A large cerebral ganglion that occupies most of the frontal part of the head forms the brain in Limnognathia maerski. A pair of ventral nerve cords extends from the brain towards the animals’ tail. This kind of nervous system is found several minor worm-like animals.

The whole body of L. maerski has scattered sensory bristles composed of one or up to three adjoined cilia. This kind of sensory structures resemble the sensoria found in the phylum Gnathostomulida (jaw worms). However, in L. maerski all cilia in the bristles that are composed of more than one cilium appear to arrive from one single cell (multicilliarity), whereas the cilia in the gnathostomulid sensoria always arrive from one cell each (monociliarity). Thus, it is not likely that the sensory structures in the two groups are derived from a common form.