ABSTRACT
The erythrocyte indices are readily obtained and easily calculated values that indicate the size, hemoglobin content and Hb concentration of the average erythrocyte circulating in a subject’s blood. The next major taxon, the Amphibia, embraces those members whose erythrocytes are the largest in existence, and the Class demonstrates the broadest spectrum of sizes of red cells. The avians are seen to continue the phylogenetic refinement of the efficiency of the circulating red cells. A definite further reduction of the size of the erythrocytes is identifiable. The size of the erythrocyte obtained in the Struthioniformes is similarly impressive by “avian standards”. Thus the ostrich, the double wattled cassowary, the emu, and the greater and lesser rhea have red cells whose mean volumes are in the ~200–225 fL range. The mean cellular hemoglobin expresses the average amount of hemoglobin present in an erythrocyte.
