Penalty in respect of certain income was earlier imposed on undisclosed income, subject to disclosure and timely tax payment exceptions. Section 443 formerly dealt with penalty in respect of certain income, but the provision has been omitted. The earlier text allowed a penalty of 10% of the tax payable where an assessee's income included income referred to in sections 102 to 106, subject to an exception where such income was disclosed in the return and tax was paid by the end of the relevant tax year. It also provided that no penalty under section 439 would apply in respect of that income.