40 A-i't. 1. — M. Yokoyama: 



:$3. I^rillia sttbnitrifomiis, Smith. 

 PI. I. Fig-. 30. 



Drillia subauriformis. Pilsbry, Cat., p. 18. Tryon, Man. Couch., YI, p. 207, pi. 12, fig. 

 35. Duuker, Index MoU.j p. 24, pL IV, tigs. 5-7. Smith, Proc. Zool. Soc. Lou- 

 don, 1879, p. 195, pi. XIX, fig. 23. 



Pleurotoma {Drillia) suhaurifonim. Toknuaga, Foss. Euv. Tokyo, p. 14, pi. I, fig. 24. 



This is a pretty little shell with about ten convex whorls, 

 longitudinally ril^bed and spirally striate. The ribs are about 

 eighteen on the penultimate whorl, although sometimes less. The 

 spiral striae are six on the penultimate and one less on a whorl 

 preceding it. The outer lip is tliickened by the last rib. Height 

 12 millim. Diameter 3.6 millim. Rare. • 



Fossil occurrence. — Otake and Kamenari. Also (Jji in 

 Musashi. 



Living. — Central and Western Japan. 



34. Drillia fjlahriuscula, iokoyaiua. 

 PI. I. Figs. 31, 32. 



Shell small, turrete. Whorls about nine, the first smooth 

 and mammillated, the second also smooth and rounded, the 

 remaining a little concave just l)elow the sutures and somewhat 

 convex on the lower portion. The sculpture is made up of longi- 

 tudinal costulae and spiral striae. The costulae are generally 

 present only on the upper whorls, about twelve on the whorl pre- 

 ceding the penultimate, broacb low, rounded, oblique and wider 

 than the intervals. The spiral striae are about four in number, 

 equally distributed and often indistinct. Now and then there is 

 an interstitial stria. Periphery rounded. Base gradually tapering 

 downward, covered with spiral tlireads. Aperture elongated, 

 narrow, with a short straight canal. Outer lip thin, with a deep 

 and rather wide sinus just below the suture. Inner lip with a thin 

 callus. 



The sculpture is often iiKÜstinct, and there are even specimens 

 in which the lower whorls are entirely devoid of it. Sometimes 

 the base narrows rother a1)ruptly downward. 



