A Bilatriene Pigment in the Green Terebellid Polychæte Eupolymnia heterobranchia (Johnson)

Abstract

Eupolymnia heterobranchia (Johnson) is a relatively large terebellid found in mud and under boulders on the Pacific coast of North America. All the specimens that I have found near Friday Harbor, Washington, had a deep green colour. This is due to granules of green pigment deposited in the cœlomic cells and in the epidermis. The pigment was readily extracted with acidified methanol, gave a good Gmelin reaction, and reacted positively to the zinc bilipurpurin test. demonstrating that it was a bilatriene. The red-fluorescent compound obtained in the latter test had a sharp maximum at 625 mµ (Unicam), indicating the presence of meso- rather than proto- side chains¹. The great resistance of the pigment to concentrated sulphuric acid also distinguished it from biliverdin. In a 5 per cent hydrochloric acid: methanol mixture the absorption spectrum showed peaks at 360 and 675 mµ, resembling mesobiliverdin hydrochloride (363 and 670 mµ; ref. 1).