[3][4] Pterobranchs are small worm-like filter feeders living on the ocean floor, often in relatively deep waters.

The proboscis is wide and flattened at the tip, and in most species contains glands that secrete a tube of organic material in which the pterobranch spends its adult life.

The single member in the genus Atubaria is unusual in lacking the tubes typical of other pterobranchs,[5] living as a naked zooid on corals.

[6] Recently, Atubaria has been regarded as a questionable species by Tassia et al. (2016) and is no longer considered valid.

The trunk includes a simple tubular gut, and is curved over so that the anus projects upwards, lying dorsal to the collar.

[17] Cephalodiscida Rhabdopleurida Dendroidea Graptoloidea Class Pterobranchia Lankester 1877[4] The two pterobranch taxa Rhabdopleura compacta and Cephalodiscus use alternative genetic codes in their mitochondrial genome.