Bumastus

thumb|upright|Bumastus barriensis, from the [[Silurian Wenlock series, found at Dudley, Worcestershire.]]

Bumastus is an extinct genus of corynexochid trilobites which existed from the Early Ordovician period to the Late Silurian period. They were relatively large trilobites, reaching a length of . They were distinctive for their highly globular, smooth-surfaced exoskeleton. They possessed well-developed, large compound eyes and were believed to have dwelled in shallow-water sediments in life.