1889.] NATURAL SCIENCES OF PHILADELPHIA. 217 



crowns, and are separated by wider spaces from each other and from 

 the canines. 



The upper canines of Dinictis are compressed and elongated tusks 

 of narrow oval section ; they are, however, shorter and less com- 

 pressed than in Hoplophoneus. 



The most anterior premolar (pm. 2) is exceedingly small, much 

 more reduced than in Cryptoprocta ; it has a compressed conical 

 crown with a sharp posterior cutting edge which is finely serrate, and 

 a very minute posterior basal cusp ; it is implanted by two fangs. 

 Pm. 3 is a large and well developed tooth ; it is much higher and more 

 compressed than in the Felidoz, and the large posterior cusp is single, 

 not double as in that family. This tooth resembles much the cor- 

 responding one in Cryptoprocta, but the principal cusp is more com- 

 pressed and has a greater antero-posterior extent. The sectorial 

 (pm. 4) is more canine than either felme or viverrine and differs from 

 pm. 3, only in its greater size, the greater proportional development 

 of the heel and the presence of the inner cusp. This tooth is very 

 like the sectorial of Cynodictis, exhibiting only the following differ- 

 ences : (1) the anterior cusp is more flattened ; (2) the heel is longer 

 and higher; (3) where the two come together there is a deeper fossa, 

 such as is found in cats ; (4) the inner cusp is less reduced, though 

 smaller than in Cryptoprocta and very much smaller than in the 

 Virerridce generally. Of the anterior basal cusp which is so char- 

 acteristic of the cats and which appears in Cryptoprocta and to a 

 certain extent in other viverrines, there is not a trace. The sectorial 

 of Hoplophoneus is decidedly more cat-like than that of Dinictis, as 

 is shown in the better development of the sectorial blade and in the 

 appearance of a small antero-external cusp. 



The single upper molar of Dinictis is very much better developed 

 than in the cats, or Cryptoprocta, or even than in Hopjlop>honens,hx\l is 

 much more reduced than in the Viverridce generally; it is not at all 

 overlapped or concealed by the sectorial, being plainly visible from 

 the side. The construction shows clearly its derivation from the 

 tritubercular pattern of Cynodictis, but the length of the tooth from 

 before backwards has been greatly reduced, so that the two outer 

 tubercles have come to stand in nearly the same transverse line, 

 while the inner cusp has extended far internally. The tooth is im- 

 planted by three fangs. In Hopjlophoneas the separation into three 

 cusps is very obscure. 



