Dr. Clay G. Huff, 81, retired head of the parasitology division at the Naval Medical Research Institute in Bethesda, died of a cardiac arrest June 26 at the Bel Pre Health Care Center in Silver Spring. He had lived at the center since 1981.

Dr. Huff was a native of Cory, Ind. He was a graduate of Southwestern College in Winfield, Kan., and earned his doctoral degree at Johns Hopkins University in 1927.

He was a professor of parasitology and a research scientist with the University of Chicago. During World War II, he worked on a malarial chemotherapy program at the Illinois State Prison.

Dr. Huff moved to Washington in 1947 when he joined the National Naval Medical Center's research institute. He was head of the parasitology division from 1960 until he retired in 1969.

He received the Navy's Distinguished Civilian Service Award in 1958 and the Superior Civilian Service Award in 1969.

Dr. Huff was a past president of the American Society of Parsitologists, the American Society of Tropical Medicine and Hygiene and the International Wood Collecting Society.

Survivors include his wife, Florence Clark Huff of Silver Spring; a son, Eskin Huff of Gaithersburg; a daughter Elaine Samstag of Simsbury, Conn.; a sister, Effie May Lawson of Harmony, Ind; five grandchildren and four great-grandchildren.