Mary Meagher and Rowdy Gaines set world records tonight during the third session of the National Swimming Indoor Championships at the Texas Olympic Swimming Center.

Gaines, 20, shattered the world 200-freestyle record of 1:49.83 set by Sergie Kipliakov of the Soviet Union. En route to a 1:49.16, Gaines recorded splits of 25.03, 52.52 and 1:20.92.

"I knew I was out a little fast because when I turned at the 100 my legs went limp,' Gaines said. "So I said to myself, 'I better take it easy.' I decided to take it steady on the third length."

Gaines, of Florida Aquatics, won the 100-meter freestyle earlier in the meet in an American record.

Meagher can add the 100-meter world record to her 200-meter world standard. The 15-year, swimming for Cincinnati Pepsi Marlins, broke East German Andrea Pollack's mark of 59.46 with a 59.26.

Meagher was third after the first 50, touching in 28.42 behind 100-meter freestyle champion Jill Sterkel's 27.93 and Tracy Caulkins' 28.07. But with 20 meters left, Meagher surged between Caulkins in lane five and Sterkel in three and with each stroke pulled a foot farther ahead to hit the wall with a full body length in front.

Caulkins, who has won the 200-meter breaststroke and the 200-meter individual medley, was second in 1:00.09, followed by Sterkel in 1:00.34.

Betsy Rapp of Starlit Aquatic Club Fairfax, Va., was 11th in the 100-meter butterfly, improving her morning qualifying time of 1:03.12 with a consolation final swim of 1:02.87.