Acoelomorpha

Acoelomorpha is a subphylum of very simple and small soft-bodied animals with planula-like features that live in marine or brackish waters. They usually live between grains of sediment, swimming as plankton, or crawling on other organisms, such as algae and corals. Except for two acoel freshwater species, all known acoelomorphs are marine.

Isodiametridae is a family of acoels.

Isodiametra is a genus of worms belonging to the family Isodiametridae.

Archaphanostoma is a genus of acoels belonging to the family Isodiametridae.

Diatomovora is a genus of worms belonging to the family Isodiametridae.

Faerlea is a genus of acoels belonging to the family Isodiametridae.

Aphanostoma is a genus of acoel flatworms in the family Isodiametridae. Individuals can grow to 5 mm. They rely on ciliary gliding to move around. They really on ocelli for vision which are small simple eyes, found in many invertebrates, usually consisting of a few sensory cells and a single lens. They move around by ciliary gliding which is a type of locomotion in which an animal moves on a secreted layer of mucus, propelled by the beating of cilia. It is characteristic of small, soft-bodied invertebrates.