Zimmah: Two Gershonites

…the son of Ethan, the son of Zimmah, the son of Shimei,

Then the Levites set to work: Mahath son of Amasai and Joel son of Azariah from the Kohathites; Kish son of Abdi and Azariah son of Jehallelel from the Merarites; Joah son of Zimmah and Eden son of Joah from the Gershonites;