Numerous remains of castoroid rodents from the Tertiary of North America have been referred to the Old World genus Dipoides Jaeger. Apparently, most of the material represents types generically distinct from Dipoides, and the genus is actually represented by very few specimens of fragmentary character. It is not the purpose of this paper, however, to present the distinguishing characters which separate the true Dipoides from other American beavers with simplified dental pattern, but to describe remains of a Dipoides species collected by California Institute of Technology field parties in Pliocene beds in the region of Rome, Oregon. R. A. Stirton, of the University of California, has made a study of the taxonomy and relationships of members of the beaver group and his report on the Castoridae is now in press
