GASTEROPODA. 99 



sides, ornamented with a strong thickening at their anterior mar- 

 gin and two ridges bordering the sinus-band. A cancellate orna- 

 ment is developed upon the marginal thickening and above the 

 sinus-band by the intersection of well-marked spiral striations 

 and cross striae. Elsewhere the sides of the cone are ornamented 

 only with transverse stria?. Base cancellated with spiral ridgings 

 and cross striae. Umbilicus moderate. Mouth rhomboid. 



Specimens vary in the development of the striae and costae. 



From P. elegans (d'Orb.), and P. Cassiana (d'Orb.), this species 

 is distinguished by the absence of spiral ridges upon the whorls 

 in front of the slit. The general proportions of the shell are, 

 as kindly pointed out to me by Prof. Renevier, similar to those of 

 the internal casts from Mont Saleve, described by M. de Loriol 

 as P. Saleviana. 



Localities. Upware. 



iV. Europe. Berklingen, Brunswick. 

 8. Europe. St Croix. 



Measurements. Height, 20 mm. ; breadth, 24 mm. ; apicial 

 angle, 85°. 



Pletjrotomaria ferruginea, sp. nov. 

 (Plate iv., fig. 2, a, b) 



Shell thick, pyramidal, elevated, slightly higher than broad, 

 consisting of nine or ten whorls which are angular so as to give 

 the shell a stepped appearance. Sinus-band mesial in each whorl, 

 occupying the axis of the keel. Base moderately convex, nearly 

 smooth, but with faint spiral ornament striations, and distinct 

 lines of growth. Mouth trapezoidal, somewhat effuse below ; 

 margin thickened. Umbilicus small, slit-like. 



The shell is ornamented at the sides with spiral striations 

 crossed by delicate striae, and by lines of growth ; about thirty 

 of the spiral ridges are present upon the later whorls. 



Measurements of type. Height, 3| inches ; breadth of base, 

 3 inches ; breadth of sinus-band, 1 mm. ; angle of spire, about 

 55°. 



This species belongs to the Gigantea group, but differs from 

 gigantea in its more convex and nearly smooth base, also in the 



7—2 



