Fiddler-Crabs and Their Immoderate Differences. Male Fiddler-Crab (Gelasimus annulipes) of the Godavari and Kistna mud-flats. One of the chelipeds is enormously enlarged, and has the 'hand' brilliantly coloured, so as to be at once a weapon and an ornament in the prolonged and savage tournaments in which these little creatures engage to win the favour of the opposite sex