The flowers are hermaphrodite and regular with parts in fives (pentamerous) throughout, though exceptions from the pentamerous arrangement occur.
The fact that all the Euthyneura are hermaphrodite is not a fundamental difference; several Streptoneura are so, likewise Valvata, Oncidiopsis, Marsenina, Odostomia, Bathysciadium, Entoconcha).
The majority of species are hermaphrodite and many are capable of self-impregnation.
(In Hydra, on the other hand, the individual is usually hermaphrodite.) The medusa always reproduces itself sexually, and in some cases non-sexually also.
Leptonidae.-Shell thin; no siphons; foot long and byssiferous; marine; hermaphrodite and incubatory.