Fig. 6

External and internal morphologies of stadium VI juveniles in Epanerchodus sp. in the rigidation period. A A live individual in a molting chamber of which the covered wall was artificially removed for observation. B Lateral view of the posterior several rings of the individual fixed in Bouin’s solution. C SEM image of the individual with the cuticles removed. Green and purple coloration, respectively, indicate an apodous ring with forming legs and a newly added ring. Arrows indicate transparent protrusions. Arrowheads indicate newly added legs elongating in the transparent protrusion. Scale bars show 1 mm (A), 500 μm (B,C). nc, new cuticle covering the ring after molting; oc, old cuticle that is later exuviated