Bonelliidae

Family Bonelliidae

Description. Echiurans with marked sexual dimorphism. Female with cylindrical or sausage-shaped trunk with a proboscis that may be either truncate or bifid; gonoducts usually single or paired; ventral setae usually either two or absent; anal vesicles usually branched. Male minute, parasitic in or on the female.

Genus Alomasoma Zenkevitch, 1958

Description. Female. Proboscis truncate; two gonoducts each with a basal gonostome. The two gonoducts open into a common duct with a single pore. Anal vesicles broom-like, with a great number of separate branches. Ventral setae may or may not be present.

Alomasoma belyaevi Zenkevitch, 1964

Description. Female. Proboscis up to 11 mm long, with small lobe at anterior end. Trunk 49–75 mm long, brown in colour and opaque. Ventral setae absent. Gonoducts one pair, opening into common duct with single genital pore; gonostomes basal in position. Anal vesicles tubular sacs covered with many long tubules.

Genus Prometor Fisher, 1948

Description. Female. Proboscis long, ribbon-like, not bifid but truncate, the lateral margins fusing at the base to form a funnel that leads to the mouth. Two ventral setae. Gonoducts one pair with a specialized basal portion into which the large fan-shaped, bilabiate gonostome opens; a single common genital pore. Anal vesicles unbranched sacs with a large number of excretory tubules with apical ciliated funnels.