Dl IV1.IN E OF AMERICA. 343 



Fig. 4. — Outer view of the lower molars. 



Figs. 5—8. — Right molar teeth of Euchrerus macrpps. The premolars were still concealed within the jaws, 

 and also the last molar partially, bul they have been represented as protruded. 



Fig. 5. — Triturating surfaces of the upper molars. 



Fig. 6. — Outer view of the upper molars. 



Fig. 7 — Triturating surfaces of the upper molars. 



Fig. 8. — Outer view of the lower molars. 



In Figs. 7, 8, the second premolar has been accidentally reversed from its true position. 



Fig. 9. — View of the posterior margin of the right side of the lower jaw of Plalygonus comprcssus, exhibit- 

 ing the exlenl of curvature of the angle outwardly. Same specimen as lig. 3, pi. 38. 



Fig. 10. — The posterior two right inferior molars of Plalygonus compresMis viewed upon the triturating sur- 

 faces. From the same specimens as the previous figure and h>. 3, pi. 88. 



Fig. 11. — Upper left premolars of Platygonus compressus viewed upon the triturating surfaces. Tin' tir-t 

 tooth is broken off at the anterior part. From the same specimen as tig. 2, pi. 38. They are unworn, and had 

 not vet protruded from the jaw. 



Figs. 12 — 15. — Upper molars of Platygonus compressus, 12, 13, and II, 15, from two different individuals; 

 the former very probably belonging to the same individual as figs. 9, 111, and lig. 3, pi. 38. 



Fig. 12. — Right upper premolars. The middle tooth in the original has its inner tubercle split to the base, a 

 thin lamina lost from the fissure, and the two portions approached together, so that it appears a little different 

 from that represented by figure 14. 



Fig. 13. — Posterior two left upper molars. 



Fig. 14. — Middle left upper premolar. 



Fisj. 15. — First and second left upper true molars. 



Fig. 10. — Left canine of Platygonus compressus. 



Fig. 17. — Temporary molars of the upper left side of Euchocrus macrops. 



Fig. 18. — Right upper last molar, with its anterior part broken off, of Protochorus prismaticui. 



Fig. 19. — Lower lateral incisor of Euchcerus macrops. 



PLtfTE 38. 



Fig. 1. — Represents the fragment half the natural size upon which is established the Dicotylea dipressifrons. 

 It exhibits portions of the parietal, frontal, nasal, maxillary, intermaxillary, and malar bones, 



Fig. 2. — View of the right side of a portion of the face of the natural size of Platygonus compressus li if 

 the same specimen represented in pis. I., 1 1., of vol. 3. of tin- Mem. Jim. ./■ ml. .Iris and fi i.,bul in this figure the 

 canine alveolus with a portion of the tooth which hid been broken off, is reattached. Anterior to the latti r. the 

 specimen is obscured by a hard brown mass, apparently consisting of a combination of linn- and oxide •■! iron. 

 Portions of the nasal, intermaxillary, and maxillary bones arc seen; and on the left side ■ portion of the maxillary 

 bone in outline with the three permanent premolars, which had not yet protruded from their aWrnli. The latter 

 teeth are represented in figure II, pi. 37. 



Fig. 8. — Portion of the right side of the lower jaw containing the lat>t two molars, the natural »ize, of an adult 

 individual of Platygonus comprcssus. \ fragment of matrix obscures the aiiL'lr, and another portion n attached 

 in advance of the condyle. 



VOL. I. — 01 



