Females. No cyst stage. Body globose, with prominent neck and no terminal cone. Cuticle thick, annulated in fore part or on the major part of body, with lace-like pattern on posterior part; D-layer present. Subcrystalline layer present (very thick in T. crassicrustatus). Vulva sub- terminal, close to anus; vulval lips non-protruding; anal-vulval region flush with body contour. Eggs retained in female body, together with hatched second-stage juveniles.
Males. Body twisted. Lateral field with four lines. Spicules slightly curved, distally notched; no cloacal tubus. Tail very short. No phasmids.
Juveniles, second stage. Lateral field with four lines. Oesophageal glands not filling body cavity (except T. crassicrustatus). Tail pointed, of medium length, with long hyaline terminal part. Phasmids with lens-like structure.