1903.] Mattheiu, Fauna of Titanotherium Beds of Montana. 203 



Fig. 2. Apternodus inediiEvus. Type, No. g6oi, 

 twice natural size, the outlines of front of jaw 

 from No. Q607. A^ crown ; .4', external. A", in- 

 ternal view. 



The cusps are all high, sharp, trigonal in cross-section, the whole tooth 

 stibtriangular with transverse and longitudinal diameters about eciual 

 and vertical diameter consider- 

 ably exceeding either. The 

 heel is much smaller than 

 in Centetidas, the protoconid 

 higher and larger in proportion 

 than in dcciy other Insectivore 

 or Chiropter. 



No. 9608, a lower jaw 

 without teeth, broken off 

 in front at about the same 

 point as the types, but 

 with the condyle complete, 

 appears to belong to the 

 same species. The condyle 

 is widely expanded trans- 

 versely, on a level with the 

 bases of the molars. The 



angle in the type specimen is extended into a rather long 

 and stout flattened process with a sharp medial ridge on the 

 internal side. The coronoid is broken off in both specimens, 

 but was evidently high, stout, placed mostly external to the 

 toothrow, and directed upwards instead of backwards. 



No. 9607, the anterior part of a lower jaw, with one pre- 

 molar preserved and the roots of other teeth, is provisionally 

 referred to this species. The premolar is either the third or 

 fourth; it is stout, two-roofed, composed of a round-conical 

 protocone and small postero-internal basal cusp. The an- 

 terior root is wider than the posterior. The premolar in 

 front of this was apparently similar but smaller, and was pre- 

 ceded by a small one-rooted premolar, and this by a larger 

 tooth, probably a canine. Behind the premolar are roots 

 of two teeth, one of which was probably m^, the other cer- 

 tainly a molar, judging from comparison of the corresponding 

 parts of the jaw in the three specimens. 



The dentition is then probably Cj P3 mj, but may be Ci p^ vcv^. 

 The weight of the anterior part of the jaw and doubtful 



