342 



Described page 176, and represented by Fig. 1, Plate IX. From the 

 Bridger Eocene of "Wyoming. 



TRIONYX UINT1EN8IS. 



Leidy : Pr. Ac. Nat. Sc. 1872, 267. 

 Described page 178, and represented by Fig. 1, Plate XXIX. From the 

 Bridger Eocene of Wyoming. 



Trioxyx .' 



.Fragments described page 180, and represented in Figs. 11, 12, Plate 

 XVI. From the Bridger Eocene of Wyoming. 



Sphargidid^; 1 



ATLANTOCHELYS. 



Atlantochelys mortoxi.* 



Agassiz : Pr. Ac. Nat. Sc. 1S49, 169. 



Mosasaurus •Mitchelli. Leidy: Cret. Eept. in Smith. Contrib. 1S65, 43, 116. De- 

 termination admitted by Cope: Pr. Post. Soc. Xat. Hist. 1S69, 253. 

 Protostega neptunia. Cope : Pr. Am. Phil. Soc. 1S72, 433. 



Founded on the fragment of a large humerus described in the "Cretaceous 

 Reptiles of the United States/' 18G5, 43, and represented in Figs. 3, 4, 

 5, Plate VIII of that work. From the Cretaceous green sand of New 

 Jersey. See page 270. 



Atlaxtochelys tdberosus. 



Holcorfics acutidess. In part of Leidy : Cret. Eept. in Smiths. Contrib. 1863, 42, 



118. Determination admitted by Cope : Pr. Bost. Soc. Nat. Hist. 1869,253. 

 Platecarpus tympaniticus. In part of Cope: Pr. Bost. Nat. Hist. Soc. 1869, 265; 



Synop. Est. Batrachia, Beptilia, &c 1870, 199. 

 Protostega. Cope: Pr. Am. Phil. Soc. 1S72, 433. 

 Platecarpus tuberosus. Cope: Pr. Am. Phil. 1872, 433. 

 Protostega tuberosa. Cope: Hayden's Eep. Geol. Sur. Montana, 1872, 339, 334. 



Founded on a humerus described in the "Cretaceous Reptiles of the 

 United States," 1865, 42, and represented in Figs. 1, 2, Plate VIII of 

 that work. From the Cretaceous formation near Columbus, Mississippi. 

 See page 270. 



It was the association of this specimen with several cervical vertebrae, and 



* Professor Cope observes that "this naine was unaccompanied with the necessary 

 description, and is hence useless to science." (Pr. Am. Phil. Soc. 1S72, 433.) As the 

 specimen on which it was founded was described and figures in my paper on the Cre- 

 taceous Eeptiles, so as to be recognized by every student, I have preferred to employ 

 the original name instead of the proposed substitute. 



