\Siv`a*the"ri*um\, n. [NL., from E. Siva + Gr. ????
a beast, an animal.] (Paleon.)
A genus of very large extinct ruminants found in the Tertiary
formation of India. The snout was prolonged in the form of a
proboscis. The male had four horns, the posterior pair being
large and branched. It was allied to the antelopes, but very
much larger than any exsisting species.