(invertebrate zoology) An order of crustaceans in the superorder Syncarida found in subterranean waters in England and central Europe.
An order of syncarid crustaceans found in subterranean waters in central Europe and England. The body is elongate and segmented. Organs and limbs are primitive. Each of the thoracic limbs has two epipodites which function as gills. The thorax and abdomen have a similar form (see illustration). These animals have no metamorphosis. See also Syncarida.

Bathynelia natans, female.