Diagnosis. Basal shell outline oblong-ovate, height moderate to elevated (h/l = 0,45-0,65); apex recurved, 0,20-0,25 of
length from posterior end; anal slit deep, selenizone slightly sunken. Sculpture coarsely and irregularly cancellate; 45-52 first and second order radial ribs which are broader than the intervals between them; concentric threads cross ribs forming nodules; interstices simple. Basal margin concave in side view, deeply crenulate. Yellowish green, slightly mottled, interior white with two red to orange marks, one each side of the selenizone ridge. Length 15,1 mm.
Description. Basal shell outline oblong-ovate, greatest width more or less median, height moderate to elevated (h/l = 0,45-0,65), apex recurved, 0,20-0,25 of total length from posterior margin; base concave, shell resting on its ends. Anal slit moderately deep (0,25-0,35 of length), selenizone slightly sunken with lunulae not corresponding to con-centric sculpture; bordering flanges steep-sided medially, rounded laterally, irregular and often broken. Inner end of anal slit V-shaped internally, selenizone marked by a thickened ridge. Sculpture coarsely and irregularly can-cellate, produced by radial ribs and concentric threads; 45-52 first and second order ribs with occasional tertiary intermediaries; ribs broader than intervals between them; concentric threads cross ribs to form nodules which become progressively stronger toward the periphery. Growth stages marked by deep concentric grooves. Interstices simple, square to rectangular, variable; each with two radially elongate intritacalx pits; pits occasionally joined, sometimes forming an inverted V. Internally glossy white, basal margin deeply crenulate with alternating large and small U-shaped bays, each corresponding to a radial rib; muscle scar not clear (at least in fresh specimens); radial rows of minute punctations underlie intervals between external ribs. Colour greyish – greenish - yellow to greyish – yellowish - green, mottled with darker and lighter shades; interior translucent white, with two faint radially elongate dark reddish-orange marks on either side of the selenizone ridge. Protoconch emarginuliform, but worn in all available specimens. Dimensions. Holotype, 15,1 x 10,6 mm, height 9,4 mm.

E. viridicana is somewhat variable in terms of shell height. Most specimens are rather elevated (though not as high as E. connelli), while others are more depressed. The sculpture is also variable, but is always coarse and the radial ribs well developed. The interstices are deep and frequently partly obscured by the rib nodules. Few species appear similar; the shape resembles that of E. fissura (Linne, 1767) from the Mediterranean, as figured by Thiele (1913), but the sculpture is very different. E. crassicostata Sowerby, 1863, from unknown locality, has a similar shape and sculpture, but has fewer ribs. Sculpturally the most similar species is E. imaizumi Dall, 1926, from Japan, but that is much more depressed.

South-Africa. Southern Natal coast to eastern Transkei, 100-142 m (living examples, 100-120 m). Apparently associated with sponges.