Fig. 1. Colorimetric scoring of hemoglobin content of daphnids. Criteria used to assign a color score to individual daphnids are listed in Table 1. Animals that were scored 9 were placed on a color grid of progressively darker shades of copper and a score was assigned based upon the best color match with the grid. Example relationships between color score assigned to daphnids and hemoglobin content normalized to the soluble protein content of the daphnids (A) and as total hemoglobin per daphnid (B). Values are means ± S.E.M.(N=2-4).