Two new species of Nereis from the Mexican Pacific are described. N. inflata, is characterized by an enlarged dorsal ligule in posterior notopodia and long shafted notopodial homogomph falcigers
N casoae belongs to the group of species with short dorsal ligules and elongate ventral ligules, but it can be differentiated by the presence of long blades in notopodial homogomph falcigers, with many small teeth on the interior margin and an apical blunt tooth.