Mitzi Harrington Parks, an educator for more than 30 years, is the new coordinator of the Hospital for Sick Children's Enrichment Program.

"These are beautiful children," said Parks of the students in the program.

She has been a preschool and elementary school teacher and, most recently, a child development specialist at Howard University.

The hospital's enrichment program teaches multiply handicapped children aged 18 months to 6 years, encouraging physical and emotional development that will allow eventual enrollment in public schools. New Notre Dame Principal

Sister Gwynette Proctor has been named the new principal of the Academy of Notre Dame, a Catholic girls' high school that has operated in the District since 1873.

Proctor was born in Washington and reared in Baltimore, where she is the coordinator of Urban Youth Ministry. Before joining the Sisters of Notre Dame de Manur in 1980, Proctor was a public school teacher in Baltimore. "I am surely looking forward to the job," said Proctor, who added that she has "the greatest admiration for young people in the '80s . . . . difficulty and turmoil are entering their lives much earlier than ever before."

Proctor has been an educational consultant to the universities of Massachusetts and Maryland. She has served on the board of the National Black Sisters Conference, and other black Catholic organizations, and is working on a special certificate program in administration at Towson State University.

She will begin her new position in July.