The neotenic adult resembles the normal adult in general form, but is considerably smaller, varying between 1·4 and 3·5 mm. in length. The caudal disc bears three pairs of suckers, incompletely developed anchor hooks, and infrequently, persistent larval booklets (Fig. 7, l.h.).

Fine brown granules colour the intestine, and anteriorly four pigment spots mark the eyes. The gonopore (Fig. 7, gon.) is posteriorly placed, lying some distance behind the transverse level of the excretory openings. Vaginal prominences and copulation pores are absent.