260 



l)ose<l to belong to a species of Procainelus. The spcciiiieiis, consisting of a 

 last premolar, aud the first and last molars of the lower jaw, are represented 

 in Figs. 26 to 29, Plate XXVII. The teeth have the same form and consti- 

 tution as those of the western species of Procamelus above named, and they 

 appear to indicate an additional species, which was about the size of the ex- 

 isting llania, and intermediate in size to P. occldcntaHs and P. graciUs 

 The measurements of the teeth are as follows : 



LiiR's. 



Autero-posterior diameter of last premolar 7 



Transverse diameter of last jiremolar 4 



Anteroposterior diameter of first molar 7;^- 



Transverse diameter of first molar (] 



Anteroposterior diameter of last molar ll'i 



Transverse diameter of last molar 



MEGxVLOMERYX. 

 Megalomeryx niobrarensis (?) 



The genus to which the above name was applied has not been determined 

 by ])()sitive characters, and may prove not to be distinct from Procamelus. 

 It was i)roposed on two specimens of teeth of a large ruminant, apparently 

 of the camel family, discovered by Professor Hayden in the Pliocene Tertiary 

 sands of the Niobrara River, Nebraska. The teeth, both lower molars, are 

 described in the " E.\tinct Mammalia of Dakota and Nebraska,'' page 161, and 

 are represented in Figs. 12-14, Plate XIV, of tliat work. 



•A similar tooth was submitted to my examination, by Professor J. D. Whit- 

 ney, fi-om the Pliocene Tertiary of Tuolumne County, California. 



Figs. 24, 25, Plate XXVII, represent a mutilated lower molar, apparently 

 (d'the same species. This was found in L'Eau qui Court County, in Northern 

 Nebraska, and was presented to Swarthmore College by George S. Truman. 



H E L N I A . 



EMYS. 



Emys petrolei. 



An extinct species thus named is indicated l)y a number of fragments of 

 several turtle-shells, which were found in association with remains of Masto- 

 don, Megalonyx, Equus, Tnicifrlis fafalis, &c., in Hardin County, Texas. 

 They were ol^tained I'roin a stratum of clay beneath a bed of bitumen, and. 



