56 F. B. Loom is —Bhinocerotidce of the Lower Miocene. 



species, characterized by the presence of two moderate crochets, 

 and two strong cristse. The cingulura is well developed both 

 in front and along the internal face of the tooth. 



Fig. 5. Diceraiherium hesperium ; after Leicly, one-half nat. size. 

 Fig. 6. Diceraiherium pacijicum L. ; the second upper molar, after Leidy, 

 one-half nat. size. 



The writer will be surprised if the second tooth assigned to 

 this species by Leidy* does not prove to belong to some as yet 

 undescribed species. The entire lack of crista and crochet 

 would 'debar it from belonging to this species. 



.Diceraiherium niobrarense Peterson. 

 Science, vol. xxiv, p. 281, 1906. 



Type is No. 1,271 in the Carnegie Museum, a nearly perfect 

 skull from the Lower Harrison beds of Agate Spring Quarry, 

 Sioux Co., Nebraska. 



The species is characterized by moderate size, the skull 

 being relatively narrow and high, with a comparatively small 

 brain case. The occipital crest is high, and joined by a strong 

 sagittal crest formed by the union of the ridges from over the 

 orbits. The nasal bones project considerably beyond the horn 

 cores : the orbit is large ; and the wide zygomatic arches are 

 heavy. Of /the teeth the premolars have preserved the cin- 

 gulum intact along the inner face, and are without either cro- 

 chet or crista. The molars are in like manner primitive, having 

 the internal cingnlum only slightly interrupted opposite 

 the hypocone, while the crista is wanting and the crochet quite 

 moderate in development. As noted by Peterson, the species 

 resembles D. armatum of the John Day and is probably a 

 direct derivative of that form, having advanced in the moder- 

 ate development of the crochet and in the skull becoming nar- 

 rower and higher. In size it is about 4/5 as large as D. 

 arrnatum. See fig. 1 on page 51, and for further figures 

 see Peterson. f 



* See Eep. U. S. Geol. Surv. Terri., vol. 1. pi. ii, fig. 7. 

 f Ann. Carnegie Museum, vol. iv, p. 46, 1906. 



