Recordings from the muscles of the pyloric chamber of the shrimp Palaemon display a rhythmic pattern which is either monophasic or biphasic, and is different from the triphasic pyloric pattern of large decapods. Identification of the pyloric neurones in the stomatogastric ganglion and study of their synaptic relationships indicate that the pyloric circuit of Palaemon is very similar to the pyloric circuit of large decapods. It is concluded that homologous neuronal circuits in related species,

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... though similar in terms of their 'wiring diagram', are able to produce significantly different patterned outputs.