A 38-year-old woman from Bangalore undergoes a routine colonoscopy for screening. A biopsy is taken from the cecum and ascending colon. Histological examination reveals simple columnar epithelium with numerous goblet cells interspersed between absorptive cells. The lamina propria is rich in lymphoid follicles and plasma cells. Crypts of Lieberkühn extend deep into the mucosa. Which of the following histological features is MOST specific to the large intestine (colon) and distinguishes it from the small intestine?