The muscles of mastication in the Macaque are generally similar to those found in man; the investigator using these forms for research purposes, however, must be aware of the differences that do exist. In the Macaque the temporalis muscle attaches not only to the ramus and coronoid process, but also to most of the bone of the edge of the entire mandibular notch. The deep head of the masseter muscle is unusual in that it has fibers of origin from the lateral and anterior surfaces of the capsule of the temporamandibular joint. The digastric muscle is interesting in that there is the continuity of one intermediate digastric tendon with the other through a single anterior belly. The mandibular nerve in the Macaque is very similar to that found in man. Nerve fibers to the submandibular gland are quite fine and are found along the duct of this gland. No submandibular ganglion is identifiable.