Unique eye of probable evolutionary significance.
The eyes in the brain of a larval flatworm studied by electron microscopy are dissimilar. Light-sensitive structures in the right eye are microvilli; those in the left eye, the unique one, are both microvillar and ciliary. Perhaps this is evidence for the origin of a microvillar line of photoreceptoral evolution from a more primitive ciliary line.
D000818:Animals; D005075:Biological Evolution; D002923:Cilia / Q000648:ultrastructure; D005123:Eye / Q000648:ultrastructure; D007814:Larva; D008854:Microscopy, Electron; D010786:Photoreceptor Cells / Q000648:ultrastructure*; D010986:Platyhelminths / Q000648:ultrastructure*