ABSTRACT
The fact that the submammalian erythrocyte has an oval, flattened, biconvex shape is well recognized. G. Gulliver’s historical panoramic illustrations were the first to reveal the spectrum of the configurations and dimensions of vertebrate erythrocytes. The evolution of the geometry of the inframammalian erythrocyte can be quantitatively assessed by different parameters including the length of the cell and the variation in the degree of cellular ovality. The constituency of the Class Amphibia, including both the urodelans and anurans, has erythrocytes whose long diameters are all greater than ~15µm. This distinguishes their red blood cells from those of the teleosts which have rbc of shorter length. It is therefore consistent with the concept of progressive enhancement of the geometry of the erythrocyte in inframammalian evolution to observe that the Aves demonstrate red cells that are further reduced in size and are even more likely to be narrower ellipsoids than those elicited by the reptilians.
