30 Art. 6.— M. Yokoyama: 



7. Cylichna orientalis, Yokoyama. 

 Pl. I. Fig. 9. 



A small sub cylindrical shell, 8 millim. in height and 3 

 millim. in diameter, slightly tapering both above and below. The 

 liiicii' aperture is dilated at thé basal portion where it is consider- 

 ably produced downward, ending in a blunt point. The columella 

 is reflected outward and broad, with the outer lip thin. The 

 surface is water-worn, but very finely transversely striated. 



The living species which may be brought into comparison 

 with the present one are Cylichna concinna A. Adams (Tiiyon, 

 Man. Conch. XV, p. 309, pl. 59, fig. 10) from the Japanese waters 

 and Cylichna ordinaria Smith (Tryon, p. 319, pl. 27, fig. 90) from 

 Australia. But both have the basal portion of the aperture not so 

 much produced, and besides, the former has a deep umbilicus. 

 Hare. 



Fossil occurrence: — Koshiba Zone (Koshiba). 



Family Ringiculidae. 



Genus Rimgicufa, Deshayes. 



8. Ringicula musashinoensis, Yokoyama. 



Pl. I. Figs. 3, 8. 



Ringicula arctata. Erauns, Ucol. Env. Tokio, p. 30, Tokunaga, Fo:s. Env. Tokyo, p. 32, 

 pl. II, fig. 11. 



Shell small, ovately globose, with apex acute. Whorls four, 

 convex, very rapidly growing and spirally ornamented with fine 

 impressed lines which number about seven on the penultimate 

 and about ten on the ultimate whorl. These lines are often faint 

 or invisible on rubbed specimens. Base rounded. Aperture 

 elongated, longer than half the height of the shell, and anteriorly 

 somewhat widened and notched. Posterior canal present. 

 Columella!' folds two, strong and prominent. Callus of the inner 

 lip broad, half as long as the aperture and projecting into the 

 latter as a broad triangular tooth. Outer lip thickened and 

 swollen, running downward so that it is more or less parallel to 

 the axis of the shell. Height 4 millim. Diameter 3 millim. 



