The purple holothurian, Psychropotes sp., feeds on organic sediment deposits on the rocky substrate. This species has a distinct sail over its posterior end. The function of the sail or what the animal uses it for isn't very clear.
Purple Holothurian
Image courtesy of the NOAA Office of Ocean Exploration and Research, Discovering the Deep: Exploring Remote Pacific MPAs. Download larger version (jpg, 1.3 MB).

The purple holothurian, Psychropotes sp., feeds on organic sediment deposits on the rocky substrate. This species has a distinct "sail" over its posterior end. The function of the sail or what the animal uses it for isn't very clear.

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