@article {5434, title = {On the phylogenetic significance of sagittocysts and copulatory organs in acoel turbellarians.}, journal = {Hydrobiologia}, volume = {227}, year = {1991}, month = {1991}, pages = {307 - 314}, keywords = {Simsagittifera, Symsagittifera}, author = {Mamkaev,YuV and Kostenko,AG} }