Several Democratic presidential candidates sharply criticized Joseph R. Biden Jr. on Wednesday for invoking two Southern segregationist senators by name as he defended himself over accusations of being “old-fashioned” and fondly recalled the “civility” of the Senate in the 1970s and 1980s.

Mr. Biden, speaking at a fund-raiser at the Carlyle Hotel in New York City on Tuesday night, stressed the need to “be able to reach consensus under our system,” and cast his decades in the Senate as a time of relative comity. His remarks come as some in his party say that Mr. Biden, the former vice president, is too focused on overtures to the right as he seeks the Democratic presidential nomination.

[Mr. Biden lashed out at his rivals and declined to apologize on Wednesday.]

At the event, Mr. Biden noted that he served with the late Senators James O. Eastland of Mississippi and Herman Talmadge of Georgia, both Democrats who were staunch opponents of desegregation. Mr. Eastland was the powerful chair of the Senate Judiciary Committee when Mr. Biden entered the chamber in 1973.

“I was in a caucus with James O. Eastland,” said Mr. Biden, 76, slipping briefly into a Southern accent, according to a pool report from the fund-raiser. “He never called me ‘boy,’ he always called me ‘son.’”