selenizone
From ZooTerms (Dictionary of Invertebrate Zoology)
selenizone (noun; Greek selene, moon; zone, girdle): (Mollusca: Gastropoda) In dibranchiates, a spiral band of crescentric growth lines or threads (lunulae) on the shell surface due to the semicircular end of a notch or slit on the outer lip; a slit band; corresponds to the anal fasciole of some other groups.
