SCANNING ELECTRON-MICROSCOPY OF RED-BLOOD-CELLS FROM 11 SPECIES OF MARSUPIAL

Samples of red of blood cells (RBC), washed free of plasma, from eleven marsupial species were examined in a Jeol JSM-6300 F scanning electron microscope. The diameters of the RBC, lying completely flat or exactly on edge, were measured on photographs using a binocular enlarging optical system with a calibrated eye piece. RBC from the following species were studied: bandicoot (Isoodon macrourus), bilby (Macrotis lagotis sagitta), Bennett's wallaby (Macropus rufogriseus), Goodfellow's tree kangaroo (Dendrolagus goodfellowi), koala (Phascolarctos cinereus), parma wallaby (Macropus parma), red kangaroo (Macropus rufus), swamp wallaby (Wallabia bicolor), Tammar wallaby (Macropus eugenii), Tasmanian devil (Sarcophilus harrisii) and whiptail wallaby (Macropus parryi). In all species the RBC were biconcave discs. The major morphological difference was in the size of the cells. Taking the human RBC as a reference (with a diameter of 8.0 mum), the RBC of the Tasmanian devil, bilby, bandicoot and Goodfellow's tree kangaroo were approximately 7 mum in diameter, whereas those of the other marsupials ranged from 7.8 to 8.6 mum.