These mentioned by their names were princes - The registered chiefs of the cities in the first list 1 Chronicles 4:28-31, in the time of Hezekiah 1 Chronicles 4:41.
SDA Bible Commentary (limited)
Volume 1-7
38. Increased greatly. Because of increase in numbers and probably also pressure from neighbors who had likewise increased, the Simeonite chieftains went forth to seek new settlements.