48 Art. 1. — M, Yokoyama : 



depression above tlie posterior end of the aperture which is 

 elongated and angular behind. Columella-lip covered with a thin 

 translucent glaze whose lower end is furnished with an oblique 

 bifid fold. Outer lip tliin, the margin being nearly straight. 

 Height 5.5 millim. Diameter 2.5 millim. 



This shell which is I'ather frequent is very much like the one 

 taken by Smith (Proc. Zool. Soc. Loud., 1879, p. 216, pi. XX, fig. 

 55) for Olivella spreta Gould (never figured); but our fossil has the 

 bod\'-whorl more curved and a little more tapering dowuAvard. 



Fossil occurrence. — Sliito. 



Genns AXC'ILLA, Lauiarck. 



47. JLneilla ftigtotitofoetisis, Yokoyama. 



PL II. Fig. 5. 



Shell solid, subfusiform. Spire ol)tuse, entirely covered wdth 

 spirally indistinctly striated callus which on the lateral side (right 

 from the aperture) of the shell overlaps each other with the left end 

 above. The suturai portion of the body-whorl is also concealed by 

 the callus, while its exposed portion is covered with coarse lines of 

 growth as well as with fine, rather indistinct, spiral ones. Spiral 

 sulcus l)road. Basal area with a spiral ridge in the middle, dividing 

 it into two nearly equal parts. Aperture fusiform, pointed behind, 

 truncate in front. Inner lip covered with a portion of the callus 

 extending from above and with the caudal end obliquely grooved; 

 grooves four or five in number. Outer lip thin, its upper portion 

 being also covered with the callus. Height 33 millim. Diameter 

 9 millim. Length of aperture about 20 millim. 



This fossil is not unlike Ancilla montrouzieri Souv. (Syst. 

 Conch. Cab., V, AnciUaria, p. 17, pi. V, figs. 5, 6) from the South 

 Sea. But in the former the callus on the apertural side of the shell 

 extends more downward, and the acute embrj^onal end found in 

 the latter is absent. 



Fossil occurrence. — Shito (frequent). 



