Also found in: Wikipedia.


n. pl.1.(Paleon.) A group of large, extinct, herbivorous mammals, common in the Tertiary formation of the United States.
Webster's Revised Unabridged Dictionary, published 1913 by G. & C. Merriam Co.
References in periodicals archive ?
Containing the order Ungulata, Suborders Perissodactyla, Toxodontia, Condylartha, and Amblypoda. London, pp.