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Table 2 Comparison of main features of the nervous system in Bryozoa

From: Morphology of the bryozoan Cinctipora elegans (Cyclostomata, Cinctiporidae) with first data on its sexual reproduction and the cyclostome neuro-muscular system

 

Phylactolaemata

Cyclostomata

Gymnolaemata

Reference

digestive tract

mostly nerve plexus

few neurite bundles, on anal and lateral sides of the foregut

few neurite bundles on anal side of the foregut

29, 32, 67, this study

lophophoral base

circum-oral nerve ring

circum-oral nerve ring plus incomplete outer ring

circum-oral nerve ring plus incomplete outer ring (trifid nerve)

29, 30, 32, this study

cerebral ganglion/brain

with cavity

without cavity, plus lateral ganglia

cavity in few ctenostomes, missing in cheilostomes

30, 32, 60, this study

tentacle innervation*

6 tentacle nerves

4 tentacle nerves

4 tentacle nerves

26, 29, 32, this study

tentacle sheath

mostly diffuse nerve plexus

two neurite bundles from cerebral ganglion

two mixed bundles

29, 67, this study

body wall

nerve plexus

mainly circular neurites in epithelium of membranous sac

separate parietal neurite bundles

29, 59, 67, this study

apertural/orificial innervation

radially via duplicature bands and vestibular wall

radially via attachment organ and vestibular wall

via few parietovaginal bands or distinct aperture

61, 67, this study

serotonergic nervous system

concentrated in cerebral ganglion, thin bundles in circum-oral nerve ring, regular perikarya at lophophoral base

concentrated in cerebral ganglion, thin bundles in circum-oral nerve ring, three oral perikarya

concentrated in cerebral ganglion, thin bundles in circum-oral nerve ring, regular perikarya at lophophoral base with three oral perikarya including ‘serotonergic gap’

31, 33, this study

  1. *possibly peritoneal neurites or subperitoneal cells not considered