PETERSON: THE AMERICAN DICERATHERES. 417 



Measurements of the Type of Diceratherium armatum. 

 Length of skull from condyles to end of nasals as preserved (Points of nasals broken off) 503 mm. 



Length from occipital condyles to M' 20S " 



M^ to end of maxillary (Point of maxillary broken off) approximatelj' 166 " 



Greatest width across the zygomatic arches 145 " 



Greatest transverse diameter of occipital condyles 112 " 



Transverse diameter of occipital plate 146 



Inferior surface of condyles to end of iuion 159 



Length of dentition (molar-premolar series) 248 



Antero-posterior diameter of P' 29 



Transverse " " P' (greatest diameter) 24 " 



Antero-posterior " " p2 " " 31 



Transverse " " P- " " 40 " 



Antero-posterior " " ps " " 35 



Transverse " " P' " " 45 " 



Antero-posterior " " P^ " " 38 



Transverse " "P^ " " 49 " 



Antero-posterior " " M' " " 44 " 



Transverse " " M' " " 53 " 



Antero-posterior " " M^ " " 53 " 



Transverse " " M" " " 53 " 



Antero-posterior " " M^ " " 45 " 



Transverse " " IVP " " 50 " 



Length of McIV 187 " 



Greatest transverse diameter of head of Mc IV 51 



Transverse diameter midway of shaft of Mc IV 40 



Antero-posterior diameter of shaft of Mc IV (approximately) 15 



Height of unciform 54 



7. Diceratherium annectens (Marsh)." (Plates LXIII, Fig. 6; LXVI, Fig. 1, 



and text-figs. 11 and 11a.) (See PL LVIII, Figs. 1, 2, 3.) 



Synonym. — Diceratherium nanum (Marsh) .^* 



Type.— A set of superior premolars of the left side ; one superior incisor asso- 

 ciated. Peabody Museum of Natural History No. 10,001. 



Hy polypes. Skull nearly complete. Cope Collection, American Museum 

 Natural History, No. 7324, a male. Front of skull and lower jaws of Professor 

 Marsh's type D. nanum in the Marsh Collection, Peabody Museum of Natural 

 History, No. 10,004, a male. 



Horizon. — Lower to Middle John Day Formation. 



Locality. — Near John Day River in eastern Oregon. 



" Marsh, 0. C, Amer. Jour. Sci., Vol. V, 1873, p. 4. Loomis, F. B., Amer. Jour. Sci., Vol. XXVI, 

 1908, p. 54, Fig. 3. 



1* Marsh, 0. C., Amer. Jour. Sci., Vol. IX, 1875, p. 243. 



