In American football and Canadian football, not all players on offense are entitled to receive a forward pass. Only an eligible pass receiver may legally catch a forward pass, and only an eligible receiver may advance beyond the neutral zone if a forward pass which crosses the neutral zone is thrown. If the pass is received by a non-eligible receiver, the penalty for the foul "illegal touching" is assessed (the play is treated as an incomplete pass, unless the ball is downed behind the line of scrimmage — in either case a down is lost). If an ineligible receiver is beyond the neutral zone when a forward pass which crosses the neutral zone is thrown, a foul of "ineligible receiver downfield" (penalty--a loss of yardage, but not loss of down) is called. Each league has slightly different rules regarding who is and is not considered an eligible receiver.