CHELMSFORD - Mark David Anderson, a Chelmsford resident who had been an auditor at a financial firm, died Saturday, Sept. 25, at his home after a long illness. He was 38.He was born in Cambridge on Sept. 20, 1966, son of Neil J. and Lillian (McIsaac) Anderson of Chelmsford. He graduated from Chelmsford High School in 1984. He received a bachelor's degree in marketing at Southeastern Massachusetts Dartmouth College in 1988.Mr. Anderson was a former auditor at Deutsche Financial.He was a communicant of St. Mary's Church in Chelmsford. He was an avid golfer and a member of the Nabnasset Country Club in Westford.He was remembered for his talents as an athlete and food critic. Mr. Anderson also enjoyed time spent at Rockingham Park in Salem, N.H., and Foxwoods Casino in Ledyard, Conn.Besides his parents, he is survived by a sister, Beth Anderson of Chelmsford; a brother, Ross Anderson of Chelmsford. He also leaves his girlfriend, Sue (Gaspar) Doherty of Lowell; and many friends.