Architecture of the lateral line organ of the sea eel Conger myriaster.

The architecture of trunk canal neuromasts of the Japanese sea eel was morphologically examined. A fluid-filled canal is connected with the outside by horn-shaped tubules whose outer openings are seen as pores, which are variable in shape and very narrow as compared to the canal diameter. A projection shaped like a semilunar valve hangs over each neuromast from the opposite wall. The total number of hair cells in a canal neuromast was 500 to 600, about fivefold more numerous than that in a superficial neuromast. Two groups of hair cells, rostrally and caudally oriented, are nearly equal in number. The observed architectures are thought to favor efficient detection of the flow of water within the canal. These findings substantiate the current understanding that each canal neuromast encodes the pressure difference between two adjacent pores.