VERTEBRATE FAUNA OF THE LOUP FORK BEDS. 37 



Inferior premolars 36 mm. ; last inferior molar 43 



mm P. angustidens, Cope.* 



aa. Premolar series equaling or exceeding last inferior premolar in 



length. 



Inferior premolars 47 mm. ; M. -j, 47 mm P. robustus, Leidy. 



Inferior premolars 41 mm.; M. -g, 38.5 mm P. occidentalism Leidy.f 



Inferior premolars 31 mm.; M. ^, 33 mm P. gracilis, Leidy. | 



II. Mandibular ramus slender; at M. 2-, 1-5 times elevation of crown 



of M. ^. 



Length of M. ^, 28.5 mm P. leptognatJms, Cope. 



PROCAMELUS ROBUSTUS, Leidy. 



Extinct Mamm. Dakota-Nebraska, p. 148, pi. XV, figs. 1-4. 

 Very abundant, but well preserved jaws and teeth are rare. 



PROCAMELUS GRACILIS, Lcidy. 



Op. cit., p. 155, pi. XIV, fig. 15. 



Represented by the almost complete dentition of the lower jaw of one 

 side. Bones of the skeleton not uncommon. 



PROCAMELUS LEPTOGNATHUS, Cope. 



Sp. nov. 



This camel is represented by a skull which includes the cranium with 

 lower jaw as far anteriorly to and including the last two true molars. The 

 considerable part of the skeleton of a camel of appropriate size was found 

 near to the skull. At present, I content myself with describing the lat- 

 ter. It was inclosed in a calcareo-siliceous concretion, from which it was 

 cut with some difficulty. The lack of the premolar teeth renders its 

 reference to the genus Procamelus uncertain; but it is nevertheless prob- 

 able that such reference is correct. 



The cranium is somewhat distorted by pressure, as it lay on its side, 

 so that it is probable that the postoptic region has been somewhat ex- 

 tended beyond its normal length. This will not, however, account for 

 the elongation of this region as compared with the crania of P. angusti- 

 dens and P. gracilis (P. occidentalism Cope olim), with which I have com- 



* Bulletin U. S. Geological Survey Territories, 1, 1874, p. 20. 



^ f Procamelus fissidenSm Cope, Report U. S. G-. G-. Surveys W. of 100th Mer- 

 idian, IV, Vertebrata, p. 327. In the drawing of the grinding face of the mo- 

 lars in Leidy's Extinct Mamm. Dakota-Nebraska the last lower molar is too 

 short by the measurements and by the profile view given in the same work. 



^Measurements taken from Texan specimen. Procamelus occidentalis, '■'■'Leidy, ^'' 

 Cope, Reports U. S. G. G. Surveys W. 100th Meridian, IV, p. 329, pi. LIII, 

 LXXVI, LXXVIII, LXXIX; P. gracilis, 1. c, p. 328. 



