Suborder (2) Endogenina Collin, 1912

Syns.

Acinetida, Acinetina, Astrosomatida, Dendrosomatida, Dendrosomatina, Endogenea, Endosphaeriina, Oligostomatida p.p.

Endogenous budding, with one or more monogemmic or polygemmic larvae produced completely internally and becoming free-swimming in brood pouch before emergence through birth pore; small permanent field of nonciliferous kinetosomes near contractile vacuole responsible for larval ciliature; migratory larval form small, with encircling band(s) of cilia; adults usually small (but ramified and of enormous size in some groups), often loricate, sometimes colonial, with tentacles frequently in fascicles but without actinophores; in fresh-water and marine habitats, with ectosymbiotic forms common (plus some endocommensals) in wide range of hosts.

Adults nearly always loricate and stalked, with stalk persisting in some but not all endosymbiotic forms; tentacles in few fascicles, or even reduced to a single organelle; larvae small, ovoid; widely distributed species, in variety of habitats (and on/in many of the hosts listed).	Family ACINETIDAE Stein, 1859
Adult stalkless (with rare exception), aloricate, occasionally planktonic, with body shape pyriform to truncate to branching; tentacles sometimes highly specialized or greatly reduced in number; often multiple budding; larvae small, with transverse band of cilia; widespread, especially in fresh-water (even on turtles); several endosymbiotic species and crustacean gill parasites.	Family DENDROSOMATIDAE Fraipont, 1878
Body flattened, stalkless, but with fascicles of tentacles from slight protuberances; larvae small, ciliated; widely distributed species, with some found on gills of fresh-water fishes.	Family TRICHOPHRYIDAE Fraipont, 1878
Small, ovoid forms, with neither stalk nor tentacles; budding monogemmic; occur solely as endoparasites of peritrich ciliates.	Family ENDOSPHAERIDAE Jankowski, n. fam.