Fig. 3
![Fig. 3](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12862-019-1498-9/MediaObjects/12862_2019_1498_Fig3_HTML.png)
Magelona mirabilis, histological cross sections (5 μm), Palmgrens silver impregnation, frontal (A) to caudal (C). a: The anterior part of the brain (abr) is composed of a compact trapezoid neuropil. so: somata. b: Neurites in the dorsal part of the brain (dpbr) is composed of neurites which are arranged in parallel to the body axis. c: Some neurites are stronger impregnated by silver ions than the surrounding neurites. mo: mouth