Capitellid connections: contributions from neuromuscular development of the maldanid polychaete Axiothella rubrocincta(Annelida)

Table 1 Comparison of the capitellid and echiuran nervous system

	Echiura	Capitellida
		Capitella(Capitellidae)	Arenicola(Arenicolidae)	Axiothella(Maldanidae)
repetitive units of nerve cells	+	+	+	+
metameric, peripheral neurites	+	+	+	(+)
single ventral neurite bundle	+	-*	+	+
simple circumesophageal connectives	+	?	?	+
stomatogastric nerve ring	+	?	+	+

+ present, (+) partly present, - absent, ? unknown character state
* The ventral connectives in Capitella are fused only in the region of the segmental ganglia. In other genera of the Capitellidae, however, there is a clear tendency towards a fused ventral nerve cord.

ISSN: 2730-7182