138 University of California Publications. [Geology 



No. 556 No. 1989 



M 1 , antero-posterior diameter 12 mm 13 mm 



M\ transverse diameter 12 12.5 



M 3 , antero-posterior diameter 19 19 



M 3 , transverse diameter 16 15 



P 4 , antero-posterior diameter 12 



P 4 , transverse diameter 7 



M,, antero-posterior diameter 13 



M,, transverse diameter 9 



M 3 , antero-posterior diameter 22 



M„ transverse diameter 12 



Approximate length of calcaneum, combined from dimensions of 



two specimens 61 



Width of tuber calcis (dorso-plantar) 18 



TH1NOHYUS (BOTHROLABIS) OSMONTI, II. Sp. 

 PI. 17. 



Type. — Cranium and mandible, No. 393, Univ. of Cal. Palaeont. Coll. 

 Locality. — Diceratherium beds, Middle John Day. West side of the 



John Day Valley, about six miles north of Clarno's Ferry, Gilliam 



Co., Oregon. 



Specific characters. — Facial region elongate, in profile an 

 even slope from frontals to tips of nasals. Forehead flat between 

 orbits, becoming slightly convex toward median line. Upper 

 molars increasing little in size posteriorly. M 3 without promi- 

 nent antero-internal style, with narrow heel extending as a shelf 

 across the entire posterior border. Inferior dentition in close 

 series, separated by a long interval from the canine. 



The species is named in honor of its discoverer, Mr. V. C. 

 Osmont. 



A second specimen referable to this species was collected by 

 Messrs. Osmont and Davis from the upper part of the Dicera- 

 therium beds on the north side of the John Day Valley at Mc- 

 Allister's ranch, Wheeler County, about 150 feet above the top 

 of the Lower John Day. This specimen, a cranium without man- 

 dible ( No. 1988 ) , has those parts of the skull anterior to P 4 and 

 posterior to the opening of the inferior nares broken away. The 

 crowns of the upper teeth are much less worn than in the type 

 specimen. 



Cranium. — The facial region is greatly elongated, forming in 

 profile an even slope from the forehead to the tips of the nasals. 

 Between the orbits the forehead is flat, becoming slightly convex 



