The nuclear envelope of both the macronucleus, seen here, and the micronucleus consists of 2 membranes containing numerous perforations called pores. Proteins are imported through these pores and ribo...

Nucleoli in a macronucleus of a cell undergoing micronuclear division. The nucleolus appears to have an organized surface layer composed of parallel threads of subunits. These may be developing riboso...

A contractile vacuole in systole. The CV has collapsed into vesicles and tubules. Three CV pores can be seen where the CV meets the pellicle. Smooth membrane cisterna surrounds some cytoplasm, possibl...

A micrograph showing the polyploidal macronucleus of Tetrahymena containing many copies of the genome. Chromatin material is found as condensed electron opaque spots as well as in an uncondensed form...

This figure shows the connection between the peristome and the food vacuole forming zone where the alveoli end. The cytostome is the opening that connects these two zones. TEM taken on 6/13/69 by R. ...

This section represents one in a series of serial sections. At this point the two parts of the macronucleus are now connected by a DNA replication band similar to the hypotrichs (e.g. Euplotes). The l...

In Euplotes a replication band of the macronucleus has larger heterochromatin masses on one side of the band after DNA replication has occurred. The replication band moves in the direction of lighter...

High resolution image of the macronucleus of Coleps hirtus. Heterochromatin and nucleoli are seen as smaller and larger stained bodies, respectively, in the macronucleus. Many nuclear pores exist in t...

A grazing section through the dorsal surface of Euplotes showing cross sections of cilia in four of the sparsely ciliated kineties . A layer of mitochondria underlies the pellicle. A replication band ...

In Euplotes a replication band of the macronucleus has larger heterochromatin masses on one side of the band after DNA replication has occurred. The replication band moves in the direction of lighter...