Striation Pattern of the Epithelium-Cells of Yolk-Sac Membrane and Embryonic Body of Oryzias latipes

Abstract

1. Remarkable cytoplasmic striation pattern is found in the epithelium-cells of yolk-sac membrane and of embryonic body of Oryzias latipes, especially of its fins.
2. The striation pattern is composed of several sets of parallel striations that are arranged in mosaic to every directions. The peripheral one or two striations are, however, arranged parallel to the border of cell, while there is none of the striation that is arranged parallel to the border of nucleus.
The parallel striations are about one micron apart from one another.
3. Each striation is made up of minute cytoplasmic particles closely arranged in a line.
4. The striations, however, are unstainable with usual cytoplasmic stains such as eosin and acid fuchsin.
5. The first indication of the striations appears in the epithelium-cells of yolk-sac membrane of 13-somite embryos. At this stage the minute cytoplasmic particles, which hithertofore distributed uniformly in the cytosome, come to be arranged closely in a line, and then the pieces of striation thus formed become continuous and finally establish the striation pattern. The complete striation pattern is found in the epithelium-cells of yolk-sac membrane of the third day embryos.
6. No correlation between the striation pattern and the rythmic contraction of yolk-sphere was found.