ART. XVI.-DESCRIPTIONS OF NEW EXTINCT VERTEBRATA 

 FROM THE UPPER TERTIARY AND DAKOTA FORMATIONS. 



By E. D. Cope. 



CARIACUS DOLICHOPSIS, sp. 710V. 



John Collett, of the Geological Survey of Indiana, discovered in a 

 late lacustrine deposit in Vandeuburg County, Indiana, a number of 

 Postpliocene fossils. One of these is the ulno-radius, etc., of a Bos^ and 

 another is the left mandibular ramus of a deer, probably of the genus 

 Cariacus. The jaw differs in its proportions from those of G. virginianus, 

 G. macrotis, and G. columbianus^ with a considerable number of which I 

 have compared it. It belonged to an animal of the average size of the 

 C. virginianus, but differs in having the diastema an inch or more longer, 

 while the tooth-line is shorter. .Placing the first molars in line, the last 

 molar of the fossil form attains only the penultimate column of that of 

 the G. virginianus; in some cases just a little farther. On the other 

 hand, the angle of the mandible extends beyond that of the G. virgini- 

 anus, and the slope of the anterior base of the coronoid process is more 

 gradual. At the same time, this portion is less oblique in the transverse" 

 direction, owing to the prominence of the external face of the ramus. 

 This ramus differs also in the great prominence and anterior position of 

 the posterior edge of the masseteric fossa, which leaves behind it a 

 wide oblique face little developed in the existing species. The species 

 being clearly new, I call it Gariacus dolichopsis. 



Measurements. 



M. 



Horizontal length of ramus from alveolar border 0.250 



Length to first molar 0.100 



Length of symphysis 0.047 



Length of dental series ,. 0.085 



Length of premolars 0.034 



Length of base of ascending ramus 0.058 



Elevation of condyle 0.075 



Length of base of coronoid process 0.021 



Width of coronoid , 0.021 



Width of last molar 0.011 



Length of last molar 0.021 



Length of third premolar 0.011 



Depth of ramus just behind symphysis 0.016 



Depth of ramus at first molar 0.026 



Depth of ramus at last molar 0.028 



379 



