Xan-thīd'i-ūm, n.

noun

(zan-), n.; pl. XAN-THĪD'I-Ā. [N. Lat., fr. Gr. ξανθός, yellow.] (Zoöl.) A microscopic plant or proto-phyte, having a globular, flattened shape, and bristled with spiracules. It is found fossil in flint or hornstone, and is common, also, as a living creature.

The illustration shows four magnified forms of xanthidia. — Xanthidia, magnified.