Fossils from the Upper Mnsashino of Kazusa and Shimosa. 37 



Family Pleurotomidas. 



Genus Pf.ErKOTOMA, Lamarck. 



29. Plenrofoiiia ret'febt'ttfd, Smith. 



PI. I. Fig. 26. 



Pleurotoma vertebmta. Smith, Ann. Mag. Nat. Hist., 1875. p. 416. Proc. Zool. Soc. 



London, 1879, p. 186, pi. XIX, fig. 6a. Pilsbiy, Catalogue, p. 15. Tokunaga, 



Foss. Env. Tokyo, p. 13, ph I, fig. 22. Chemnitz and Martini, Conch. Cab., lY, pt. 



3, p. 31. 



The shell is quite chmacteristic by its fusiform shape and 



angulate whorls, the angle being a little below their middle. The 



sculpture consists only of spiral threads large and small, the large 



ones being one at the angle, one above the suture and one below 



it. The sinus is somewhat distaiit from the suture, deep, very 



wide at mouth, and much narrowed and rounded at bottom. The 



largest specimen obtained is 32 millim. high and 10 millim. broad. 



Tryon unites this species with Pleurotoma violacea Hinds (Man. 



Conch., vol. VI, p. 169) of the Öoutli Sea. 



Fossil occurrence. — Otake, Shisui, Kamenari and Shito. 

 Rather rare at all the above localities, though frequent at Oji in 

 Musashi. 



Living. — Central and Western Japan. 



Genus GEIXOTIA, H. and A. Adams. 



SO. fwenotia psetidopattnus, Yokoyama. 



PL I. Figs. 27, 28? 



Shell moderately thick, subfusiform. Whorls seven and a half, 

 the first two and a half sniooth and rounded, the remaining some- 

 what shouldered, the surface above the shoulder steepl}'- sloping 

 and slightly excavated, below vertical and a little convex. The 

 sculpture consists of longitudinal plicte and spiral grooves. The 

 plicae are obtuse and broad, wider than tlie interspaces and about 

 twenty on the penultimate whorl, while on the body-whorl they 

 are almost obsolete. As to the spiral grooves, there are two of 



