Short Description:

Purple-grey to slate grey to off-white; tends to be darker along rows of oscules (this is caused by microsymbiont algae). It may be white in dark niches such as caves. The interior is dull greyish yellow.
Massive-lobose, hemispherical to irregularly rounded,  On overhangs it may become pendulous. Surface clean-looking, even, granular-smooth, without projections. Just beneath the surface is a hard layer, the 'sterrastral layer' packed with sterraster microscleres. Oscules rounded, evenly spaced, often in rows, flush with the surface along the tops of the ridges, 2-3 mm in diameter. Consistency: firm-hard, but slightly compressible. Contraction not noticeable.

• Marine Secies Identification Portal
  http://species-identification.org

• None on database