1. Anus outside the lophophore; zooids not stalked; tentacular crown capable of being retracted within zooecium; without a protonephridial system; statoblasts present or absent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ectoprocta, 2
Anus on the lophophore; each zooid on a flexible stalk composed of sclerotized urn-shaped segments; one to six such stalks arising from one basal plate; stalks may be branched or unbranched and up to 5 mm long; lophophore circular with 8 to 16 tentacles, and incaplable of being retracted within ooecium; with a simple protonephrical suystem; with statoblasts; on objects in running waters on in large lakes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Entoprocta, Urnatella gracilis
2. Stratoblasts all free, annulated, and with processes; colony soft, gelatinous, transparent, without septa, and not dendritic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Often with two types of stratoblasts; one attached and without float cells(sessoblasts); the other unattached, funicular, and annulated (floatoblasts)(except Fredericella); statoblasts without processes; colony most often dendritic, with either tubular opaque or swollen gelatinous cystid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. With a transient secretion elaborated by flat base of colony; colony elongated and slowly motile; statoblast with two circlets of hooked spines; dorsal circlet with 10 to 34 hooks and ventral circlet with 20 to 50 hooks; zooids on upper surface and arranged marginally in symmetrical fashion; all polypides retract into a acommon cavity; usually 80 to 90 tenticacles; long dimention of colony sometimes as much as 10 to 30 cm, but morer typically 2 to 6 cm; in standing waters or slow currents, on upper side of submerged objects and vegatation. . . . . . . . . . . . . . . . . . . .. Cistatellidae, Cristatella mucedo
Lobular gelatinous cystid present throughout life of colony and sometimes very well developed colony not usually motile; statoblasts never with two circlets of hooked spines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Colonies in the form of rosettes on gelatinous base or surrounding a gelatinous core; very young colonies motile; colonies commonly investing twigs and other submerged objects, especially in shaded places in quiet waters; 60 to 84 tentacles; episome red in fresh animals; free statoblasts with single row of marginal anchorlike spines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pectinatellidae, Pectinatella magnifica
Colonies in the form of small gelatinous masses with radiate branching; a few to 70 zooids per colony; episome not red; free statoblasts poited or with hooked spines at each end. . . . . . . . . . . . . . . . . . . . . . . . . . . . Lophopodidae, Lophopodella carteri
5. Lophophore circular or elliptical; colony tubular, branched, and anterlike; outer layer usually opaque and braown; aredericellidaell statoblasts (piptoblasts) free, without annulus; no floatoblasts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fredericellidae, 6
Lophophore horseshoe-shaped even if very small; floatoblasts present; sessoblasts also present in most species. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plumatellidae, 7
6. With 24 to 30 tentacles; polypides short; zooecia not especially slender; ectocyst thin, chitinoid, and opaque; most sessoblasts rounded or broadly elliptical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fredericella australiensis
With 17 to 24 tentacles; polypides longer; zooecia slender, with anthler-like branching; mos tsessoblasts reniform or elongated; on submerged objects and vegetation in standing ad slowly flowing waters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fredericella indica
7. With soft, hyaline, gelatinous cystid; thichkly branched, often completely covering the substrate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hyalinella punctata
With thick and somewhat gelatinous branches or thin, firm, and sometimes horny branches; outer layer usually long and tubular, pale and transparent to dark brown; in masses up to 5 cm high or closely adherent to substrate. . . . . . . . . . . . Plumatella, 8
8. With two types of floatoblasts, the more common type is somewhat narrow, very thin-walled and has the annulus the same width all around the capsule; the less common type is the usual thick-walled capsuled form similar to those of the other forms in this genus; colony without free, uprightt branches; zooecia keeled (Lake Erie and Tippycanoe River, Ind). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plumatella casmiana
With only thick-walled capsuled floatoblasts; annulus not of the same width all around capsule; zooecia often keeled; 40 to 60 tentacles; at least 6 varieties and two phases; on underside of vegetation and objects; typically in lakes and ponds but also occurring in running waters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
9. Zooecia strongly keeled, furrowed, and with an emarginate oriface; ectocyst dark. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plumatella emarginata
Zooecia not strongly keeled. . . . . . . . . . . . . . . . . . . . . . . . . . . . Plumatella repens
Sessoblast reticulated, abundant septa, well-sclerosized ectocyst and relatively small number of tentacles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plumatella reticulata