Shell up to 1,13 mm wide, depressed-turbiniform, slightly broader than high, spire up to 0,42 x height of aperture, narrowly umbilicate, thin, colourless and translucent. Periostracum very thin, smooth, pale buff.
Protoconch 170 µm wide, tip of apical fold rounded. Sculptured throughout with fine, crisply defined, densely crowded, anastomosing vermiculate granules. A low, rounded axial varix immediately behind sigmoidal apertural rim.
Teleoconch of up to 1 - 8 whorls, end of mature body whorl descending more rapidly than before. Whorls convex, slightly flattened above and below very weak peripheral and basal angulations. Sculptured throughout with numerous fine, crisply defined, reticulating spiral threads and collabral axial riblets, the axials stronger. Spiral threads slowly multiplying by intercalation, similar. Axials prosocline, gently flexed backwards at weak peripheral and basal angulations, each alternate riblet vanishing between periphery and umbilical rim. Umbilicus deep, wall steep and smooth apart from collaboral growth lines, rim flange-like. Aperture large, D-shaped. Lips thin, parietal contact area narrow, outer lip shallowly indented against peripheral and basal angulations.
Known distribution. Off Broken Bay, New South Wales, 714 m. Remarks. Bathyxylophila peroniana is very similar to the New Zealand species B.excelsa, and differs primarily in its basal sculpture, each alternate axial riblet becoming obsolete between the periphery and the umbilicus. In B. excetsa, most if not all of the axials extend to the umbilical rim, and the few that do become obsolete do so close to the umbilical rim.