25 U.S.C. § 871
The Secretary of the Interior is authorized and directed to prepare a roll of the Indians of the blood of the Otoe and Missouria Tribe whose names appear on the allotment rolls of the tribe approved , , and , and who are living on , and the descendants of such allottees who are living on , regardless of whether such allottees are living or deceased. Applications for enrollment shall be filed within six months after . The determination of the Secretary regarding the eligibility of an applicant for enrollment shall be final and conclusive.