432 



University of California Publications. 



[Geology 



18 



Fig. 15. — TSntoptyclius minimus. Portion of left mandible with P 4) M„ and 



M 2 . No. 12569, X 4. 

 Fig. 16. — Peromyscus antiquus. Portion of left mandible with complete 



molar series. No. 12471, X 4. 

 Figs, l't i and 176. — Diprionomys parvus. Portion of right mandible with 



incisor, P 4 and M,. No. 12566, X 4. 



Fig. 17a, lateral view; fig. 176, superior view. 

 Fig. 18. — Diprionomys magnus. Fragments of left mandible with P 4 , M 1; 



and JVL. No. 12567, X 4. 



PEEOMYSCUS ANTIQUUS, n. sp. 

 Fig. 16. 



Type no. 12571, Univ. Calif. Col. Vert. Palae., a left ramus of 

 the lower jaw with complete molar series, incisor broken, and 

 posterior portion lacking. Cotype no. 12572, a right ramus of the 

 lower jaw with incisor present, no molar teeth, and the posterior 

 portion gone. Locality no. 1103 at Thousand Creek, Humboldt 

 County, Nevada. 



Specific Characters. — Its large size distinguishes it from 

 Peromyscus calif ornicus but the tooth pattern is practically 

 identical, except that M 2 and M 3 have a ridge on the anterior 

 face which is present in M 2 of P. calif ornicus but not in M 3 . 



