ELECTRON MICROSCOPY OF GROWING OOCYTES OF RANA PIPIENS

Abstract

1. In the cytoplasm of oocytes of stage Y₀, prior to the appearance of yolk, one observes a few scattered profiles of endoplasmic reticulum and numerous filamentous mitochondria, usually distributed at random but sometimes clustered. As the nuclear membrane begins to bulge outward, small granules and short rods appear in the perinuclear cytoplasm and endoplasmic reticulum becomes more prominent throughout the cytoplasm.