Thomas hauled down 10 rebounds for the Tigers (22-3, 11-0 C-USA), who remained undefeated in conference play and won for the 16th straight time overall.
Their last loss was Dec. 15 against Louisville.
Joe Jackson added 12 points and Geron Johnson scored 11 for Memphis.
DeAndre Kane and Elijah Pittman scored 16 points each for the Thundering Herd (11-15, 4-7).
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