Fig. 7

Type 3 postembryonic development of Pycnogonida. a-c Three postembryonic instars of Nymphonella tapetis, parasitizing in the mantle cavity of the lamellibranch bivalve Paphia philippinarum (modified from [79]). a Newly hatched protonymphon larva 1, dorsal view. b Presumable postembryonic instar 2 (modified protonymphon larva 2), ventral view. c Older postlarval instar, ventral view. Note incompletely differentiated walking leg pairs 1–4. d Protonymphon larva of Achelia chelata, its further developmental having been suggested to follow type 3, ventral view, SEM (modified from [62] and reproduced with permission of Cambridge University Press). Arrowheads mark gland processes of palpal and ovigeral larval limbs