DISCOVERY OF THE TITANOTHERES AND ORIGINAL DESCRIPTIONS 



229 



at right angles to the median line of the skull. The two in- 

 cisors on each side are quite small and separated from each 

 other and from the canine. There is a slight diastema behind 

 the canine. The first premolar is small and triangular in out- 

 line. The second premolar is of moderate size, and the third 

 and fourth premolars have only an incomplete inner basal ridge. 

 The width of this skull across the horn cores is 23 inches, 

 and the distance from the end of the nasals to the front of the 



XAST SPECIES DESCRIBED BY COPE, 1891 

 Menodus peltoceras Cope, 1891 



Cf. Brontotherium curtum, this monograph, page 574 



Original reference. — Am. Naturalist, vol. 25, p. 48, 

 January, 1891 (Cope, 1891.1). 



FiGUKE 189. — Type skull of Allops crassicornis 

 Palatal view. Nat. Mus. 4289. After Marsh. One-fifth natural size. 



posterior nares is 16 inches. The extent of the upper dental 

 series is 17 inches. 



Etymology. — medius, middle; in allusion to the in- 

 termediate character (between the species elatus and 

 curtus) of this form. 



Present determination. — The species is probably 

 valid and is referable to Brontotherium. 



Type locality and geologic horizon. — " Titanotherium 

 beds of northern Nebraska" (Chadron formation). 



Type. — "Represented by the nasal region and the 

 horn cores; the apex of one of the latter being broken 

 away." Am. Mus. 10719. Dr. Hobart Hare, col- 

 lector, Nebraska. Presented by the Museum of the 

 University of Pennsylvania. (See fig. 192.) 



