Karyokinetic Spindles and the Behavior of Centrioles in the Spermatocyte Meiosis of Silkworms and Grasshoppers

抄録

1. The behavior of centrioles in spermatocyte meiosis of silkworms and of grasshoppers was reinvestigated by in vivo observations and by the use of improved fixatives.
2. In both insects, the centrioles behave exclusively outside the spindle membrane. The centrioles participate in the sperm-tail filament formation at the spermatocyte stage in silkworms and at the spermatid stage in grasshoppers. However, no centrioles participate in spindle formation.
3. Taking these facts into consideration, it is concluded that the centriole is intrinsically a primordial organelle for flagellum formation of the sperms and remains in an inactive state in other than male gametic cells in animals.
4. Based on the atractoplasm theory, suggestions are made concerning the mechanism of mitosis for some divergent achromatic figures and on the generalization of mitosis mechanisms in plants and animals.