PROSOBRANCHIATA. 173 



depresso-convexis : aperturd oblongo-ovali, antice efficsd ; labro ad marginem, tenui, acuto, 

 intus incrassato ; labio angustissimo, crasso ; columella leviter arcuatd, pluries plicatd, plica 

 penultimd majori. 



Shell ovately fusiform, ribbed, transversely furrowed, deeply notched, and bent 

 backwards at the base ; spire elevated, obtuse, with a small conical pullus ; whorls 

 six or seven, exclusive of the embryonic shell, convex, flattened at the sides, and 

 separated by a deep suture. Ribs numerous, thick, rounded, slightly waved, and pro- 

 longed to the base ; transverse furrows shallow, irregular, becoming faint, frequently 

 almost obsolete, over the middle of the whorl. Aperture of an oblong-oval shape, wide 

 in front, narrowing behind ; outer lip simple, sharp-edged, and thickened within ; inner 

 lip very narrow, thick ; columella slightly curved and furnished with ten or twelve 

 folds, of which the front one is very oblique and moderately prominent, and the last 

 but one larger and more transverse ; the others rise almost to the suture, becoming 

 feebler and more transverse as they ascend the columella. The ridge or crest on the 

 columella, found in all the deeply notched species, is half concealed by the thick inner 

 lip, but bulges out beyond the contour of the whorl. 



The specimen of V. magorum figured by Brocchi was imperfect, and his description 

 is short and unsatisfactory ; it is, therefore, difficult to decide whether the shells 

 described by Mr. Sowerby have been correctly referred by him to the Subapennine 

 species. Judging, however, from Brocchi's figure and description, the V. magorum 

 appears to be a more regularly convex shell, attenuated more equally at the extremi- 

 ties, and to have a more conical spire than the English shells. It is stated, also, to be 

 smooth ; but much reliance cannot be placed on this character, for Brocchi describes 

 the shell as convertita in ispato, and the transverse furrows may have become 

 obliterated in that process. The ribs are more numerous, and are slender and straight ; 

 the columellar folds also are more oblique, and the three front ones are nearly equal. 

 The aperture appears to have been but slightly notched in front, inasmuch as the 

 uninterrupted contour of the body whorl does not present the ridge caused by the 

 retroflexion of the base, which always accompanies a deep notch. These distinctions, 

 I think, show that the English shells, although closely allied to, are yet distinct from, 

 Brocchi's species, or at all events that they cannot be safely considered as belonging 

 to it. 



The shells (figs. 2 a, b) referred by Mr. Sowerby to V. harpula (Lamk.), are only 

 young shells of the present species, and are distinguished from the French species as 

 well by the transverse striation as by the shorter and more obtuse spire, the more 

 distant, thicker, and rounded ribs, the thinner outer lip, and the greater obliquity 

 of the columellar folds. 



Dr. Beyrich {loc. cit.) has described a Volute from Westeregeln {Voluta decora) 

 which resembles the present species so closely that it is difficult to separate the two. 

 The chief differences appear to be that the transverse striation is perceptible on the 



