Species: flatworm
Any member of the diverse phylum Platyhelminthes. The majourity of these are free-living worms with a sac-like, often branching gut, with some flatworms bearing an eversible pharynx, and even a small yet well-organised and complex brain; though the phylum also contains parasitic and commensal flatworms, as well. The parasitic forms are often the most studied, due to their roles in disease.
The following tags implicate this tag: planarian (learn more).