title: Discrete slow potentials and threshold-level spikes in the Limulus ommatidium.
mesh_terms: D000200:Action Potentials; D000818:Animals; D003445:Crustacea; D004594:Electrophysiology; D010786:Photoreceptor Cells / Q000502:physiology*; D012168:Retinal Pigments / Q000502:physiology; D013057:Spectrum Analysis
chemical_list: D012168:Retinal Pigments