80 Art. 1.— M. Yokoyama : 



longitudinall_y plicate. Plicae straight, vertical, l;>lunt, narrower 

 than interspaces, about twenty in number, very weak on the 

 penultimate Avhorl and almost obsolete on the ultimate, which 

 latter is higher tlian the spire. Base spirally striate. Periphery 

 broadly rounded. Aperture ovately semilunar, pointed behind, 

 rounded in h'ont, with peristome continuous. Height 4.5 millim. 

 Diameter 1.8 millim. 



Fossil occurrence. — (^take (frequent). 



Genus FEXELLA, A. Adams. « 



104. JFenella septenfrionalis, (Tokuna,e;a). 

 PI. IV. Fig. 5, 6. 

 Eibsoa seiitentrioiKtHs. Tokuuaga, Foss. Env Tokyo, p. 26, pi. I, lig. 55. 



Shell small, turriculate, pupoidal. Whorls nine, the first two 

 smooth and rounded, the remaining convex, usually with two 

 prominent spiral cords, the one on the upper and the other on the 

 lower half of the whorl, making its surface often subangulate at 

 these places. Besides these two cords, there are also tAvo spiral 

 threads lese prominent than the cords and situated just above and 

 below the suture. Sometimes there is a third thread between the 

 cords. These cords and threads may sometimes become nearly 

 equal in size on the body-whorl. The longitudinal sculpture consists 

 of rigid, vertical, distant riblets nearly equal in size to the cords. 

 The riblets, however, are often indistinct and obsolete. Intersec- 

 tion-points of spiral and longitudinal sculptui'es more or less 

 tubercular. Periphery rounded with a spiral thread on it, which 

 is a continuation of tlie suprasutural one of the preceding, whorls. 

 •Base convex with several spii-al threads. Umbilicus sometimes 

 furnished with a small narrow chink. Aperture oval, bluntly 

 angulate behind. 



The shells are very variable in shape, some being long and 

 slender (height 4.9 millim and diameter 1.4 millim.), while others 

 are short and more pyramidal (height 2.6 millim. and diameter 

 1.2 millim.). These, however, are connected by intermediate 

 forms. In several specimens, one of the upper whorls is specially 



