by William Swainson

“ But in several small species allied to O. conoidalis, another modification of form has evidently commenced: the spire is regularly acute; the upper plaits disappear; and those which remain, are only at the thickened base of the pillar: the aperture, no longer narrow, becomes wide at the base, where the pillar takes an oblique direction inward: we are thus led to the form of O. hiatula, E. M. pl. 368, f. 5, where the characters of Ancillaria become apparent in the effuseness of the mouth, the double belt at the base, and the imperfect groove on the outer side of the pillar. ”

“ It is, in short, one of those forms too hazardous to class without a complete knowledge of the animal.
OLIVA striata.
Shell small, cylindrical, sub-effuse, distinctly marked by regular longitudinal striæ; upper part of the body whorl with one, lower part with four, belts; spire short, channelled, sub-papillary, naked; base of the pillar striated and externally detached by a groove. ”

“ There are reasons for believing the genus Voluta, as defined by Lamarck, to be typical of a natural group, comprising the genera Mitra, Oliva, Ancillaria and Marginella. The obvious affinity between Voluta and Mitra need not be dwelt upon. The connexion of Mitra with Oliva, we noticed in describing Mitra olivæformis, at pl. ”