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Show 1881.] ON NEW SHELLS FROM LAKE TANGANYIKA. 559 versely lirate, the points of intersection of the lirae and costse being more or less granular. The aperture is ovate, and not produced into a canal at the base as in Tiphobia; and the columella and upper extremity of the outer lip are connected by a thickish callosity. This division {Paramelania) will also include the 31elania nassa of Woodward, so remarkable for its great variability. PARAMELANIA, subgen. nov. Shell solid, ovate-conical, imperforate, longitudinally ribbed and transversely lirate, covered with a thin epidermis. Aperture ovate, entire, indistinctly effuse at the base. Last whorl sometimes slightly prolonged inferiorly. Peristome thick, margins joined by a callosity. Operculum like that of Tiphobia. PARAMELANIA DAMONI. Shell solid, imperforate, ovate turreted, white, covered with an olive-brown epidermis, prettily sculptured with fine yet distinct wavy lines of increment, and more or less distinct transverse impressed striae. Whorls 10, very concave at the upper part, the concavity Fig. 1. Paramelania damoni. occupying about one third of the whorl; concavity smooth, merely exhibiting the epidermal sculpture; rest of the whorls coarsely plicated and spirally ridged. Plicae rather acute, about 12 in number on the penultimate whorl, a little oblique on the last, and becoming obsolete about the middle. Spiral lirae rather slender, equal, continuous on and between the plicae ; 4 upon the upper volutions, and about 14 on the last. The uppermost, which defines the upper end of the costae, is produced into very short hollow scales or spines upon the ribs ; and the second and sometimes the third have the same character in a less marked degree. Aperture obliquely ovate, occupying about half the length of the shell, covered with a slight callous deposit far within, not quite obscuring the external |