Magnets in guitarfish vestibular receptors.

O'Leary D P, Vilches-Troya J, Dunn R F, Campos-Munõz A

Experientia. 1981 Jan 15;37(1):86-8. doi: 10.1007/BF01965587.

Black magnetic particles are intermixed with white crystalline otoconia in the inner ear gravity receptors of a saltwater ray. Their size and composition suggest that they are multidomains of magnetite-ilmenite.