Cheek pouches of the macaque

"They use the pouches while foraging in the same way that hamsters do."

For reasons I can't quite comprehend, this illustration comes from a medical textbook entitled "The Anatomy of the Human Peritoneum and Abdominal Cavity, Considered from the Standpoint of Development and Comparative Anatomy," by George S. Huntington, 1903.

Via Biomedical Ephemera.