Hooks: 5-6; anterior teeth: 7-10; posterior teeth: 11-15.
Maximum adult body length: 20 mm; tail: 26-31 %.
Body firm and muscular; transversal musculature absent; head wide; hooks not serrated. Fin bridge absent. Anterior fins of medium length, fully rayed, rounded; posterior fins of medium length, fully rayed, rounded. Collarette absent; gut diverticula present Large eyes with round pigment spot. Seminal vesicles with narrow knob and trunk; position of seminal vesicles: touching both posterior fins and tail fin. Ovaries long, to neck region; ova fairly large. Adhesive papillae and adhesive organs absent; apical glands absent.
Distribution: neritic; Japanese waters.
Type locality: Sagami and Suruga Bays, Japan.