John ap Hugh
Another name for John was John Hugh.
From Reifsnyder-Gillam Ancestry, Edited by Thomas Allen Glenn at the request of Howard Reifsnyder, privately printed, Philadelphia, 1902, provided by http://books.google.com, p. 31:
"The witnesses to [the marriage contract and settlement made upon the marriage of Ellis Price and Anne Humphrey in 1649] were: John ap William ap Humffrey, David John Hugh, Griffith ap Rees Lewis, Edward Waughn and John ap Hugh."
And from p. 46:
"Issue [of Hugh ap David and Catherine]:
1. Humphrey ap Hugh; of whom presently.
2 John ap Hugh, living 21 January, 1649.
3. Rice ap Hugh; buried at Llangelynin Church, 13 March, 1623.
4. David ap Hugh.