Hello Duncan. The man on the far right is indeed Capt. Angus McMillan. I received a copy of this photo from Roy Lawrence Grissett, son of Mrs Jessie McAlister(Horne) Grissett, Roy is the great-grandson of Col. Daniel Hilliard Horne of Company K. Roy has identified the man at fourth from right as his great-grandfather Col. Daniel Hilliard Horne. Angus McMillan is my great-grandfather. I hope this is of help to you. Should you have any questions or comments please don't hesitate to reply. My email is trex@jps.net Thank you. Chris McMillan