I've been accused of swinging wildly between the easy and the impossible for these ID challenges. The last one was fairly easy, so I suppose it's time for the impossible:
To give a bit of a hand, the animal shown is a marine species of its phylum.
Attribution to follow.
Update: Identity available here. Figure from Pollock (1976).
TMI Friday: The worst way to be caught dead
2 hours ago in Memoirs of a Defective Brain