MATURATION OF THE GOLDFISH (CARASSIUS-AURATUS) ERYTHROCYTE

1. Cohorts of [H-3]thymidine-labelled erythrocytes were examined over a 42-day period in goldfish (Carassius auratus L.) recovering from phenylhydrazine HCl-induced anemia under normoxic conditions at 20 +/- 1-degrees-C and maintained with minimal disturbance on a high nutritional plane. 2. As judged by changes in primary and derived hematological variables, maturation required 16-20 days. 3. Similar estimates were obtained using cytomorphic variables obtained by image analysing methods. 4. These suggest that juvenile red cells in this species can be identified on the basis of the following characteristics: major axis < 9.2-mu-M; one-sided surface area not greater than approximately 50-mu-m2; axis ratio > 0.774; form factor > 0.938. 5. Corresponding values for mature cells are: major axis > 11.2-mu-m; area > 68.5-mu-m2 ; axis ratio < 0.716; form factor < 0.912. 6. These criteria, with values for dividing and karyorrhectic cell numbers, offer a basis for more detailed and dynamic characterization of the erythron during response to environmental variation than has previously been possible.