.

Females:

• mouth opening circular or subtriangular; surrounded by 8 sub-median papillae or labiopapillae
• Pair of small lateral amphids.
• Eesophagus tripartite with anterior subcylindrical corpus, isthmus (often short) and posterior valvular bulb.
• Nerve ring around corpus.
•  Intestine wide anteriad, then parallel or subparallel sided to rectum or wide posteriad. Rectal glands between rectum and anus sometimes distinct.
• Excretory pore in anterior third of body.
• Vulva in posterior quarter of body.
• Monodelphic and prodelphic. Uterus may lead to well developed muscular vagina which forms an ovijector.
• Eggs oval or ellipsoidal, colourless, surface often punctate.
•  Tail short, conical.

Males:

•  much smaller than females.
• Esophagus tripartite.
•  Nerve ring around esophageal corpus or isthmus.
• Excretory pore posterior to base of esophagus.
• Monorchic, testis reflexed or outstretched.
• Tail conical, with or without constrictions,
• 3-4 pairs of genital papillae.
• Spicule single, without capitulum.
• No gubernaculum

Ref; Zervos, 1987