42 Art. 6.— M. Yekoyama : 



This shell is, I believe, what Dunker described under the 

 above name, though his description is brief and the figures are 

 ratli er indistinct. 



Fossil occurrence. — Koshiba Zone (Koshiba); Upper Musa- 

 shino of Shimosa. 



Living. — Western Japan . 



'25. Pleurotoma (Mangilia) miyatensis, Yokoyama. 

 Pl. V. Fig. 2. 



Shell small, rather thick, fusiform. Whorls about seven, the 

 first two being smooth and rounded, and the remaining ones with 

 the upper one-third sloping and slightl} T concave and the lower 

 two-thirds perpendicular and nearly flat. The sculpture consists 

 of longitudinal costellae and spiral threads whose crossing points 

 are more or less tuberculated. The costellae are numerous, close, 

 rounded or even flattened, about twenty-one in the penultimate 

 whorl, separated by interspaces of a less breadth, somewhat bent 

 backward at the angles with the part above them strongly oblique, 

 below them only a little so. The threads are finer on the sloping 

 surface, coarser on the perpendicular, usually five in each, some- 

 times with one or two interstitial unes. Un the body-whorl, the 

 eostella? become obsolete towards the aperture and base which 

 lattei- is usually provided only with spiral threads. Aperture 

 elongated. Inner lip smooth. Outer lip rather thin, with a 

 broad shallow notch, a little below the suture, situated where the 

 surface makes an angle. 



There are several examples, of which the largest shows the 

 following dimensions: 



Height 20 millim. Diameter 7 millim. Length of body- 

 whorl 1 '1 millim. Length of aperture 9,5 millim. 



Fossil • occurrence. — Miyata Zone (Shimo-Miyata and Kami- 

 Miyata). 



20. Pleurotoma (Surcula ?) nojimensis, Yokoyama. 

 Pl. I. Fig. 19. 

 A single specimen lacking apex and outer lip. 



