(Sarah of the Clue Crew delivers the clue) Sea urchins' body symmetry makes their teeth fit together in a way that this pupil of Plato compared to a five-sided lantern.  2300 years later, it's still known as his lantern
There are 
several highly-developed types of pedicellariae among the spines ... 
LOCOMOTION: Sea urchins move in a similar way to sea stars, using a ... it is 
known as Aristotle's lantern Aristotle's lantern is made of five long, chisel-like...