0. P. Hay — Fossil Turtles in the Marsh Collection. 267 



vated. This may be an individual variation, or it may indicate 

 a distinct species. In all the known specimens of this species 

 the intergular and gular scutes are absent, and the numerals 

 extend forward to the front of the plastron. 



A comparison of the skull of this species with that of Der- 

 matemys mawii, as described and figured by Bienz (Rev. suisse 

 de Zool., iii, 1895, p. 61, pi. ii, figs. 1-5) shows that the two 

 are similar in general form and in the absence of a temporal 

 roof. The structure of the upper and lower jaws is quite dif- 



Figure 2. — Baptemys wyomingensis. Diagram of plastron. 



ferent in the two genera. In Dermatemys the choanse are 

 undernoored by the palatal plates of the maxillge and are 

 pushed well backward. In Baptemys they are far forward in 

 the vaulted palate. 



Chrysemys wyomingensis Leidy. 



Plate XIV ; Text-figures 3, 4. 



Emys ivyomingensis Leidv, J., Proc. Acad. Nat. Sci. Phila., 1869, p. 66; 

 Contr. Ext. Fauna West. Terrs., 1873, pp. 140, 340, pi. ix, figs. 4, 5, pi. x, 

 figs. 1, 2. Hay, 0. P., Bibliog. and Cat. Foss. Vert. N. A., 1902, p. 448. 



In the collection of fossil vertebrates made by Professor 

 Marsh in the year 1874, there is an unusually interesting speci- 

 men of turtle. This is a nearly complete shell, and was 

 obtained in the Briclger beds at Millers ville, a point a few 

 miles east of Fort Bridger, Wyoming. It is referred without 

 doubt to the species above named. It is interesting from the 

 fact that it possesses a number of supernumerary structures. 

 That is, it has nine neurals, instead of eight ; ten pairs of costal 



