Purple slime on Duran beach. See "The Natural History of Bodega Head" blog, http://bodegahead.blogspot.com/2016/05/purple-pools-and-purple-waves.html?m=1
Floating around 9m deep off of San Carlos Beach Park, Monterey, CA
Found two colonies in shallow water. Roughly apricot-sized. The colonies are cylindrical but almost look like plicate, or built from sausage-shaped elements around a superior dimple. Also, it looks like the tentacles are in a veil, like the Ctenophoran order Lobata.
This is the first time I see this genus, and my ID may be wrong.
This is also posted on jellywatch.org, at: http://jellywatch.org/node/6278
The Thaliacea comprise a class of marine animals within the subphylum Tunicata. Unlike their benthic relatives the ascidians, thaliaceans are free-floating (pelagic) for their entire lifespan. The group includes species with complex life cycles with both solitary and colonial forms.