THE OCCURRENCE OF PORPHYRIN IN THE PLANARIAN

1. A porphyrin was extracted from the water-insoluble residue of homogenates of the planarian, Dugesia dorotocephala. The porphyrin extract is characterized by a red fluorescence under ultra-violet light.2. The solubility properties of the porphyrin, the absorption spectra of the porphyrin and its methyl ester, and paper chromatographic behavior show a similarity to those described for uroporphyrin.3. The amount of porphyrin seems to be a constant per planarian of a given wet weight, when the animals are under the same physiological condition. The porphyrin is also found in starved and in regenerating animals.4. The whole planarian emits a red fluorescence under ultra-violet light if the animal is first immersed in one of several organic solvents which remove a lipochrome or carotenoid substance.5. The light sensitivity which has often been described for these animals may to some degree be due to the presence of the porphyrin.