Annelida, mainly consisting of marine Polychaeta and in faunal and partly parasitic Clitellata, is one the most significant metazoan taxa. Its more than 20.000 described species invade nearly all habitats and play a central role in marine benthic systems as well as in terrestrial soil communities. Annelids include all soft-bodied segmented worm-like organisms and have been recognized as a separate "phylum" for almost 200 years.

Recently, evidence has been accumulated which shows that some of the groups formerly regarded as independent "phyla" such as Pogonophora (now recognized as...

The nervous system is particularly fascinating for many biologists because it controls animal characteristics such as movement, behavior, and coordinated thinking. Invertebrate neurobiology has traditionally been studied in specific model organisms, whilst knowledge of the broad diversity of nervous system architecture and its evolution among metazoan animals has received less attention. This is the first major reference work in the field for 50 years, bringing together many leading evolutionary neurobiologists to review the most recent research on the structure of invertebrate nervous...