(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
The sea urchin builds its spicules, the sharp, crystalline "bones" 
that ... known as Aristotle's lantern (image), from Aristotle's description in his 
History of... [DOC] [TLE] Sea Urchins - info and games - Sheppard Software [PAR] Sea urchins are spiny sea creatures of the class Echinoidea found in oceans all 
over the world.