342 A MEMOIR ON THE EXTINCT 



Dicotyles Major, Lund: Clausen, in neues Jahrbuch fur Mineralogie, etc., 1843; 

 Bronn, Index Pakeontologicus, Abth. 1, s. 422. 



Dicotyles depressifrons, Le Conic: Proc. Acad. Nat. Sci., vi. 3. 



Probably all tbe fragments mentioned in the latter communication belong to this animal, 

 except the " four teeth from the upper jaw." 



Hyops depressifrons, Lcc: Am. Journ. Sci., 2d ser., 5, 104; Proc. A. N. S., vi. 57: "a 

 cranium." 



Dicotyles costatus, Le Conle: Pr. A. N. S., vi. 5. 



Platygonus compressus, Le Conte: Am. Jour. Sci., 2d ser., 5,103; Trans. Am. Acad. 

 Arts and Sci., n. ser., 3, 257. All the specimens represented in the accompanying plates 

 to the latter memoir, I think, belong to this animal. 



Hyops depressifrons, Lee. : Pr. A. N. S., vi. 57: "fragments of anterior part of head 

 with premolars and canines : the entire dental series of upper jaw." 



Protochoerus prismaticus, Le Conte: Am. Jour. Sci., 20. 5, 105; Pr. A. N. S., 

 vi. 5. 



Hyops depressifrons, Le Conte: Pr. A.N. S., .vi. 57: "the canine and two inferior 

 molars of lower jaw." 



Euchcerus (Protochoerus?) macrops, Leidy : hoc opera. 



references to the PLATES. PLATE 35. 



Represents a view of the left side of the skull of Euchoerus macrops two-thirds the size of nature. In the 

 original, the nasal bones are broken, as indicated, and the right intermaxillary only exists ; but the latter has been 

 transferred to the left side, being otherwise the best preserved, principally on account of the teeth. The latter 

 visible in the upper jaw, are the canine, the three temporary molars, and the succeeding permanent true molars, 

 the last of which is just commencing to protrude. In the lower jaw are visible a portion of the third perma- 

 nent premolar ready to protrude, and the succeeding true molars ; the last partially only. 



PLATE 36. 



Two views, one-half the natural size of the skull of Euchoerus macrops. 



Fig. 1. — Upper view. The nasal bones in greater part, and the left intermaxillary are broken away, permit- 

 ting the ossa turbinata, etc. to be seen. 



Fig. 2. — View of the base of the skull. The left side of the upper jaw contains the three temporary molars, 

 and the three permanent true molars. The right side, from which the temporary molars were lost, has exposed 

 in their place the permanent premolars. 



PLATE 37. 



All the figures are of the natural size. 



Figs. 1 — 4. — Molar teeth of the right side of Dicotyles torquatus, represented for comparison. 



Fig. 1. — View of the triturating surfaces of the upper molars. 



Fig. 'i. — Outer view of the upper molars. 



Fig. 3. — Triturating surfaces of the lower molars. 



