Tenures and farms of the third exceptional class described in Section XXXVII of this Act, for the special registration of which application shall be made within the prescribed time, and in respect of which the Collector shall have commenced the enquiry prescribed in Section XLII, shall, in case of the sale of the parent estate for arrears of revenue, be protected pending the duration of such enquiry, and shall be protected eventually by registration, if the final award of the Revenue Authorities, upon such application, be in favor of the claimant.