Wirenia argentea larvae and postlarvae (40 days), anti-α tubulin labeling, overlay of confocal images. A, B. Day 4 larva, ventral view; scale bars 40 μm. A. Image stack through entire Z-axis showing prototrochal ciliary band (pro), telotroch (tt), foot cilia (fc), and longitudinal neurite bundles (arrow). B. Reduced image stack omitting outermost cell layers; note apical organ (ao) with associated nerves, paired longitudinal neurite bundle (arrows), stomodaeum (st), and protonephridia (pn); oral troch (arrowheads). C, D. Day 6 larva, lateral view; scale bars 50 μm. C. Overlay of light micrograph and confocal image; apical cap (ac) covers part of the trunk (t); apical organ with ciliary tuft (ao); prototrochal cilia (pro) and telotroch (tt) brightly labeled, oral troch faintly visible (arrowheads). D. Reduced image stack omitting outermost cell layers and layers below sagittal plane; dorsal part of oral troch (arrowhead); fc: foot cilia, pn: protonephridium, pro: prototroch cilia, st: stomodaeum, tt: telotroch. E. Day 11 postlarva, crawling stage; pretrochal part of apical cap (prt) still present, oral troch (ot) exposed; foot cilia (fc) and prepedal ciliary pit (asterisk); note lateral longitudinal neurite bundle (arrow); st: stomodaeum, tt: telotroch; scale bar 50 μm. F. Anterior end of a postlarva 30 days after hatching; cilia present in the gut (arrow), but distal pharynx (ph) devoid of cilia; prepedal ciliary pit marked by asterisk, sensory nerve endings by arrowheads; cer: cerebral ganglion, fc: foot cilia, ve: vestibular cirri, yg: yolk granules; scale bar 25 μm.