Scallops have a large number (up to 200) of small (about 1 mm) eyes arranged along the edge of their mantles. Each one relies on a concave, parabolic mirror of guanine crystals to focus and retro-reflect light thru millions of square tiles https://t.co/BaRL65MA72 pic.twitter.com/dsfsw32sQy

— Massimo (@Rainmaker1973) September 19, 2019