Transmission electron micrograph (TEM) of the eukaryotic nucleus, as seen in a cell from bat liver, fixed in osmium tetroxide, which preserves fibrous components. The nucleolus and two chromosome areas are within the nucleoplasm of the nucleus. Ribosomes are attached only to the outer membrane of the nuclear envelope. Note the resemblance between the rough endoplasmic reticulum elements and the nuclear envelope. Two nuclear pores are present in the plane of this section through the nuclear envelope. Glycogen and mitochondrial profiles are in the cytoplasm surrounding the nucleus. Magnification: x24,570 @ 8x10 inches.