1916] Chandler: Skull and" Dentition of Bison antiquus 125 



an excellent opportunity for such a determination in Bison antiquus, 

 at least. There are thirteen more or less complete crania of various 

 ages, four of which have the horn-cores practically perfect, four have 

 the entire skull perfect or almost so, and five have the dentition almost 

 complete. In addition to this there are numerous fragments, and a 

 very large series of rami, in fact parts of sixteen different animals. 



Following is a general description of the specimens at hand, by 

 numbers : 



19478. The forehead, with complete horn-cores, of an old male individual. 



Pleistocene of the John Day region, Oregon. Figs, la and lb. 

 21154. A complete cranium of an adult male, with one horn-core. Eancho 



La Brea. Figs. 3a and 36. 

 21153. A complete cranium of a young adult male with both horn-cores. 



Kancho La Brea. Figs. 4a and 46. 

 21152. A skull of a young adult, complete with the exception of the outer 



part of both horn-cores. Inner pillar of M 1 connected, those of 



M2 and Ms unworn. Eancho La Brea. Figs. 7 and 9. 

 21151. A complete cranium of an adult, with both horn-cores. Eancho La 



Brea. Figs. 2a and 2h. 



21184. A complete skull of an adult, on mounted specimen in University of 



California. Eancho La Brea. 



21182. An imperfect cranium of a young adult, with both horn-cores broken. 



Eancho La Brea. 



21183. A complete skull with the exception of a few teeth, of middle-aged 



animal. Inner pillars of M 1 and M- connected, that of Ms only 

 slightly worn. Eancho La Brea. 



21186. An incomplete cranium of a young adult, with one horn-core missing. 



Eancho La Brea. 



21187. Portion of skull, with one horn-core, and a few teeth. Eancho La 



Brea. 



21188. Nearly complete skull of a calf, but both horn-cores broken. Milk 



molars present, permanent Mi just coming in. Eancho La Brea. 



21185. fcjkull of old animal, complete with exception of one horn-core. Inner 



pillars of all molars well worn. Eancho La Brea. 

 21190. Incomplete cranium of young adult, with both horn-cores broken. 

 Eancho La Brea. 



21443. Left half of upper jaw, with four teeth. Old, inner pillars of all 



molars well worn. Eancho La Brea. Fig. ] 0. 



21444. Premaxilla and front part of maxilla of rather young animal. Inner 



pillar of M 1 slightly worn. Eancho La Brea. 



21433. Imperfect ramus, old. Only molars present. Eancho La Brea. 

 21432. Imperfect ramus, old. All teeth present. Eancho La Brea. 

 21432. Imperfect ramus, old. All teeth present. Eancho La Brea. 



21434. Ramus, old, complete except for Ms and P 4 . Rancho La Brea. 

 21442. Complete ramus, middle-aged. Eancho La Brea. 



21445. Incomplete ramus, middle-aged. Only molars present. Eancho La Brea. 



21184. Eestored ramus, middle-aged, all teeth present. Eancho La Brea. 



21189. Complete lower jaw, with both rami, only P- absent. Middle-aged. 



Rancho La Brea. Fig. 11. 



