Ecdysteroids and embryonic development in the shore crab, Carcinus maenas

Eggs at various stages of embryonic development of Carcinus maenas contain high concentrations of the ecdysteroid ponasterone A together with lower titres of 20-hydroxyecdysone and ecdysone. Correlative studies on ecdysteroid titres and developmental characteristics of Carcinus embryos indicate that one function of ponasterone A might be related to the control of deposition of an embryonic envelope.