On average, female worms are larger than males by an estimated 4 mm in length and 0.65 mm in width. Respectively, their size ranges from 11 to 54 mm and 11 to 31 mm long. Females are different from males in that they possess only two large papillae around their slightly rounded posterior ends. From the side view, the dorsal outline is rounded, whereas the ventral side appears flat. Males have eight caudal papillae encompassing the anus on their bluntly rounded ends. Characteristic of males is the presence of blunt spicules that play the important reproductive role of holding open the vagina during sperm transfer. These male copulatory organs measure 1.1 mm and 0.4 mm long.