statoblast

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An asexually produced encapsulated bud of certain freshwater bryozoans that is released upon disintegration of the parent colony and develops into a new organism after a period of dormancy.

from The Century Dictionary.

• noun One of the peculiar internal asexual buds developed in the body-cavity of the fresh-water or phylactolæmatous polyzoans, comparable to the gemmules of the fresh-water sponges, and serving for reproduction.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Zoöl.) One of a peculiar kind of internal buds, or germs, produced in the interior of certain Bryozoa and sponges, especially in the fresh-water species; -- also called winter buds.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun zoology One of a peculiar kind of internal buds, or germs, produced in the interior of certain Bryozoa and sponges. They are protected by a firm covering, and are usually destined to perpetuate the species during the winter season. They burst open and develop in the spring. In some freshwater sponges they serve to preserve the species during the dry season.