[taxon-note] "In lampreys and apparently in some fossil fish, the parapineal body and the pineal body (epiphysis) are a bilateral pair of structures rather than being located in series, one in front of the other. A pair of visual structures may have been the ancestral condition of this pineal complex (Weichert, 1970, p.622). The parapineal organs of lampreys, tadpoles, and lizards possess cells similar to rods and cones. Frogs possess a brow spot or frontal organ where ancestral pineal eye might have been (Weichert, 1970, p.622)"