BissoA. Panama Shells. 179 



247. Rissoa inA'equens. Nov. fsp. 



Shell v6ry long, ovate conic: white: with, on each whorl, 

 sixteen very obtuse slightly elevated indistinct ribs, which are 

 separated only by striae, and a few microscopic revolving striae : 

 apex subacute: spire with the outlines nearly rectilinear: 

 whorls seven, contracted above, otherwise convex or subangular 

 with a moderately impressed suture ; last whorl long, subangu- 

 lar : aperture oblique, subovate, scarcely effuse : labrum much 

 excurved, well thickened : umbilicus wanting. 



Mean divergence about 28° ; length .24 inch ; breadth .076 

 iiich ; length of spire .18 inch. 



Station. — Unknown. 



Hahitat. — Panama ; C. B. A. I 



1 specimen was obtained. 



248. Rissoa Janus. Nov. sp. 



Shell long, ovate conic : white : anteriorly with fine crowded 

 spiral striae ; elsewhere covered with small crowded transverse 

 ribs, which on the last whorl appear merely as transverse striae 

 becoming obsolete near the periphery : apex acute : spire with 

 the outlines moderately curvilinear: whorls nine, moderately 

 convexj with a lightly impressed suture : aperture large, oblique, 

 moderately effuse below, more deeply effuse above : . labrum 

 much advanced along the middle, thickened by a broad stout 

 varix : umbilicus wanting. 



Mean divergence about 30° ; length .19 inch ; breadth ,07 

 inch ; length of spire .115 inch. 



Station. — Unknown. 



Habitat. — Panama ; C. B. A. I 



2 specimens were found in the sand. 

 Var. a is larger, being .24 inch long. 



