Section 21.8 - Chapters and subchapters(a) The normal divisions of a title are chapters, assigned to the various agencies within a title descriptive of the subject matter covered by the agencies' regulations.(b) Subchapters may be used to group related parts within a chapter.(c) Chapter and subchapter assignments are made by the Office of the Federal Register after agency consultation.37 FR 23611, Nov. 4, 1972, as amended at 54 FR 9682, Mar. 7, 1989