The geographic distribution of echiurans in the Atlantic Ocean (Phylum Echiura) Author Biseswar, Ramlall text Zootaxa 2009 2222 17 30 journal article 40586 10.5281/zenodo.190138 5a2b24d7-5527-4650-96a4-1404035191d2 1175-5326 190138 Family Bonelliidae Description. Echiurans with marked sexual dimorphism. Female with sac-like trunk with a proboscis that may be either truncate or bifid; gonoducts usually one or two; ventral setae, usually either two or absent; anal vesicles usually branched. Male, usually minute, degenerate and parasitic in or on the female. The zoogeographical composition and bathymetric range of the bonelliids from the Atlantic are given in Table 1. The localities in the Atlantic where the different species of bonelliids have been collected are indicated in maps 1–3.