Fig. 3. Differentiated pattern elements arising from the O and P lineages in stage 9 embryos. (A) The descendants of the O lineage (red) are generally located more ventrally than are the descendants of the P lineage (green). The arrow indicates the ventral midline. For labeled tissues, ventral is towards the left and anterior towards the top. (B,C) Pattern elements derived from the O lineage. (D,E) Pattern elements derived from the P lineage. The more superficial pattern elements of the body wall are shown in B and D. Pattern elements in the ganglia of the ventral nerve cord are shown in C and E, in which Hoechst 33258 counterstaining (blue) was used to visualize the segmental ganglia. CR, crescent neuron cluster; AD, anterodorsal neuron cluster; PV, posteroventral neuron cluster; WE, wedge-shaped neuron cluster; c.f.3, cell floret 3; n.t., nephridial tubule. pz6, pz10, LD1 and LD2 are identified peripheral neurons. Scale bar: 30 µm in A; 15 µm in B,E.