Characteristics of Polyphemoidea

carapax as brooding bag is dorsally attached, therefore, carapax is not ensheating legs and abdomen, with big dorsal neck organ, big head and compound eye, w/o nauplius eye, mandible hook-like and serrated, 4 pairs of limb legs with exopodit but w/o epipodit, in males the 1st pair with distal hook, furca claws reduced, abdominal appendix holds steerring bristles, latency eggs are released into the water, males with coitus organ behind the last pair of legs, cosmopolitans with 7 species in the seas, 2-3 species in fresh waters, but 25 species in the salty inland waters of the ponto-caspian region