EEPTILIA. 



TESTUDINATA. 



TRIONYX, Geoffr. 



Trionyx letjcopotamicus. Sp. nov. 



This species is represented by a part of a single costal bone, with the sculpture well 

 preserved. This specimen would scarcely serve as a basis for a specific description, but 

 I have a number of well-preserved fragments of apparently the same turtle from the 

 White Buttes of Dakota, which render important aid. The latter furnished me with the 

 first indication of the presence of this genus in beds of "White River age, as they have not 

 been yet found in the best known regions of this formation in Southern Dakota and 



Eastern Colorado. 



The costal bones are flat and rather thin, but thickest medially, as usual. The sculp- 

 ture consists of large, sub-round and sub-oval fosste, which are separated by ridges much 

 narrower than themselves. In the Cypress Hills specimen the fossae tend to form long- 

 itudinal series towards the distal extremity of the bone. The suturai borders are not 

 preserved, but in the Dakota specimens the sculpture continues to show, and does not 

 give place to a band of nearly smooth and transversely-lined surface, as is the case in the 

 T. punctiger, ' Cope, also from the White River bed of Central Dakota. 



This species resembles in its sculpture the Trionyx uintaensis of Leidy from the 

 Bridger Eocene. The sole difference which the latter presents is the presence of bands of 

 grooves parallel to the long axis of the carapace, along the intercostal sutures. It is pro- 

 bable that the costals are thicker in the Bridger species, a character still more strongly 

 marked in those of the Wasatch series. 



STYLEMYS, Leidy. 



(?) Stylemys nebrascensis, Leidy. 



A few fragments, including a marginal bone, not distinguishable from this species, 

 were obtained by Mr. Weston. 



MAMMALIA. 



GLIRES. 



PAL^OLAGTJS, Leidy. 



Pal^olagtjs turgidtjs, Cope. 



Report TJ. S. Geol. Survey Terrs., Ill, Bk. I., p. 882, pi. lxvi., f. 28 ; lxvii., 13-27. 



Mandibular rami identical in character with those from the White River beds of 



Dakota and Colorado. 



1 Besides the character above described, the sculpture of the costal bones of the T. pimctigcr is much less dis- 

 tinct than in the T. leucopotamicus. It is both punctate and groove-like, and the ridges are thickened and irregu- 

 lar, and towards the distal ends of the bones obscure. While not wider than those of the latter species, the costals 

 are thicker and more curved, the thickness continuing to the free margin, where they are bevelled off, with a 

 prominent rib-end in the middle. Measurements of No. 1 : — Width of costal, 4S mm. ; thickness at lateral suture, 

 5 mm. ; at middle, 9 mm. No. 2 : — Width of costal, 52 mm. ; thickness at middle, 11 mm. This is Trionyx sp. 2, 

 Cope Proceeds. Am. Philos. Soc, 1883, p. 217. 



