

 155, Mj, no. 23227, outer view, X 1,4; n, occlusal view, X 1. Eden beds, California. 



