Sub section (2 a) of section 31 of the Bihar Finance Act, 1981 was substituted by Bihar Finance Act, 1984 as follows: "(2 a) A person transporting goods shall carry a declaration in such form as may be pre scribed by the commissioner supported by either a cash memo, bill or a challan, in case the movement is otherwise than as a result of sale, in respect of goods which is being transported on a goods carrier, or a vessel and shall produce such challan, cash memo or bill along with the aforesaid form of declara tion on demand before the prescribed authori ty: Provided that the Commissioner, by notifica tion in this respect, may prescribe a form of declaration or adopt a form of declaration or permit prescribed for the purpose of Sections 34 & 35 of this part, and, he may also pre scribe in the said notification, the manner in which such declaration 801 or permit shall be utilised for verification and assessment of tax payable under this part.