A descriptive account is given of the post-embrionic development of Amphilochus neapolitanus Della Valle, 1893 and Ampilhoe ramondi Audouin, 1826 living on Sargassum cymosum C. Agardh, 1820 of Ubatuba, Brazil (23º30'S-45º06'W) through the growth stage based on the morphological changes at each moult. The growth stages are described on the increase of antennal and pleopodal articles number and morphological alterations of gnathopods. The number of stages was found to be different for males and females and the maturity occurs after 6 and 5 post marsupial stages for A. neapolitanus and A. ramondi respectively.
Amphipods gammarids; growth stages; morphological variations