This section of the colon is lined with rugae precisely like those which are found in the caecum.
plural of ruga (1775), from Latin ruga "a wrinkle in the face," from PIE *rug-, variant of *reue- (see rough (adj.)).
ruga ru·ga (rōō'gə)n. pl. ru·gae (-gē', -gī') A fold, crease, or wrinkle, as in the lining of the stomach. Often used in the plural.