Did Saul?

Have two sons named Mephibosheth? I am not sure I understand this passage in 2 Samuel 21. Anyone have any insight?

7 The king spared Mephibosheth son of Jonathan, the son of Saul, because of the oath before the LORD between David and Jonathan son of Saul. 8 But the king took Armoni and Mephibosheth, the two sons of Aiah’s daughter Rizpah, whom she had borne to Saul, together with the five sons of Saul’s daughter Merab, [a] whom she had borne to Adriel son of Barzillai the Meholathite. 9 He handed them over to the Gibeonites, who killed and exposed them on a hill before the LORD. All seven of them fell together; they were put to death during the first days of the harvest, just as the barley harvest was beginning.