A nucleated immature erythrocyte, having cytoplasm generally similar to that of the earlier proerythroblast but sometimes even more basophilic, and usually regular in outline. The nucleus is still relatively large, but the chromatin strands are thicker and more deeply staining, giving a coarser appearance; the nucleoli have disappeared. This cell is CD71-positive and lacks hematopoeitic lineage markers. [ https://www.worldcat.org/search?q=bn%3A0721601464 ]