Specification of bonds under the section 193 proviso: transferee must notify issuer by registered post within sixty days to secure benefit. Central Government specifies '12.5% HDFC Bonds, 1998 (B)' as covered by the proviso to section 193; benefit under that proviso is admissible on transfer by endorsement or delivery only if the transferee informs the issuer by registered post within sixty days of the transfer.