Shell squat with low spire, angle usually 70-80°. Shell width more than half shell length. Aperture approximately twice as long as spire. Periphery of body whorl situated slightly closer to apex. Sculpture usually in the form of weak spiral ribs with fine spiral striae on and between ribs, sometimes with spiral striae and a few weak ribs on lower half of body whorl. Typically between 4 and 9 spiral ribs on body whorl. Whorls moderately to strongly depressed below suture; profile of upper whorls stepped to straight. Outer lip usually crenulated at edge, aperture smooth internally, sometimes plicate. Dark brown parietal scar usually present. Periostracum thick, fibrous, brown, often stained with green algae. Shell colour often with yellowish-brown to brown ground colour, with well-defined alternating dark brown and pale whitish-brown to yellowish dashes on main spiral ribs, sometimes giving a wavy axially flamed appearance; the dashes on the spiral ribs are usually present over most of the body whorl, and are most prominent just below the suture and on the shoulder of the body whorl; sometimes the alternating dashes are not well defined, giving the shell a streaky appearance; shell colour sometimes dark brown, completely lacking the alternating dark and light dashes; upper whorls of shell usually worn. Aperture usually dark brownish-violet, or yellowish-violet, often with a yellowish to whitish outer edge. Proboscis flesh coloured. Maximum shell length 45 mm.

Burnupena lagenaria is common to abundant throughout most of its range, and is found in the mid- to high-intertidal zone in pools and exposed habitats. This species not only has the widest distribution, but also exhibits greater variation in shell form and coloration than the other species in the genus. In terms of shell form, populations on the west and east coasts tend to be squat and have shorter spires and larger apertures , whilst those on the south coast are generally less squat with slightly longer spires and shorter apertures . The population from Kommetjie is an exception, and resembles the south coast populations. The west and east coast populations also tend to have smoother shells, and a higher proportion of shells in which the aperture is plicate internally. In terms of shell colour, the east coast populations are generally dark with no pattern, as are some of the west coast populations. The south coast populations usually exhibit alternating dark and light dashes to a greater or lesser extent. The west coast populations are more variable, with some populations being mostly dark (for example Blouberg), whilst others show varying degrees of axial streaking.
Burnupena lagenaria has most often been confused with B. catarrhacta and B. cincta. The character states that distinguish it from these species have already been discussed under the remarks relating to them.

From Luderitz (in Namibia) on the west coast, extending to northern KwaZulu-Natal on the east coast