S8 ' Art. 6.— M. Yokoyama: 



Fossil occurrence. — Miyata Zone (Kami-Mij T ata and Maru- 

 yama-no-Saka in Shiino-Mi3'ata). 



96. Chlorostoma quantoanum, Yokoyama. 

 Pl. V. Fig. 24. 



Shell umbilicate, coiioid, rather thick; whorls about six, 

 parted by deep canaliculated sutures, slightly convex in the upper 

 half and somewhat concave in the lower half, closely spirally 

 striated; stria? subequal except the one at a small distance from 

 the lower suture which is much stronger than the others, more 

 than ten in number on the penultimate whorl, crossed by fine 

 incremental lines making them appear finely granulate; the upper 

 edge of the body-whorl coarsely and irregularly though weakly 

 tuberculated. Periphery angular, yet not quite sharp. Base 

 convex, finely and closely spirally striated, crossed by coarse lines 

 of growth. Umbilicus deep, margined by a rounded ridge outside 

 of which and at a little distance from it there is also a spiral cord, 

 though not so large and elevated as the inner ridge. Aperture 

 squarely rhombic, with breadth greater than height. Inner lip 

 covered by a callus which is also partly spread on the inner side 

 of the umbilicus. Height 7 mi Hi m . Diameter 10 millim. 



The only specimen present is coloured dark-red or purple. 



Fossil occurrence. — Yokosuka Zone (Yokosuka). 



97. Chlorostoma tokunagai, Yokoyama. 

 Pl. V. Fig. 25. 



Shell small, conoid, rather thick; whorls about live, separated 

 by somewhat canaliculated sutures, with four spiral threads except 

 on the last whorl, of which the lowest situated somewhat above 

 the suture is the largest, while the upper three are subequal; the 

 space between the lowest thread and the suture is provided with 

 a few fine spiral striae; body-whorl provided with many unequal 

 spiral threads, the periphery two-angled being formed by two 

 larger threads somewhat distant from each other and with the 

 interstice concave and spirally striated ; above the upper thread of 



