1. The photosynthetic pigments of the green subsurface layer (Ostreobium) of The pigments found were chlorophylls a and b, α- and β-carotene, siphonein, traces the brain coral Favia were studied by two-dimensional paper chromatography. of siphonaxanthin and neoxanthin, and an unknown yellow-orange xanthophyll.

2. The pigment composition of Ostreobium closely resembled that of two members of the Siphonales, Halimeda and Codium. Therefore, this alga may be appropriately grouped within the Siphonales.

3. The three algae, Halimeda, Codium, and Ostreobium contained a high proportion of chlorophyll b, from two-thirds to three-quarters that of chlorophyll a.