EXPLANATION OF PLATE IX. 



All the figures half the natural size. 



Fig. 1. Tkionyx guttatus : 



Portion of a carapace, consisting of the third to the sixth vertebral plates, inclusively, 

 together with parts of the contiguous costal plates. Specimen obtained at Church Buttes 

 during Professor Hayden's exploration of 1868. 



Figs. 2-6. Emys wyomingensis : 



Fig. 2. Portion of a carapace comprising the vertebral plates from the first to the eighth 

 inclusively, together with small portions of some of the contiguous costal plates. 

 Specimen, originally referred to Emys Steven son Ian us, obtained by Dr. Carter in the 

 vicinity of Fort Bridger, and presented by him to the Smithsouian Institution. 



Fig. 13. Portion of a plastron, which accompanied the preceding specimen and was origi- 

 nally referred to E. Stevensonianus. 



Fig. 4. Anterior fragment of another plastron, accompanying the former two specimens, and 

 likewise referred to E. Stevensonianus. 



Fig. 5. An episternal, upon which the species Emys wyomingensis was first noticed. Specimen 

 found by Dr. Carter near Fort Bridger. 



Fig. 6. Central portion of a carapace, originally attributed to Emys Hqydeni. Specimen 

 obtained near Fort Bridger. Hayden's collection. 



Fig. 7 Emys petrolei: 



Two epistevnals from different individuals. Specimens from Hardin County, Texas. 



