This spectacular group of stalked sea-squirts clinging to a mussel was washed up on the beach the other day. Their other name is sea-tulip and they are common in the southern part of New Zealand's South Island.
The long felxible stem can withstand quite a wave-bashing, but there were clearly just too many grouped onto this hapless mussel for it to survive the swaying over the last few days of turbulent weather. Pyrua pachydermatina lives just below low tide down to quite deep water, often in large quantities, amnogst kelp and other brown seaweeds. You can see them in the harbour too, and apparently they dominate the sub-littoral at Portobello.
The body is free of other critters but the brown tufts are bryozoans which are using the stem as a substrate.
see: Batham, E.J. 1956. Ecology of Southern New Zealand Sheltered Rocky Shore. Transacions of the Royal Society of New Zealand, vol 84 part 2, pp 447-465
