COPE.] PALEONTOLOGY MIOCENE PERIOD. 467 



Measurements. 



M. 



Length of dental series, omitting canine and P. m. 1 0. 0072 



Length of first true molar 0013 



Elevation of first true molar 0010 



Length of third true molar , 0013 



Depth of ramus at third true molar 0019 



Dedicated to my friend Prof. T. Sterry Hunt, of Boston. 



Herpetotherium: stevensonii, Cope, Synopsis, loc. cit., p. G. 



A very small species. Median cusps of molars unequal ; the exter- 

 nal much elevated, and separated by a deep notch from the anterior. 

 Heel of M. 4 contracted. 



Measurements. 



M. 



Length of last two molars 0. 0029 



Length of third true molar 0015 



Elevation of third true molar 0012 



Dep th of ramus at third true molar .... , 0020 



Abundant. Dedicated to my friend James Stevenson, of the United 

 States Geological Survey, the discoverer of the deposit from which the 

 fossils here described were procured. 



H*erpetotheriu]vi fugax. Cope, Paleontological Bulletin, No. 16, p. 

 1 5 Synopsis New Vert. Colorado, p. 6. 



Cranium wide; interorbital region flat ; muzzle narrowed, but still wide 

 and plane above. Mandibular rami long and slender; mental foramina 

 below the first premolar and the first molar. The foramen infraorhitale 

 anterius is situated above the third premolar. There is a short diastema 

 behind the first premolar in both jaws. There are rudimental basal 

 tubercles fore and aft on the second superior premolar. The superior 

 canine issues a short distance behind the maxillo-premaxillary suture. 

 In the inferior molars, all of the five cusps are distinct to the 

 base, except the median pair, which are connected by a deeply-notched 

 yoke. Enamel smooth ; no cingula. The nasal bones are expanded 

 behind and their posterior suture is medially emarginate. 



, Measurements. 



M. 



Width of cranium at front orbit 0. 0160 



Width of muzzle at canines 0050 



Length of bases of crowns of four true molars of upper jaw 0070 



Length of bases of five inferior molars 0100 



Length of basis of crown of last molar 0020 



Length of basis of crown of penultimate molar ^. 0020 



Heiglit of crown of penultimate molar 0017 



Depth of jaw at penultimate molar 0036 



Established on jaws of many individuals and a nearly complete cra- 

 nium. These indicate a species of about the size of our commou Sea, 

 lops aquations. 



Herpetotherium scalare. Cope, Synopsis, Vert. Col., 1873, p. 7. 



Keadily distinguished by the increased disparity in the elevations of 

 the anterior and posterior i)ortions of the molar teeth, resembling in 

 this respect the Embassis alternans. It is a considerably larger species 

 than the latter, and exhibits a distinct anterior cusp, of moderate eleva- 



