EXPLANATION OF PLATE VI. 



Figs. 1-9. Hyopsodus paulus. All of the natural size except Figs. 2, 5, 8, 9, which are niagnified four 



diamoters. 

 Fig. 1. Right side of lower jaw, with the three molars. From au individual past maturity. 



Specimen from which the genus and species were firsfeuoticod. 

 Fig. 2. Triturating surfaces of the molars of the same specimen. 

 Fig. 3. Left side of lower jaw, with last premolar and the three molars. Specimen obtained 



by Dr. Corson at Grizzly Buttes. 

 Fig. 4. Eight side of lower jaw, with last premolar and the molars, but slightly worn. 



Specimen obtained by Dr. Carter. 

 Fig. 5. Triturating surfaces of the teeth from the same. 



Figs. 6, 7. Left side of two lower jaws containing the molars. From mature but compara- 

 tively young individuals. Dr. Carter. 

 Fig. 8. Series of the back two premolars and the molars of the right side. From a specinleu 



loaned by Dr. Carter. 

 Fig. 9. First and second lower molars of the right side. From another specimen loaned by 



Dr. Carter. 



Figs. 10, 11. MicROsns cuspidatus : 



Fig. 10. Portion of left side of lower jaw, with back two molars, natural size. Specimen 



from Black's Fork of Green -River. 

 Fig. 11. Triturating surfaces of the two molars, magnified four diameters. 

 Fig. 12. Portion of right side of lowcfi- jaw, probably pertainiug to the last-named animal. 



It coutaius the roots of the molars and the last premolar, the triturating surface of which 



is represented in Fig. 13, magnified four diameters. Specimen obtained by Dr. Carter near 



Fort Bridger. 



Figs. 14-17. MiCRO.SYOPS gracilis: 



Fig. 14. Left side of lower jaw with the molars, natural size. Fig. 15. Triturating surfaces 



of the molars, magnified four diameters. Specimen obtained at Grizzly Buttes by Dr. 



Carter. 

 Fig. 16. Left side of lower jaw, with the second molar and portions of the others, natural 



size. Fig. 17. The triturating surface of the second molar magnified four diameters. 



Specimeu obtained by Dr. Carter at Grizzly Buttes. 



Figs. 18-22. Hyopsodus padlus: 



Fi"-. 18. Right upper jaw, with three premolars and the molars, magnified 'two diameters. 



Fig. 19. Tritiu-atiug surfaces of the teeth magnified four diameters. Specimen obtained 

 by Dr. Carter at Grizzly Buttes, aud apparently pertaining to the same individual as that 

 of Fig. 14. 



Fig. 20. Triturating surfaces of the right upper molars, magnified four diameters, from a 

 second specimen. Dr. Carter. 



Fig. 21. Triturating surfaces of back two premolars and first molar of the left side, magni- 

 fied four diameters. Obtained by Dr. Carter at Lodge-polo trail. 



Fi"'. Hi. Triturating surfaces of upper secoud and third premolars of right side, magnified 

 four diamoters. Dr. Carter. 



Figs. 23-25. PARAMY.S del!Catu.s : 



Fig. 23. Right side of lower jaw, with all the molars, natural size. Fig. 24. Triturating 

 surfaces of the molars except the last, which is broken away csccptiug the outer portion, 

 magnified three diameters. Grizzly Buttes. Dr. Carter. 

 Fi". 2.'>. Triturating surfaces of the molar series, except the last, of the lower right side, 

 magnified three diameters. From another specimen loaned by Dr. Carter. 



