Animal with an oval, broad, or narrow foot, truncated anteriorly ; rostrum rather short, truncate ; tentacles long, slender, cylindrical, the eyes on peduncles at their exterior bases. Across the front of the head, between the tentacles, extends the more or less developed " veil " ; and from a point below the tentacles a fleshy ridge (the " epipodial line ") extends backward parallel with the margins of the foot, and bearing usually several slender cirri on either side.
Radula usually with the formula oo + 5 + 1 + 5 + 00, but sometimes lacking the median and 1 outer lateral tooth. The lateral teeth are all of nearly the same form. Jaws usually present.
Shell turbinate or trochiform, generally solid, smooth or rugulose ; aperture circular, oval, or subtetragonal; peristome simple ; operculum calcareous, heavy, flat or concave, with a thin corneous layer internally, the nucleus multispiral and either subcentral or at the margin.
Ordovician to Recent.
They are mostly littoral in station, and inhabitants of tropical and subtropical seas. They are herbivorous.

Diagnosis. Shell small to large, interior usually nacreous, umbilicate or non-umbilicate; aperture oblique, sculpture varied. Operculum with paucispiral pattern on corneous inner surface; outer surface with thick calcareous deposit, with pattern of sculpture produced by envelopment by foot. Protoconch with pointed tip. Ctenidium bipectinate, having free tip and either long or very short dorsal afferent membrane. Radula rhipidoglossate; rachidian tooth larger than laterals; marginals numerous.
Biology. Turbinids generally live on hard bottoms, grazing on algal films. They are broadcast spawners, with short veliger stages.
Remarks. Turbinids are characterized by a calcareous operculum, which is secreted by, and enveloped by, the foot, except when the animal is disturbed and the foot withdrawn into the shell. Hickman and McLean (1990) divided the family into several subfamilies, including Liotiinae, Colloniinae, Turbininae, and Tricoliinae. The rhipidoglossate radula has a similar pattern throughout the family, unlike the Trochidae in which there is much greater radular diversity. The relatively unspecialized radula led Hickman and McLean (1990) to regard the Turbinidae as more primitive than the Trochidae.

Turbinidae Rafinesque, 1815 Diagnosis. Shell small to large-sized; relatively thick; quite different in shape: turbiniform to coniform, from shells with rounded whorls, periphery and base to straight-sided whorls with peripheral angulation, flat base; sculpture from smooth to well expressed, often pustular, scaly or with axial or spiral ridges and protrusions, sometimes highly variable within species; aperture markedly oblique, interior nacreous; columellar callus covering umbilicus, most of base present in some genera; juvenile shells bicarinate, umbilicate; operculum calcareous, with later whorls rapidly expanding, changing from multispiral to paucispiral, fitting perfectly into aperture, exterior surface convex, smooth to variously sculptured; some species with spectacular coloration, pattering. Remarks. Today, Turbinidae only contains the former Turbininae and the Prisogasterinae, while the Liotiidae, Angariidae, Tegulidae, Colloniidae and Phasianellidae are considered as valid and separate families (Williams et al. 2008, Alf & Kreipl 2011). Most Turbinidae species live on hard substrates from shallow water to about 30 meters.

The gastropod genera related to Astraea Rdding (Bolma Risso, Astralium Link, Guildfordia Gray, Lithopoma Cray, Pomaulax Cray, etc.) have smooth surfaces or finely to coarsely gemmate sculpture, a very low to very prominent row (or rows) of peripheral spines that in many species are situated on a weak to marked peripheral angulation, and heavy calcareous opercula that place them in the family Turbinidae. They are often included in a separate subfamily Astraeinae (= Bolmidae Delpey, 1942, p. 181) but several typical turbinids have granular sculpture (e.g., Modelia granosa (Martyn), New Zealand; Euninella gruneri (Philippi), South and south Western Australia) and some species of Turbo Linne have a row of peripheral spines (e.g., Turbo (Batillus) cornutus (Solander/n Lightfoot), in which peripheral spines may be absent or small to very large). The opercula of most "Astraeinae" are oval, whereas most Turbininae have circular opercula. The opercula of species of Bolma are oval, circular or intermediate in shape. Apart from the enigmatic Triassic genus Rothpletzella Bohm, 1895, (Kinght et al. 1960, p.l264, fig. 170,1) both the "subfamilies" Turbininae and Astraeinae are known earliest in Upper Cretaceous rocks (Knight et al. 1960). In the absence of any distinguishing shell characters other than that many members have a peripheral angulation, and of any difference in stratigraphic range, and because of the intergrading opercula features, we do not recognise a subfamily for the genera related to Astraea.