(Lohmann, 1896)
Trunk up to 1.7 mm long, flattened (Tectillaria fertilis), anteriorly pointed (Tectillaria fertilis 2). Two cylindrical testes, sharply bent at their posterior end. Two ovaries near the spiracles. Tail musculature moderately broad (Tectillaria fertilis 3). Fin end tricuspate. Amphichordal cells large and plate-shaped.