Correction to: Fine structure of mushroom bodies and the brain in Sthenelais boa (Phyllodocida, Annelida)

Correction to: Zoomorphology https://doi.org/10.1007/s00435-021-00546-0

Unfortunately, the captions of Figures 7 and 8 were incorrectly published in original publication. Also, in Figure subheading 4 is a label B1 which should be moved to figure subheading 3. The corrected Figs. 7 and 8 updated here.

Fig. 7

A Toluidine-blue, semi-thin Sects. (1 µm), only left half of brain shown. B, C, D Ultrastructure (70 nm). A Three cluster of glomerular neuropils (arrows) are present (two shown), two at the base of the pedunculus (pd) of the mushroom bodies and one in the dorso-median part of the brain (br). Lobes (lb) of mushroom bodies connect both mushroom bodies medially. gc globuli cells; gl glia cell layer. B Neurites of the brain (nebr) are more prominent compared to the neurites of the pedunculus (pd) of the mushroom body. Glia cell processes (glpr) partly separate the neuropil of the pedunculus (pd) from the neuropil of the brain. arrows glomerular neuropil; nucgl nucleus glia cell. C Higher magnification of (B) the region of the glomerulum (dashed circle) is discernible from the remaining neuropil of the pedunculus, since it contains more electron-dense glia cell processes (glpr) and a high abundance of synaptic cleft material (arrowheads). mt mitochondria; nebr neurites of the brain. D Cytoplasm of the glia cell processes (glpr) is almost black. Much more dense- (dcv) and few more lucent- (lcv) core vesicles are present in the neurites of the glomeruli than in the surrounding neuropil. The synaptic cleft material (arrowheads) is located inside the synaptic cleft, is electron-dense and contributes to the darker coloration of the glomerular neuropil. mt mitochondria. E High abundance of the synaptic cleft material (arrowheads) is an indicator for high number of synaptic connections in the glomerulum. lcv lucent core vesicles

Fig. 8

Ultrastructure (70 nm) of glia cells. A Prominent glia layer (gl) surrounds the whole brain. Small glia cell processes (glpr) separate the globuli cells (gc) from the glia layer. B Glia cell membranes are highly fringed and interlocked. Gliosomes (gli) are present. C Neurites of the nuchal organ nerve (non) are arranged in parallel to the body axis. Several layers of glia cell processes (glpr) enwrap the nerve. gl glia layer; ncgl nucleus of glia cell. D Cluster of somata of glia cells (sogl). Somata as well as nuclei (ncgl) are electron-dense. E Radial glia cells which contain prominent intermediate filaments (if) occasionally cross the neuropil of pedunculus of the mushroom body (mbnp). Neurites of the mushroom body contain numerous small mitochondria (mt). F Epidermal cell layer (asterisk) which secretes the cuticle (cu) is situated above the glia cell layer (gl). gc globuli cells; glpr glia cell processes

The original article has been corrected.