Haliclona sp. A (Hartman, 1975)
Phylum Porifera, Class Demospongiae, Order Haplosclerida, Family Chalinidae
Purple sponge; thin crust 2-3 mm thick with raised tubular oscula 1-3 mm diameter.
Moderately common on sides of rocks, but spotty in space and time; mid- to low intertidal zones, protected outer coast; only sponge to occur on open rock this high on the shore.
Geo Range: central to southern California
Synonyms: formerly thought to be the Atlantic Haliclona permollis
Similar species: this is the only sponge that lives this high in the intertidal zone; all other sponges occur much lower and into the subtidal.
Image: dark brown crust is Petrocelis phase of (probably) Mastocarpus papillatus.