Bonds of any flood control and water conservation districts, or any zone thereof, having an assessed valuation on taxable real property of not less than one million dollars ($1,000,000), county, city and county, city, metropolitan water district, municipal utility district, special districts established by and within any municipal utility district, transit district, rapid transit district including sales tax revenue bonds of the district, metropolitan transit authority, flood control
district, or school district of the State of California (herein referred to generally as public corporation) except the bonds of any particular such public corporation which may be declared ineligible for investment by savings banks by regulations of the commissioner.