Studies on Giant Amoeboid Organisms: 2. Nuclear Division and Cyst Formation in Leptomyxa reticulata Goodey with Remarks on the Systematic Position of the Organism

Abstract

Cytological prepns. were made using Carnoy fixative and iron hematoxylin stain. Cultures for examination were grown on agar films on cover slips. The organism is multinucleate; each nucleus contains a deep-staining nucleolus surrounded by a clear zone in which the chroma-tinic material lies. Mitosis is rapid and occurs within the nucleus. All nuclei within an individual divide simultaneously. A spindle was seen but no centrosomes. The nuclear membrane disappears at late anaphase. At telophase the chromosomes fuse and the daughter nuclei separate. The formation of mutlinucleate cysts is descr. and reasons advanced for a closer systematic relationship to the Amoebaea.