CHIROPTEEA. 811 



the crown. The heel of the last molar is very small, and consists of only- 

 one obtuse cusp. The oblique anterior borders of the two triangles are 

 sectorial in their character. There is a low cingulum on the external base 

 of the crown, which bridges the interval between the lobes. 



As compared with the Peratlierium fugax, with which this species agrees 

 in size, it diifers, besides the generic characters, in the relatively larger an- 

 terior molar teeth and shallow ramus. 



Measurements. 



M. 



Length of last three true molars 0060 



Length of first true molar 0024 



Width of first true molar 0013 



Depth of ramus at first true molar 0025 



Length of last molar 0016 



From the same locality as the species above described. 



DOMNINA CRASSIGENIS Cope. 



Annual Report U. S. Geol. Survey Terrs., 1873 (1874), p. 470. Miothen crasaigenia Cope, Synopsis New 



Vertebrata Colorado, 1873, p. 8. 

 Plate LXII ; figs. 27-9. 



This species is known from the posterior portion of a pair of mandib- 

 ular rami of opposite sides, which look as though they might have belonged 

 to the same individual. These show that the external border of the base 

 of the coronoid process is prominent, but the inferior border is not, as in 

 Peratheriiim Imntii, well defined. The inner face of the rami is very 

 flat, without the horizontal ridge behind the dental series seen in Dom- 

 nina gradata, nor the internal pterygoid fossa of the Peratlierium alternans. 

 The inner face of the ramus towards the angle is gently concave. The 

 external face of the ramus at the last two molars is convex. The last molar 

 is only as large as the posterior triangle of the penultimate molar, and its 

 anterior triangle is not larger than the heel. The two triangles of the 

 penultimate are equal, and their section is strongly convex on the external 



side. 



Measurements. 



Length of last two molars 0032 



Width of penultimate molar 0014 



Length of last molar 0012 



Depth of ramus at penultimate molar 0030 



From the same locality and horizon as the preceding species. 



