part of part of immediately preceded by immediately preceded by occurrent late juvenile stage adult period adult stage gravid sea urchin The adult stage corresponds to a fully formed pentaradial sea urchin individual that has reached sexual maturity. The gonads have developed within the perivisceral cavity and are connected to the outside by the genital pores pierced into the genital plates. UBERON:0000113 ecao_developmental_stage sexual mature sea urchin