It was first described and illustrated based on 82 whole mounts, from the gills of the silver eye, Polymixia japonica (Polymixiidae) off Hawaii.

The haptor is symmetrical, hatchetshaped in profile and bears 57-88 clamps, arranged as two rows, one on each side(26-47 on the right and 27-47 on the left).

There are also two small buccal suckers strongly muscular, septate, unarmed and located at the anterior extremity.

The digestive organs include an anterior, terminal mouth, a simple esophagus, a muscular rounded pharynx, and a posterior intestine with two lateral blind-ending branches terminating separately at posterior end of body proper.

The reproductive organs include an anterior circular genital atrium opening a little in front of intestinal bifurcation., with spines, a dorsal vagina unarmed, opening middorsally just in front of body constriction, a single ovary, and 15 to 75 oval testes occupying the entire postovarian interintestinal field.