Megastraea undosa, common name the wavy turban snail, is a species of sea snail, a marine gastropod mollusk in the family Turbinidae, the turban snails. This species is native to the coast of California.
(REF: Megastraea undosa (W. Wood, 1828).) (REF: Astraea undosa - Properties - The Taxonomicon)
Megastraea Undosa dwell in the eastern Pacific Ocean from California, to Central Baja California, Mexico
These species have been found to grow from 1 1/2 to 6 inches. The shell lacks an umbilicus, and has a turbinate-conical shape. Like other shells of the family turbinidae it is composed of a thick inner nacreous layer, covered by a thinner porcellanous layer. In this species both are covered by a dark brown shaggy periostracum in life. The periphery of the shell forms a twisted ridge at the outer edge of each whorl. Each whorl also has regular, coarsely sculpted rows of fine knobs and folds. The base is marked with several spiral cords concentric to the arcuated columella which has a pearly groove. The unusual operculum has four strong ridges on its outer side decorated with hard shelly bristles that radiate in a curvilinear fashion from its pointed edge.
periostracum is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks, it is primarily seen in snails and clams, i.e. in gastropods and bivalves, but it is also found in cephalopods such as Allonautilus scrobiculatus. The periostracum is an integral part of the shell, and it forms as the shell forms, along with the other shell layers. The periostracum is used to protect the organism from corrosion.
The Megastraea Undosa snail can be found along rocky shores in shallow waters, generally protected areas below the low tide level.
(REF: "periostracum". Dictionary.com Unabridged (Online))(REF: W.H. Dall, Thesaurus conchyliorum, or, Monographs of genera of shells, v. 5 (1887)) (REF: Rogers, Julia Ellen (1907), The shell book)
Super family: Trochoidea
Species: M. undosa
Binomial name: Megastraea undosa
(W. Wood, 1828)
One Megastraea Undosa shell 3 to 4 inches.....$9.95