WORTH NOTING ON TV

* SATURDAY

Christy (Family, 7-8 p.m.): The CBS family drama, which the network didn't renew this year for a second season, finds a home for reruns on the Family Channel. Based on the best-selling novel by Catherine Marshall, the series follows a young woman (Kellie Martin) who leaves her comfortable urban life to teach at a missionary school in a remote Appalachian community before World War I. In this pilot episode (which concludes next Sunday), Christy finds the challenges of poverty, ignorance, and violence in her new environment almost overwhelming.

* SUNDAY

The Magic School Bus (PBS, broadcast time varies): What an extraordinary bus that can take Ms. Frizzle's class back in time, underwater, and to outer space! These young science explorers make their second-season debut with two half-hour episodes: ''The Magic School Bus Blows Its Top'' and ''The Magic School Bus Flexes Its Muscles.''

Malcolm-Jamal Warner produces this Emmy-winning animated series, and Lily Tomlin is the voice of Ms. Frizzle.

World Gymnastics Championships (ABC, 4-6 p.m. EDT): The Sun Dome Fukui in Sabae, Japan, hosts these 31st world championships. Top women contenders include Svetlana Boguinskaya of Belarus, Lavinia Milosovici and Gina Gogean of Romania, and Shannon Miller of the United States; top men participants are Ivan Ivankov and Vitaly Scherbo of Belarus.

Masterpiece Theatre (PBS, 9-11 p.m. EDT): To celebrate 25 years on PBS, ''Masterpiece Theatre'' presents Edith Wharton's unfinished novel ''The Buccaneers,'' about four nouveau-riche American women who invade British aristocracy. The production features an American-British cast and scenery from England and Newport, R.I. - which testify to the cross-continental collaboration of the long-running show.

''The Buccaneers'' continues the next two evenings, with a conclusion provided by screenwriter Maggie Wadley. A look at Wharton will follow on Wednesday at 9 p.m., with ''A Lady Does Not Write: Edith Wharton's American Life.''

Please check local listings for these programs.