New biphasic C-type horizontal cells were identified physiologically and morphologically in the ret-ina of live immobilized crucian carp. These cells, like commonly studied R/G type cells, hyperpolarizedto short wavelength lights and depolarized to long wavelength lights, but inverted response polarity atabout 560 nm. Spectral sensitivities of hyperpolarizing and depolarizing components showed that they wereproduced by inputs from blue-sensitive cones and green-sensitive cones respectively. These cells are thusreferred to as G/B type horizontal cells. Inputs from blue- and green-sensitive cones were not linearlysummated, but interacted strongly at G/B type cells. G/B type cells stained intracellularly with HRP hadsmaller cell body and dendritic field, distinctly differing from R/G type cells. New biphasic C-type horizontal cells were identified as physiologically and morphologically in the ret-ina of live immobilized crucian carp. These cells, like commonly studied R / G type cells, hyperpolarized to short wavelength lights and depolarized to long wavelength lights, but inverted response polarity atabout 560 nm. Spectral sensitivities of hyperpolarizing and depolarizing components showed that they wereproduced by inputs from blue-sensitive cones and green-sensitive cones respectively. These cells are thus derived to as G / B type horizontal cells. Inputs from blue- and green-sensitive cones were not linearlysummated, but interacted strongly at G / B type cells. G / B type cells stained intracellularly with HRP hadsmaller cell body and dendritic fields, distinctly differing from R / G type cells.