Semi-enclosed volume serving an animal for both and distribution of nutrients about an animal's body.

Gastrovascular cavities are seen particularly with phylum Cnidaria and phylum Platyhelminthes, both of which possess only a single opening to their gastrovascular cavity that serves as both and .

In animals with more sophisticated body plans there not only is a separate mouth and anus, as well as movement in direction from the former to the latter, but body cavities, , and/or provide conduits for movement of materials about the body.

Contrast, for example, with alimentary canal, but see also gut as well as archenteron.