Gemmules | Milwaukee Public Museum

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Gemmules are seed-like capsules formed by sponges for overwintering, containing cells from which a new sponge can grow.

Gemmules have the characteristics that identify sponges to the species level:

With a tube (surrounding the foraminal opening (f) to the exterior of the gemmule) extending from the gemmule surface

With no tube extending from the gemmule surface (though may have a short collar)
- Gemmoscleres embedded radially and extending beyond the surface
- Gemmoscleres tangential to the surface
- Gemmoscleres embedded radially and barely visible at the surface
Species with two different kinds of gemmules, one lacking gemmoscleres