338 THE PUERCO FAUNA. 



MiOCLAENUS SUBTRIGOKUS Cope. 



Paleontological Bulletin, No. 33, p. 491. Proced. Amer. Philos. Soc, 1881, p. 4'Jl; 1B83, p. 555. 



Plate XXIV f, fig. 4; LVIIf, fig. 5. 



This species was originally represented by a portion of a cranium an- 

 terior to the orbits and lacking the extremity of the muzzle, distorted by 

 pressure. It exhibits nearly all of the molar teeth. The species differs 

 from M. targidus in the greater acuteness of all its cusps, and in the equi- 

 lateral form of the fourth premolar. It is too large to belong to the M. 

 minimtis, which is represented by mandibles only; and too small to be the 

 M. mandihularis, whose maxillary dentition is unknown. 



The inner borders of the molar teeth are shorter than the outer, espe- 

 cially in the last two molars. The last true molar is smaller than either of 

 the others. The cusps are all subconical, but the internal is connected with 

 the intermediate by ridges, which give it a triangular section. The latter 

 form a V, homologous with that in AnisoncliMS, but not so distinct, and the 

 intermediate tubercles are not lost in its branches as in that genus. The 

 posterior inner lobe of that and other genera is represented by a thicken- 

 ing of the cingulum. This cingulum extends entirely round the P-m. iv 

 and M. i, and M. ii; the M. iii is injured. The sides of the base of the 

 base of the P-m. iv are slightly concave. The enamel of all the molars is 

 wrinkled. 



Measurements. 



u. 



Length of baees of last five molars 0285 



Diametere of base of P-m. j,. 5 ant^^opo^tMior (XMH) 



( transverse 00.50 



Diameters of base of M. i J ''"^"''P"^*"'"^ • 0^ 



(transverse 0000 



Diameters of base of M. ii 1 "°"='°P»«t"'°' *'*'" 



c transverse 0075 



DiameteiB of base of M. ju 5 anteroposterior 0040 



( Ininsverse (KXiO 



I now give the characters of the inferior molar series, which have been 

 found, by Mr. Baldwin, associated with the true superior molars. Of the 

 latter, it may be remarked that the second true molar is not so much longer 

 than the first as in M. hucculentus, although the diflPerence in size is very 

 evident. The third is smaller than the first, and ovoid in outline, while the 

 first and second are subquadrate. The external cusps are conic and widely 



