Undisclosed income of another person under search proceedings is transferred to the jurisdictional Assessing Officer for special assessment. Undisclosed income relating to a person other than the specified person in a search or requisition is to be handed over to the Assessing Officer having jurisdiction over that other person, who must then proceed under the special assessment provisions for search cases. The section also fixes the block period by reference to the connected specified person or persons and provides special block-period rules where the undisclosed income relates only to the immediately preceding year or to a single tax year. For abatement, the relevant date is the date on which the material is received by the other person's Assessing Officer.