137 



Portions of the shell of another specimen, apparently referable to Testudo 

 Corsoni, were discovered by Dr. Corson on Dry Creek Buttes. Several of 

 the fragments so far recompose one side of the back lobe of the plastron as 

 to determine its identity with that of T. Corsoni. It is especially interesting 

 from its being accompanied by a number of fragments of the upper shell, 

 which being reunited compose the middle portion, as represented in Fig. 1, 

 Plate XXX. This specimen tends to confirm what [ have latterly suspected, 

 namely, that the specimens formerly described and represented in Plate XI, 

 under the name of Emys Carteri, really belong to Testudo Corsoni. The 

 specimens originally referred to the former, though much more complete 

 than the one upon which the latter was founded, completely misled me. The 

 spade-like process of the plastron was not simply broken off, but, while 

 imbedded in its matrix, was crushed or squeezed off in such a manneras to 

 leave but little trace of its true character. The accompanying portion of the 

 carapace exhibited the costal plates with strong costal capitula as in living 

 species of Emys. This emydoid character with others are probably suffi- 

 cient indications that the specimens would properly be referable to a genus 

 distinct from either Testudo or Emys, and is probably the same as that 

 recently proposed by Professor Cope, under the name of Hadrianus. 



The specimens originally referred to Emys Carteri, but now viewed as 

 pertaining to Testudo Corsoni, were discovered by Dr. Carter in the buttes 

 near Fort Bridger. They consist of the greater part of a mutilated plastron 

 with the ends broken off, and the anterior median portion of the carapace. 



The plastron represented in Fig. 1, Plate XI, resembles, in its size, form, 

 and proportions, the nearly complete specimen above described and repre- 

 sented in Fig. 2, Plate XXX. It is not so concave posteriorly, but other- 

 wise presents nothing peculiar. 



The portion of the carapace represented in Fig. 2, Plate XI, consists of 

 the nuchal and anterior three vertebral plates with fragments of the contig- 

 uous costal plates. 



The anterior border of the fragment is slightly emarginate. The vertebral 

 region is flat, and slopes forward, from the anterior half of the first vertebral 

 plate. The nuchal plate is nearly as long as wide, and its antero-latcral 

 borders are moderately convergent. 



The first vertebral plate is clavate in outline with the broad end behind. 

 The anterior narrow end dips into an emargination of the nuchal plate. Its 

 widest part is less than a fourth of its length in advance of its posterior 

 18 G 



