Richard Penhallurick named one of his sons Arthur. This leads me to believe that your Arthur was probably Richard's older brother. Do you know anything else about Arthur's mother and father, possible brothers and sisters, etc?
Check out my website at www.tiffany-salls.com
When you search initially, type in Richard Penhallurick. He is the last ancestor I have so far for the Penhallurick family going back. You'll see the decendant line from that point.
I'd like to add your information to my database. If you would like to provide it, please email me at email@example.com with birthdates, marriage dates, death dates, places, etc. I also can take blurbs about people and place it in the database.
When my research is more complete, I'll burn you a portion of the database on CD on this family so that you can have your own copy.