DEVELOPMENTAL STAGES OF ANTARCTOMYSIS-OHLINII HANSEN, 1908 (MYSIDACEA) IN TERRA-NOVA BAY, ROSS SEA, ANTARCTICA

Detailed descriptions of 2 intramarsupial stages, the juvenile stages, and male and female immature stages are given. Stage II shows an abun dant yolk mass, 2 Pairs of rudimentary antennae, and Poorly developed mandibles. In stage III the yolk is absorbed and all the thoracic and abdominal appendages project freely. The juvenile stage starts when th e larva leaves the marsupium. The antennulae, the antennae, and the ma ndibles assume the typical aspect of those of the adults. A statolith inside the statocyst appears in the endopod of the uropods. A morpholo gical peculiarity of its immature stages (both in males and females) i s described and referred to as sexual dimorphism.