410 M. R. Thorpe — Leptauchenia Leidy ayid 



do those of either L. decora or L. nitida. They are robust, 

 nearly straight below the dental series, with a distinct 

 downward trend at the angle. They are wide and moder- 

 ately hea^^ below the coronoid and condyle. 



The molar teeth are characterized by very heavy exter- 

 nal styles, heavier than in any other of the species of this 

 genus, and likewise heavier than in Merycliyus. 



Measurements. 



(Cat. No. 10118, Y. P. M.) 



mm. 



Skull, length, occip. condyles to canines, inc., approx 139 



Bizygomatic diam., approx 100 



Diam. of postorbital constriction 22.3 



Max. diam. of brain-case 41 



Width above P^ 31 



Width between middle of orbits 46 



Ant.-post. diam. of facial vacuity 34 



Depth of malar below middle of orbits 23 



Depth of paramastoid below inferior border of auditory 



meatus ^ • . 28 



Ant.-post. diam. of bulla 27 



Transverse diam. of bulla 18.5 



Ramus, depth, coronoid to angle . 60 



Depth below M. 25 



Total length from incisor border 113 



Superior molar series, length 40 



Superior premolar series, length 35 



Inferior molar series, length 44 



Inferior premolar series, with P-^, length 31 



Leptauchenia nitida Leidy 1869. 



This comparatively rare and little known species is 

 represented in the Marsh Collection by several specimens 

 collected on Pumpkin Creek, along AVhite River, at Scott's 

 Bluff, and near Fort Mitchell — all in Nebraska. Two 

 skulls represent immature individuals, one of which is 

 extremely delicate and fragile, with even the lower incis- 

 ors preserved. Another skull, Cat. No. 10122, is that 

 of a fully mature individual, and is remarkably well 

 preserved. It lacks both rami and the incisor border, 

 together with part of the zygomata. 



Specific Characters. — This species is the smallest 

 kno^vn in the genus. The muzzle is short and pointed; 

 facial vacuities are smaller absolutelv than in L. decora, 



