Edward M. Kennedy Jr. invoked the memory of his famous father in announcing that he is running for the state Senate in Connecticut. The son of the late US Senator Edward M. Kennedy said Tuesday evening that he intends to seek the Democratic nomination for the 12th Senatorial District. The 52-year-old health care lawyer lives in Branford. He has long been an advocate for the disabled after losing a leg to cancer as a child. The district is represented by Edward Meyer, Democrat of Guilford, who is retiring. There are no other declared candidates, but Republicans have vowed to vigorously contest the seat.