The peripheral dependency of Rohon‐Beard cells

Sensory Rohon‐Beard cells of Rana pipiens embryos were examined for dependency on the peripheral innervation. Flank ectoderm was surgically removed, the area being maintained skinless by lateral parabiosis. The Rohon‐Beard cells in each side of the spinal cord were counted at a later developmental stage; the number was always less on the side with the reduced skin area. Intact animals, operated controls, and tails of the parabiotic pairs did not show such a bias in cell distribution. Deprivation of the neurotrophic periphery is postulated as the cause of the premature disappearance of the Rohon‐Beard cells; it is further suggested that the disappearance of these cells during normal development might be effected through the peripheral innervation.