1883.] "1* [Cope. 



Measurements. M. 



Diameter of M. i { anteroposterior 0058 



I transverse 0050 



Diameter of M. iii { anteroposterior 0030 



•-transverse 0048 



A pair of mandibular rami, found on the same day, and at or near the 

 same place, probably belong to the same species, if not to the same animal, 

 they support all the teeth, but only the P-m iv and the M. i and ii have 

 yet been disengaged from the matrix. The P-m. iv is rather large and 

 robust, and has a short wide heel, and an anterior cusp which leaves the 

 main cusps half way to the apex, or at the same elevation as the internal 

 cusp. The anterior three cusps of the true molars are elevated above the 

 heel, and the anterior is nearly median, forms no blade with external ante- 

 rior, and is smaller than the anterior internal cusp. The heel is well de- 

 veloped, and its borders rise in two obtuse open Vs, whose apices look away 

 from each other. The internal supports two cusps, the external, but one. 

 No cingula ; enamel smooth. 



Measurements of inferior teeth. M. 



-r.. . « -d . (anteroposterior 0060 



Diameters of P-m. iv 1 t nnn 



(■ transverse 003o 



Diameters of m. ii { anteroposterior 0050 



<- transverse 0039 



Length of bases of m. i and m. ii 01 10 



From Upper Puerco ; D. Baldwin. 



Tjucentes in^qtjidens, sp. nov. 



This species is represented by two mutilated crania, obtained on the 

 same day and near the same locality as the preceding species. One of 

 these, which I select as type, embraces the muzzle and palate anterior to 

 the posterior border of the maxillary bone. 



Besides its inferior size, other characters distinguish this species. The 

 simplicity of the superior molars is seen in no other, and the very reduced 

 size of the third superior molar is not found in any of its allies. This is 

 correlated with an oblique reduction of the maxillary bone behind, which 

 gives the second true molar an oblique external border instead of the longi- 

 tudinal one seen in the other species. The external cusps Of the molars 

 a re conic, and are not in contact at the base. The internal cusp is also 

 conic, and is larger than the external. The internal cusp of the fourth pre- 

 molar is large. It is probable that the third premolar supports an internal 

 cusp, as the crown base is as wide as long. The premolars are spaced in 

 this species, as in the last, but the diastema is shorter than in the T. crassi- 

 collidens, not exceeding the premolar interspaces. The external cingulum 

 is quite weak. The canine alveolus is large. The incisors are wanting j 

 but the premaxillary region is wide. The inferior dentition is unknown. 



