miracidium of Megalodiscus temperatus from  Rana pipiens.  This section includes a cross section through one of  the two flame cells.  The circular bodies are cilia which fuse into a cone of cilia.  They rhythmically undulate, forcing fluids down the excretory ducts toward the bladder for elimination.  The open space to the lower right is an excretory duct, revealing the presence of sparse microvilli.  The black material is glycogen. 35,000x