On the Microanatomy of the Brain and the Innervation and Homologues of the Cephalic Appendages of Hesionidae and Syllidae (Polychaeta)

• Published in: Acta zoologica (Stockholm) Vol. 77; no. 2; pp. 137 - 151
• Main Author: Orrhage, Lars
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.04.1996
• Subjects: Hesionidae; Marine; Polychaeta; Syllidae
• ISSN: 0001-7272; 1463-6395
• DOI: 10.1111/j.1463-6395.1996.tb01258.x

Earlier papers dealing with the anatomy of the hesionids and syllids were studied. Thereby it was found that information about the structure of the central nervous system was meagre. As a result, the anterior end appendages, especially the large, laterloventral ones of the Syllidae, have been differently interpreted. This prompted a re‐investigation. The circum‐oesophageal connectives, the brain commissures and the innervation of the alimentary canal and the cephalic appendages of a number of hesionid and syllid species were studied. The results, summarized in schematic diagrams, were compared with corresponding observations in other polychaete families. Among other things, it was concluded that not only the latero‐ventral cephalic appendages of the hesionids but also those of the syllids are homologous with the palps of the nereids and of many other “errant” and “sedentary” families.