1 Body wider medially; dorsal surface sometimes areolated..................................................... 2
- Body cylindrical, barely swollen medially; dorsum never areolated.............................................. 5
2(1) Chaetiger 2 with notopodia larger than following ones; body wall areolated............. B. rugosa (Hansen, 1880) n. comb.
- Chaetiger 2 with notopodia about as large as following ones; body wall never areolated.............................. 3
3(2) Gonopodial lobes close to neuropodia (shorter distance than gonopodial length).................................... 4
- Gonopodial lobes displaced midventrally (longer distance than gonopodial length); body with 35–40 chaetigers (24–39 mm long, 4–6 mm wide).............................................. B. nuda (Annenkova-Chlopina, 1922) n. comb.
4(3) Neuropodia barely projected; median parapodia with 3–4 notochaetae and 4–5 neurospines per bundle; body with 26–29 chae- tigers (16–38 mm long, 3–4 mm wide)..................................................... B. alaskensis n. sp.
- Neuropodia markedly projected; median parapodia with 5–6 notochaetae and 6–7 neurospines per bundle; body with 27–36 chaetigers (19–32 mm long, 3–6 mm wide).................... B. strelzovi (Jirkov & Filippova in Jirkov, 2001) n. comb.
5(1) Anterior dorsal papillae of two different sizes.............................. B. bransfieldia (Hartman, 1966) n. comb.
- Anterior dorsal papillae of a similar size.................................... B. antarctica (Hartman, 1978) n. comb.