Cephalodiscida is one of two orders in the class Pterobranchia, which are small, worm-shaped animals.

[1][2] Species in this order are sessile, living in clear water and secrete tubes on the ocean floor.

[3] The order is a small one, with only two known families, each containing a single extant genus.

The validity of the family Atubaridae, who has only a sole member, is regarded as questionable.

The Pterobranchia ol the Siboga-Expedition.