Shell ventricose, thin; spire short, body-whorl and aperture very large. Operculum usually wanting; when present, at first with apical nucleus, afterward becoming annular. (Tryon, Structural and Systematic Conchology.)
This little group of Mollusks is confined in distribution to the North Pacific, its metropolis being Japan. Three species were described as Bullia, from which genus it differs in its simple foot and in possessing eyes as well as in dentition. The form and porcellaneous texture of the shell are like Bullia, and serve to separate it from Buccinum. With regard to the Volutharpa ampullacea, a very remarkable fact may be mentioned. The majority of the individuals are without opercula, even without a trace of the pad-like gland or area from which the operculum is secreted. About ten per cent are without, and about fifteen per cent have well-developed opercula in the proper position. The ovicapsules are not at all like those of Buccinum, but rather like those of Busycon, though smaller, consisting of disk-like capsules, united by one edge to a ribbon or stalk. (Dall.)
TYPE. Volutharpa ampullacea Middendorff. RANGE. North Pacific, also Japan.