If any member of such fire department shall die after having been retired and pensioned by reason of injuries sustained or disease contracted while serving as a member of the department, his widow, provided their marriage shall have occurred prior to such retirement, and children under sixteen years of age, if any, shall be paid monthly out of the pension fund such sum of money as may be determined by the rules and regulations provided for the management of said funds. If there be no widow, or if such widow die while unmarried, the amount of her said benefit may be added to the said benefits for such children.