Genus Zonothrix Todd, 1942

Generic diagnosis. Female: Cephalic extremity formed by circumoral annule and simple second annule. Oesophageal end bulb gently clavate with or without pseudobulb. Isthmus a constriction between corpus and bulb. Cardia may or may not be modified into a branch-like structure posteriorly. Vulva with protruding anterior lip near posterior-third of the body. Vagina short, anteriorly directed. Gonads amphidelphic. Eggs broadly oval with filaments coiled around shell. Tail conical

Male: Cephalic extremity formed by single annule. Corpus cylindrical. Caudal extremity conical. Spicule present. Caudal papillae consisting of one pair pre-anal sub-ventral, one pair adanal sub-lateral, three pairs circumanal of which one pair pre-anal, one pair adanal and one pair post-anal and two pairs on tail, of which one is sub-lateral and one sub-ventral.