PEKIPTYCHID^:. 175 



M. 2569. Fragment of the right maxilla, containing the last five 

 cheek-teeth; from the Puerco Eocene of New Mexico. 

 The premolars are well worn. 



Presented by R. LydeTcTcer, Esq., 1885. 



M. 2569 a. Two fragments of mandibular rami, one showing pm. 3, 

 pmT4, mTl, and m . 3, and the other the premolars and the 

 broken bases of the cutting- teeth ; from New Mexico. 



Presented by R. LydeJcJcer, Esq., 1885. 



Genus HAPLOCONUS, Cope l . 



Dentition : I. ~, C. [, Pm. |, M. |. The upper true molars have 

 three main cusps arranged in a V-shape, and an accessory postero- 

 internal cusp. The fourth upper premolar has an inner lobe, the 

 others being simple. 



Haploconus lineatus, Cope 2 . 



This is the type species ; the premolars are larger than the true 

 molars. 



Hab. North America. 



M. 2570. Fragment of the right maxilla, showing all the cheek- 

 teeth except pm- 1 ; from the Puerco Eocene of New 

 Mexico. The specimen agrees precisely with the one 

 figured by Cope in the Amer. Nat. vol. xviii. p. 804, 

 fig. 13 (1884). Presented by R. Lydeklcer, Esq., 1885. 



M. 2570 a. Fragment of the left ramus of the mandible, with u7T2~ 

 and m73 ; from New Mexico. 



Presented by R. LydeJcJcer, Esq., 1885. 



Suborder AMBLYPODA 3 . 



In this Suborder the carpus is characterized by the scaphoid being 

 supported by the trapezoid and not by the magnum, while the 

 latter and the unciform support the lunar ; in the tarsus the cuboid 

 articulates proximally with both the calcaneum and the astragalus. 



1 Amer. Nat. vol. xvi. p. 417 (1882). 



2 Loc. tit. 



3 See Cope, Proc. Amer. Phil. Soc. vol. xx. p. 444 (1882) ; see also Amer. 

 Nat. vol. xviii. pp. 1110-1121, 1192-1202 (1884), and six. pp. 40-55 (1885). 

 The name Amblydactyla was substituted by Marsh (' Monograph of the Dino- 

 cerata,' pp. 173, 193, U. S. Geol. Surv. vol. x. [1884]), but Cope (Amer. Nat. 

 vol. xix. p. 704 [1S85]) regards this as unnecessary. 



