Since more leaders were found among Eleazar’s descendants than those of Ithamar, they were divided accordingly. There were sixteen heads of families from the descendants of Eleazar and eight from the descendants of Ithamar.
Jewish Publication Society of America Version (JPS1917) - 1 Chronicles 24:4 >And there were more chief men found of the sons of Eleazar than of the sons of Ithamar; and thus were they divided: of the sons of Eleazar there were sixteen, heads of fathers' houses; and of the sons of Ithamar, according to their fathers' houses, eight.