Description. - Shell rather small, holotype 4.8*2.3 mm, slender pagoda-shaped, spire about one fourth of total height.
Protoconch smooth, globular, transparent reddish-brown, hypertrophic, approxi-mately diverging 40-45° from teleoconch axis; embryonic whorl not exposed, multispiral, number of whorls not ascertained; protoconch diameter 500 µm.
Teleoconch reddish-brown, translucent, cone-shaped with angulated whorls. Base acutely angled. Suture not distinct. Pattern of spiral (more prominent) and axial ribs (24 on last whorl) crossing at approximately right angles. Spacing of the axial ribs regular, the crossing of spiral and axial ribs form a well ordered arrangement of rectangles, the bigger created between the third and the fourth spiral ribs. Spiral sculpture consisting of four ribs ("2+1+1" pattern), the two uppermost ones and the fourth lowermost one (that serves as attachment of the subsequent whorl) weak, while the middle third rib is the most prominent. One additional fine spiral thread is visible among the first and the second spiral ribs, starting from the third whorl. In the last whorl, a strong basal rib, covered and not visible at the suture in the previous whorls, on half the base is more exposed and separated, forming a clear double keel. Another basal rib and four irregular threads are visible at the basal area, crossed by many axial growth lines. Umbilicus closed. Aperture small, angulated, columellar and outer lips thin.
Habitat . - The specimens were dredged from a bottom with rocks, sand and coral rubble at 70 m depth.
Distribution. - Only known from type locality.
Etymology. - This species is named in honour of Dr Dai Herbert, recognized scientist who greatly contributed to malacology, and particularly to the knowledge of land snails of South Africa.
Remarks. - This new taxon shares a "2+1+1" rib pattern with some small mathildids discussed by Bieler (1995: 610); among these only Mathilda hendersoni Dall, 1927, can be considered vaguely similar to M. herberti. The new taxon can be easily separated conchologically, i.e. by being less pagoda-shaped, with a completely different sculpture (Bieler, 1995: 620). It is noteworthy to mention that paratype A shows a slightly different protoconch development, albeit conserving a PD value on the average, since its embryonic whorl is partially exposed.