446 Thorpe — Some Tertiary Carnivora in 



Pseudcdurus intrepidus Leidy. 



Two specimens of this genus and species, found on the 

 Niobrara River in Cherry County, Nebraska, exceed the 

 type in size. The difference is not of specific value, but 

 worthy of notice, as heretofore the type of the species 

 has been regarded as representing the maximum size to 

 which this genus attained in America. The posterior 

 half of a left ramus, Cat No. 12830, Y. P. M., was col- 

 lected by Professor Lull in 1914. The other specimen, 

 Cat. No. 12816, Y. P. M., consists of a third lower pre- 

 molar, which is 2 mm. higher, 1.5. mm. wider, and 2 mm. 

 greater in antero-posterior diameter than Leidy 's type. 



Pseudcelurus marshi, sp. nov. 



(Fig. 12.) 



Holotype, Cat. No. 12865, Y. P. M. Upper Miocene (Valentine beds), 

 Niobrara Eiver, near mouth of Minnechaduza Creek, Cherry Co., Nebraska. 

 Collected by Professor O. C. Marsh in 1873. Paratype, Cat. No. 12315, 

 Y. P. M. Middle or Upper Miocene, northwestern Colorado. 



The holotype consists of both lower jaws, partially 

 restored, and the paratype of a left ramus with the 

 alveolar parapet complete, as well as P 3 and P 4 . The 

 new species is about the size of Hoplophoneus primcevus, 

 or one fourth smaller than P. intrepidus and hence con- 

 siderably smaller than P. intrepidus sinclairi Matthew. 

 The mandible is very much more slender than either of 

 the above forms and does not exhibit so great depth below 

 the tooth-row, although both the holo- and paratype are 

 fully adult. The teeth are not crowded as in the above 

 mentioned variety. Both types of the new species pos- 

 sessed a very diminutive P 2 , the antero-posterior diameter 

 of which is not over 2 mm. The position of this premolar 

 is inward from the true line of the tooth-row, as in 

 Matthew's variety. The posterior basal tubercle of P 3 

 in the paratype is exceedingly small and that of the holo- 

 type is much reduced. The fourth premolar, in its com- 

 ponent parts, most closely resembles the analogous tooth 

 in P. intrepidus sinclairi, while the metaconid of M 2 has 

 not suffered so great a reduction as in the latter variety. 

 The paratype alone shows a distinct, but very small 

 alveolus for M 2 , its antero-posterior diameter being 3 mm. 



