Douglass : Merycochozrus. 107 



Ticholeptus breviceps sp. nov. 

 (Plate XXIX.) 



(Type No. 1191, Carnegie Museum Catalogue of Vertebrate Fossils.) 



The type, which was collected by the writer in 1903, consists of a 

 skull, mandible, left humerus, left radius and ulna, right radius and 

 part of the right humerus, a tibia, a fibula, a tarsus with two metatar- 

 sals, greater portions of the pelvis, and the right manus with several 

 metacarpals and phalanges. 



This specimen was found enclosed in a nodular mass in deposits 

 composed of gravel and cream-colored sands, about one mile southeast 

 of Woodin on Divide Creek six or seven miles south of the Conti- 

 nental Divide in Silver Bow County, Montana. 



The skull is short and broad and the facial portions rather high, 

 though the frontal plane is nearly flat. The teeth, especially the pos- 

 terior molars, are hypsodont. The molar series is much longer than 

 the premolar, the second and third molars being longer than the four 

 premolars. The anterior rarial border rises steeply above P^. The 

 premaxillaries are coossified for a distance of 1.4 cm. The superior 

 portion of the narial opening is large and rounded. The infraorbital 

 foramen is above the anterior portion of P±. Apparently there were 

 preorbital vacuities. The posterior portion of the skull has a flattened 

 appearance ; the paroccipital processes are broad transversely, thin 

 antero-posteriorly, convex behind and concave in front. The tym- 

 panic bullae are lost, but apparently they were extremely large. 



The anterior teeth in the mandible are crowded. The length of 

 the lower premolar series equals the combined length of the first two 

 molars and the anterior lobe of the third. The horizontal ramus is 

 only moderately deep, the angle large, and the upper part of the 

 ascending ramus not very broad antero-posteriorly. 



The limbs and feet are short, but not heavy. They are about the 

 same length as those of Merycoidodon culbertsoni. The skull is shorter, 

 broader, and higher than in that species. 



Measurements. 



mm. 



Length of skull at base 196 



Width of skull including zygomatic arches 138 



Height of skull above and including M- 82 



Length of upper molar-premolar series 101 



Length of upper premolar series measured along alveolar border 43 



