Athersuch, Horne & Whittaker, 1983
Carapace large, 0.75-0.8 mm long, strongly inflated, greatest width a little behind mid-length. Dorsal margin straight. Posterior margin smooth. Greatest height well behind mid-length. Dorsomedian sulcus weak. Distal process of male copulatory appendage relatively long, with a convex anterior margin and an almost straight posterior margin (B. zetlandica 4 ).
B. zetlandica was formerly confused with B. constricta Sars, which does not live in British waters (Athersuch, Horne & Whittaker, 1983) See also remarks on B. intermedia).
British coasts, particularly in the north.