Fossils from the Upper Musasliino of Kazusa and Shiinosa. 97 



six in a specimen 5.5 millim. high, shghtly convex and apparently 

 smooth, though with a strong lens fine spiral lines are visible. 

 Periphery rounded. Aperture subovate, acute behind, produced 

 and rounded in front. Columella-fold strong and obliciue. 



Dall and Bartsch figure a young as well as an adult specimen 

 in which tlie anterior end of the aperture is somewhat different. 

 Such a difference, though not so strong, is also found in our fossil. 



Perfect specimens do not exceed 5.5 millim. in height with 

 diameter 2 millim. But there is an imperfect one with the last 

 three whorls preserved. It is 6 millim. in height and 3 millim. in 

 diameter. 



Fossil occurrence. — Otake (rare), Tega (do), Shito (not very 

 rare). 



Living. — Central and Western Japan. 



138. OtJosfomia {Otlostotnia) hi%a1iiensi^, Yokoyama. 

 PI. IV. Fig. 29. 



Shell small, elongate-conic. Post-nuclear whorls five, smooth, 

 only a little convex and shouldered at the summit, so that the shell 

 appears subtabulated. Body-whorl a little higher than one-half 

 the height of the shell. Periphery broadly rounded. Base convex, 

 Aperture ovate, pointed behind, a little produced and rounded 

 in front. Lamellar plait distinct, oblique. Height 4 millim. 

 Diameter 1.8 millim. A few specimens 



Fossil occurrence. — Tega. 



139. f>ilostonii<i (Oflosfontia) retiusfa, Yokoyama. 



PI. IV. Fig. 30. 



Shell small, elongate-oval. Post-nuclear whorls about four, 

 somewhat convex, shouldered at the summit. Body-whorl very 

 large, the height being more than double that of the spire. Peri- 

 phery very broadly rounded. Aperture longly ovate, acute behind, 

 much produced and rounded in front. Columella-fold very strong 

 and oblique, its anterior portion forming the inner peristome of the 



