Expression of Nvi-Hox2 in nectochaete (A) and juvenile worms (B-G). The anterior end is directed upwards on panel A, and to the right on panels B-G. (A) Nvi-Hox2 expression at the nectochaete stage. (B) Nvi-Hox2 expression in small juvenile worm. (C) Nvi-Hox2 expression in juvenile worm, general view. Arrows point to the expression domains in small patches of 3 to 5 cells at the midline. (D) Nvi-Hox2 expression in the pharynx. (E) Posterior part of juvenile worm, deep view. Nvi-Hox2 is expressed in the deep layer of GZ and the posterior segment. (F, G) Expression domains on the midline. (F) Several medial body segments. Expression of Nvi-Hox2 is detected in small domains in each segment. Arrows point to the expression domains. Arrowheads mark a background in epithelial glands. (G) Several posterior segments. Expression of Nvi-Hox2 is detected in small domains in each segment. See text for details. GZ, growth zone.