Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera. They are sessile filter feeders that are bound to the seabed, and are one of the most ancient members of macrob
A stove-pipe sponge
Spongia officinalis, "the kitchen sponge", is dark grey when alive.
Euplectella aspergillum, a glass sponge known as "Venus's flower basket"