Transferrin phenotypes were determined by starch-gel electrophoresis and autoradiography for 31 Galago crassicaudatus crassicaudatus; 22 G. c. argentatus, melanotic and silver-gray varieties; 10 G. demidovii; and 9 G. senegalensis. Four distinct phenotypes, controlled by three nondominant autosomal alleles, are found in G. c. crassicaudatus; 14 animals are homozygous and 17 are heterozygous. One phenotype is found in G. c. argentatus, and this cannot be distinguished from one of the homozygous phenotypes of G. c. crassicaudatus. Two phenotypes, controlled by two alleles, are found in G. demidovii; one of the phenotypes is homozygous, one heterozygous. A single homozygous phenotype is found in G. senegalensis. Red-cell hemolysates were examined from 57 G. crassicaudatus, both G. c. crassicaudatus and G. c. argentatus; 12 G. demidovii; and 9 G. senegalensis. All species of Galago, on the basis of starch-gel electrophoresis, have two distinct hemoglobins. The a chains are the same in the two hemoglobins of a species and the p chains are different. The two hemoglobins of G. c. crassicaudatus were readily separated and purified by chromatography on columns of DEAE-Sephadex. © 1969 S. Karger AG, Basel.