« Shell extremely slender, tapering to an exceedingly fine point, milk white, semitransparent. Spires seven or eight, rounded and well defined by a deep depression, each with four or five regular equidistant and rather deep spiral grooves. Aperture nearly orbicular, the inner-lip a little rejected. […] It is impossible to mistake this minute and very elegant species for the young of T. Terebra, which is always opake and horn-color, suddenly tapering to an obtuse point, with the ribs coarse, three or four of them much raised above the rest, and the interstices regularly striate. The spires are also less rounded and defined than in the present species. » – W. Turton: A conchological dictionary of the British Islands vol. II, p.217 Turbo ascaris, the –“Vermicular Turban”.

The Dunkeria incostans from De Folin, introduced as a synonym of ascaris by Monterosato, may have been named after a similar shell, devoid of sculpture. The spiral ribs are weakly represented in the very first whorls of the teleoconch, after what the shell becomes entirely smooth. Above, a smecimen collected in sediment at 25m deep, Zaplopatica submarine cave, Korčula island. 3,2mm. Original pictures provided by N. Lete (HR) – (CC BY-NC-SA).

« Body slender [“entirely white” (Hanley)]. Head not beaked [not snout-shaped]. Proboscis long, strong, and retractile. Tentacles cylindrical, slender, somewhat inflated at the top, close together at the base. […] Eyes immersed at the base of the tentacles, and placed rather laterally. […] Foot having the “mentum” [or upper edge] somewhat detached, narrower than the sole, and extended. […] Opercular lobe ample, of a different shape on each side, being on the right larger and forming 3 or 4 folds, on the left produced into a single rounded lobe which is folded behind ; sole tongue-shaped, truncated in front. Tongue unarmed ? (Lovén.) » – J. G. Jeffreys: British conchology vol. IV, London 1867.

« Shell […] distinctly and deeply umbilicate in every stage of growth ; sometimes there are 5 ridges on each whorl, at other times 3 only on the body-whorl and 2 on each of the other whorls, occasionally none on the body-whorl and 2 or 3 on each of the upper ones, or else there are no ridges at all and the whole surface is quite smooth and glossy ; the suture is more deeply excavated, and nearly straight ; this species has 12 whorls, and the mouth is more round than oval. […] This shell is Brown’s Turritella ascaris, the type of which I examined in the collection of the late Mr. Lyons at Tenby ; but I certainly should not have recognized it by the description. » – J. G. Jeffreys: op. cit.