Judah’s sons: Er, Onan, Shelah, Perez, and Zerah; but Er and Onan died in the land of Canaan.
Perez’s sons: Hezron and Hamul.

The descendants of Perez:
the Hezronite clan from Hezron;
the Hamulite clan from Hamul.

Perez’s sons: Hezron and Hamul.