Astomes (order Astomatida) are a group of

ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to eukaryotic flagella, but are in general shorter and present in much larger numbers, with a differen ...

eukaryotes commonly found in the guts of

annelid The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecol ...

worms, especially

oligochaete Oligochaeta () is a subclass of animals in the phylum Annelida, which is made up of many types of aquatic and terrestrial worms, including all of the various earthworms. Specifically, oligochaetes comprise the terrestrial megadrile earthworm ...

s, and other

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s. As their name implies, these parasites are characterized by an absence of mouth. The cell is covered by uniform cilia; in addition, some astomes attach themselves to their hosts by suckers, while others use various hooks or barbs. Asexual reproduction is by transverse fission. In some cases, chains of individuals form by repeated fission without separation of the cells. The sexual phenomenon of

conjugation Conjugation or conjugate may refer to: Linguistics *Grammatical conjugation, the modification of a verb from its basic form * Emotive conjugation or Russell's conjugation, the use of loaded language Mathematics *Complex conjugation, the change ...

also occurs. Representative genera include '' Cepedietta'', which lives in the amphibian digestive system, and '' Radiophrya''.

References

Oligohymenophorea {{Ciliate-stub