Cephalothrix linearis, light micrographs of Azan stained neurons.

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