What phylum has a true coelom?

Coelom is a Word used to describe a body cavity of an animal, so there are three different types of coeloms:

• Acoelomate
• • Most Primitive Type
  • No body cavity around gut
• Pseudocoelomate ("fake Ceolom")
• • The cavity surrounding the gut is lined, but the gut itself is not
  • Gut and body cavity are lined
• Eucoelmate ("true Ceolom")
• • Gut and body cavity are lined
  • Allows organs to move without friction

If you are referring to the true ceoloms, there are no invertabrates with this body type, as it is only found in higher organisms.