Moderate-sized; very slender ("a" values range from 37 to 176), cephalic
region with fine annuli present up to labial plate which bears small
ovate amphid apertures (Ecphyadophora, Mitranema) or cephalic region
high, dorso-ventrally narrowed, smooth, amphidial apertures long slits
(Ecphyadophoroides, Epicharinema, Lelenchus).
Males with flap-like caudal alae (except Lelenchus); tail narrows markedly
after cloacal opening; tail long, filiform.
[Ref: Geraert & Raski, Rev. Nematol. 10(2):143-161 (1987).]