"This is another one of those that seems in between different species. It could be a heavily pustulose form of Phyllidiella pustulosa, although I think that would put it at the far end of its range of variation."
Comment from Scott Johnson
This is another one of those that seems in between different species. It could be a heavily pustulose form of Phyllidiella pustulosa, although I think that would put it at the far end of its range of variation.