LIFE CYCLE OF Acanthonyx lunulatus (RISSO, 1816) (CRUSTACEA: DECAPODA: MAJIDAE) ON THE EAST IBERIAN COAST (WESTERN MEDITERRANEAN).- The biology of A. lunulatus was studied on the Mediterranean coast of Valencia Gulf. Its life cycle is annual. Ovigerous females were observed from May to September with recruitment of juvenile crabs to benthic population in August. The females reached their ovigerous state from 5.0 mm of size and the number of eggs carried on the pleopods is according to size. During June-August the number of females was greater than males (7:3) but the sex ratio is 1:1 for the others months of the life cycle.