Vol. 6] Merriam: Virgin Valley and Thousand Creek. 



237 



M 2 is relatively large, and an extraordinarily developed tooth. 

 Its fore and aft diameter 

 equals almost three-fourths 

 that of the carnassial, and 

 there is a well - developed 

 paraconid present. The 

 protoconid and the meta- 

 eonid are nearly equal in 

 size. The paraconid may 

 nearly equal the other 

 cones in size. On the 

 large basin-shaped heel the 

 nearly equally developed 

 hypoconid and entoconid 

 are connected posteriorly 

 by a low marginal ridge. 

 On the antero-external side 

 of the base of the trigonid 

 a prominent ridge is de- 

 veloped on the cingulum. On the specimens available a minute 

 tubercle is present in the valley between the protoconid and 

 hypoconid. 



M 3 is not represented on any of the specimens. Judging 

 from the form and size of the alveolus, this tooth was relatively 

 large, and its anteroposterior diameter was considerably greater 

 than the transverse. 



Measurements. 



Type 

 specimen, 

 no. 11562 



Length of mandible from anterior side of P x to posterior 



side of condyle 103.7 mm. 



Height of mandible below protocone of Mj 21. 



Greatest thickness of mandible below talonid of M 2 9. 



P 2 , anteroposterior diameter 6. 



Pa, anteroposterior diameter 6.7 



P 4 , anteroposterior diameter 8.4 



Mj, anteroposterior diameter 15. 



M,, anteroposterior diameter of heel 4. 



M,, transverse diameter of heel 7. 



M 2 , anteroposterior diameter 10.5 



M 2 , greatest transverse diameter 6.7 



5a 



Figs. 5a and 5b. Tepluocyon Icelloggi, 

 n. sp. M 2 , unworn tooth. No. 10651, X 

 iy 2 . Virgin Valley Beds, Virgin Valley, 

 Nevada. Fig. 5a, outer side; fig. 56, 

 superior side. 



Fig. 6. Tephrocyon Icelloggi, n. sp. 

 M 2 , worn tooth. No. 11474, X 1%. Vir- 

 gin Valley Beds, Virgin Valley, Nevada. 



Fig. 7. Tephroeyon, near Tcelloggi, 

 n. sp. M... No. 12542, X 1%. Thousand 

 Creek Beds, Thousand Creek, Nevada. 



