Whenever property is held in the joint names of two or more persons and the survivor or survivors of them, the right of the survivor or survivors to the immediate ownership or possession and enjoyment of such property shall be a taxable transfer and the tax shall be computed as though a fractional part of the property, determined by dividing the fair market value of the entire property by the number of persons in whose joint names it was held, belonged absolutely to the deceased person and had been bequeathed or devised by him to the survivor or survivors by will; provided, in addition to any exemption granted under the provisions of this chapter, the provisions of this section shall not render subject to a succession tax joint checking or savings accounts in banks or savings banks, savings and loan associations or credit unions, or United States war or savings bonds, payable to either or to the survivor, if the aggregate thereof is less than five thousand dollars, but a fractional share of any excess over five thousand dollars shall be taxable. The provisions of this section shall not be construed to prevent the taxability, in whole or in part, under the provisions of subsection (c) or (d) of § 12-341 or 12-341b of any property held in the joint names of two or more persons and the survivor of them, including any joint checking or savings account in any bank, savings bank, savings and loan association or credit union, or United States war or savings bonds. The limitations imposed by § 12-340 shall apply to any tax imposed under the provisions of this section.