Eight species are here described, all characterized by the presence of a band on the whorls: in seven it is probably the result of a sinus or slit in the outer lip, but in the eighth it is merely ornamental, as the lines of growth pass over it. These species are referable to six genera or subgenera, five of which are new, namely Tropidostropha, Trechmannia, Foordella, Tmetonema , and Microptychis ; the other genus, Pithodea De Kon., has not been previously recorded from the British Isles. Family ? Raphistomidæ Ulrich. Diagnosis.—Shell conical, of medium height Whorls with a prominent, flange-like keel a little above the middle of the body-whorl, and considerably below the middle of the penultimate whorl; convex, except immediately above and below the keel, where they are concave. Test thin, composed of two layers. Outline of the keel slightly convex below, and slightly concave above. Under the keel is an inner, flat or somewhat concave band, covered with arched striæ, and formed of the inner shell-layer. Lines of growth strong and irregular: above they slope backwards with moderate obliquity to the edge of the keel, over which they pass without break; while below they at first curve sharply forwards, and then run almost vertically into the umbilicus. Aperture subquadrate. Umbilicus open. Genotype.— Pleurotomaria griffithi M'Coy. Remarks and resemblances.—This genus is suggested for two species, the characteristics of which do not exactly agree with any genus or subgenus known to me. These are Pleurotomaria griffithi M'Coy and Tropidostropha punctata , sp. nov. Both