Fig. 2

Organization of the cerebral ganglion of Crisia eburnea. a The scheme of the cerebral ganglion with upper concavity and neuropile inside. Different levels of the ultrathin sections are shown by number and letter on the left. b Longitudinal sagittal section of the cerebral ganglion (shown in cyan) and envelope cell (shown in magenta); TEM. c Cross section through the cavity in the upper part of the cerebral ganglion: the cavity is filled with thin microvilli. d A portion of the cavity: the microvilli and desmosomes (arrowheads) between cells are visible; TEM. e Cross section of the upper portion of neuropil (shown in yellow) surrounding several central perikarya; TEM. f Tiny cavity in the cerebral ganglion is filled with microvilli and cilia. Neurones are connected via desmosomes (arrowheads); TEM. g Cross section of the perikarya with basal body and accessory centriole; TEM. Abbreviations: ac – accessory centriole; bb – basal body; ccg – upper concavity of the cerebral ganglion; ci – cilia; ic – internal cavity; mi – microvilli; lnp – lower neuropil of the cerebral ganglion; lw – lateral weir of the cerebral ganglion; n – nucleus; ph – pharynx; sv – synaptic vesicle; unp – upper neuropil of the cerebral ganglion