440 Thorpe — Some Tertiary Camivora in 



and the lower jaw corresponds most closely with the type 

 of A. ivheelerianus , except that both P 2 and P 3 are set 

 obliquely, anterior end internal, in the mandible, and the 

 two premolars preserved do not possess anterior basal 

 cnsps, as seen in No. 8307 (Cope Collection), A. M. N. H. 

 The crowns of all teeth in the specimen (supposedly the 

 type) figured by Cope in 1877 were broken away, so that 

 the presence or absence of anterior basal cusps on the 

 premolars can not be determined. Matthew and Gidley 

 (1904) have definitely said that all of the superior and 

 inferior premolars of this species had anterior basal 

 cusps. Both the type and the Yale specimen are of 

 Upper Miocene (Valentine beds) age. 



JElurodon taxoides lacks the anterior basal cusp on 

 P 2 and P 3 , but differs in its much larger size, in which it 

 approaches A. haydeni. 



Another lower jaw, Cat. No. 12785, Y. P. M., was also 

 collected on the Niobrara River. This right ramus is 

 somewhat smaller and much more slender, possibly being 

 that of a female. The differences, however, are not suffi- 

 ciently great to invalidate the identification, in my 

 opinion. 



JElurodon taxoides magnus, mut. nov. 



(Figs. 9-11.) 



Holotype, Cat. No. 10057, Y, P. M. Upper Miocene (Valentine beds), 

 Niobrara Eiver, a few miles east of the mouth of Antelope Creek, Nebraska. 

 Collected by E. S. Lane in 1873. 



The type material consists of both rami, with part of 

 the right side of the face, with complete superior dental 

 parapet, containing P 1 , P 2 , P 4 , and M 1 , all others being- 

 represented by alveoli, together with the distal half of 

 the tibia and part of a cervical vertebra. 



This new mutation is the nearest in size to A. taxoides 

 Hatcher, but differs from it in possessing prominent 

 anterior basal cusps on all of the premolars, both superior 

 and inferior, with the possible exception of P 1 , the 

 anterior part of which is broken away. The presence 

 of these anterior basal cusps would seem to refer it to 

 A. wheelerianus , but such is apparently not the case. 

 Both A. taxoides and this new form are approximately 

 25 per cent larger. Moreover, in the latter the alveolar 



