Carapace with concentric ribbing in anterior and ventral areas. The anterior ribs are conspicuous and beaded with small tubercles. Sieve-pores particularly conspicuous. Anterior vestibulum relatively broad. Distal process of male copulatory appendage relatively small for genus, rounded (E. argus 8 ).
Horne & Rosenfeld (1986) discussed the former confusion over the relationship between E. argus and E. undulata, described by Klie (1929) from the Baltic, and concluded that the two were synonymous.
E. argus is a fairly common species around British coasts; it has also been widely recorded off NW European and Scandinavian coasts and in the Baltic.