The green pigment in the foot of Monodonta (mollusca) species

1. 1. The green pigment in the foot of Monodonta turbinata was isolated. 2. 2. The free pigment was found to be a hydrophilic substance green in acid and yellow in alkaline solution. 3. 3. The absorption spectrum of the pigment in methanolic HCl showed maxima at 680 and 370 mμ (E370/E680=0.87), and inflexions at 440, 330 and 270 mμ. The zinc complex exhibited an absorption maximum at 665–670 mνm, and in inflexion at 615 mμ, after oxidation with iodine. 4. 4. The pigment gave the Gmelin reaction. It did not react with diazotised sulphanilic acid. 5. 5. It is suggested that the pigment is a bilatriene. 6. 6. Green pigment with an identical absorption spectrum was isolated from foot tissue of the realted species Monodonta articulata.