50 Art. 6. — M. Yokoyatna : 



suturai canals, and dense, rather insignificant spiral striae instead 

 pf regular, distant, impressed lines. 



Fossil occurrence. — Kanazawa Zone (Nojima); Koshiba Zone 

 (Koshiba); Naganuraa Zone (Naganuma), 



Genus Sipho. Klein. 



39. Sipho obesiformis, Yokoyama. 



Pl. II. Fig. 13. 



Shell small, rather thin, ovately fusiform; whorls seven, the 

 uppermost smooth and mammillary, the others somewhat convex. 

 spirally striated and longitudinally plicated; striae subequal, flat- 

 topped, with or without a finer interstitial line, about ten in 

 number on the penultimate, more than thirty on the last whorl; 

 longitudinal plica? most distinct on the upper whorls, thirteen on 

 the fourth whorl, almost or wholly obsolete on the last two. 

 Aperture ovate with a posterior corner acute. Canal short, much 

 recurvod. Inner lip smooth. Outer lip thin, sharp, smooth 

 within and describing a broad arc. 



Two specimens. One is 16 millim. in height and 7 millini. 

 in diameter; the other 12 millim. in height and 6 millim. in 

 diameter. 



In shape, this shell is like Sipho obesus Sow. (Tryon, Man. 

 Conch., Ill, p. 132, pl. 87, fig. 624, Sowerby Thes. Conch.. IV. 

 Fusus, fig. 92) which is, however, much larger and devoid of 

 longitudinal plicae. 



Fossil occurrence. — Naganuma Zone (Naganuma). 



Genus Siphonalia. SwainsON. 



40. Siphonalia dilatata, (Quoy). 



Pl. II. Fig. 12. 



Siphonalia dilatata. Tryon, Man. Conch., HI, p. 135, pl. 54, figs. 356-359. 

 lusus dilatatiis. QaoY, Voy. de l'Astrolabe, pl. I, pl. 34, figs. 15-16. 



A fine speoimen, 45 millim. in height. It has only about 

 five whorls and a half of which the first one and the next half are 

 mammillary and smooth. The shoulders are sharp and distinct as in 



