抄録
An electron-microscopical study of the fine structure of the nuclei of Paramecium caudatum has been carried out by means of ultra-thin sections.
The results of the observations are summarized as follows:
1) The macronucleus is surrounded by thin nuclear membrane.
2) Throughout the whole macronucleus many globular bodies connected by thin strands of bead-like structures are distributed. They measured about 0.1 to 0.2μ in diameter.
3) It is inferred that bead-like structures are related to chromosomes.
4) In the micronucleus a stage resembling a prophase of nuclear division could be observed.
5) Spherical granules which measure 1μ or more in diameter are scat-tered here and there in the macronucleus, and we suppose these granules are nucleoli. These granules are often fused into two or more large vacuolated masses.
Some of the nucleoli in the macronucleus have fine-grained centers and densely osmiophilic perimeters.
