446 Eaton — John Day Felidce in Marsh Collection. 



of the arch, at the point of junction of the molar with 

 the maxillary, there is a prominent process for the 

 tendinous origin of the most anterior fibres of the 

 masseter. This process is apparently wanting in the 

 carnassident skull, but is large and prominent in that of 

 the Opossum, Dasyure, and to a less extent in 

 Sarcophilws." 



One of the most distinctive characters of this skull 

 is the form of the portion of the maxilla that, for want 

 of a better name, I have termed the anterior zygomatic 

 pedicle. The minimum height from the alveolar margin 

 to the inferior margin of the orbit is 46 mm. and the 

 minimum length, measured on the outer face of the 

 maxilla, from the infra-orbital foramen to the posterior 

 margin of the zygomatic process, is 30.5 mm. Dividing 

 the first of these measurements by the second, and multi- 

 plying the quotient by 100, an index of 151 is obtained. 

 Inspection of Table B for allied genera and species will 

 show that by the proportions of this part of the skull, 

 the present species is easily distinguished from Nimravus 

 and from Dinictis cyclops, D. squalidens , and D. felina. 

 Judging from Riggs' figure of the skull of Dinictis 

 paucidens 16 and Adams' figure of D. fortis, 17 the anterior 

 zygomatic pedicle in these species also is low and long, 

 as in D. felina. 



The glenoid fossae are projected no further below the 

 basicranial plane than in Nimravus. The mastoid and 

 paroccipital processes are similar in size and direction 

 to those of Nimravus. The basicranial foramina occur 

 as in Dinictis and Nimravus, with this important 

 exception that in Dincelurus crassus the posterior opening 

 of the carotid canal is a veritable foramen, completely 

 enclosed by the thin lateral expansion of the basi-occipi- 

 tal, and not merely an open notch in this lateral expan- 

 sion, as is the case in various examples of Nimravus, and 

 as represented in Cope's figure of the type of Nimravus 

 debilis. 18 Scott's illustration of the skull of Dinictis 

 felina 19 might be supposed to indicate that the carotid 



16 Elmer S. Biggs, Kan. Univ. Quar., 4, No. 4, 239, 1896. 

 "'Geo. I, Adams, Am. Nat., 29, pi. XXVI, 1895. 



18 E. D. Cope, Eeport of the U. S. Geol. Survey of the Territories, vol. 3, 

 952, 1884. 



19 W. B. Scott, Proc. Acad. Nat. Sci., Philadelphia, 41, 213, 1889. 



