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Concentrations of trace elements in sagittal otoliths of orange roughy (Hoplostethus atlanticus) from three areas (off Adelaide, and off the eastern and western coasts of Tasmania) were measured by inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry. Canonical-variate (discriminant) analyses of the concentrations of 10 elements (Ba, Cd, Cu, K, Mg, Na, Pb, S, Sr, Zn) showed that the patterns of element concentrations were specific to the areas where fish were captured. These results suggest that there is little movement of fish between the three areas. The elements that were most important in discriminating between the areas were Mg, Na and S.

The use of chiral N.M.R. shift reagents in the identification of diastereomers has been extended to asymmetric bianthrones. Studies on model systems have reinforced the stereochemical assignment of meso- and ()-emodin bianthrone.

The major polycyclic constituent of an asterolecaniid Callococcus acaciae (Maskell) is shown to be the 10,l0'-dimer of acetylemodin anthrone glucoside. This follows from hydrolytic, reductive andoxidative reactions. The coccid Cryptes baccatum Maskell is shown to contain ceroalbolinic acid as its principal colouring matter. On decarboxylation it gave isoerythrolaccin, identical with a syntheticspecimen

Synthetic emodin bianthrone is separated into meso- and ()-diastereomers which are identified by means of an asymmetric p.m.r. shift reagent. They behave differently on mild oxidation. Both give protohypericin accompanied by an anthraquinone fraction but, whereas the major anthraquinone from the meso is emodin, the (k) gives chiefly the bianthraquinonyl, skyrin. This difference is accounted for in terms of the geometry of oxidative coupling. Oxidation of emodin anthrone in alkaline dimethyl sulphoxide gives a l,4-anthraquinone as major product. The scope of this novel oxidation has been extended to other anthrones and it has been utilized in the controlled synthesis of purpurin derivatives. It may involve anthrslnol tautomers as intermediates.

Arsenobetaine has been isolated from the tail muscle of the western rock lobster (Panulirus cygnus George) and from the flesh of the dusky shark (Carcharhinus obscurus Le Sueur), both of which are commercially important seafoods. Trigonelline has also been isolated from the lobster and both arsenobetaine and trigonelline have been isolated from human urine obtained after ingestion of cooked rock lobster. The crystal structures of the monohydrates of arsenobetaine and trigonelline have been determined and a simple synthesis of arsenobetaine has been developed.