Vol. 5] 



Merriam. — J ohn Day Carnivora. 



23 



posterior basal tubercle in addition to the prominent eusp arising 

 from the posterior side of the protoconid. 



T. altigenis Cope. Species of medium size. Length of skull 

 178 mm. in No. 9999, somewhat greater in No. 1549. P 4 heavy 

 and wide anteriorly; deuteroeone very large and heavy, separated 

 from protocone by deep valley, without anterior conule. P 3 

 without posterior basal tubercle. Protocone of M 1 nearly conical, 

 regularly rounded posteriorly but with a short antero-external 

 ridge. M 2 with metacone smaller than paracone, but consider- 

 ably larger than in the other species. P 4 considerably shorter 

 antero-posteriorly than M 1; with prominent cusp on posterior 

 side of protoconid and with incipient posterior basal tubercle. 



T. wallovianus Cope. Species of medium size. Deuteroeone 

 of P 4 apparently not greatly enlarged. P 3 without posterior 

 basal tubercle. M 2 small, with reduced metacone. This species 

 should possibly be included in T. altigenis. 



The principal features of the skeleton of T. altigenis as shown 

 in specimens 9999 and 1549 mainly confirm the generic charac- 

 ters represented in the specimen of T. ferox described by Eyer- 

 man. In some cases, however, the specific differences are great 

 enough to modify slightly our estimate of the generic characters 

 based on the description of ferox. 



Shall. — The skull of T. altigenis differs considerably from that 

 of ferox in general outlines. As represented by Eyerman, 12 the 

 cranium of ferox is relatively high and narrow compared with 

 the undistorted specimen of altigenis seen in No. 1549. A part 

 of this difference may be due to lateral crushing in the ferox 

 specimen, which would produce the deviation in height and width 

 at the same time. The palate of altigenis is decidedly narrow, 

 but that of ferox is extreme in this respect. In ferox the sagittal 

 crest is high and narrow over the greater part of the brain case ; 

 in specimens 1549 and 9999 the sagittal ridge is very low except- 

 ing over the most posterior portion of the brain case, where it 

 attains a considerable height. In specimen 9999 the ridge is 

 divided almost to the posterior third of its length by a sharp but 

 very narrow groove. The lambdoidal crest is strong and high. 



The broad frontal region is slightly concave in front of the 



12 J. Eyerman. Amer, Geol., Vol. 17, p. 267. 



