1921] Frick: Faunas of Bautista Creek and San Timoteo Caiion 303 



The limbs are also represented by material from various localities which con- 

 forms with the foregoing: 



Portions of navicular and cuneiform bones (pi. 45, figs. 4, 5), nos. 23471a, 23765. 



Cuneiform, no. 23765. 



Portion of cuboid, no. 23766. 



Inner pulley of astragalus, no. 23769. 



Head and pulley of a metatarsus, nos. 23468 and 23471. 



Metapodial pulley and fragment of a second, nos. 23467 and 23468. 



Distal portion of a first phalanx, no. 23469. 



Second phalanx, no. 23465. All in Univ. Calif. Coll. Vert. Pal. Various 

 localities. 



Characters. — Equus bautistensis is characterized by: (1) The 

 prominent bilobed form of the anteroposteriorly elongated protocone 

 in the large sized premolar teeth and by the considerable anterior 

 extension of the protocone throughout the series, the protocone averag- 

 ing longer anteroposteriorly than that of the Rancho La Brea form of 

 Equus occidentalis Leidy ; (2) the relative amount and complexity 

 of the infolding of the fossette margins, which is less than that seen 

 in certain of the later equines and more than that occurring in E. 

 occidentalis; (3) the comparative narrowness in transverse diameter 

 of the referred lower teeth, and the relative flatness of the outer faces 

 of the protoconid and hypoconid; (4) the average sharpness of the 

 gutter of the metaconid-metastylid column, and the considerable 

 prominence of the valley between the protoconid and hypoconid ; 

 (5) the depth of the referred mandible viewed laterally, as compared 

 with E. cahallus, and the relatively slight concavity of the inferior 

 border of the mandible anterior to the angle of the jaw as compared 

 to E. occidentalis of Rancho La Brea. 



Description. — The upper dentition is of large size. The mesostyle 

 and parastyle of the premolars are relatively broad, in the molar series 

 the styles become progressively narrower. The protocone is large and 

 elongated, the anterior projection varying to less in well worn teeth 

 (see series no. 23244, folder 2, fig. 3). In the premolars it is deeply 

 bilobed, being sharply concave in the inner border; in the posterior 

 portion of the series the protocone progressively lengthens, and becomes, 

 markedly narrower and flatter. The postprotoconal valley is broad 

 in the premolars, and narrows slightly through the series. The de- 

 velopment of the fold at the anterior end of the postprotoconal valley 

 varies somewhat throughout the series, being considerable in certain 

 premolars and in some molars. The fossettes are long and have a 

 narrow appearance, owing to the deep incision of the opposed anterior 

 and posterior walls. The inner walls are considerably complicated by 



