“Canterbury’s Law,” the new Fox legal drama, felt dark, mature and realistic — fare found more often on cable than on broadcast television. Julianna Margulies, the show’s star, said the network wanted to “bring a little FX to Fox.” But young viewers showed little interest in “Canterbury’s Law,” as the show’s premiere finished in fourth place in the 18- to 49-year-old demographic at 8 p.m. on Monday, Nielsen reported. Fox suggested that the transition to daylight saving time might have had some impact on the ratings. “Canterbury’s Law” averaged 7.6 million viewers, enough to place second in total viewers behind ABC’s “Bachelor,” but delivered a disappointing 1.7 rating in the 18-to-49 demographic favored by advertisers. At 9 p.m. “New Amsterdam” picked up some viewers for Fox, averaging 8.8 million viewers and a 2.5 rating in that demographic. The 11.7 million viewers for “Two and a Half Men” and the 10.1 million viewers for “CSI: Miami” put CBS into first place for the night. NBC was a close second, as ho-hum viewership for “My Dad Is Better Than Your Dad” (6.9 million) was offset by high ratings for “Deal or No Deal” (11.6 million) and “Medium” (9.2 million). ABC placed fourth for the night with two episodes of the low-rated “October Road” (4.6 million at 9, and 4.8 million at 10).