The Atlantic bubble shell, Bulla striata, is a member of the Family Bullidae
, the true bubble shells. The shell is thin and usually delicate, smooth, oval and inflated with an umbilicate (depressed) spire. The aperture is longer then the shell and is rounded at both ends, narrow posteriorly and wde anteriorly. The lip is thin and slightly constricted centrally. No operculum is present. The foot is well developed and the foot and mantle are slightly translucent. When the foot and mantle are extended, the animal completely envelops the shell, but it also can retract completely into it. There are no parapodia (fleshy winglike outgrowths). The head is broadened and lacks tentacles. The small eyes occur on the dorsal surface of the cephalic shield. (Abbot 1974, Abbot and Morris 1995, Baily-Matthews Shell Museum undated).Color is variable, pale reddish gray to brown-gray, mottled with darker smudged purplish brown dots. The aperature and the smooth, thin columellar callus is white (Abbot 1974, Abbot and Morris 1995, Oliver and Nicholls 2004).Tucker (1974) remarks that the type striata specimen comes form the Mediterranean, and that the Caribbean form is sometimes designated as the subspecies Bulla striata umbilicata. The author also notes that specimens identified as Bulla amygdale are probably a smooth form of B. striata.Bubble shells belong to the gastropod suborder Cephalaspidea
, the headshield slugs, and to the order Opisthobranchia
which also contains the sea hares, saccoglossans, nudibranchs, and others. The flattened cephalic shield possessed by members of the suborder is used for burrowing (Rupert and Fox 1988).