lamina propria mucosae

The etymology suggests this, since the Latin names translate to "the mucosa's own special layer" (lamina propria mucosae) and "muscular layer of the mucosa" (lamina muscularis mucosae).

The lamina muscularis mucosae (or muscularis mucosae) is the thin layer of smooth muscle found in most parts of the gastrointestinal tract, located outside the lamina propria mucosae and separating it from the submucosa.