Anal pore

[citation needed] The anal pore is an exterior opening of microscopic organisms through which undigested food waste, water, or gas are expelled from the body.

The opening and closing of the cytoproct resemble a reversible ring of tissue fusion occurring between the inner and outer layers located at the aboral end.

In ciliates, the anal cytostomes and cytopyge pore regions are not covered by either ridges or cilia or hard coatings like the other parts of the organism.

[citation needed] Ctnephores are marine animals which superficially resemble jellyfish, but have biradial symmetry and use eight bands of transverse ciliated plates to swim.

All ctenophores possess a pair of small anal pores located adjacent to the apical sensory organ which is thought to control osmotic pressure.