Lip region continuous with body contour. In SEM face views, oral disc
lemon- shaped, submedian lobes low and flattened, lateral lobes completely
regressed, amphid apertures appear as slits or pores at lateral edge of
labial disc. Stylet attenuated, 15-25 um long, with needle-like cone (somewhat
stronger in T. palustris). Lateral field areolated, with three lines.
Deirids absent. Tail long, three to six times as long as wide, cylindroid,
with a broadly rounded or clavate end, sometimes with thicker cuticle at
tail tip. Male spicules with well developed velum, and bent gubernaculum.