3^()4 Art. 1. — M. Yokoyama : 



nally ribbed. Ribs broad, flatly i-ounded, separated b}- much 

 narrower interspaces, slightly flexuous and oblique, about sixteen 

 on the body-whorl in which they end at the periphery without 

 fusing with one another. Periphery subangulate. Base convex, 

 smooth. Aperture subquadrate, the inner lip bending in the 

 middle at a broad angle. Height 4 millim. Diameter 1.8 millim. 

 Rare. 



Fossil occurrence. — Shito. 



151. TiU'honilla {Pyrgolani^vos) planicosffifa, Yokoyama. 



PI. V. Fig. 11. 



Shell small, elongate-conic. Nuclear whorls two, smooth, 

 rounded, standing on edge at the summit. Post-nuclear whorls 

 about nine, moderately convex, straight, nearly vertical, twenty- 

 one on the penultimate and twenty-three on the ultimate whorl, 

 separated by much narrower interspaces which are finely spirally 

 striate. On the bodj^-whorl the costellse continue a little into the 

 convex base and then vanish, leaving the place near the umbilicus 

 smooth. Periphery rounded. Aperture oval, the bending of the 

 inner lip in its middle being shght. Height 7.3 millim. Diameter 

 2 millim. A single specimen. 



This species is still living, and the shell, when fresh, is 

 ornamented with two chestnut spiral l:>ands, the one in the middle 

 of the wdiorls and the other near the lower suture. In the fossil 

 the upper band is distinctly preserved. 



Fossil occurrence. — Shisui. 



Living. — Central Japan. 



152. TurhoniUa {Striotuvbotiilla) saffftmiana, Yokoyama. 



PI. V. Fig. 12. 



Shell small to medium-sized, elongate-conic. Nuclear whorls 

 one and a half, immersed to a greater part in the first post-nuclear 

 whorl. Post-nuclear whorls nine, flat, somewhat shouldered at the 

 summit and contracted near the lower suture. The sculpture con- 

 sists of longitudinal costellœ and spiral threads and striae. Costella? 



