Bursa lamarckii is easily recognised by its very dark brown to black aperture, with prominent, paler, transverse ridges on both lips, by its unusually tall spire for a shallow-water Bursa species, by its long posterior siphonal canals remaining up the opposing sides of the spire as two rows of prominent spines, and by its irregularly nodulose and marbled exterior. Most specimens have a dark brown exterior, irregularly marbled with much paler brown and grey, but some are uniformly paler, with a pale brown to fawn background and a few darker maculations. Parth (1990) named this paler form Bursa angioyorum, but because of the lack of any differentiating characters in the aperture and the intergradation in exterior colour it seems likely that this is a colour form of B. lamarckii. The single specimen now reported from the Marquesas Islands is this paler colour form, whereas the one recorded earlier (Beu 1998: 155) is darker and resembles the neotype, so should these prove to be distinct species, one specimen each of B. angioyorum and B. lamarckii is recorded from the Marquesas Islands. Dimensions: H 46.0, D 31.9 mm.

Bursa lamarckii occurs widely, particularly on coral reefs, throughout the Indo-West Pacific region in its broadest sense, from East Africa and the Red Sea to Hawaii and the Marquesas Islands, and from southern Japan to the southern Great Barrier Reef in eastern Australia. Beu (1998) recorded a single specimen from New Caledonia, and another is present in recent MNHN collections from Lifou. Richard (1985) also reported it from the Society Islands. However, there are no specimens in MNHN collections from the Austral Islands, including Rapa, or in private collections from the Society or Tuamotu Islands.