Persistent expansion follows denervation of the erythrophores by section of the sympathetic cord at various levels. Faradic stimulation of the anterior end of the medulla however leads to an immediate and pronounced contraction of the erythrophores, except those previously denervated. These facts are evidence of nervous control for the erythrophores of S. ustulata. Injection of hypophyses extracts of Thynnus thynnus or Trigla sp. leads to a pronounced contraction of the erythrophores of Scorpaena. It is doubtful however whether the hypophysis of S. ustulata plays any part in governing the responses of the erythrophores in this form. Isolated scale erythrophores of S. ustulata react to nicotine first by an expansion and then by a contraction. Physostigmine, pilocarpine, and atropine all produce a typical "ringed" expansion. After atropine the usual lasting contracting effect of N/10 KCl persists only for 1 or 2 min. and is replaced by a permanent expansion. Ethyi alcohol (10-5%) first expands, then contracts and finally produces a "ringed" expansion of the scale erythrophores. Ethyl alcohol (1%) produces a persistent contraction. Acetyl-choline has no effect. Injection of these same drugs into the abdominal cavity produced varying effects. After treatment with N/10 BaCl2 isolated scale erythrophores show rhythmical pulsations in N/10 NaCl.