TICHOLEPTUS 



195 



Foramina: The infraorbitals are above the posterior part of M 1 in the holotype, while in the 

 paratypes they range as far forward as to be over the interval between P 4 and M 1 . This position is 

 farther aft than normal for Ticholeptus. The supraorbitals are 35 mm. apart. 



Dentition: The teeth are moderately hypsodont. The incisors and canines are small and 

 crowded, the premolars are crowded so that the first superior three are set obliquely, and the molars 



Fig. 142. — Ticholeptus rusticus (Leidy). Skull. PLT. Cat. No. 19-104 A.M. 2/5 nat. size. (After Loomis, 1920.) 



Fig. 143. — Ticholeptus rusticus (Leidy). 



Superior view of skull. PLT. 

 (After Loomis, 1920.) 



Cat. No. 19-104 A.M. 2/5 nat. size. 



increase in size from 1 to 3. In the structure of the crowns of the premolars the closest resemblance 

 is the pattern characteristic of Ticholeptus. Molar-premolar index is 0.65-0.70 (superior) and 

 0.65-0.72 (inferior). 



Skeleton: Loomis (1920, p. 284) calls attention to the fact that "the feet are of the medium 

 type, with metapodials comparable with those of Oreodon; the phalanges are short and stocky, 

 especially the unguals, which are flattened from top to bottom in strong contrast to the same bones in 

 Merychyus; . . . the tibia is rather stocky, and . . . the tibia and fibula are entirely separate." 



Certain other skeletal characters are shown in the American Museum material, as pointed out by 

 Matthew (1901 A). The stylohyal resembles that bone of Mesoreodon, except that it is longer in 

 proportion and more expanded at either end. The spines of the dorsal vertebras are longer, and the 

 transverse processes are wider and heavier than those in Merycoidodon or Eporeodou. The lumbars 

 are small and unusually short in proportion, with the length of the centra actually less than in 



