Whenever shares of such a Federal credit union shall be issued to any person, describing himself, in subscribing for such shares, as trustee for any person or persons, and no other notice of the existence and terms of a valid trust than such description shall have been given to the Federal credit union, the dividends or earnings on such shares, as well as the withdrawal value of such shares, shall, in the event of the death of the person so described as trustee, be paid to the person or persons for whose benefit the shares were stated to have been subscribed if, at the time of payment, such beneficiary is not less than sixteen years of age. Payment may be made to any such beneficiary who is not less than sixteen years of age under the same conditions as if such shares had been originally subscribed for by him. If there are two or more beneficiaries named on any such shares, the Federal credit union shall, in the absence of written notice to the contrary, make payment to such of the beneficiaries as may survive the trustee, in equal portions. The receipt or acquittance of any such beneficiary or beneficiaries for payments, made in accordance with this section, shall be a full, complete and valid release of the Federal credit union from any further liability for the amounts so paid.