Sea Urchins 3 - Aristotle's Lantern

The mouth of a sea urchin on the underside of the test (in situ above), contains five sharp teeth, which form part of a complicated structure, which I was fascinated to read is called 'Aristotle's lantern' because it was first described by the Greek philosopher in his 'Historia Animalium'. I carefully removed the structure from the test so that I could take photos.

The view from above.

Side view of the structure.

The view from below.

Outer and inner view of an individual tooth.