Fossils from the Miura Peninsula and its Emmediate Xbrth. 73 



rounded by a spiral groove, or not. Aperture subangulated at the 

 outer side. 



We possess two specimens, both with the outer lip broken. 

 The larger measures 6 millim. in height and 11 millim. in 

 diameter, and is much water-worn; the smaller measures 5 

 millim. in height and millim. in diameter and lias the sculpture 

 better preserved. 



Fossil occurrence. — Koshiba Zone (Koshiba). 



Family Rissoidae. 



Genus Hissohia, cTOrbigny. 



71. Rissoina submerculialis, Yokoyama. 



Pl. IV. Fig. 15. 



Shell small, turreted with apex bluntly pointed and base 

 rounded. Whorls eight, slightly convex, separated by deep 

 impressed sutures, the first two smooth, the others longitudinally 

 ribbed; ribs somewhat oblique, elevated, with rounded ridges 

 and somewhat wider intervals, nineteen on the body-whorl, the 

 last growing into a strong, rounded varix on the back of the outer 

 lip. Base with a strong, rounded, transverse or rather spiral cord 

 which is longitudinally costellated. Aperture semilunar, anterior 

 angle with a shallow notch. Inner lip smooth, slightly concave. 

 •Outer lip thickened by the dorsal varix. Height 4,5 millim. 

 Diameter 1,5 millim. 



A single example. 



This shell is much like Rissoina mevcwialis Watson (Challenger 

 -Gastropoda, p. 010, pl. XLVI, tig. 8) from Cape York in Australia, 

 but in the latter, tlie ribs are less (fifteen on the body-whorl) and 

 the interspaces transversely striated, Avhile in the former they are 

 smooth. 



Fossil occurrence. — Yokosuka Zone (Yokosuka). 



1-1. Rissoina zeltnerioides, Yokoyama. 

 Pl. IV. Fig. 20. 

 Shell small, solid, turreted, bluntly pointed at apex, rounded 

 at base. Whorls about six and a half, somewhat convex, the first 



