119 



Mean divergence as far as the penult whorl about 17°; length 

 .09 inch ; breadth .035 inch. 



Cerithium intermedium. Shell conoid, turrited, sinistrorsal : 

 reddish black or dark brown, with a broad white spiral band on the 

 lower part of the whorls; white near the apex : with, on the upper 

 whorls, two, and on the lower whorls, three nodulous spiral ridges, 

 and anteriorly three additional less strongly nodulous spiral ridges: 

 apex acute : spire with the outlines rectilinear above, moderately cur- 

 vilinear below : whorls about twelve, nianulale, with the place of the 

 suture distinguished by a rather deeper groove : last whorl termi- 

 nating rather abruptly : aperture rather small, obliquely obcordate : 

 canal short, nearly closed at the origin, much deflected obliquely 

 backwards. This species is intermediate between C. ornatum and C. 

 niodestum. 



Mean divergence about 20° ; length .2 inch ; breadth .07 inch. 



Cerithium versicolor. Shell ovate conic, turrited : usually 

 mottled irregularly with reddish black and white, white prevailing 

 on the varices and on the upper whorls, and the black on the lower 

 whorls and especially on the granules; sometimes mostly white; 

 sometimes mostly black : with numerous transverse ridges, which are 

 prominent on the upper whorls; with, on most of the whorls, three 

 spiral ridges, the intersections being developed into very prominent 

 subacute nodules ; and a fourth smaller spiral ridge in the suture of 

 the last whorl ; with intermediate spiral strife ; anteriorly with four 

 additional smaller less strongly nodulous spiral ridges and interme- 

 diary striae ; with rather less than two irregular varices to each 

 whorl : apex very acute : spire with the outlines slightly curvilinear : 

 whorls ten or eleven, a little convex, with a well impressed suture: 

 aperture subovate, rather acuminate at both extremities : labrum rath- 

 er sharp, very much thickened both externally and internally a 

 little behind the edge, deeply striated within : labium with a small 

 callus on the upper part : canal very short, rather wide, much de- 

 flected to the left. 



Mean divergence about 26° ; length of spire .42 inch ; total 

 length .57 inch ; breadth .2 inch. 



Cerithium megaso.ma. Shell long ovate conic : mostly brownish 

 or reddish black, white within the aperture : thick, with three small 

 spiral rather minutely granulous ridges, of which the upper two are 



