Studies of the Blood and Tests of Some Australian Ascidians. I. The Blood of Pyura stolonifera (Heller)

Abstract

The blood cells of Pyura stolonifera are described and figured. Descriptions are given of the formation of the various cell types from the primitive lymphocytes of the blood. The presence of morula-shaped cells, which appear to correspond structurally with the vanadium-containing cells of members of the family Ascidiidae, is noted and the reaction of these cells to certain histological and histochemical reagents described. Vanadium cannot be detected spectrographically in the ashed corpuscles but an iron compound with somewhat similar properties to the vanadium chromogen of the Ascidiidae is present. The iron is present in the ferrous condition and is capable of being liberated by acids. The iron compound has marked reducing properties and will reduce cytochrome c anaerobically. It is found in association with protein and an aminopolysaccharide. The importance of this association is discussed. Investigations on the intracorpuscular acidity of the morula-shaped corpuscles reveal that, although acid is present, the hydrogen ion concentration is not as great as in the vanadium-containing cells of the Ascidiidae. This can be correlated with the lower intracorpuscular sulphate concentration of the present species. Analyses of the inorganic composition of the plasma show that the sulphate concentration is slightly over half that of the external sea-water. The results of these and other investigations are compared with those obtained by workers using ascidians belonging to other families.