What is planaria's phylum?

Planaria are non-parasitic flatworms that are grouped in the phylum Platyhelminthes. This puts planaria in the same general family as tapeworms and liver flukes. Planaria are distinguished by their lack of a body cavity and circulatory system.

In general, Platyhelminthes have comparatively simple body plans, and many are parasites. Platyhelminthes are an extremely ancient group, and they are in many ways among the simplest of animals. Most of them lack digestive organs and simply absorb nutrients through their exterior. However, members of this phylum show significant variation on a molecular level, and it is possible that some are more closely related to earthworms than they are to other Platyhelminthes. If this is the case, the phylum would have to be revised.