Polymastia mamillaris is a sponge with a hemispherical base reaching 10 to 20 cm
in diameter. The base is often covered with sand or mud from which emerge many flattened outgrowths
up to 3 cm in height and 3 to 5 mm in diameter. The base is dirty yellow and the outgrowths are clearer
and slightly translucent. It lives on rocks near sandy bottoms and bear algae or benthic animals on its body.
It is found in the Atlantic Ocean, the North Sea, the English Channel and the Mediterranean Sea.
Polymastia mamillaris is a sponge similar in size and form to Polymastia boletiformis. However the outgrowths of the latter have a larger diameter and a conical shape, and its colour is yellow orange.
Phylum Porifera, class Demospongiae, order Hadromerida, family Polymastiidae, Polymastia mamillaris (Müller, 1806).
Please contact us if the meaning of one of the words used in this page is not clear.
Photograph: © Wilfried Bay-Nouailhat. Published with author's kind permission.
Polymastia mamillaris, Iles Glénan, South-Brittany, West of France. Depth 14 meters.
Text: Wilfried Bay-Nouailhat © 2004-2008.
Translation: Anne Bay-Nouailhat © 2007-2008.
