218 PROCEEDINGS OF THE ACADEMY OF [1889. 



Lower Jaiv. The crowns of the lower incisors are broken away in 

 all the specimens I have had the opportunity of examining, but the 

 fangs show that, as in the upper jaw, the outer teeth are the largest 

 of the series, and that, as in the cats, the lower incisors form a straight 

 row, the second one not being pushed back as is so commonly the 

 case among the Carnivora. 



In correspondence with the lesser development of the upper tusks, 

 the lower canine is larger than in Hoploplioneus. The crown is high, 

 conical and somewhat recurved. The most anterior premolar (pm. 2) 

 is very small and more reduced than in Oryptoprocta ; it consists of a 

 simple compressed cone implanted by two fangs. Pm. 3 is propor- 

 tionally larger, higher, more acute and more compressed than in the 

 cats ; it is composed of a principal conical cusp, with small anterior 

 and posterior cingular cusps. Pm. 4 is almost exactly like pm. 8 

 except that it is somewhat larger, and that the accessory cusps are 

 more conspicuous. Both of these teeth differ from the correspond- 

 ing ones of Fells not only in their relatively larger size and smaller 

 transverse diameter, but also in the absence of the posterior cingulum. 

 In Oryptoprocta the principal cusp is more slender and pointed and 

 the cingulum is better developed, especially on pm. 4, than in 

 Dinictis. In Proallurus these teeth are much like those of Orypto- 

 procta. 



The first or sectorial molar is very feline in appearance, though 

 with very obvious signs of its derivation from the tuberculo-sec- 

 torial type. The anterior cusp is formed just as in the cats, but 

 the posterior cusp is higher and less flattened and more distinctly 

 angulate between the lateral and posterior surfaces. In many speci- 

 mens there is a small but perfectly distinct postero-internal cusp, 

 which thus completes the primitive triangle of the tuberculo-sec- 

 torial molar, and in these specimens the tooth is almost a reproduc. 

 tion of the lower sectorial of Proallurus, as figured by Filhol (No. 

 4, PL 2, fig. 2). But in Dinictis this cusp is evidently on the point 

 of disappearing, as in some specimens it is present only on one side, 

 in others hardly visible at all. The talon is also very small and 

 has a sharp cutting edge, with no trace of accessory tubercles. The 

 second molar is very much reduced and has a small oval crown; the 

 fang, though single, is elongate and obviously formed by the coales- 

 cence of two, as is shown by the median groove which runs down 

 the inner face and by a partial division of the alveolus. The tooth 

 is much less reduced than in Proailurus. 



