Description (from Thorne, 1929)
Micoletzky gave this species the specific name because of the deep vestibule forming the pharynx. The slightly set off head bears two circlets of large papillae. The posterior half of the esophagus is enlarged by a rather sudden expansion. The cardia is pyriform and as long as the width of the base of the esophagus. The symmetrical ovaries are reflexed one-half their length the front being on the left, the rear on the right, side of the body. The prerectum is about twice as long as the rectum.
The male tail bears a pair of supplementary organs just in front of the anus and beginning at a distance about one anal body-diameter in front of this pair is a series of ventral supplementary organs varying in number from eleven to twenty-one. Four pairs of pores are located on the tail.
Several dozen specimens on the collection.