The enigmatic Cambrian and Ordovician animals `` Heliomedusa '' , `` Marocella '' and `` Conchopeltis '' warrant comparison , although again large differences exist between these taxa .
The Ordovician Cambrian and enigmatic animals `` Heliomedusa '' , `` Marocella '' and `` Conchopeltis '' warrant comparison , although again large differences exist between these taxa .