Schizocele

The body cavity or schizocele is filled with a clear liquid which functions as blood. The viscera—digestive tract and reproductive organs—are suspended in the schizocele.

There remains for discussion the mesenchyme theory, which proposes that a mesenchymal schizocele evolved into a cavity lined by a typical ciliated epithelium.

The adult body cavity is not the direct continuation of the embryonic blastocele as indicated by Hyman (1951) but is rather a schizocele (Remane, 1963).