Parenchymella is a type of

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

of a

demosponge Demosponges or common sponges are sponges of the class Demospongiae (from + ), the most diverse group in the phylum Porifera which include greater than 90% of all extant sponges with nearly 8,800 species A species () is often de ...

composed of an envelope of flagellated cells surrounding an internal mass of cells.Parenchymella at portol.org/thesaurus
/ref> Demospongiae develops directly into solid stereoblastula. It then develops flagellae to form parenchymella.

References

Larvae Demospongiae Sponge biology {{sponge-stub