Kathryne M. Bricker, 77, a lifelong resident of Montgomery County who served as principal of Somerset Elementary School in Chevy Chase for 37 years, died of cardiac arrest Friday at Suburban Hospital. She lived in Chevy Chase.

Mrs. Bricker was principal of the town of Somerset's only school from the time the school opened in 1928 until her retirement in 1965. She was 25 years old and had taught at Potomac and Bethesda elementary schools when she was made principal of the old 8-room building, which then had 60 students.

She recalled in a 1965 Washington Post story on her retirement that the school, which had grown by three additions and approximately 500 students by then, wasn't finished on the first day of school in 1928 and pupils had to register for classes at the house next door.

Mrs. Bricker subsequently was honored by the city of Somerset, one of Montgomery County's oldest incorporated villages, first in 1958, on the occasion of her 30th anniversary as principal, and again when she retired.

In a ceremony held at the school auditorium in 1958, the mayor of the city called her "one of our town's rarest treasures," and presented her with an illuminated scroll in recognition of the "high standards of elementary public education" she and her staff had achieved.

She received a watch from the school's parent-teacher association on her 20th anniversary as principal.

Mrs. Bricker was a life member of the National Education Association and a member of the Montgomery County, Maryland and National Retired Teachers Associations.

Her marriage to William E. Bricker ended in divorce. There are no immediate survivors.