<i>Cephalothrix linearis</i>, light micrographs of Azan stained neurons.

<p><b>a</b>: Transverse section, overview of the brain, position of the three different types of neurons (<i>S1</i>–<i>S3</i>). <b>b</b>: Frontally, only type <i>1</i> and type <i>2</i> neurons are present. <b>c</b>: Nuclei of type <i>1</i> neurons stain red. Nuclei of type <i>2</i> neurons stain bright purple; the cell body is slightly enlarged. The cell body of type <i>3</i> neurons is the most prominent. Their nuclei stain red. <i>in</i> inner neurilemma, <i>np</i> neuropil.