The ultrastructure and distribution of micropores in the various developmental forms of Eimeria brunetti

The structure and distribution of micropores in the various developmental stages of Eimeria brunetti was examined. Micropores were observed in all the endogenous forms with the exception of the microgamete. Oocysts from chicken faeces were also examined at various stages of sporulation and micropores were demonstrated in zygotes, sporoblasts, sporozoites, and the residual cytoplasmic masses. The number of micropores per organism appeared to be correlated with the surface area of the organisms irrespective of whether these were endogenous or sporulating forms. The increase in the number of micropores did not appear to be related to micropore activity because semmingly active micropores were observed only in the trophozoites, in the early multinucleate forms (early shizonts and microgamonts), and in the early macrogamonts. All these forms, however, possessed relatively few micropores. No active micropores were ever observed within the sporulating oocysts.