Actin filaments of the turbellarian flatworm Archimonotresis sp.
Actin filaments of the turbellarian flatworm Archimonotresis sp. stained with Alexa Fluor® 488 phalloidin (Cat. No. A12379) to reveal a meshwork of longitudinal, circular and diagonal muscles. The large, bright ring with muscle fibers radiating outward is the muscular pharynx, and the small, bright ring at the posterior is part of the reproductive system. This epifluorescence image was contributed by Matthew D. Hooge and Seth Tyler, University of Maine, Orono.