The article reports the first description of the architecture of the musculature and cholinergic nervous system of the parasitic turbellarian Notentera ivanovi from the White Sea using histochemistry and confocal scanning laser microscopy. It has been demonstrated that the body wall is composed of layers of circular and longitudinal muscles between which there are diagonal muscles described here for the first time. The nervous system is of the regular closely spaced orthogon type with pronounced radiality. In order to make it clear whether the orthogon of this type is a phylogenetic characteristic of this group of worms or its shape is associated with the flat rounded body, the study of other representatives of the Fecampiida group is required.