purposes of section fifteen of this Constitution, the term of service of that senator shall be deemed to be, and to have been, the period for which he would have held his place, in accordance with this section, if his place had not become vacant. (6.) Subject to sub-section (7.) of this section, in the case of a senator holding office at the commencement of this section— (a) if his term of service would, under the provisions in force before that commencement, have expired on the thirtieth day of June, One thousand nine hundred and seventy-eight, his term of service shall expire upon the expiry or dissolution of the second House of Representatives to expire or be dissolved after that commencement or, if there is an earlier dissolution of the Senate, upon that dissolution; or (b) if his term of service would, under the provisions in force before that commencement, have expired on the thirtieth day of June, one thousand nine hundred and eighty-one, his term of service shall expire upon the expiry or dissolution of the third House of Representatives to expire or be dissolved after that commencement or, if there is an earlier dissolution of the Senate, upon that dissolution. The election to fill vacant places shall be made within one year before the places are to become vacant. For the purposes of this section the term of service of a senator shall be taken to begin on the first day of July following the day of his election, except in the cases of the first election and of the election next after any dissolution of the Senate, when it shall be taken to begin on the first day of July preceding the day of his election. Casual Vacancies The Senate Casual Vacancies bill proposed to change the way in which casual vacancies were filled and so the proposal included that the following amendments would not take effect if that referendum was carried. Section 13 (7.) A senator holding office at the commencement of this section under the first paragraph of section fifteen of this Constitution shall hold office until the expiry or dissolution of the first House of Representatives to expire or be dissolved after that commencement unless, being a senator appointed by the Governor of the State, he is sooner replaced by a person chosen by the Parliament of a State under that paragraph. (8.) For