444 Eaton — John Day Felidce in Marsh Collection. 



Pogonodon davisi 43 (approx.) ; P. platycopis 31 

 (approx.) ; P. serrulidens 36 (approx.). From the follow- 

 ing values of this index for Dinictis, it will be seen that 

 only one species of this genus is known to have a 

 relatively greater postorbital breadth than Dincelurus 

 crassus: Dinictis cy clops 51; D. squalidens, No. 8777, 

 A. M. N. H., 35; D. felina 34; D. fortis 37 (from 

 illustration). 



The breadth of the anterior nares, relative to the basal 

 length, when reduced to an index of 21, is also greater 

 than in the other species with which it has been compared 

 in Table B. Pogonodon platycopis with an anterior 

 narial index of 19 approaches the present species most 

 closely in this character, but this index has been computed 

 for only a few type skulls. The breadth of the postorbi- 

 tal constriction, which may in like manner be expressed 

 by the index 25, separates the present species from 

 Nimravus, but not from all the species of Dinictis and 

 Pogonodon, Dinictis cyclops having a corresponding 

 index of 27 and Pogonodon serrulidens of 25 (approx.), 

 while the highest value in Nimravus is an index of 21 

 for N. debilis. The bimastoid diameter is relatively 

 greater than in Nimravus gomphodus, N. debilis, 

 Pogonodon platycopis, P. serrulidens, and Dinictis squali- 

 dens (No. 8777, A. M. N. H.), but slightly less than in 

 Dinictis cyclops and D. felina. With regard to the 

 bicondylar diameter, the series of type skulls, on which 

 this measurement has been taken, is too limited to admit 

 of any definite statement about the generic value of the 

 bicondylar index. 



In conformity with the remarkable breadth of the fore 

 part of the skull, the palate also is broader than in the 

 allied genera with which comparison has been made. 

 This is especially noticeable in the posterior palatal 

 breadth as expressed by the transverse measurement 

 between the inner roots of the upper carnassials. In 

 the present species the index derived from this measure- 

 ment and the palatal length is 72, which greatly exceeds 

 the corresponding indices computed for Nimravus debilis, 

 N. debilis major, Pogonodon davisi, P. platycopis, P. 

 serrulidens, and Dinictis cyclops. The species that 

 approaches nearest in this respect is Nimravus debilis 

 major with an index of 59. The three species of Pogono- 

 don and Dinictis cyclops fall short of this last value. 



