Flabelligeridae is a family of polychaete worms, known as bristle-cage worms, notable for their cephalic cage: long slender chaetae forming a fan-like arrangement surrounding the eversible (able to be turned inside-out) head.

[1][2] Unlike many polychaetes, they also have large, pigmented, complex eyes.

[3][4] These worms live under stones and are known to burrow into sand.

[5] They have a cosmopolitan distribution and live in a variety of marine habitats, from the deep sea to shallow coastal regions.

[6] The first species was Amphridite plumosa, described from Norway.