HYDROMEDUSAE, a group of marine animals, recognized as belonging to the Hydrozoa by the following characters.
The Hydromedusae represent, therefore, a sub-class of the Hydrozoa.
The Hydromedusae contrast with the Scyphomedusae in the following points.
The Hydromedusae form a widespread, dominant and highly differentiated group of animals, typically marine, and found in all seas and in all zones of marine life.
In fresh-water Hydromedusae the life-cycle is usually secondarily simplified, but in marine forms the life-cycle may be extremely complicated, and a given species often passes in the course of its history through widely different forms adapted to different habitats and modes of life.
How would you define hydromedusae? Add your definition here.