Spongilla

Spongilla is a genus of freshwater sponges containing over 200 different species. Spongilla was first publicly recognized in 1696 by Leonard Plukenet and can be found in lakes, ponds and slow streams.Spongilla have a leuconoid body form with a skeleton composed of siliceous spicules. They are sessile organisms, attaching themselves to hard substrate like rocks, logs. and sometimes to ground. Using their ostia and osculum these sponges filter the water for various small aquatic organisms such as protozoans, bacteria, and other free-floating pond life. Sponges of the genus Spongilla partake in symbiotic relationships with the green algae, zoochlorellae, which gives the sponges a green appearance, and without which they would appear white.

Spongilla was used by John Hogg in the 19th century to attempt to justify a fourth kingdom of life.