Gastrotricha

Gastrotricha isphylumtiny, free-living, freshwatermarine-dwelling animals. Theybilaterally symmetricalacoelomate. They havemouthan anus, as well as circulatorynervous systemssome poorly understood sensors. The skeletonhydrostatic. The body surface has cilia, scales,adhesive tubes. About 450 speciesknown,no fossils.