The origin of erythrocytes in herring ( Clupea harengus )

Abstract

The herring larva is transparent and without erythrocytes until about 25 mm. in length. The heart has been beating for some time and at this stage the endocardium has developed into a syncytial sponge-work which fills most of the cavity of the heart. Large spherical nuclei which appear in this sponge-work at about the 28-mm. stage multiply as the network grows; their behavior and staining properties indicate that they bud off as megaloblasts. These multiply rapidly and become erythrocytes. This is interpreted to mean that erythrocytes primitively arise from endothelium. The larval eel, Anguilla vulgaris, is transparent and without erythrocytes until 78 mm. in length.