Developmental expression of Pdu-sna1 and Pdu-sna2. All pictures are ImageJ projections from WMISH for Pdu-sna1 or Pdu-sna2 on a selection of larval stages (A-L) and posterior growth (M-O). Posterior growth has been investigated in regenerating posterior part of adult worms (indicated as 'reg'). (A, C-K, M-O) are ventral views with anterior up, (B) is an optical section of the larva (ventral is up) shown in (A) at the level of the trunk (position is indicated by the white dashed lines on picture A), and (L) is a lateral view with ventral side on the left. Black dashed lines delimit the prototroch and the yellow dashed circles surround the stomodeum (closing blastopore in 24 hpf larvae and developing foregut in the next stages). Blue arrows point to neural cells expressing Pdu-sna1 or Pdu-sna2, filled blue arrows point to cells belonging to the ventral nerve cord and open blue arrows to cells of the peripheral nervous system. Red arrows point to Pdu-sna1-expressing mesodermal cells. White arrows point to Pdu-sna2-expressing cells belonging to the foregut and the pink arrow to an expression in the developing brain and/or head sense organs.