EXPLANATION OF PLATE IX. 



All the figures lialf the natural size. 



Fig. I. Trionyx guttatus : 



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

 together with parts of the contignous 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 jjlates from the first to the eighth 

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

 Specimen, originally referred to Emijs Sterensoniamis, obtained l)y Dr. Carter in the 

 vicinit.'^of Fort Bridger, and presented by him to the. Smithsonian Institution. 



Fig. 3. Portion of a plastron, ivhich accompanied the jireceding specimen and was origi- 

 nally referred to E. Slcrcnsoiiianus. 



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

 likewise referred to E. Steveiisoriiaiuis. 



Fig. 5. An episternal, upon which the species Emys wijomiiif/ensiii was first noticed. Specimen 

 found by Dr. Carter near Fort Bridger. 



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

 obtained near Fort Bridger. Haj'den's collection. 



Fig. 7 Emys petrolei: 



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



