Fig. 3.

Body plans and nervous systems in Rotifera and Chaetognatha. a Diagram of Hox gene expression in the nervous system of Brachionus manjavacas. b Comparison of rotiferan and chaetognath body plans with respect to the structure of the nervous system. Both groups have a dorsal brain and additional nerve plexi: mastax nerves and ganglia in rotifers and vestibular, and esophageal ganglia in chaetognaths as well as a caudal ganglion in rotifers and a ventral nerve centre in chaetognaths with the latter possibly incorporating functional subsets, these are still separated from the caudal ganglion in rotifers, e.g., innervation of sensory lateral antennae