Pauley Perrette and Sean Murray Pauley Perrette and Sean Murray

CBS topped Tuesday with another big NCIS showing, while NBC's sitcoms slid to new lows.

NCIS returned to 21.8 million viewers and a 3.7 in the adults 18-to-49 demographic, down two-tenths from its last new episode. NCIS: Los Angeles (17.2 million, 3.1) and Vegas (11.1 million, 1.9) were both up.

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