ABSTRACT
Sternal bone marrow aspirations were performed on 4 infant, 8 young, and 28 adult Macaca mulatta that were residents of the Santiago Island Primate Colony, Puerto Rico where environmental conditions approach the most natural habitats for these animals (Suarez et al. 1942, 1943). The monkeys were caged only a day or two prior to the experiment. Twenty-one monkeys were males and 19 were females, but the sexes of the animals in the age groups were not otherwise indicated. Dry lm smears were prepared and stained with Jenner-Giemsa stain. Differential counts were obtained on all subjects. The nomenclature for the erythroid series used for this study was megaloblast (for the youngest progenitor), followed by the early erythroblast, and then late erythroblast, and nally the normoblast. It can be assumed that these four stages are equivalent to the pronormoblast, basophilic normoblast, the early polychromatophilic (polychromatic) normoblast, and the pool of cells comprised of late polychromatic and orthochromic normoblasts.
