270 Palmer — Generic and Family Names of Rodents. 



Palaiotrogus Jiiger, 1839 ... Palaiotrogus steinheimensis. 



Paradoxomys^ Ameghino, 1885. . Paradoxomys cancrivorus. 



Protechymis Filliol, 1891 Nomen nudum. 



Protoptychus^ Scott, 1895 Protoptychus hatcheri. 



^ Paradoxomyina Ameghino, Bol. Acad. Nac.Cien., Cordoba, IX, p. 79, 1886. 



Paradoxomydx Ameghino, Mam. Fos. Repub. Argentina, in Actas Acad. 

 Nac. Ciencias, Cordoba, VI, p. 122, 1889. 



■'' "The genus is probabl}'' to be regarded as the ancestral type of the 

 Dipodidse, and indicates an American origin for this family."— Scott, 

 Proc. Acad. Nat. Sci. Phila., 1895, p. 286. 



