English: Rhizocephala. A–H, life cycle stages and larval morphology of selected Rhizocephala. A, nauplius larva of Sacculina carcini. B, male cyprid of S. carcini. C, settled male cyprid of Lernaeodiscus porcellanae in the mantle aperture of a virginal female reproductive body (externa). Box D indicates the receptacle holding the trichogon. D, male trichogon of S. carcini dissected from the mantle cavity of a virginal female externa. E, female cypris of S. carcini. F, kentrogon of S. carcini, inside the empty cuticle of the spent female cyprid, in the process of injecting the primordial parasite. G, vermigon of Loxothylacus panopaei. H, scanning electron micrograph of Peltogaster curvata, showing the reproductive sac (externa) connected to the ramified internal root system. I–P, diversity of selected Rhizocephala externae. I, Peltogasterella sulcata on its host, Pagurus cuanensis. J, Briarosaccus auratum on its host, Lithodes aequispinus. K, Parthenopea subterranea on its host, Calianassa subterranea. L, Sacculina carcini on its host, Carcinus manaeas. M, Thompsonia sp. on its host, Thyraplax truncata, courtesey of Peter Castro. N, Sylon hippolytes on its host, Spirontocaris lilljeborgi. O, Heterosaccus dollfusi on its host, Charybdis longicollis. P, Polyascus gregarius on its host, Eriocheir japonica.