Bill O'Reilly shot back at his fellow Fox News host Megyn Kelly on Tuesday, though the two are avoiding mentioning each other's names.The on-air jousting began on Monday when O'Reillyopining that U.S. District Judge Gonzalo Curiel should recuse himself from the class-action lawsuit against Trump University.While O'Reilly said that he has investigated the judge and found him to be fair to Donald Trump, he still believes the judge should step aside to avoid the appearance of unfairness. Trump has said Curiel can't be fair to him because he is of Mexican heritage, and Trump has called for a border wall with Mexico and the deportation of illegal immgrants during his presidential campaign."That is not the way our system works," Kelly said one hour later on her program "The Kelly File."Kelly did not specifically say she was talking about O'Reilly's comments, and O'Reilly didn't bring up Kelly's name on his show Tuesday night, though he appeared to be critical of her.O'Reilly played a clip of New York City Council Speaker Melissa Mark-Viverito from Kelly's show where she called him a "charlatan and a racist.""Ms. Viverito has despised Donald Trump for years. Everybody in New York City knows that," O'Reilly said. "Her charge of racism went unchallenged. That's wrong. Whether it's Trump or Hillary Clinton or President Obama, no ad hominem attacks carry any credibility. They should all be condemned."