Protostome orders

Canalipalpata, also known as bristle-footed annelids or fan-head worms, is an order of polychaete worms consisting of 31 families such as the Serpulidae (tubeworms), Sabellidae (fanworms and feather duster worms), and Siboglinidae (beardworms) of the suborder Sabellida, and the Alvinellidae, a family of worms often associated with hydrothermal vents (though a number of Siboglinids also inhabit hydrothermal vents, like the giant tube worm Riftia pachyptila). Most canalipalpatans are considered to be tube worms, with some exceptions.

Neoechinorhynchida is an order of parasitic worms from the phylum Acanthocephala. It contains 3 families:

Ploima is an order of rotifers, microscopic invertebrates found in marine and freshwater habitats.

Aphragmophora is an order of sagittodieans in the phylum Chaetognatha.

Flosculariaceae is an order of rotifers, found in fresh and brackish water.

Phragmophora is an order of sagittoideans in the phylum Chaetognatha.