title: Studies on the pigmented and unpigmented photoreceptors of the cercaria of Cryptocotyle lingua (Creplin) from Littorina littorea (L.).
mesh_terms: D000818:Animals; D004463:Ecology; D008974:Mollusca / Q000469:parasitology*; D010786:Photoreceptor Cells / Q000648:ultrastructure*; D014200:Trematoda / Q000648:ultrastructure*