any of various extinct herbivorous hoofed mammals of the genus Brontotherium and related genera,of the Eocene and Oligocene epochs,resembling the rhinoceros

• 雷兽类一种已绝迹的雷兽属和其它相关属类的有蹄食草哺乳动物，生长于始新世和渐新世，类似于犀牛