Anthony (Fat Tony) Salerno, the ailing 78-year-old former boss of the Genovese organized crime family who is already serving sentences totaling 170 years in prison, pleaded guilty to conspiracy in two New Jersey mob cases. Salerno was allowed to remain seated throughout a hearing in U.S. District Court in Newark in which he entered his plea. Salerno remained mute as federal prosecutors read into the record allegations that he had conspired to force a competing group to give up development plans for an Edgewater, N.J., property and to extort $500,000 from the owner of a Morris County gravel pit. Salerno’s guilty plea was to a single conspiracy charge combining the two cases. He faces a maximum additional prison term of five years and a $10,000 fine. Defense lawyer John Jacobs insisted that Salerno had not admitted to any illegal activity and pleaded guilty only to avoid a long legal battle.