NIMRAVID^. 985 



together, anterior to it. There are three anterior mentals on each side, a 

 superior smaller, and two inferior larger. 



Dentition. — The crowns of the superior incisors are all broken off, while 

 they remain on two of the corresponding inferior teeth. The latter are 

 acutely, but not regularly, conical; the internal face is oblique forwards, 

 while the external face is slightly convex from base to apex. The external 

 incisors are twice as large as the internal, and the inferior canines are one- 

 half larger than the external incisors in linear diameters. Their crowns are 

 lost. The external superior incisors are a little smaller than the inferior 

 canines, and the superior median incisors are half as large again in linear 

 diameters as those of the inferior series. The superior diastema is rather 

 short, or about as long as the base of the third inferior premolar. The 

 superior canine is a very large tooth, exceeding in size that of any North 

 American feline. It is similar in form to that of the European Machoero- 

 diis cultridens. Both its cutting edges are denticulate, the posterior having 

 thirteen teeth in .005". The crown, near the apex, has a regularly lenti- 

 cular section, but the anterior edge turns gradually inwards until it leaves 

 an anterior face external to it, which presents at right angles to the external 

 face. These faces unite by a regular curve. The posterior edge is straight 

 in the vertical plane. " The second (first) superior premolar is quite small, 

 and is probably only one-rooted, though I cannot be sure of this. Its 

 position is near the base of the third premolar. The base of the latter is as 

 long as the space between it and the canine. It is relatively smaller than 

 in the species Archcelurus debilis and Nimravus gomphodus, and consists of 

 only a principal rather obtuse cusp and a moderately long cutting heel. 

 The sectorial tooth is not as large relatively as that of the species just 

 named, and is less compressed in form, both its cusp and heel being com- 

 paratively obtuse. The tubercular or true molar has remarkable trans- 

 verse extent. Its external and posterior borders are all that can be seen 

 in the present condition of the skull. The latter presents two concavities 

 of the crown, separated by a low median elevation. The second inferior 

 premolar is longer than the corresponding tooth of the superior series, and 

 has one stout and much compressed root. Tlie crown has a semicircular 

 profile, and is more convex externally than internally. The third premolar 



