PLATE LXVI. 
Figs. 1-6. Jaws and dentition of lEyracotherium angustideiis, Cope, naturai size. Pago 265. 
Fig. 1. Maxillary bones, with teeth of both sides, from below ; la, right maxillary from the outer side. 
Fig. 2. Portion of the mandible of the same individual, with the posterior three molar teeth viewed 
from above; 2a, the same, from.the outer side. 
Fig. 3. Mandible of a smaller individual of the same species, with the three true molars from the outer 
side; 3a, the sauie jaw, from above. 
Fig. 4. The posterior two superior molar teeth of another individual, from the outer side; 4a, the same 
fragment, from below. 
Fig. 5. The third and fourth premolars of another individual, abnormally separated from each other, 
viewetl from above. 
Fig. G. The fourth premolar, with the first and part of the second true molars, viewed from above.- 
Figs. 7-11. Jaws and dentition of Hyracotherium vasaccie/ise, Cope, natural size. Page 264. 
Fig. 7. Last two molars of the right side of both jaws, closed in natural relation, viewed from the outside. 
Fig. 8. Maxillary bone, with teeth of the same, viewed from below. 
Fig. 9. Mandibular fragment of the same, viewed from above. 
Fig. 10. Portion of left mandibular ramus of another individual, supporting the last five molars (sev¬ 
enth and fifth imperfect), viewed from the inner side; 10a, the same, from above. 
Fig. 11. Portion of the left mandibular ramus of another individual, containing the molars from the 
third to the sixth, viewed from the outer side ; 11a, from the inner side ; lift, from above. 
Figs. 12-16. Jaws and other bones of Hyracotherium iapirinum, Cone, natural size. Page 263. 
Fig. 12. Posterior part of right mandibular ramus, supporting the posterior two molars, viewed from the 
inner side ; 12a, the same, from above. 
Fig. 13. Fragment of left mandibular ramus, with second and third true molars of another individual, 
viewed from the inner side ; 13a., the same, from above. 
Fig. 14. Astragalus found with the jaw, I'ig. 13, and perhaps belonging to the same animal, from above; 
a, .anterior extremity. 
Fig. 15. Tibia, viewed on its distal end, belonging to the animal whose astragalus is represented in Fig. 14. 
Fig. 16. Fr.agment of the left mandibular ramus of another individual, containing the first and second 
true molars, viewed from the outside; 16a, the same, from above. 
Fig, 17. Right maxillary bone of Ryrachym aiiigidaris, Cope, with the last live molars, viewed from be¬ 
low, natural size ; 17a, from the outer side. Pago 267. 
Fig is. A part of the right maxillary bone of Alniiscotkcriiiin chamense, Cope, one-half larger than na¬ 
ture, containing more or less of the posterior four molars from below; 18a, the same, from 
the right side. Pago 252. 
