COPE.] PALEONTOLOGY LOUP FORK EPOCH. 529 



the cuboid bone in P. sejunctus. Were the bone a metacarpal, this facet 

 would relate to the trapezoides, a contact which does not exist in either 

 of the genera of three-toed horses, Hippotherium and AncMtherium^ ac- 

 cording to Kowalevsky.* 



AETIODACTTLA. 

 MBEYOHYUS, Leidy. 



Merychyus major, Leidy, Anc. Fauna Dak. and Keb., 121. 



A single superior first molar, presenting some peculiarities perhaps 

 individual. 



Merychyus eleg-ans, Leidy, loc. cit, 118. 



A mandibular ramus, with the molars and last premolar ; a little 

 larger than Leidy's specimens from Nebraska. 



PEOCAMELUS, Leidy. 

 Procajmelus, sp. 



Numerous parts of skeletons of a large species without teeth ; possi- 

 bly the P. niobrarensis, Leidy. 



Procamelus angustidens, Cope, Bull. U. S. Geol. Surv. Terrs., No. 



1, 20. . 



Eepresented by the nearly entire mandibles, with most of the teeth 

 of two individuals, and two superior molars referred with probability to 

 the same. 



This camel is the size of the P. rol)ustus, Leidy, but differs from it in 

 the much narrower teeth, especially the last molar and last premolar, 

 the much smaller first molar, and totally different form of the second 

 premolar. Thus, while the last molar has the same length, it supports 

 an anterior expansion whose angles are the summits of ridges on the 

 inner and outer sides of the crown, which are wanting in P. robustus. 

 Behind the outer rib in P. angustidens, there is a considerable groove. 

 "While the third molar is as large as that of P. robustus, the first molar 

 is strikingly smaller, while the third premolar is about as long, is only 

 half as wide when worn to the same degree. The second premolar, 

 instead of presenting a contracted subconic crown, is longitudinally 

 extended and compressed, resembling closely the third premolar. The 

 molars are remarkably flat on the outer side; each lobe being devoid of 

 a median ridge, and the first and second even wanting that between the 

 lobes. The diastemata are long, and the first premolar is compressed 

 and equidistant between the canine and the second premolar. The dia- 

 stema in front of the canine is not wider than one tooth. The lower 

 incisors are broad and oblique. The lower posterior boundary of the 

 symphysis. is almost immediately below the first premolar. 



Measurements. 



M. 



Total length of dental series to first incisor 0.240 



Length from first to third incisor on crowns .035 



Length from first incisor to canine .040 



Length from first incisor to first premolar .073 



Length from first incisor to second premolar , .103 



Length of molar series .134 



Length of premolars 2-3-4 039 



Length of second premohir .OIG 



Length of fourth X)rimolar .016 



* Paluioutographica, 1873, pi. vii. 

 34 GS 



