Family Stylochidae Stimpson, 1857

Diagnosis (from Bulnes et al, 2005): Stylochoidea, mostly provided with dorsal pigmentation, which consists of irregular darker spots or streaks. Tentacles anterior. Ruffled pharynx usually highly folded, more or less centrally orientated within the body. Male copulatory apparatus directed backwards, prostatic vesicle with long-fingered extensions having polyglandular outlets or provided with several ducts, each with a central, monoglandular outlet; prostatic glands extravesicular. Gonopores in the second half of the body.