(iii)"annuity" includes any series of payments, whether interconnected or not, whether of the same or of varying amounts, and whether payable at regular intervals or otherwise, and payment of dividends or interests on shares in or debentures of a company shall be treated for the purposes of this section as a serious of payments constituting an annuity limited to cease of a death if the payments are liable to cease on the death, or the amounts thereof are liable to be reduced on the death, by reason directly or indirectly of the extinguishment or any alteration of rights attaching to, or of the issue of any shares in or debentures of a company ;