The morphology of the amphibian papilla in the bullfrog has been studied with light and electron microscopy. The hair cells in the amphibian papilla are equipped with sensory hairs, one of which is a kinocilium. The orientation of the kinocilium varies in a complicated way along the sensory epithelium. At their basal ends, the hair cells are contacted by two types of nerve endings, morphologically identified as afferent- and efferent-type terminals. Efferent-type endings are more abundant in the broader anterior portion of the sensory epithelium than in the posterior portion. In the middle portion, tight junctions have been found between axons within the epithelium. In some cases, one of these axons could be traced to an afferent-nerve ending. Tight junctions between neurons have been shown in a number of other systems to represent electrical synapses that transmit impulses with short delay.