121 



whitish at the apex, darkest on the ridges, paler between them and 

 anteriorly : with, on most of the whorls, three spiral ridges, of which 

 the upper two are nearer together and in the upper half of the shell 

 are confluent, and of which the upper one is larger : with numerous 

 scarcely perceptible transverse ridges, which on the spiral ridges are 

 excessively developed into closely set nodules ; anteriorly with ano- 

 ther subnodulous spiral ridge, and with transverse stria3 : apex acute : 

 spire with the outlines curvilinear : whorls eight or nine, slightly 

 convex, with an indistinct suture ; last whorl much smaller than the 

 penult whorl : aperture suborbicular : labrum well excurved and ad- 

 vanced, slightly thickened : labium with a small callus above : canal 

 very short, straight, wide. 



Divergence in the upper whorls about 35*^ ; length of spire .075 

 inch; total length .1 inch ; breadth .04 inch. 



Cerithium pulchellum. Shell turrited, conic above, subcylin- 

 dric in the lower three-fifths, conic above : snow white, with a spiral 

 band of bright brown, which commences several whorls below the 

 apex, and is placed on the inferior spiral ridge : with two spiral 

 ridges, of which the upper one is larger, and is double on the lower 

 whorls ; with small transverse ridges, which are developed on the 

 spiral ridges into rather large nodules ; anteriorly with two other spi- 

 ral ridges, of which the upper one is subnodulous : apex acute ; spire 

 with the outlines slightly concave in the upper half and slightly con- 

 vex in the lower half, often truncate with the loss of five whorls : 

 whorls about eleven, a little convex, with a well impressed suture ; 

 last whorl a little smaller than the penult whorl, terminating ob- 

 tusely : aperture suborbicular : labrum well excurved, moderately 

 thickened : canal very short and wide, nearly straight. 



Divergence in the upper whorls about 22° ; length of spire .135 

 inch ; total length .17 inch ; breadth .045 inch. 



Cerithium rugulosum. Shell conoid, turrited : white : with one 

 slightly elevated and three much elevated spiral lines, and on each 

 whorl about sixteen to eighteen transverse ridges, the intersections 

 being well developed into nodules , anteriorly with a fourth spiral 

 nodulous slender ridge : apex acute : spire with the outlines nearly 

 rectilinear : whorls about ten, quite convex, with a well impressed 

 suture ; last whorl terminating rather abruptly, somewhat concave 



